WorldWideScience

Sample records for refractory alloy performance

  1. Radiation Effects in Refractory Alloys

    Science.gov (United States)

    Zinkle, Steven J.; Wiffen, F. W.

    2004-02-01

    In order to achieve the required low reactor mass per unit electrical power for space reactors, refractory alloys are essential due to their high operating temperature capability that in turn enables high thermal conversion efficiencies. One of the key issues associated with refractory alloys is their performance in a neutron irradiation environment. The available radiation effects data are reviewed for alloys based on Mo, W, Re, Nb and Ta. The largest database is associated with Mo alloys, whereas Re, W and Ta alloys have the least available information. Particular attention is focused on Nb-1Zr, which is a proposed cladding and structural material for the reactor in the Jupiter Icy Moons Orbiter (JIMO) project. All of the refractory alloys exhibit qualitatively similar temperature-dependent behavior. At low temperatures up to ~0.3TM, where TM is the melting temperature, the dominant effect of radiation is to produce pronounced radiation hardening and concomitant loss of ductility. The radiation hardening also causes a dramatic decrease in the fracture toughness of the refractory alloys. These low temperature radiation effects occur at relatively low damage levels of ~0.1 displacement per atom, dpa (~2×1024 n/m2, E>0.1 MeV). As a consequence, operation at low temperatures in the presence of neutron irradiation must be avoided for all refractory alloys. At intermediate temperatures (0.3 to 0.6 TM), void swelling and irradiation creep are the dominant effects of irradiation. The amount of volumetric swelling associated with void formation in refractory alloys is generally within engineering design limits (>10 dpa). Very little experimental data exist on irradiation creep of refractory alloys, but data for other body centered cubic alloys suggest that the irradiation creep will produce negligible deformation for near-term space reactor applications.

  2. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, R.; Sedlatschek, K.; Braun, H.

    1971-12-15

    Dependence of the melting point of the refractory metals on their positions in the periodic system - alloys of tungsten with other refractory metals - sintering of the alloys - processing of the alloys - technological properties.

  3. Alloy design for intrinsically ductile refractory high-entropy alloys

    Science.gov (United States)

    Sheikh, Saad; Shafeie, Samrand; Hu, Qiang; Ahlström, Johan; Persson, Christer; Veselý, Jaroslav; Zýka, Jiří; Klement, Uta; Guo, Sheng

    2016-10-01

    Refractory high-entropy alloys (RHEAs), comprising group IV (Ti, Zr, Hf), V (V, Nb, Ta), and VI (Cr, Mo, W) refractory elements, can be potentially new generation high-temperature materials. However, most existing RHEAs lack room-temperature ductility, similar to conventional refractory metals and alloys. Here, we propose an alloy design strategy to intrinsically ductilize RHEAs based on the electron theory and more specifically to decrease the number of valence electrons through controlled alloying. A new ductile RHEA, Hf0.5Nb0.5Ta0.5Ti1.5Zr, was developed as a proof of concept, with a fracture stress of close to 1 GPa and an elongation of near 20%. The findings here will shed light on the development of ductile RHEAs for ultrahigh-temperature applications in aerospace and power-generation industries.

  4. Kinetics and Structure of Refractory Compounds and AlloysObtained by Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Refractory compounds are material with interesting properties for structural applications. However, the processing of such material is a great challenge because of their high melting temperature and limited ductility. Mechanical alloying is a novel technique of producing refractory compounds with specific properties. Kinetical and structural peculiarities of refractory compounds and alloys obtained by mechanical alloying are discussed.

  5. Pumped lithium loop test to evaluate advanced refractory metal alloys and simulated nuclear fuel elements

    Science.gov (United States)

    Brandenburf, G. P.; Hoffman, E. E.; Smith, J. P.

    1974-01-01

    The performance was determined of refractory metal alloys and uranium nitride fuel element specimens in flowing 1900F (1083C) lithium. The results demonstrate the suitability of the selected materials to perform satisfactorily from a chemical compatibility standpoint.

  6. Refractory alloy technology for space nuclear power applications

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.H. Jr.; Hoffman, E.E. (eds.)

    1984-01-01

    Purpose of this symposium is twofold: (1) to review and document the status of refractory alloy technology for structural and fuel-cladding applications in space nuclear power systems, and (2) to identify and document the refractory alloy research and development needs for the SP-100 Program in both the short and the long term. In this symposium, an effort was made to recapture the space reactor refractory alloy technology that was cut off in midstream around 1973 when the national space nuclear reactor program began in the early 1960s, was terminated. The six technical areas covered in the program are compatibility, processing and production, welding and component fabrication, mechanical and physical properties, effects of irradiation, and machinability. The refractory alloys considered are niobium, molybdenum, tantalum, and tungsten. Thirteen of the 14 pages have been abstracted separately. The remaining paper summarizes key needs for further R and D on refractory alloys. (DLC)

  7. Directed Light Fabrication of Refractory Metals and Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

    1999-05-14

    This report covers work performed under Order No. FA0000020 AN Contract DE-AC12-76SN00052 for deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents the progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. 1. Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. 2. The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. 3. The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06{micro}m), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. 4. The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required.

  8. Thermal aging effects in refractory metal alloys

    Science.gov (United States)

    Stephens, Joseph R.

    1987-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  9. Research on High Performance New Refractories

    Institute of Scientific and Technical Information of China (English)

    Zhong Xiangchong

    2007-01-01

    @@ At the age of 86,Prof.Zhong Xiangchong has his new book-"Research on High Performance New Refractories" published by Henan Science and Technology Publishing House to commemorate his 65 years service in the refractories science and technology including the recent 6 years at High Temperature Ceramics Institute which he founded in Zhengzhou University in 2001.

  10. Processing of Refractory Metal Alloys for JOYO Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    RF Luther; ME Petrichek

    2006-02-21

    This is a summary of the refractory metal processing experienced by candidate Prometheus materiats as they were fabricated into specimens destined for testing within the JOYO test reactor, ex-reactor testing at Oak Ridge National Laboratory (ORNL), or testing within the NRPCT. The processing is described for each alloy from the point of inception to the point where processing was terminated due to the cancellation of Naval Reactor's involvement in the Prometheus Project. The alloys included three tantalum-base alloys (T-111, Ta-10W, and ASTAR-811C), a niobium-base alloy, (FS-85), and two molybdenum-rhenium alloys, one containing 44.5 w/o rhenium, and the other 47.5 w/o rhenium. Each of these alloys was either a primary candidate or back-up candidate for cladding and structural applications within the space reactor. Their production was intended to serve as a forerunner for large scale production ingots that were to be procured from commercial refractory metal vendors such as Wah Chang.

  11. Directed light fabrication of refractory metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

    1999-05-30

    This report covers deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. (1) Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. (2) The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. (3) The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06{micro}m), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. (4) The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required.

  12. Modeling of high entropy alloys of refractory elements

    Energy Technology Data Exchange (ETDEWEB)

    Grosso, M.F. del, E-mail: delgrosso@tandar.cnea.gov.ar [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, (B1650KNA), San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina); Bozzolo, G. [Loyola University Maryland, 4501 N. Charles St., Baltimore, MD 21210 (United States); Mosca, H.O. [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, (B1650KNA), San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina)

    2012-08-15

    Reverting the traditional process of developing new alloys based on one or two single elements with minority additions, the study of high entropy alloys (HEA) (equimolar combinations of many elements) has become a relevant and interesting new field of research due to their tendency to form solid solutions with particular properties in the absence of intermetallic phases. Theoretical or modeling studies at the atomic level on specific HEA, describing the formation, structure, and properties of these alloys are limited due to the large number of constituents involved. In this work we focus on HEA with refractory elements showing atomistic modeling results for W-Nb-Mo-Ta and W-Nb-Mo-Ta-V HEA, for which experimental background exists. An atomistic modeling approach is applied for the determination of the role of each element and identification of the interactions and features responsible for the transition to the high entropy regime. Results for equimolar alloys of 4 and 5 refractory elements, for which experimental results exist, are shown. A straightforward algorithm is introduced to interpret the transition to the high entropy regime.

  13. Integrated Design and Rapid Development of Refractory Metal Based Alloys for Fossil Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.N.; King, P.E.; Gao, M.C.

    2008-07-01

    One common barrier in the development of new technologies for future energy generating systems is insufficiency of existing materials at high temperatures (>1150oC) and aggressive atmospheres (e.g., steam, oxygen, CO2). To overcome this barrier, integrated design methodology will be applied to the development of refractory metal based alloys. The integrated design utilizes the multi-scale computational methods to design materials for requirements of processing and performance. This report summarizes the integrated design approach to the alloy development and project accomplishments in FY 2008.

  14. Microstructure and nano-mechanical property of cold spray Co-base refractory alloy coating

    Institute of Scientific and Technical Information of China (English)

    Yongli LIANG; Bi SHI; Xiaoping YANG; Junbao ZHANG; Xianming MENG

    2011-01-01

    Co-base refractory alloy coating was prepared on carbon steel substrate by cold spray technology; microstructure and nano-mechenical property were examined by scanning electron microscope (SEM) and nano indenter individually. The results showed that about 250 μm Co-base refractory alloy coating could be deposited on steel substrate by cold spray technique, interface between coating and substrate was combined well, and the refractory alloy particle had a significant plastic deformation during deposition process; mixing Ni powders into Co-base refractory alloy powders could increase the density and decrease the nano-hardness of coating, the nano-hardness and elastic modulus of refractory alloy coating was higher than 6 GPa and 160 GPa, respectively.

  15. Microstructure and Elevated Temperature Properties of a Refractory TaNbHfZrTi Alloy

    Science.gov (United States)

    2012-01-24

    alloy was prepared by vacuum arc melting of the equimolar mixtures of the corresponding elements. Titanium, zirconium, and hafnium were in the form of...AND ELEVATED TEMPERATURE PROPERTIES OF A REFRACTORY TaNbHfZrTi ALLOY (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM...6260-2. 14. ABSTRACT Compression properties of a refractory multicomponent alloy , Ta20Nb20Hf20Zr20Ti20, were determined in the temperature range

  16. Direct Metal Deposition of Refractory High Entropy Alloy MoNbTaW

    Science.gov (United States)

    Dobbelstein, Henrik; Thiele, Magnus; Gurevich, Evgeny L.; George, Easo P.; Ostendorf, Andreas

    Alloying of refractory high entropy alloys (HEAs) such as MoNbTaW is usually done by vacuum arc melting (VAM) or powder metallurgy (PM) due to the high melting points of the elements. Machining to produce the final shape of parts is often needed after the PM process. Casting processes, which are often used for aerospace components (turbine blades, vanes), are not possible. Direct metal deposition (DMD) is an additive manufacturing technique used for the refurbishment of superalloy components, but generating these components from the bottom up is also of current research interest. MoNbTaW possesses high yield strength at high temperatures and could be an alternative to state-of-the-art materials. In this study, DMD of an equimolar mixture of elemental powders was performed with a pulsed Nd:YAG laser. Single wall structures were built, deposition strategies developed and the microstructure of MoNbTaW was analyzed by back scattered electrons (BSE) and energy dispersive X-ray (EDX) spectroscopy in a scanning electron microscope. DMD enables the generation of composition gradients by using dynamic powder mixing instead of pre-alloyed powders. However, the simultaneous handling of several elemental or pre-alloyed powders brings new challenges to the deposition process. The influence of thermal properties, melting point and vapor pressure on the deposition process and chemical composition will be discussed.

  17. Comprehensive Creep and Thermophysical Performance of Refractory Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ferber, M.K.; Wereszczak, A.; Hemrick, J.A.

    2006-06-29

    Furnace designers and refractory engineers recognize that optimized furnace superstructure design and refractory selection are needed as glass production furnaces are continually striving toward greater output and efficiencies. Harsher operating conditions test refractories to the limit, while changing production technology (such as the conversion to oxy-fuel from traditional air-fuel firing) can alter the way the materials perform [1-3]. Refractories for both oxy- and air-fuel fired furnace superstructures (see Fig. 1) are subjected to high temperatures that may cause them to creep excessively or subside during service if the refractory material is not creep resistant, or if it is subjected to high stress, or both. Furnace designers can ensure that superstructure structural integrity is maintained if the creep behavior of the refractory material is well understood and well represented by appropriate engineering creep models. Several issues limit the abilities of furnace designers to (1) choose the optimum refractory for their applications, (2) optimize the engineering design, or (3) predict the service mechanical integrity of their furnace superstructures. Published engineering creep data are essentially nonexistent for almost all commercially available refractories used for glass furnace superstructures. The limited data that do exist are supplied by the various refractory suppliers. Unfortunately, the suppliers generally have different ways of conducting their mechanical testing, and they interpret and report their data differently. This inconsistency makes it hard for furnace designers to draw fair comparisons between competing grades of candidate refractories. Furthermore, the refractory suppliers' data are often not available in a form that can be readily used for furnace design or for the prediction and design of long-term structural integrity of furnace superstructures. As a consequence, the U.S. Department of Energy (DOE) Industrial Technology Program

  18. Computational Capabilities for Predictions of Interactions at the Grain Boundary of Refractory Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Debasis; Kwak, Shaun; Vasenkov, Alex; Shin, Yun Kyung; Duin, Adri van

    2014-09-30

    New high performance refractory alloys are critically required for improving efficiency and decreasing CO2 emissions of fossil energy systems. The development of these materials remains slow because it is driven by a trial-and-error experimental approach and lacks a rational design approach. Atomistic Molecular Dynamic (MD) design has the potential to accelerate this development through the prediction of mechanical properties and corrosion resistance of new materials. The success of MD simulations depends critically on the fidelity of interatomic potentials. This project, in collaboration with Penn State, has focused on developing and validating high quality quantum mechanics based reactive potentials, ReaxFF, for Ni-Fe-Al-Cr-O-S system. A larger number of accurate density functional theory (DFT) calculations were performed to generate data for parameterizing the ReaxFF potentials. These potentials were then used in molecular dynamics (MD) and molecular dynamics-Monte Carlo (MD-MC) for much larger system to study for which DFT calculation would be prohibitively expensive, and to understand a number of chemical phenomena Ni-Fe-Al-Cr-O-S based alloy systems . These include catalytic oxidation of butane on clean Cr2O3 and pyrite/Cr2O3, interfacial reaction between Cr2O3 (refractory material) and Al2O3 (slag), cohesive strength of at the grain boundary of S-enriched Cr compared to bulk Cr and Ssegregation study in Al, Al2O3, Cr and Cr2O3 with a grain structure. The developed quantum based ReaxFF potential are available from the authors upon request. During this project, a number of papers were published in peer-reviewed journals. In addition, several conference presentations were made.

  19. Computational Capabilities for Predictions of Interactions at the Grain Boundary of Refractory Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Debasis; Kwak, Shaun; Vasenkov, Alex; Shin, Yun Kyung; Duin, Adri van

    2014-09-30

    New high performance refractory alloys are critically required for improving efficiency and decreasing CO2 emissions of fossil energy systems. The development of these materials remains slow because it is driven by a trial-and-error experimental approach and lacks a rational design approach. Atomistic Molecular Dynamic (MD) design has the potential to accelerate this development through the prediction of mechanical properties and corrosion resistance of new materials. The success of MD simulations depends critically on the fidelity of interatomic potentials. This project, in collaboration with Penn State, has focused on developing and validating high quality quantum mechanics based reactive potentials, ReaxFF, for Ni-Fe-Al-Cr-O-S system. A larger number of accurate density functional theory (DFT) calculations were performed to generate data for parameterizing the ReaxFF potentials. These potentials were then used in molecular dynamics (MD) and molecular dynamics-Monte Carlo (MD-MC) for much larger system to study for which DFT calculation would be prohibitively expensive, and to understand a number of chemical phenomena Ni-Fe-Al-Cr-O-S based alloy systems . These include catalytic oxidation of butane on clean Cr2O3 and pyrite/Cr2O3, interfacial reaction between Cr2O3 (refractory material) and Al2O3 (slag), cohesive strength of at the grain boundary of S-enriched Cr compared to bulk Cr and Ssegregation study in Al, Al2O3, Cr and Cr2O3 with a grain structure. The developed quantum based ReaxFF potential are available from the authors upon request. During this project, a number of papers were published in peer-reviewed journals. In addition, several conference presentations were made.

  20. Computational Capabilities for Predictions of Interactions at the Grain Boundary of Refractory Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Debasis [CFD Research Corporation, Huntsville, AL (United States); Kwak, Shaun [CFD Research Corporation, Huntsville, AL (United States); Vasenkov, Alex [CFD Research Corporation, Huntsville, AL (United States); Shin, Yun Kyung [Pennsylvania State Univ., University Park, PA (United States); Duin, Adri van [Pennsylvania State Univ., University Park, PA (United States)

    2014-12-01

    New high performance refractory alloys are critically required for improving efficiency and decreasing CO2 emissions of fossil energy systems. The development of these materials remains slow because it is driven by a trial-and-error experimental approach and lacks a rational design approach. Atomistic Molecular Dynamic (MD) design has the potential to accelerate this development through the prediction of mechanical properties and corrosion resistance of new materials. The success of MD simulations depends critically on the fidelity of interatomic potentials. This project, in collaboration with Penn State, has focused on developing and validating high quality quantum mechanics based reactive potentials, ReaxFF, for Ni-Fe-Al-Cr-O-S system. A larger number of accurate density functional theory (DFT) calculations were performed to generate data for parameterizing the ReaxFF potentials. These potentials were then used in molecular dynamics (MD) and molecular dynamics-Monte Carlo (MD-MC) for much larger system to study for which DFT calculation would be prohibitively expensive, and to understand a number of chemical phenomena Ni-Fe-Al-Cr-O-S based alloy systems . These include catalytic oxidation of butane on clean Cr2O3 and pyrite/Cr2O3, interfacial reaction between Cr2O3 (refractory material) and Al2O3 (slag), cohesive strength of at the grain boundary of S-enriched Cr compared to bulk Cr and Ssegregation study in Al, Al2O3, Cr and Cr2O3 with a grain structure. The developed quantum based ReaxFF potential are available from the authors upon request. During this project, a number of papers were published in peer-reviewed journals. In addition, several conference presentations were made.

  1. Strip Casting of High Performance Structural Alloys

    Institute of Scientific and Technical Information of China (English)

    S S Park; J G Lee; Nack J Kim

    2004-01-01

    There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

  2. Approaches to oxidation-resistant refractory metal alloys

    OpenAIRE

    Wright, I; Nagarajan, V.

    1993-01-01

    The focus of the research reported here was on the design of high-temperature alloys which would form protective SiO2 and Al2O3 scales on exposure to high-temperature, oxidizing environments. One way to promote the growth of such scales is to incorporate sufficient amounts of Si or Al in the alloy substrate ; typically, additions of approximately 35 to 45 weight percent (all alloy compositions are given in weight percent unless explicitly stated otherwise) of Si or Al would be required to for...

  3. Effect of CaF2 on Interfacial Phenomena of High Alumina Refractories with Al Alloy

    Science.gov (United States)

    Koshy, Pramod; Gupta, Sushil; Sahajwalla, Veena; Edwards, Phil

    2008-08-01

    An experimental study was conducted to investigate the interfacial phenomena between Al-alloy and industrial grade high alumina refractories containing varying contents of CaF2 at 1250 °C. Interfacial reaction products and phases formed in the heat-treated refractory samples were characterized using electron probe microanalysis (EPMA) and X-ray diffraction (XRD), respectively, while interfacial phenomena including dynamic wetting behavior were analyzed using the sessile drop technique. Refractories containing less than 5 wt pct CaF2 showed good resistance to reactions with the molten alloy, due to the dominance of corundum, and the presence of anorthite at the interface. However, with a further increase in the additive content, a glassy matrix of anorthite with CaF2 was formed. Formation of this phase significantly increased the intensity of reactions resulting in the buildup of an interfacial layer. The study thus revealed the strong catalytic effect of CaF2 on reactions of high alumina refractories with Al-alloy.

  4. Compressive Creep and Thermophysical Performance of Mullite Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, JG

    2002-04-01

    Compressive creep testing of ten commercially available mullite refractories was performed at 1300-1450 C and at static stresses between 0.2-0.6 MPa. These refractories were examined because they are used in borosilicate glass furnace crowns and superstructures along with in sidewall applications. Additionally, despite their high cost ({approx}$500/ft{sup 3}) they are cheaper than other refractories such as chrome alumina ({approx}$3000/ft{sup 3}) or fusion-cast alumina ({approx}900/ft{sup 3}) which are used as replacements for traditional silica refractories in harsh oxy-fuel environments. The corrosion resistances of these ten materials were also evaluated. In addition, measurements were made that tracked their dimensional stability, phase content, microstructure, and composition as a function of temperature and time. The techniques used for these characterizations and their respective analyses are described. An intent of this study was to provide objective and factual results whose interpretations were left to the reader.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-10

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

  6. Dendritic solidification and thermal expansion of refractory Nb-Zr alloys investigated by electrostatic levitation

    Science.gov (United States)

    Yang, S. J.; Hu, L.; Wang, L.; Wei, B.

    2017-05-01

    The dendritic growth and thermal expansion of isomorphous refractory Nb-5%Zr, Nb-10%Zr, and Nb-15%Zr alloys were studied by electrostatic levitation technique. The obtained maximum undercoolings for the three alloys were 534 (0.2 T L), 498 (0.19 T L), and 483 K (0.18 T L), respectively. Within these undercooling ranges, the dendritic growth velocities of the three alloys all exhibited power laws, and achieved 38.5, 34.0, and 27.1 m s-1 at each maximum undercooling. The microstructures were characterized by coarse dendrites at small undercooling, while they transformed into refined dendrites under large undercooling condition. In addition, the measured thermal expansion coefficients of solid Nb-Zr alloys increased linearly with temperature. The values at liquid state were more than double of those at solid state, which also displayed linear dependence on temperature.

  7. Effect of Silica on High-Temperature Interfacial Phenomena of Monolithic Refractories with Al Alloy

    Science.gov (United States)

    Koshy, Pramod; Gupta, Sushil; Sahajwalla, Veena; Edwards, Phil

    2008-04-01

    An experimental study was conducted to study the interfacial phenomena between monolithic refractories and Al alloy at 1250 °C. Dynamic contact angles of monolithic substrates with varying silica levels were measured using the sessile drop technique, while phases present in the preheated monolithic samples and interfacial reaction products were characterized using X-ray diffraction (XRD) and an electron probe microanalyzer (EPMA). The contact angles in the Al alloy/silica system were found to change much more rapidly as compared to that of the alloy/alumina system, clearly demonstrating the high wetting tendency of silica. Under the tested conditions, the corundum phase forms at the interface while Mg was found to vaporize from the alloy and accumulate at the bottom of the monolithic substrate. Both these phenomena are shown to influence the intensity of contact angle variations with time and, thereby, the wetting behavior of monolithic substrates. Based on dynamic contact angles and equilibrium calculations, monolithic refractories are further classified into three groups, such that the wetting characteristics of those with compositions in the ranges of 0 to 25 pct, 25 to 45 pct, and >45 pct silica were shown to be dictated by the presence of corundum, mullite, and free silica, respectively, as the predominant phase.

  8. Determination of the transition to the high entropy regime for alloys of refractory elements

    Energy Technology Data Exchange (ETDEWEB)

    Grosso, Mariela F. del [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 (B1650KNA), San Martin (Argentina); CONICET, Buenos Aires (Argentina); Grupo de Caracterizacion y Modelizacion de Materiales, UTN, FRGP, H. Yrigoyen 288, (B1617FRG) Gral. Pacheco (Argentina); Bozzolo, Guillermo, E-mail: guille_bozzolo@yahoo.com [Loyola University Maryland, 4501 N. Charles St., Baltimore, MD 21210 (United States); Mosca, Hugo O. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 (B1650KNA), San Martin (Argentina); Grupo de Caracterizacion y Modelizacion de Materiales, UTN, FRGP, H. Yrigoyen 288, (B1617FRG) Gral. Pacheco (Argentina)

    2012-09-05

    Highlights: Black-Right-Pointing-Pointer Atomistic modeling using a quantum approximate method for the energetics. Black-Right-Pointing-Pointer Modeling of the phase structure of high entropy alloys of refractory elements. Black-Right-Pointing-Pointer Comparison of modeled structure with experimental results for five-element alloys. Black-Right-Pointing-Pointer Determination of bulk properties of transitional chains from 4 to 5 element alloys. Black-Right-Pointing-Pointer Introduction of an algorithm to aid in the design of high entropy alloys. - Abstract: The development of high entropy alloys is currently limited to experimental work aimed at the determination of specific compositions that exhibit particular properties. The main feature of these alloys is their particular phase structure, which tends to be a continuous solid solution in spite of the large number of constituents which would otherwise form a large number of intermetallic phases. While it is known that equimolar concentrations and large number of elements are two necessary conditions for achieving high entropy behavior, not much is known regarding the transition to this regime in the presence of specific elements. Such knowledge would be useful when determining alloy compositions, as it would set boundaries for the necessary concentrations of each element in experimental situations. In this work, results of a computational modeling effort are presented, where a recently developed 5-element high entropy alloy of refractory elements is used as the foundation needed to examine such transition and determine the necessary lower bounds for the concentration of each element. Details of the phase structure of the quaternary combinations of W, Nb, Mo, Ta and V as they evolve upon the addition of a fifth element are discussed. The results are compared to the experimental case for the case of V added to W-Nb-Mo-Ta. Using these examples as a reference, the concept of critical concentrations for each element

  9. Cost Estimate for Molybdenum and Tantalum Refractory Metal Alloy Flow Circuit Concepts

    Science.gov (United States)

    Hickman, Robert R.; Martin, James J.; Schmidt, George R.; Godfroy, Thomas J.; Bryhan, A.J.

    2010-01-01

    The Early Flight Fission-Test Facilities (EFF-TF) team at NASA Marshall Space Flight Center (MSFC) has been tasked by the Naval Reactors Prime Contract Team (NRPCT) to provide a cost and delivery rough order of magnitude estimate for a refractory metal-based lithium (Li) flow circuit. The design is based on the stainless steel Li flow circuit that is currently being assembled for an NRPCT task underway at the EFF-TF. While geometrically the flow circuit is not representative of a final flight prototype, knowledge has been gained to quantify (time and cost) the materials, manufacturing, fabrication, assembly, and operations to produce a testable configuration. This Technical Memorandum (TM) also identifies the following key issues that need to be addressed by the fabrication process: Alloy selection and forming, cost and availability, welding, bending, machining, assembly, and instrumentation. Several candidate materials were identified by NRPCT including molybdenum (Mo) alloy (Mo-47.5 %Re), tantalum (Ta) alloys (T-111, ASTAR-811C), and niobium (Nb) alloy (Nb-1 %Zr). This TM is focused only on the Mo and Ta alloys, since they are of higher concern to the ongoing effort. The initial estimate to complete a Mo-47%Re system ready for testing is =$9,000k over a period of 30 mo. The initial estimate to complete a T-111 or ASTAR-811C system ready for testing is =$12,000k over a period of 36 mo.

  10. Alloying effects of refractory elements in the dislocation of Ni-based single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Shiyu Ma

    2016-12-01

    Full Text Available The alloying effects of W, Cr and Re in the [100] (010 edge dislocation cores (EDC of Ni-based single crystal superalloys are investigated using first-principles based on the density functional theory (DFT. The binding energy, Mulliken orbital population, density of states, charge density and radial distribution functions are discussed, respectively. It is clearly demonstrated that the addition of refractory elements improves the stability of the EDC systems. In addition, they can form tougher bonds with their nearest neighbour (NN Ni atoms, which enhance the mechanical properties of the Ni-based single crystal superalloys. Through comparative analysis, Cr-doped system has lower binding energy, and Cr atom has evident effect to improve the systemic stability. However, Re atom has the stronger alloying effect in Ni-based single crystal superalloys, much more effectively hindering dislocation motion than W and Cr atoms.

  11. Supporting data for senary refractory high-entropy alloy CrxMoNbTaVW

    Directory of Open Access Journals (Sweden)

    B. Zhang

    2015-12-01

    Full Text Available This data article is related to the research paper entitled “senary refractory high-entropy alloy CrxMoNbTaVW [1]”. In this data article, the pseudo-binary Cr-MoNbTaVW phase diagram is presented to show the impact of Cr content to the senary Cr-MoNbTaVW alloy system; the sub-lattice site fractions are presented to show the disordered property of the Cr-MoNbTaVW BCC structures; the equilibrium and Scheil solidification results with the actual sample elemental compositions are presented to show the thermodynamic information of the melted/solidified CrxMoNbTaVW samples; and the raw EDS scan data of the arc-melted CrxMoNbTaVW samples are also provided.

  12. Performance Evaluation of Refractory Composite Coatings in Potassium Rich Environment

    Directory of Open Access Journals (Sweden)

    Kristina BRINKIENĖ

    2016-09-01

    Full Text Available A laboratory scale method was used to study the performance of reinforced cement composites in potassium rich environment of biomass combustion. Buckwheat husk (BH was used as potential source of unexploited biomass product applicable as biomass derived fuel. In order to enhance the alkali effect on the properties of the investigated materials, the solution of potassium carbonate (K2CO3 was selected as potassium rich aggressive environment. Two reinforced cement composites as potential repair coatings for restoration of damaged refractory surfaces with different composition of aggregate were used in corrosion tests. Performance of refractory coatings was evaluated by analysing the microstructure of the treated composites as well as mechanical properties. Energy-dispersive X-ray spectroscopy (SEM/EDS and optical microscopy were used to study the microstructure in the corroded region of the refractory coatings. Long term studies in the solution of 1M K2CO3 for 56 months have demonstrated that composite with the additive of fluid cracking catalyst of oil refinery and petrochemical industries is more durable in the potassium rich environment.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.8348

  13. Liquid Supercoolability and Synthesis Kinetics of Quinary Refractory High-entropy Alloy

    Science.gov (United States)

    Wang, W. L.; Hu, L.; Yang, S. J.; Wang, A.; Wang, L.; Wei, B.

    2016-11-01

    The high-entropy configuration of equiatomic multicomponent alloys opens an effective access to the development of advanced materials. Here we report the synthesis of a new quinary refractory WMoTaNbZr high-entropy alloy under electrostatic levitation condition. It showed a high liquidus temperature of 2686 K and achieved a maximum supercooling of 640 K (0.24 TL) at molten state. The containerless measurements revealed a linear increasing tendency for both its liquid state density and the specific heat to emissivity ratio versus alloy supercooling. A high-entropy body-centered cubic (HEB) phase dominated its phase constitution despite the formation of a negligible amount of solid solution (Zr) phase. The dendritic growth of HEB phase always governed the crystallization process, attained a fastest growth velocity of 13.5 m/s and displayed a power function relation to alloy supercooling. The high speed videographic research of recalescence phenomenon indicated Johnson-Mehl-Avrami type transition kinetics for its rapid solidification process. As supercooling increases, the microstructures of primary HEB phase were refined conspicuously and exhibited an obvious solute trapping effect of the segregative Zr component. Meanwhile, the Vickers hardness of HEB phase displayed the rising tendency with supercooling.

  14. Corrosion performance of structural alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  15. High Temperature Silicides and Refractory Alloys Symposium Held in Boston, Massachusetts on November 29 -December 2, 1993. Volume 322

    Science.gov (United States)

    1993-12-02

    Kinetics, M. Atzmon, J.M.E. Harper, A.L. Greer, M.R. Libera, 1993, ISBN: 1-55899-207-3 Volume 312- Common Themes and Mechanisms of Epitaxial Growth, P...characteristics. Table TH1. Commercial Refractory Metals and Alloys and Associated Melting Processes Base Metal Alloy Additions, wt. % How Made Nb EBM Nb 171... EBM ; EBM +VAM; PHM Nb 7.5Ta EBM +VAM Nb 45-48Ti EBM +VAM; PHM. Nb 44TI-25Ta PHM Nb 55Tt PEIM Ta ERM Ta 2.5W EBM +VAM Ta low EBM +VAM Ta 4ONb EBM + YAM Mo(Low

  16. Development of Ion-Plasma Coatings for Protecting Intermetallic Refractory Alloys VKNA-1V and VKNA-25 in the Temperature Range of 1200 - 1250°C

    Science.gov (United States)

    Budinovskii, S. A.; Matveev, P. V.; Smirnov, A. A.

    2017-05-01

    Multilayer heat-resistant ion-plasma coatings for protecting the parts of the hot duct of gas-turbine engines produced from refractory nickel alloys based on VKNA intermetallics from high-temperature oxidation are considered. Coatings of the Ni - Cr - Al (Ta, Re, Hf, Y) + Al - Ni - Y systems are tested for high-temperature strength at 1200 and 1250°C. Metallographic and microscopic x-ray spectrum analyses of the structure and composition of the coatings in the initial condition and after the testing are performed. The effect of protective coatings of the Ni - Cr - Al - Hf + Al - Ni - Y systems on the long-term strength of alloys VKNA-1V and VKNA-25 at 1200°C is studied.

  17. Synthesis of nanometric refractory alloys powders in the Mo−Nb−W system

    Energy Technology Data Exchange (ETDEWEB)

    Kentheswaran, Vasuki; Dine, Sarah [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France); Vrel, Dominique, E-mail: dominique.vrel@lspm.cnrs.fr [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France); Couzinié, Jean-Philippe [ICMPE, Université Paris Est, UMR 7182, CNRS, UPEC, 94320 Thiais (France); Dirras, Guy [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France)

    2016-09-15

    Nanometric powders of stoichiometric compositions in the Mo−Nb, Mo−W, Nb−W binary systems and in the Mo−Nb−W ternary system were produced by highly exothermic reactions using Mechanically Induced Chemical Reaction (MICR), Self-propagating High-temperature Synthesis (SHS) and Mechanically Activated Self-propagating High-temperature Synthesis (MASHS), through the reduction of their oxides by magnesium, with sodium chloride used as a reaction moderator. Results demonstrate the possibility to obtain high purity nanostructured products in the 20–150 nm range, with an average equivalent diameter, from specific surface measurements, of 44 nm. However, in Nb containing samples, the main BCC phase always comes with one or more secondary phases, for which further developments are necessary in order either to avoid its formation or to find a way to eliminate it. - Highlights: • Nanometric refractory powders in the Mo−Nb−W system have been synthesized. • Three high-energy processes (SHS, MASHS, milling) have been compared. • Process parameters can be adjusted to yield homogeneous alloys in the nanoscale.

  18. Compressive Creep Performance and High Temperature Dimensional Stability of Conventional Silica Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Karakus, M.; Kirkland, T.P.; Liu, K.C.; Moore, R.E.; Pint, B.A.; Wereszczak, A.A.

    1999-03-01

    Furnace designers and refractory engineers recognize that optimized furnace superstructure design and refractory selection are needed as glass production furnaces are continually striving toward greater output and efficiencies. Harsher operating conditions test refractories to the limit, while changing production technology (such as the conversion to oxy-fuel from traditional air-fuel firing) can alter the way the materials perform. Refractories for both oxy- and air-fuel fired furnace superstructures are subjected to high temperatures during service that may cause them to excessively creep or subside if the refractory material is not creep resistant, or if it is subjected to high stress, or both. Furnace designers can ensure that superstructure structural integrity is maintained if the creep behavior of the refractory material is well understood and well represented by appropriate engineering creep models. Several issues limit the abilities of furnace designers to (1) choose the optimum refractory for their applications, (2) optimize the engineering design, or (3) predict the service mechanical integrity of their furnace superstructures. Published engineering creep data are essentially non-existent for almost all commercially available refractories used for glass furnace superstructures. The limited data that do exist are supplied by the various refractory suppliers. Unfortunately, these suppliers generally have different ways of conducting their mechanical testing and they also interpret and report their data differently; this makes it hard for furnace designers to draw fair comparisons between competing grades of candidate refractories. Furthermore, the refractory supplier's data are often not available in a form that can be readily used for furnace design and for the prediction and design of long-term structural integrity of furnace superstructures. With the aim of providing such comparable data, the US DOE's Office of Industrial Technology and its

  19. Microstructure and Mechanical Properties of a Refractory CoCrMoNbTi High-Entropy Alloy

    Science.gov (United States)

    Zhang, Mina; Zhou, Xianglin; Li, Jinghao

    2017-08-01

    In this work, a new refractory high-entropy alloy, the Co-Cr-Mo-Nb-Ti system, was proposed as a family of candidate materials for high-temperature structural applications. CoCrMoNbTi x ( x values in terms of molar ratios, x = 0, 0.2, 0.4, 0.5 and 1.0) alloys were prepared by vacuum arc melting. The effects of variations in the Ti content on the phase constituents, microstructure and mechanical properties of the alloys were investigated using x-ray diffractometry, scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy and compressive testing. The results showed that the CoCrMoNbTi0.4 alloy possessed a typical cast dendritic microstructure consisting of a single body-centered cubic (BCC) solid solution. Laves phases (Cr2Nb and Co2Ti) were formed in other alloys with different Ti contents. The results were discussed in terms of the mixing enthalpy, atomic size difference, electronegativity difference and valance electron concentrations among the elements within alloys. The alloy hardness exhibited a slightly decreasing trend as the Ti content increased, resulting from the coarser microstructure and reduced amount of Laves phases. Augmented Ti content increased the compressive strength, but decreased the ductility. Particularly, for the CoCrMoNbTi0.2 alloy, the hardness, compressive strength and fracture strain were as high as 916.46 HV0.5, 1906 MPa and 5.07%, respectively. The solid solution strengthening of the BCC matrix and the formation of hard Laves phases were two main factors contributing to alloy strengthening.

  20. SPINEL-BASED REFRACTORIES FOR IMPROVED PERFORMANCE IN COAL GASIFICATION ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Armstrong, Beth L [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2013-01-01

    Oak Ridge National Laboratory, in collaboration with refractory manufacturer Minteq International, Inc., academic partner Missouri University of Science and Technology and refractory end users have developed novel refractory systems and techniques to reduce energy consumption of refractory lined vessels. The objective of this U.S. DOE funded project was to address the need for innovative refractory compositions by developing MgO-Al 2O3 spinel gunnable refractory compositions utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Materials have been developed specifically for coal gasification environments and work has been performed to develop and apply low cost coatings using a colloidal approach for protection against attack of the refractory brick by the service environment and to develop a light-weight back-up refractory system to help offset the high thermal conductivity inherent in spinel materials. This paper discusses the systematic development of these materials, laboratory testing and evaluation of these materials, and relevant results achieved toward the reduction of chemical reactions and mechanical degradation by the service environment though compositional and processing modifications.

  1. Corrosion of refractory alloys induced by sodium sulphate in simulated low oxygen potential atmospheres of the BTL plants

    Energy Technology Data Exchange (ETDEWEB)

    Couture, Ludovic [Grenoble Univ., Saint Martin d' Heres (France). SIMaP; IFP, Solaize (France). Materials Dept.; Galerie, Alain; Wouters, Yves [Grenoble Univ., Saint Martin d' Heres (France). SIMaP; Grosjean, Francois; Kittel, Jean; Ropital, Francois [IFP, Solaize (France). Materials Dept.

    2010-07-01

    BTL (biomass to liquid) is an innovative process to synthesize second generation bio-gasoline from wood and farm residues. In the present work, the effect of sodium sulphate on the high-temperature corrosion at 900 C of two refractory alloys, the chromia-forming Haynes {sup registered} HR-120 and the alumina-forming Haynes {sup registered} 214 in a simulated process atmosphere CO/H{sub 2}/CO{sub 2} (45/45/10% vol.), was investigated for durations up to 96 h. (orig.)

  2. Development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P.C.; DePoorter, G.L.; Munoz, D.R.

    1991-02-01

    We have initiated a three phase investigation of the development of high performance refractory fibers with enhanced insulating properties and longer usable lifetimes. This report presents the results of the first phase of the study, performed from Aug. 1989 through Feb. 1991, which shows that significant energy saving are possible through the use of high temperature insulating fibers that better retain their efficient insulating properties during the service lifetime of the fibers. The remaining phases of this program include the pilot scale development and then full scale production feasibility development and evaluation of enhanced high temperature refractory insulting fibers. This first proof of principle phase of the program presents a summary of the current use patterns of refractory fibers, a laboratory evaluation of the high temperature performance characteristics of selected typical refractory fibers and an analysis of the potential energy savings through the use of enhanced refractory fibers. The current use patterns of refractory fibers span a wide range of industries and high temperature furnaces within those industries. The majority of high temperature fiber applications are in furnaces operating between 2000 and 26000{degrees}F. The fibers used in furnaces operating within this range provide attractive thermal resistance and low thermal storage at reasonable cost. A series of heat treatment studies performed for this phase of the program has shown that the refractory fibers, as initially manufactured, have attractive thermal conductivities for high temperature applications but the fibers go through rapid devitrification and subsequent crystal growth upon high temperature exposure. Development of improved fibers, maintaining the favorable characteristics of the existing as-manufactured fibers, could save between 1 and 4% of the energy consumed in high temperature furnaces using refractory fibers.

  3. Microstructure and properties of novel quinary multi-principal element alloys with refractory elements

    Directory of Open Access Journals (Sweden)

    Na-na Guo

    2015-09-01

    Full Text Available Five equiatomic alloys (TiZrHfVNb, TiZrHfVTa, TiZrNbMoV, TiZrHfMoV and ZrNbMoHfV composed of five elements with high melting temperature, respectively were prepared by arc-melting to develop a novel high temperature alloy. The five alloys exhibit different dendritic and interdendritic morphologies. The TiZrHfVNb, TiZrHfVTa and TiZrNbMoV alloys formed disordered solid solution phases with body-centered cubic structure, and exhibited high compressive strength and good plasticity. The TiZrHfMoV and ZrNbMoHfV alloys are composed with Laves phase (HfMo2 and disordered solid solution phases with body-centered cubic structure. The TiZrHfMoV and ZrNbMoHfV alloys are harder and more brittle than the other three alloys due to the existence of hard and brittle Laves phases. At high temperatures, the strength decreases to below 300 MPa for the TiZrHfVNb and TiZrHfMoV alloys. Solution strengthening is the primary strengthening mechanism of the TiZrHfVNb, TiZrHfVTa and TiZrNbMoV alloys, and brittle Laves phase is the main cause for the low ductility of the TiZrHfMoV and ZrNbMoHfV alloys.

  4. Mechanical Properties of Refractory High Entropy Alloys Fabricated by Powder Processing

    Energy Technology Data Exchange (ETDEWEB)

    Kuk, Seoung Woo; Kim, Ki Hwan [Korea Atomic Energy Research Institute, Yuseong, Daejeon (Korea, Republic of); Lim, Woo Jin; Kang, Byung Chul; Hong, Soon Hyung; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    The effects of high configurational entropy, lattice distortion and sluggish diffusion are attributed to the distinguishable behavior of high entropy alloys. The structural applications of high entropy alloys are also promising in advanced nuclear energy systems for nuclear fission and fusion applications. Because of the randomly occupied lattice points by atoms with different atomic radius, lattice distortions and local atomic level strain were developed. The local lattice distortions influence the mechanical properties of high entropy alloys. The strengthening of high entropy alloys is attributed to the lattice distortions and local atomic level strain that increase the resistance to the dislocation motion. Some high entropy alloys exhibit remarkable irradiation resistance. Nagase et al. reported that the Conference alloy was irradiation resistant up to 40 dpa. Ega mi proposed that the irradiation defects can be self-healed because the recrystallization happens more easily in high entropy alloys. The mechanically alloyed and sintered samples have a much smaller grain size than that in cast high entropy alloys.

  5. Low-Density, Refractory Multi-Principal Element Alloys of the Cr-Nb-Ti-V-Zr System: Microstructure and Phase Analysis (Postprint)

    Science.gov (United States)

    2012-12-19

    three disordered bcc phases . The CrNbTiZr and CrNbTiVZr alloys contain a disordered bcc phase and an ordered Laves phase . The lattice parameters and...trends, but are unable to accurately predict vol- ume fractions and compositions of the Laves phases in the CrNbTiZr and CrNbTiVZr alloys. 5. Although the...REFRACTORY MULTI-PRINCIPAL ELEMENT ALLOYS OF THE Cr–Nb–Ti–V–Zr SYSTEM: MICROSTRUCTURE AND PHASE ANALYSIS (POSTPRINT) 5a. CONTRACT NUMBER In-house

  6. Some Aspects in the Development of High Performance Refractories for Iron and Steel Making in China

    Institute of Scientific and Technical Information of China (English)

    ZHONG Xiangchong; YE Fangbao

    2005-01-01

    In the past 25 years in China, to meet with the rapid increase in steel production accompanied by adoption of advanced metallurgical technologies, there has been fast development of China's refractories industry in production capacity, in quality improvement and in development of new products. Sophisticated high performance refractory materials mainly based on our rich reserves of magnesite, bauxite and flake graphite have been developed, such as carbon-bonded products, high purity oxide products, bauxite-based low creep and high strength high alumina bricks and LC, ULC and ZC castables. They have been used in blast furnaces, BOFs, EAFs, secondary refining and continuous casting with considerable improvement in service performance.

  7. Alloy development for irradiation performance: program strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, E. E.; Stiegler, J. O.; Wiffen, F. W.; Dalder, E. N.C.; Reuther, T. C.; Gold, R. E.; Holmes, J. J.; Kummer, D. L.; Nolfi, F. V.

    1978-01-01

    The objective of the Alloy Development for Irradiation Performance Program is the development of structural materials for use in the first wall and blanket region of fusion reactors. The goal of the program is a material that will survive an exposure of 40 MWyr/m/sup 2/ at a temperature which will allow use of a liquid-H/sub 2/O heat transport system. Although the ultimate aim of the program is development of materials for commercial reactors by the end of this century, activities are organized to provide materials data for the relatively low performance interim machines that will precede commercial reactors.

  8. The Influence of Novel Alloying Additions on the Performance of Magnesium Alloy AZ31B

    Science.gov (United States)

    2013-11-01

    alloys are based on a rather small group of alloying elements, there are often limited differences between them in properties (strength, corrosion ...Research Laboratory (ARL). Initially, the discussions focused on ways to improve the corrosion resistance of magnesium ( Mg ) alloys to increase the...elements display little tendency to alter precipitates or otherwise adversely influence the corrosion performance of the base alloy . Based on these

  9. Looking Ahead—A New Generation of High Performance Refractory Ceramics

    Institute of Scientific and Technical Information of China (English)

    ZHONGXiangchong

    2002-01-01

    It is expected that in the new century, to cope with developments of new high temperature technologies, a new generation of high performance refractory ceramics will emerge and flourish which should include the following (1) oxide and nonoxide composites characterized by a unique combination of high hot strength, high thermal shock resistance and high corrosion resistance;(2) free CaO bearing basic refractories capable of purifying molten metal for improving cleanliness and of absorbing contaminants from waste gases for reducing environmental pollution;(3) free flowing zero cement castables with improved thermomechanical properties, thermal shock resistance and corrosion resistance and gradient castables with varying matrix composition and varying texture.

  10. Effect of Al addition on mechanical properties and microstructure of refractory Al{sub x}HfNbTaTiZr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Ming, E-mail: clin112@asu.edu; Juan, Chien-Chang; Chang, Chia-Hsiu; Tsai, Che-Wei; Yeh, Jien-Wei, E-mail: jwyeh@mx.nthu.edu.tw

    2015-03-05

    Highlights: • The study developed a series of refractory Al{sub x}HfNbTaTiZr HEAs. • The aim to improve strength, and reduce density of the very ductile base alloy. • These HEAs mainly consist of a simple BCC solid solution. • The addition of Al significantly improved the strength characteristics. • Solution hardening led to a decrease in ductility. - Abstract: This study developed a series of refractory Al{sub x}HfNbTaTiZr high-entropy alloys (HEAs) with an aim to improve strength, and reduce density of the very ductile base alloy HfNbTaTiZr. Despite the diversity of crystal structures among the constituent elements, all the HEAs are single solid solution phase with body-centered cubic (BCC) structure. The addition of Al significantly improves the strength but reduces the ductility due to large solution hardening. The linear relation between yield strength and atomic percentage of Al suggests that the strengthening effect of a certain element in a single-phase HEA alloy can be explained based on quasi-binary alloy concept. Crack formations in deformed AlHfNbTaTiZr alloy with the lowest fracture strain are mainly along the boundaries between dendrite and interdendrite. This agrees with its large deviation of Al content and thus strength between dendrite and interdendrite.

  11. Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High Entropy Alloys (Postprint)

    Science.gov (United States)

    2011-05-01

    temper ature from 548 MPa at 1000 C to 405 MPa at 1600 C (Table 2).ublic release; distribution unlimited. Table 4 Composition (in wt.%) of Inconel 718 ...values of the refractory HEAs are much higher than those of Haynes 230 at all studied temperatures and higher than those of Inconel 718 at...than twice (for the Nb25Mo25 Ta25W25 alloy) or four times (for the V20Nb20Mo20Ta20W20 alloy) higher than for Inconel 718 or Haynes 230 at 1000 C. The

  12. Microstructure Evolution in a New Refractory High-Entropy Alloy W-Mo-Cr-Ti-Al

    Science.gov (United States)

    Gorr, Bronislava; Azim, Maria; Christ, Hans-Juergen; Chen, Hans; Szabo, Dorothee Vinga; Kauffmann, Alexander; Heilmaier, Martin

    2016-02-01

    The microstructure of a body-centered cubic 20W-20Mo-20Cr-20Ti-20Al alloy in the as-cast condition as well as its microstructural evolution during heat treatment was investigated. Different characterization techniques, such as focused ion beam-scanning electron microscope, X-ray diffraction, and transmission electron microscope, were applied. Experimental observations were supported by thermodynamic calculations. The alloy exhibits a pronounced dendritic microstructure in the as-cast condition with the respective dendritic and interdendritic regions showing significant fluctuations of the element concentrations. Using thermodynamic calculations, it was possible to rationalize the measured element distribution in the dendritic and the interdendritic regions. Observations of the microstructure evolution reveal that during heat treatment, substantial homogenization takes place leading to the formation of a single-phase microstructure. Driving forces for the microstructural evolution were discussed from a thermodynamic point of view.

  13. Senary Refractory High-Entropy Alloy HfNbTaTiVZr

    Science.gov (United States)

    Gao, M. C.; Zhang, B.; Yang, S.; Guo, S. M.

    2016-07-01

    Discovery of new single-phase high-entropy alloys (HEAs) is important to understand HEA formation mechanisms. The present study reports computational design and experimental validation of a senary HEA, HfNbTaTiVZr, in a body-centered cubic structure. The phase diagrams and thermodynamic properties of this senary system were modeled using the CALPHAD method. Its atomic structure and diffusion constants were studied using ab initio molecular dynamics simulations. The microstructure of the as-cast HfNbTaTiVZr alloy was studied using X-ray diffraction and scanning electron microscopy, and the microsegregation in the as-cast state was found to qualitatively agree with the solidification predictions from CALPHAD. Supported by both simulation and experimental results, the HEA formation rules are discussed.

  14. EVOLUTION OF PERFORMANCE OF REFRACTORY LINING FOR THE SLAG LINE OF STEEL LADLES AT USIMINAS IPATINGA

    Directory of Open Access Journals (Sweden)

    Sávia Cristina Lacerda Poubel Bastos

    2012-12-01

    Full Text Available Since 2008, Usiminas has initiated a series of actions aiming to increase the life of the refractory lining for the steel ladles and boost technological development in this area. The limitation of the lining was the performance of the bricks used in the slag line. In this sense, the results of tests that show the evolution of the main properties of MgO-C bricks used in this area are presented and discussed. The permanent characterization has permitted the selection of those with best suited properties for the Usiminas process conditions, and assisted refractory suppliers in the development of these materials. These efforts provided an average increase in the lining campaign about 6%, since the beginning of the actions in 2008, without increase the cost.

  15. Development and Application of Refractory Materials for Molten Aluminum Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Headrick, William [University of Missouri, Rolla; Peters, Klaus-Markus [ORNL

    2008-01-01

    Two new refractory materials have been developed for use in molten aluminum contact applications which exhibit improved corrosion and wear resistance, along with improved thermal management through reduced heat losses. The development of these materials was based on understanding of the corrosion and wear mechanisms associated with currently used aluminum contact refractories through physical, chemical, and mechanical characterization and analysis performed by Oak Ridge National Laboratory (ORNL) and the University of Missouri, Rolla (UMR) along with their industrial partners, under the ITP Materials project "Multifunctional Metallic and Refractory Materials for Energy Efficient Handling of Molten Metals". Spent castable refractories obtained from a natural gas fired reverberatory aluminum alloy melting furnace were analyzed leading to identification of several refractory degradation mechanisms and strategies to produce improved materials. The newly developed materials have been validated through both R&D industrial trials and independent commercial trials by the refractory manufacturers.

  16. Development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes: Phase 2, Improved refractory fiber and industrial benefit development. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yifang; Curtis, J.M.; DePoorter, G.L.; Martin, P.C.; Munoz, D.R. [Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering

    1995-05-01

    This is Phase II of a three-phase study for the development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes, for use in the aluminum, glass, cement, and iron and steel industries. Fiberization of 24 out of 25 compositions in the Al{sub 2}O{sub 3}-Si0{sub 2}-Zr0{sub 2} system were achieved. These 24 and three existing fiber compositions were evaluated: The shrinkage and the crystalline and vitreous phases were determined vs heat treatment time and temperature. Four theoretical models were developed: Shrinkage, devitrification kinetics, density change, and fiberization. Although some of the fibers formed during Phase II had properties as good as the reference ASZ fiber, no fiber had a significantly improved performance. This work, although not entirely successful, did produce significant benefits to refractory insulating fiber manufacturers and users: Mechanisms of both linear and thickness shrinkage for vitreous refractory fibers were determined, devitrification kinetics were quantified and used in models to predict shrinkage during service, and the mechanism of fiber formation in the melt spinning process was studied.

  17. Materials Design for Joinable, High Performance Aluminum Alloys

    Science.gov (United States)

    Glamm, Ryan James

    An aluminum alloy compatible with friction stir welding is designed for automotive and aerospace structural applications. Current weldable automotive aluminum alloys do not possess the necessary strength to meet safety standards and therefore are not able to replace steel in the automotive body. Significant weight savings could be achieved if steel components are replaced with aluminum. Current aerospace alloys are not weldable, requiring machining of large pieces that are then riveted together. If an aerospace alloy could be friction stir welded, smaller pieces could be welded, reducing material waste. Using a systems approach for materials design, property goals are set from performance objectives. From previous research and computational predictions, a structure is designed for a prototype alloy containing dynamic precipitates to readily dissolve and re-precipitate and high stability precipitates to resist dissolution and coarsening in the weld region. It is found that a Ag modified Al-3.9Mg-0.04Cu (at. %) alloy enhanced the rate and magnitude of hardening during ageing, both beneficial effects for dynamic precipitation. In the same alloy, ageing at 350°C results in hardening from Al 3(Sc,Zr) precipitates. Efforts to effectively precipitate both populations simultaneously are unsuccessful. The Al3(Sc,Zr) precipitation hardened prototype is friction stir processed and no weak zones are found in the weld hardness profile. An aerospace alloy design is proposed, utilizing the dual precipitate structure shown in the prototype. The automotive alloy is designed using a basic strength model with parameters determined from the initial prototype alloy analysis. After ageing to different conditions, the alloy is put through a simulated heat affected zone thermal cycle with a computer controlled induction heater. The aged samples lose hardness from the weld cycle but recover hardness from a post weld heat treatment. Atom probe tomography and transmission electron

  18. Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic refractory composite

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S., E-mail: msunanda_cct@yahoo.co.in

    2013-07-15

    Graphical abstract: - Highlights: • Sol–gel Ca-doped γ-Al{sub 2}O{sub 3} accomplished graphite retention. • Nanocoating considerably improved matrix-aggregate bonding. • Less porous simulated matrix upgraded slag resistance. - Abstract: The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in refractory composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of refractory researchers and producers.

  19. Interaction mechanism between niobium-silicide-based alloy melt and Y2O3 refractory crucible in vacuum induction melting process

    Directory of Open Access Journals (Sweden)

    Gao Ming

    2011-05-01

    Full Text Available The Y2O3 crucibles were introduced in the study as an alternative to the traditional ceramic ones in vacuum induction melting of multi-component Nb-16Si-22Ti-2Al-2Hf-17Cr (at.% alloys, to reveal the possible interactions between the alloy melt and the refractory crucible. Multiple melting time lengths and two cooling schemes were designed and used for the experiments. The chemical composition and microstructure of the tested alloy and the melt-crucible interaction were investigated and evaluated. In the experiments, Y2O3 crucible displays good physical-chemical compatibility. The results indicate that the increment of O element in the as-cast ingot is 0.03at.%-0.04at.% (72-97 ppm and the increment of Y element is very insignificant. The key features of the alloy melt interacting with Y2O3 ceramics are analyzed and concluded in the paper. As a result of the dissolution reaction xY2O3 (in molten alloy + (1-xHfO2 (impurity →Hf1-xY2xO2-x, a continuous double-layer solid film consisted of HfO2 solid solution (~2 μm and pure HfO2 (~5 μm is formed on the surface of the test ingot after cooled down in the crucible. The experimental results show that the Y2O3 crucible is applicable to the vacuum induction melting of Nb-Si based alloys.

  20. Refractory Materials based on Magnesia-Alumina Spinel for Improved Performance in Coal Gasification Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Armstrong, Beth L [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2013-01-01

    As part of a larger project to develop novel refractory systems and techniques to reduce energy consumption of refractory lined vessels, a team composed of Oak Ridge National Laboratory, refractory manufacturer Minteq International, Inc., and academic partner Missouri University of Science and Technology have developed new refractory materials and coating systems specifically for application in coal gasification environments. Materials were developed under this U.S. DOE funded project to address the need for innovative refractory compositions by developing MgO-Al2O3 spinel gunnable refractory compositions utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Work was conducted to develop and deploy these new materials and to develop and apply low cost coatings using a colloidal approach for protection against attack of the refractory brick by the serviced environment. Additionally, a light-weight back-up refractory system was developed to help offset the high thermal conductivity inherent in spinel materials. This paper discusses the efforts involved in the development of these materials, along with the laboratory testing and evaluation of these materials leading to relevant results achieved toward the reduction of chemical reactions and mechanical degradation by the service environment though compositional and processing modifications.

  1. Microstructural design of magnesium alloys for elevated temperature performance

    Science.gov (United States)

    Bryan, Zachary Lee

    Magnesium alloys are promising for automotive and aerospace applications requiring lightweight structural metals due to their high specific strength. Weight reductions through material substitution significantly improve fuel efficiency and reduce greenhouse gas emissions. Challenges to widespread integration of Mg alloys primarily result from their limited ductility and elevated temperature strength. This research presents a microstructurally-driven systems design approach to Mg alloy development for elevated temperature applications. The alloy properties that were targeted included creep resistance, elevated temperature strength, room temperature ductility, and material cost. To enable microstructural predictions during the design process, computational thermodynamics was utilized with a newly developed atomic mobility database for HCP-Mg. The mobilities for Mg self-diffusion, as well as Al, Ag, Sn, and Zn solute diffusion in HCP-Mg were optimized from available diffusion literature using DICTRA. The optimized mobility database was then validated using experimental diffusion couples. To limit dislocation creep mechanisms in the first design iteration, a microstructure consisting of Al solutes in solid solution and a fine dispersion of Mg2Sn precipitates was targeted. The development of strength and diffusion models informed by thermodynamic predictions of phase equilibria led to the selection of an optimum Mg-1.9at%Sn-1.5at%Al (TA) alloy for elevated temperature performance. This alloy was cast, solution treated based upon DICTRA homogenization simulations, and then aged. While the tensile and creep properties were competitive with conventional Mg alloys, the TA mechanical performance was ultimately limited because of abnormal grain growth that occurred during solution treatment and the basal Mg2Sn particle morphology. For the second design iteration, insoluble Mg2Si intermetallic particles were added to the TA alloy to provide enhanced grain boundary pinning

  2. Microstructure and Performances of Nanocrystalline Zinc-nickel Alloy Coatings

    Institute of Scientific and Technical Information of China (English)

    LI Guang-yu; LIAN Jian-she; NIU Li-yuan; JIANG Zhong-hao

    2004-01-01

    Nanocrystalline zinc-nickel alloy coatings were deposited from an alkaline zincate bath contained an organic additive that can reduce polarization and a complexing agent. SEM and TEM observations and XRD analysis were performed to examine the microstructure and phase composition of the coatings. The nickel content in deposits is 12.0~14.7% and the coating is consisted of single nanocrystalline γ-phase structure (Ni5Zn21), with grain average grain size about 15nm. The nanocrystalline zinc-nickel alloy coatings have better corrosion resistance, less brittleness and higher microhardness than the conventional zinc coatings.

  3. Microstructure and Performances of Nanocrystalline Zinc-nickel Alloy Coatings

    Institute of Scientific and Technical Information of China (English)

    LIGuang-yu; LIANJian-she; NIULi-yuan; JIANGZhong-hao

    2004-01-01

    Nanocrystalline zinc-nickel alloy coatings were deposited from an alkaline zincate bath contained an organic additive that can reduce polarization and a complexing agent. SEM and TEM observations and XRD analysis were performed to examine the microstructure and phase composition of the coatings. The nickel content in deposits is 12.0-14.7% and the coating is consisted of single nanectystalline γ-phase structure (Ni5Zn21), with grain average grain size about 15nm. The nanocrystalline zinc-nickel alloy coatings have better corrosion resistance, less brittleness and higher microhardness than the conventional zinc coatings.

  4. Bulk Vitrification Performance Enhancement: Refractory Lining Protection Against Molten Salt Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.; Bagaasen, Larry M.; Schweiger, Michael J.; Evans, Michael B.; Smith, Benjamin T.; Arrigoni, Benjamin M.; Kim, Dong-Sang; Rodriguez, Carmen P.; Yokuda, Satoru T.; Matyas, Josef; Buchmiller, William C.; Gallegos, Autumn B.; Fluegel, Alexander

    2007-08-06

    Bulk vitrification (BV) is a process that heats a feed material that consists of glass-forming solids and dried low-activity waste (LAW) in a disposable refractory-lined metal box using electrical power supplied through carbon electrodes. The feed is heated to the point that the LAW decomposes and combines with the solids to generate a vitreous waste form. This study supports the BV design and operations by exploring various methods aimed at reducing the quantities of soluble Tc in the castable refractory block portion of the refractory lining, which limits the effectiveness of the final waste form.

  5. Pressurized metallurgy for high performance special steels and alloys

    Science.gov (United States)

    Jiang, Z. H.; Zhu, H. C.; Li, H. B.; Li, Y.; Liu, F. B.

    2016-07-01

    The pressure is one of the basic parameters which greatly influences the metallurgical reaction process and solidification of steels and alloys. In this paper the history and present situation of research and application of pressurized metallurgy, especially pressurized metallurgy for special steels and alloys have been briefly reviewed. In the following part the physical chemistry of pressurized metallurgy is summarized. It is shown that pressurizing may change the conditions of chemical reaction in thermodynamics and kinetics due to the pressure effect on gas volume, solubility of gas and volatile element in metal melt, activity or activity coefficient of components, and change the physical and chemical properties of metal melt, heat transfer coefficient between mould and ingot, thus greatly influencing phase transformation during the solidification process and the solidification structure, such as increasing the solidification nucleation rate, reducing the critical nucleation radius, accelerating the solidification speed and significant macro/micro-structure refinement, and eliminating shrinkage, porosity and segregation and other casting defects. In the third part the research works of pressured metallurgy performed by the Northeastern University including establishment of pressurized induction melting (PIM) and pressurized electroslag remelting (PESR) equipments and development of high nitrogen steels under pressure are described in detail. Finally, it is considered in the paper that application of pressurized metallurgy in manufacture of high performance special steels and alloys is a relatively new research area, and its application prospects will be very broad and bright.

  6. Special Features of Creep and Long-Term Strength of Single-Crystal Refractory Nickel-Base Alloys

    Science.gov (United States)

    Semenov, S. G.; Getsov, L. B.; Tikhomirova, E. A.; Semenov, A. S.

    2016-03-01

    Results of experimental studies of creep in a wide range of temperatures and stresses are presented for three modern single-crystal nickel-base alloys. A method for determining the creep characteristics by tests including step increase of the tension is suggested and tested. The effect of transition into plastic condition on the creep parameters, the influence of the chemical composition and loading conditions on the duration of creep stages I, II and III, and the conditions of appearance of crystallographic and not crystallographic modes of fracture are analyzed. Possible simple approximations of the creep curves are considered with allowance for the accumulation of damage and occurrence of unsteady creep stages.

  7. 高纯难熔金属及其合金单晶的发展%Development of Single Crystals of High-Purity Refractory Metals and Alloys

    Institute of Scientific and Technical Information of China (English)

    李来平; 胡忠武; 殷涛; 张文; 高选乔; 郭林江; 任广鹏; 张平祥; 李中奎

    2014-01-01

    In this paper,we report the processing technology of single crystals of high-purity refractory metals and alloys, and compare the electron-beam floating zone melting(EBFZM)with the plasma arc melting(PAM).By EBFZM,the tem-perature gradient could be controlled easily and the contamination by crucible materials is avoided,whereas the surface tension of melt is sensitive to the active impurity content and the temperature gradient.Furthermore,the dimensions of high-purity refractory metals and the monocrystalline materials are severely limited and the dislocation density in the mate-rials is relatively high.PAM has the advantages such as high energy density of heating and various specifications of raw materials,by which the single crystal castings could be processed in the shape of rod,plate,tube and other specific shapes.Meanwhile,the impurity elements (especially carbon)are maximally removed.However,the equipment is com-plex and the dislocation density is high.We also discuss the status of development for single crystal materials,such as im-proving the resistance to high temperature and stablilty by solid-solution strengthening.The processing of single crystal tubes is also an interesting topic.We make some suggestions on the processing technology and developing prospect for sin-gle crystals of refractory metals and alloys.%介绍了难熔金属及其合金单晶的制备技术,对电子束悬浮区域熔炼技术和等离子弧熔炼技术进行了比较。电子束悬浮区域熔炼法温度梯度易于控制、材料不受坩埚材料污染,但熔体表面张力对活性杂质和温度梯度敏感性高,所能制备的高纯难熔金属及其单晶材料尺寸规格受到很大限制,且材料内部位错密度较高。等离子弧熔炼法加热源能量密度高,原料规格形式多样,可制备单晶棒材、板材、管材及其他特定形状的单晶铸件,可最大程度地去除杂质元素(尤其是C元素),但设备系统复杂,

  8. Modification performance on 4032 Al alloy by using Al–10Sr master alloys manufactured from different processes

    Directory of Open Access Journals (Sweden)

    Chengwei Liao

    2014-04-01

    Full Text Available The microstructures and modification performance on 4032 aluminum alloy of the Al–10Sr master alloy wire prepared from “direct reaction-hot extrusion” and the trapezoidal block from “direct reaction” were systemically studied by using optical metallurgical microscope, XRD and SEM. It was found that the preparation processes exhibited a significant effect on the microstructures of the Al–10Sr, which thereby influenced its modification performance. It has been found that when the Al–10Sr alloy wire was used, a desirable modification was obtained after 2 min and reached to the best performance at 60 min, and the optimum Sr addition amount was 0.04–0.06 wt%, and the good modification performance was kept even after 300 min. However, when the Al–10Sr alloy trapezoidal block was used, a desirable modification was started after 30 min and reached to the best performance as long as 120 min, and the optimum Sr addition amount was 0.06–0.08 wt%, and the effective modification period was only 180 min. Therefore, comparing with the Al–10Sr alloy trapezoidal block, the Al–10Sr alloy wire had better modification efficiency, which not only reduced the Sr addition amount of about 30%, but also greatly decreased the incubation time and improved the ability of anti-fading.

  9. Examining the performance of refractory conductive ceramics as plasmonic materials: a theoretical approach

    OpenAIRE

    Kumar, Mukesh; Umezawa, Naoto; Ishii, Satoshi; Nagao, Tadaaki

    2015-01-01

    The main aim of this study is to scrutinize promising plasmonic materials by understanding their electronic structure and correlating them to the optical properties of selected refractory materials. For this purpose, the electronic and optical properties of the conductive ceramics TiC, ZrC, HfC, TaC, WC, TiN, ZrN, HfN, TaN, and WN are studied systematically by means of first-principles density functional theory. A full ab initio procedure to calculate plasma frequency from the electronic band...

  10. Effect of Microstructure on the Performance of Corrosion Resistant Alloys

    OpenAIRE

    Kishan Roodbari, Marzieh

    2015-01-01

    Corrosion by pitting in aluminum alloys is a very complex process that can be affected by various factors such as chemical composition and microstructure of the alloys. The electrochemistry and distribution of second phases populating the alloy are the main factors that significantly influence the corrosion of aluminum alloys. The purpose of the present work is to contribute to a deeper understanding of how the chemical composition and microstructure affect the ability of an al...

  11. Dynamic Testing of Gasifier Refractory

    Energy Technology Data Exchange (ETDEWEB)

    Michael D. Mann; Wayne S. Seames; Devdutt Shukla; Xi Hong; John P. Hurley

    2005-12-01

    The University of North Dakota (UND) Chemical Engineering Department in conjunction with the UND Energy & Environmental Research Center (EERC) have initiated a program to examine the combined chemical (reaction and phase change) and physical (erosion) effects experienced by refractory materials under slagging coal gasification conditions. The goal of this work is to devise a mechanism of refractory loss under these conditions. The controlled-atmospheric dynamic corrodent application furnace (CADCAF) was utilized to simulate refractory/slag interactions under dynamic conditions that more realistically simulate the environment in a slagging coal gasifier than any of the static tests used previously by refractory manufacturers and researchers. High-alumina and high-chromia refractory bricks were tested using slags obtained from two solid fuel gasifiers. Testing was performed at 1475 C in a reducing atmosphere (2% H{sub 2} in N{sub 2}) The CADCAF tests show that high-chrome refractories have greater corrosion resistance than high-aluminum refractories; coal slag readily diffuses into the refractory through its grain boundaries; the refractory grains are more stable than the matrix in the tests, and the grains are the first line of defense against corrosion; calcium and alkali in the slag are more corrosive than iron; and silicon and calcium penetrate the deepest into the refractory. The results obtained from this study are preliminary and should be combined with result from other research programs. In particular, the refractory corrosion results from this study should be compared with refractories removed from commercial gasifiers.

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

    Institute of Scientific and Technical Information of China (English)

    Fabio Casciati; Lucia Faravelli; Karim Hamdaoui

    2007-01-01

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

  13. Refractory vasculitis

    NARCIS (Netherlands)

    Rutgers, Bram; Kallenberg, Cees G. M.

    2011-01-01

    Refractory vasculitis occurs in 4-5% of patients with anti-neutrophil cytoplasmic antibody associated vasculitis (AAV). Differences between therapies used for refractory disease are mostly reflected in the percentages of complete and partial remissions, but also in the number of serious side effects

  14. Refractory vasculitis

    NARCIS (Netherlands)

    Rutgers, Bram; Kallenberg, Cees G. M.

    Refractory vasculitis occurs in 4-5% of patients with anti-neutrophil cytoplasmic antibody associated vasculitis (AAV). Differences between therapies used for refractory disease are mostly reflected in the percentages of complete and partial remissions, but also in the number of serious side

  15. Concretos de alto desempenho: um novo conceito em refratários A new concept in refractories: high performance castables

    Directory of Open Access Journals (Sweden)

    R. G. Pileggi

    2002-03-01

    Full Text Available A história recente da indústria de refratários tem sido caracterizada pela contínua evolução dos concretos. Atualmente, são comuns os auto-escoantes, os bombeáveis, os de projeção, além dos tradicionais vibráveis, entre outros. Contudo, a classe reológica de um concreto define sua distribuição granulométrica, a qual também é responsável pelo comportamento de mistura, velocidade de secagem, consumo de água, fluência do material, etc. O presente trabalho teve como objetivo desenvolver um novo tipo de concreto, denominado de Alto Desempenho, o qual alia fácil mistura, fluidez elevada com baixo consumo de água, alta velocidade de secagem e reduzida deformação por fluência. As formulações estudadas foram projetadas no software PSDesigner, sendo misturadas e avaliadas em um reômetro para concretos. Os resultados demonstram que determinadas composições, baseadas no modelo de Andreasen com q = 0,26, resultam em concretos de alto desempenho.The recent history of refractory industry has been characterized by a continuous evolution in castables' technology. Nowadays, self-flowing, pumpable and shotcreting castables usually replace the traditional vibrated materials. However, the rheological specification of a castable determines its particle size distribution characteristics, what directly influences its mixing behavior, water consumption, creep rate, drying speed, etc. The present work describes the development of a new class of refractory named as high-performance castable. This kind of material simultaneously combines easy mixing behavior, high fluidity, low water content, superior drying speed and low creep rate. In order to develop this material, distinct particle size distributions were formulated using PSDesigner software and experiments were performed to evaluate the high-performance specified properties. The mixing behavior, the rheology, and the water consumption were measured in a rheometer for refractory castables

  16. High-Strength Low-Alloy (HSLA) Mg-Zn-Ca Alloys with Excellent Biodegradation Performance

    Science.gov (United States)

    Hofstetter, J.; Becker, M.; Martinelli, E.; Weinberg, A. M.; Mingler, B.; Kilian, H.; Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-04-01

    This article deals with the development of fine-grained high-strength low-alloy (HSLA) magnesium alloys intended for use as biodegradable implant material. The alloys contain solely low amounts of Zn and Ca as alloying elements. We illustrate the development path starting from the high-Zn-containing ZX50 (MgZn5Ca0.25) alloy with conventional purity, to an ultrahigh-purity ZX50 modification, and further to the ultrahigh-purity Zn-lean alloy ZX10 (MgZn1Ca0.3). It is shown that alloys with high Zn-content are prone to biocorrosion in various environments, most probably because of the presence of the intermetallic phase Mg6Zn3Ca2. A reduction of the Zn content results in (Mg,Zn)2Ca phase formation. This phase is less noble than the Mg-matrix and therefore, in contrast to Mg6Zn3Ca2, does not act as cathodic site. A fine-grained microstructure is achieved by the controlled formation of fine and homogeneously distributed (Mg,Zn)2Ca precipitates, which influence dynamic recrystallization and grain growth during hot forming. Such design scheme is comparable to that of HSLA steels, where low amounts of alloying elements are intended to produce a very fine dispersion of particles to increase the material's strength by refining the grain size. Consequently our new, ultrapure ZX10 alloy exhibits high strength (yield strength R p = 240 MPa, ultimate tensile strength R m = 255 MPa) and simultaneously high ductility (elongation to fracture A = 27%), as well as low mechanical anisotropy. Because of the anodic nature of the (Mg,Zn)2Ca particles used in the HSLA concept, the in vivo degradation in a rat femur implantation study is very slow and homogeneous without clinically observable hydrogen evolution, making the ZX10 alloy a promising material for biodegradable implants.

  17. Surface analysis, hydrogen adsorption and electrochemical performance of alkali-reduce treated hydrogen storage alloy

    Institute of Scientific and Technical Information of China (English)

    陈卫祥; 徐铸德; 涂江平; 李海洋; 陈石; 袁俊; 鲍世宁

    2002-01-01

    The hydrogen storage alloy powders (MlNi4.0Co0.6Al0.4, Ml=rich-La mischmetal) were treated in a hot 6mol/L KOH+0.02mol/L KBH4 solution, the surface compositions and chemical states of the treated and untreated alloys were analyzed by XPS and EDX, the hydrogen adsorption on the surface of these alloys was evaluated by thermal desorption spectroscopy (TDS), the effects of the surface treatment on the electrochemical performances of the alloy electrodes were investigated. The results show that the hydrogen adsorption is greatly strengthened by the surface modification, and hence leads to marked improvement in the electrocatalytic activity, the treated alloy exhibits higher exchange current density and lower apparent activation energy for the hydrogen electrode reaction than the untreated alloy.

  18. Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part II corrosion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    Surface treatment of aluminium alloys using steam with oxidative chemistries, namely KMnO4 and HNO3 resulted in accelerated growth of oxide on aluminium alloys. Detailed investigation of the corrosion performance of the treated surfaces was carried out using potentiodynamic polarisation...

  19. Performance evaluation of several commercial alloys in a reducing environment

    Science.gov (United States)

    Liu, Y.

    Several commercial alloys including Ebrite, Crofer 22 APU, Haynes 230 and Haynes 242, which are candidates for intermediate-temperature solid oxide fuel cell (SOFC) interconnect materials, were isothermally and cyclically oxidized at 900 °C in the reducing atmosphere of Ar + 5 vol.% H 2 + 3 vol.% H 2O corresponding to the SOFC anode environment. Results indicate that these alloys exhibited good scale spallation resistance with the Ni-base alloys possessing better oxidation resistance over the Fe-base alloys. Both Mn-Cr spinel and Cr 2O 3 were formed in the oxide scales of these alloys. For Crofer 22 APU and Haynes 242, a continuous protective MnO and Mn-Cr spinel layer formed outside on the inner layer of Cr 2O 3. The increase in scale ASR after longer-term thermal exposure in the reducing environment was relatively slower for the Ni-base alloys than for the Fe-base alloys.

  20. Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe)-Gallium (Ga) Alloy

    Science.gov (United States)

    2013-09-01

    Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe)-Gallium (Ga) Alloy by Andrew James Murray and Dr. JinHyeong Yoo...Aberdeen Proving Ground, MD 21005 ARL-TN-0566 September 2013 Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe... Magnetostrictive Shunt Damper Performance Using Iron (Fe)- Gallium (Ga) Alloy 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  1. Refractories Utilizability for Slagging Gasifiers

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Slagging coal gasification process became a highlight of coal chemical industry in China during the last decade. Refractory lining's life of slagging gasifiers is one of the most critical factors for a cost -effective operation. The paper introduces current status of coal gasification in China, lining structure of slagging gasifiers and performance of refractory lining. It also summarizes the major factors impacting on refractory wear in slagging coal gasifiers in four Chinese chemical plants, based on ten years of industrial experience. The utilizability is discussed in terms of cost -effectiveness of high chromia refractories and possibility of the alternatives.

  2. Research and Application of New Type of High Performance Titanium Alloy

    Directory of Open Access Journals (Sweden)

    ZHU Zhishou

    2016-06-01

    Full Text Available With the continuous extension of the application quantity and range for titanium alloy in the fields of national aviation, space, weaponry, marine and chemical industry, etc., even more critical requirements to the comprehensive mechanical properties, low cost and process technological properties of titanium alloy have been raised. Through the alloying based on the microstructure parameters design, and the comprehensive strengthening and toughening technologies of fine grain strengthening, phase transformation and process control of high toughening, the new type of high performance titanium alloy which has good comprehensive properties of high strength and toughness, anti-fatigue, failure resistance and anti-impact has been researched and manufactured. The new titanium alloy has extended the application quantity and application level in the high end field, realized the industrial upgrading and reforming, and met the application requirements of next generation equipment.

  3. Electrochemical comparison and biological performance of a new CoCrNbMoZr alloy with commercial CoCrMo alloy

    Energy Technology Data Exchange (ETDEWEB)

    Andrei, M. [Department of General Chemistry, University Politehnica Bucharest, Spl. Independentei 313, 060042 Bucharest (Romania); Galateanu, B. [Department of Biochemistry and Molecular Biology, University of Bucharest, 91–95 Spl. Independentei, Bucharest 050095 (Romania); Institute of Life Sciences, Vasile Goldis Western University of Arad, 86 Rebreanu, 310414 Arad (Romania); Hudita, A. [Department of General Chemistry, University Politehnica Bucharest, Spl. Independentei 313, 060042 Bucharest (Romania); Costache, M. [Department of Biochemistry and Molecular Biology, University of Bucharest, 91–95 Spl. Independentei, Bucharest 050095 (Romania); Osiceanu, P.; Calderon Moreno, J.M. [Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Drob, S.I., E-mail: sidrob@chimfiz.icf.ro [Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Demetrescu, I. [Department of General Chemistry, University Politehnica Bucharest, Spl. Independentei 313, 060042 Bucharest (Romania)

    2016-02-01

    A new CoCrNbMoZr alloy, with Nb and Zr content is characterized from the point of view of surface features, corrosion resistance and biological performance in order to be proposed as dental restorative material. Its properties are discussed in comparison with commercial Heraenium CE alloy based on Co, Cr and Mo as well. The microstructure of both alloys was revealed by scanning electron microscopy (SEM). The composition and thickness of the alloy native passive films were identified by X-ray photoelectron spectroscopy (XPS). The surface characteristics were analyzed by atomic force microscopy (AFM) and contact angle techniques. The quantity of ions released from alloys in artificial saliva was evaluated with inductively coupled plasma-mass spectroscopy (ICP-MS) measurements. The electrochemical stability was studied in artificial Carter–Brugirard saliva, performing open circuit potentials, polarization resistances and corrosion currents and rates. The biological performance of the new alloy was tested in vitro in terms of human adipose stem cells (hASCs) morphology, viability and proliferation status. The new alloy is very resistant to the attack of the aggressive ions from the artificial saliva. The surface properties, the roughness and wettabiliy sustain the cell behavior. The comparison of the new alloy behavior with that of existing commercial CoCrMo alloy showed the superior properties of the new metallic biomaterial. - Highlights: • SEM evinced finer microstructure of new CoCrNbMoZr alloy comparing with commercial one. • XPS data showed a thicker, more resistant native passive film on new alloy surface. • Ion release is very low for the new alloy proving its very high stability. • New alloy exhibits very good corrosion resistance in artificial Carter–Brugirard saliva • CoCrNbMoZr revealed an increased overall biocompatibility as compared with Heraenium CE.

  4. Alloy

    Science.gov (United States)

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2014-07-01

    The Mg98.5Gd1Zn0.5 alloy produced by a powder metallurgy route was studied and compared with the same alloy produced by extrusion of ingots. Atomized powders were cold compacted and extruded at 623 K and 673 K (350 °C and 400 °C). The microstructure of extruded materials was characterized by α-Mg grains, and Mg3Gd and 14H-LPSO particles located at grain boundaries. Grain size decreased from 6.8 μm in the extruded ingot, down to 1.6 μm for powders extruded at 623 K (350 °C). Grain refinement resulted in an increase in mechanical properties at room and high temperatures. Moreover, at high temperatures the PM alloy showed superplasticity at high strain rates, with elongations to failure up to 700 pct.

  5. Electrochemical performance of La-Co-Sn alloys as anode materials for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.; Gao, X.P. [Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071 (China); Lu, Z.W. [Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071 (China); Tianjin Institute of Power Sources, Tianjin 300381 (China); Liu, X.J.; Wang, J.Q. [Tianjin Institute of Power Sources, Tianjin 300381 (China)

    2009-04-01

    Sn-rich La-Co-Sn ternary alloys were obtained by arc-melting process and subsequent ball-milling. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the structure and morphology of the obtained alloys. In addition, the galvanostatic discharge/charge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out to characterize the electrochemical properties of these alloys as anode materials for Li-ion batteries. It is found that all the as-cast La-Co-Sn ternary alloys have the same main phase of La{sub 3}Co{sub 4}Sn{sub 13} and low electrochemical capacities. Among these alloys, the as-cast LaCoSn{sub 4} alloy exhibits the best electrochemical performance. The ball-milling process results in the reduced cystallinity, and the enhanced electrochemical capacities as compared to the as-cast alloy. In particular, the LaCoSn{sub 4} alloy, obtained after ball-milling for 16 h, provides the higher reversible discharge capacity and the better cycle stability. (author)

  6. Design, construction, and performance of a device for directional recrystallization of metallic alloys.

    Science.gov (United States)

    Vallejos, J M; Leonard, M E; Sobrero, C E; La Roca, P M; Druker, A V; Malarria, J A

    2017-02-01

    A device was designed to apply the directional recrystallization method to Fe-based alloys in order to obtain bamboo-like microstructures. This microstructure is suitable for improving creep properties and resistance to fatigue in some alloys and for enhancing pseudoelastic properties in shape memory alloys. The design and construction of a flat coil are described in detail. In addition, we developed an electromechanical system to control the movement of a wire within the flat coil. The construction details and system performance are presented. Furthermore, metallographic studies taken from the directionally recrystallized low-carbon steel samples are shown. Nearly monocrystalline and bamboo-like microstructures were achieved in the steel wires.

  7. Design, construction, and performance of a device for directional recrystallization of metallic alloys

    Science.gov (United States)

    Vallejos, J. M.; Leonard, M. E.; Sobrero, C. E.; La Roca, P. M.; Druker, A. V.; Malarria, J. A.

    2017-02-01

    A device was designed to apply the directional recrystallization method to Fe-based alloys in order to obtain bamboo-like microstructures. This microstructure is suitable for improving creep properties and resistance to fatigue in some alloys and for enhancing pseudoelastic properties in shape memory alloys. The design and construction of a flat coil are described in detail. In addition, we developed an electromechanical system to control the movement of a wire within the flat coil. The construction details and system performance are presented. Furthermore, metallographic studies taken from the directionally recrystallized low-carbon steel samples are shown. Nearly monocrystalline and bamboo-like microstructures were achieved in the steel wires.

  8. Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part II corrosion performance

    Science.gov (United States)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-11-01

    Surface treatment of aluminium alloys using steam with oxidative chemistries, namely KMnO4 and HNO3 resulted in accelerated growth of oxide on aluminium alloys. Detailed investigation of the corrosion performance of the treated surfaces was carried out using potentiodynamic polarisation and standard industrial test methods such as acetic acid salt spray (AASS) and filiform corrosion on commercial AA6060 alloy. Barrier properties of the film including adhesion were evaluated using tape test under wet and dry conditions. Electrochemical results showed reduced cathodic and anodic activity, while the protection provided by steam treatment with HNO3 was a function of the concentration of NO3- ions. The coating generated by inclusion of KMnO4 showed highest resistance to filiform corrosion. Overall, the performance of the steam treated surfaces under filiform corrosion and AASS test was a result of the local coverage of the alloy microstructure resulting from steam containing with KMnO4 and HNO3.

  9. Corrosion performance of Fe-Cr-Al and Fe aluminide alloys in complex gas environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Lab., IL (United States); Johnson, R.N. [Pacific Northwest Lab., Richland, WA (United States)

    1995-05-01

    Alumina-forming structural alloys can offer superior resistance to corrosion in the presence of sulfur-containing environments, which are prevalent in coal-fired fossil energy systems. Further, Fe aluminides are being developed for use as structural materials and/or cladding alloys in these systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve their engineering ductility. In addition, surface coatings of Fe aluminide are being developed to impart corrosion resistance to structural alloys. This paper describes results from an ongoing program that is evaluating the corrosion performance of alumina-forming structural alloys, Fe-Al and Fe aluminide bulk alloys, and Fe aluminide coatings in environments typical of coal-gasification and combustion atmospheres. Experiments were conducted at 650-1000{degrees}C in simulated oxygen/sulfur gas mixtures. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HCl-containing gases. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales and to determine the modes of corrosion degradation that occur in the materials when they are exposed to S/Cl-containing gaseous environments.

  10. Study on High Rate Discharge Performance and Mechanism of AB5 Type Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    郭靖洪; 陈德敏; 于军; 张建海; 刘国忠; 杨柯

    2004-01-01

    The effects of surface treatment, particle size distribution,rare earth composition and B additive on the high rate discharge performance of hydrogen storage alloys were investigated. It is found that the activity, discharge capacity and high rate dischargeability of the alloys are improved after physical and chemical modification as a result of the increase of the surface area and formation of the electrocatalysis layers, which increase both the electrochemical reaction rate on the alloy surface and H diffusion rate in the alloy bulk. It is also found that both the over-coarse and over-fine particle size increase the contact resistance of the electrode, resulting in a decrease of discharge capacity, deterioration of high rate dischargeability and lower discharge plateau. In another word, a suitable particle size distribution can enhance the alloy activity, discharge capacity and high rate dischargeability. In addition, the high rate dischargeability is enhanced by increasing La content and decreasing Ce content of the alloy composition because of enlargement of the unit cell volume and the improvement of the surface activity. Moreover, B additive resultes in the formation of the second phase, and makes the alloys easier pulverization, which greatly improves the activity, discharge capacity and high rate dischargeability.

  11. Selection of High Performance Alloy for Gas Turbine Blade Using Multiphysics Analysis

    Directory of Open Access Journals (Sweden)

    H Khawaja

    2016-09-01

    Full Text Available With the extensive increase in the utilization of energy resources in the modern era, the need of energy extraction from various resources has pronounced in recent years. Thus comprehensive efforts have been made around the globe in the technological development of turbo machines where means of energy extraction is energized fluids. This development led the aviation industry to power boost due to better performing engines. Meanwhile, the structural conformability requirements relative to the functional requirements have also increased with the advent of newer, better performing materials. Thus there is a need to study the material behavior and its usage with the idea of selecting the best possible material for its application. In this work a gas turbine blade of a small turbofan engine, where geometry and aerodynamic data was available, was analyzed for its structural behavior in the proposed mission envelope, where the engine turbine is subjected to high thermal, inertial and aerodynamic loads. Multiphysics Finite Element (FE linear stress analysis was carried out on the turbine blade. The results revealed the upper limit of Ultimate Tensile Strength (UTS for the blade. Based on the limiting factor, high performance alloys were selected from the literature. The two most recommended alloy categories for gas turbine blades are NIMONIC and INCONEL from where total of 21 types of INCONEL alloys and 12 of NIMONIC alloys, available on commercial bases, were analyzed individually to meet the structural requirements. After applying selection criteria, four alloys were finalized from NIMONIC and INCONEL alloys for further analysis. On the basis of stress-strain behavior of finalized alloys, the Multiphysics FE nonlinear stress analysis was then carried out for the selection of the individual alloy by imposing a restriction of Ultimate Factor of Safety (UFOS of 1.33 and yield strength. Final selection is made keeping in view other factors

  12. Optimising homing endonuclease gene drive performance in a semi-refractory species: the Drosophila melanogaster experience.

    Directory of Open Access Journals (Sweden)

    Yuk-Sang Chan

    Full Text Available Homing endonuclease gene (HEG drive is a promising insect population control technique that employs meganucleases to impair the fitness of pest populations. Our previous studies showed that HEG drive was more difficult to achieve in Drosophila melanogaster than Anopheles gambiae and we therefore investigated ways of improving homing performance in Drosophila. We show that homing in Drosophila responds to increased expression of HEGs specifically during the spermatogonia stage and this could be achieved through improved construct design. We found that 3'-UTR choice was important to maximise expression levels, with HEG activity increasing as we employed Hsp70, SV40, vasa and βTub56D derived UTRs. We also searched for spermatogonium-specific promoters and found that the Rcd-1r promoter was able to drive specific expression at this stage. Since Rcd-1 is a regulator of differentiation in other species, it suggests that Rcd-1r may serve a similar role during spermatogonial differentiation in Drosophila. Contrary to expectations, a fragment containing the entire region between the TBPH gene and the bgcn translational start drove strong HEG expression only during late spermatogenesis rather than in the germline stem cells and spermatogonia as expected. We also observed that the fraction of targets undergoing homing was temperature-sensitive, falling nearly four-fold when the temperature was lowered to 18°C. Taken together, this study demonstrates how a few simple measures can lead to substantial improvements in the HEG-based gene drive strategy and reinforce the idea that the HEG approach may be widely applicable to a variety of insect control programs.

  13. Biodegradable Orthopedic Magnesium-Calcium (MgCa Alloys, Processing, and Corrosion Performance

    Directory of Open Access Journals (Sweden)

    Yuebin Guo

    2012-01-01

    Full Text Available Magnesium-Calcium (Mg-Ca alloy has received considerable attention as an emerging biodegradable implant material in orthopedic fixation applications. The biodegradable Mg-Ca alloys avoid stress shielding and secondary surgery inherent with permanent metallic implant materials. They also provide sufficient mechanical strength in load carrying applications as opposed to biopolymers. However, the key issue facing a biodegradable Mg-Ca implant is the fast corrosion in the human body environment. The ability to adjust degradation rate of Mg-Ca alloys is critical for the successful development of biodegradable orthopedic implants. This paper focuses on the functions and requirements of bone implants and critical issues of current implant biomaterials. Microstructures and mechanical properties of Mg-Ca alloys, and the unique properties of novel magnesium-calcium implant materials have been reviewed. Various manufacturing techniques to process Mg-Ca based alloys have been analyzed regarding their impacts on implant performance. Corrosion performance of Mg-Ca alloys processed by different manufacturing techniques was compared. In addition, the societal and economical impacts of developing biodegradable orthopedic implants have been emphasized.

  14. Corrosion Performance of Zinc and Zinc-cobalt Alloy Compositionally Modulated Multilayer (CMM) Coatings

    Institute of Scientific and Technical Information of China (English)

    FEI Jingyin; LIANG Guozheng; XIN Wenli; LIU Jianghong

    2006-01-01

    Varieties of zinc and Zn-Co alloy compositionally modulated multilayer (CMM) coatings were electrodeposited onto steel substrates using dual bath technique. The surface and cross-sectional morphologies of coated samples were examined using scanning electron microscopy ( SEM ). The existence of internal stress in ZnCo alloy deposits was corfirmed by the cross-sectional morphologies for the occurrence of micro-cracks in the thick Zn-Co alloy deposit alone. The corrosion performance was evaluated using neutral salt spray testing, corrosion potential measurement and anodic polarization methods. The experimental results show that the zinc and Zn- Co alloy CMM coatings were more corrosion-resistant than the monolithic coatings of zinc or Zn-Co alloy alone with a similar thickness. The analysis on the micrographic features of zinc and Zn- Co alloy CMM coatings, using field emission gun scanning electron microscopy (FEGSEM) after corrosion testing, explains the probable reasons why the Zn-Co/ Zn CMM coating system has a better protective performance.

  15. Refractories for Industrial Processing. Opportunities for Improved Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hayden, H. Wayne [Metals Manufacture Process and Controls Technology, Inc., Oak Ridge, TN (United States); Angelini, Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moore, Robert E. [R.E. Moore Associates, Maricopa, AZ (United States); Headrick, William L. [R.E. Moore Associates, Maricopa, AZ (United States)

    2005-01-01

    Refractories are a class of materials of critical importance to manufacturing industries with high-temperature unit processes. This study describes industrial refractory applications and identifies refractory performance barriers to energy efficiency for processing. The report provides recommendations for R&D pathways leading to improved refractories for energy-efficient manufacturing and processing.

  16. Database on Performance of Neutron Irradiated FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States); Littrell, Ken [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    The present report summarizes and discusses the database on radiation tolerance for Generation I, Generation II, and commercial FeCrAl alloys. This database has been built upon mechanical testing and microstructural characterization on selected alloys irradiated within the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) up to doses of 13.8 dpa at temperatures ranging from 200°C to 550°C. The structure and performance of these irradiated alloys were characterized using advanced microstructural characterization techniques and mechanical testing. The primary objective of developing this database is to enhance the rapid development of a mechanistic understanding on the radiation tolerance of FeCrAl alloys, thereby enabling informed decisions on the optimization of composition and microstructure of FeCrAl alloys for application as an accident tolerant fuel (ATF) cladding. This report is structured to provide a brief summary of critical results related to the database on radiation tolerance of FeCrAl alloys.

  17. Corrosion Performance of Fe-Based Alloys in Simulated Oxy-Fuel Environment

    Science.gov (United States)

    Zeng, Zuotao; Natesan, Ken; Cai, Zhonghou; Rink, David L.

    2017-02-01

    The long-term corrosion of Fe-based alloys in simulated oxy-fuel environment at 1023 K (750 °C) was studied. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of the corrosion products, and the cracking of scales for the alloys after exposure at 1023 K (750 °C) for up to 3600 hours. An incubation period during which the corrosion rate was low was observed for the alloys. After the incubation period, the corrosion accelerated, and the corrosion process followed linear kinetics. Effects of alloy, CaO-containing ash, and gas composition on the corrosion rate were also studied. In addition, synchrotron nanobeam X-ray analysis was employed to determine the phase and chemical composition of the oxide layers on the alloy surface. Results from these studies are being used to address the long-term corrosion performance of Fe-based alloys in various coal-ash combustion environments and to develop methods to mitigate high-temperature ash corrosion.

  18. Influence of Mg and Ti on the microstructure and electrochemical performance of aluminum alloy sacrificial anodes

    Institute of Scientific and Technical Information of China (English)

    MA Jingling; WEN Jiuba; LI Xudong; ZHAO Shengli; YAN Yanfu

    2009-01-01

    The experiments focused on the influence of magnesium and titanium as additional alloying elements on the microstructure and electro-chemical behavior of Al-Zn-ln sacrificial anodes. The electrochemical behavior of the aluminum sacrificial anode with 3 wt.% sodium chlo-fide solution was studied by electrochemical impedance spectroscopy (EIS) tests. It was found that a microstructure with few precipitates and refined grains could be achieved by adding 1 wt.% Mg and 0.05 wt.% Ti to the Al-Zn-In alloy, resulting in the improved current capacity and efficiency of the alloy. The equivalent circuit based on the EIS experimental data revealed less corrosion and lower adsorbed corrosion pro-duction on the surface of the aluminum alloy with a combination of 1 wt.% Mg and 0.05 wt.% Ti, which suggested that the corrosion behav-ior seemed to be strongly related to the presence of precipitate particles in the aluminum alloy, and moderate amounts of precipitate particles could be beneficial to the electrochemical performance of the aluminum alloy sacrificial anode.

  19. Performance of V-4Cr-4Ti alloy exposed to the JFT-2M tokamak environment

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.R. E-mail: bob.johnson@gat.com; Trester, P.W.; Sengoku, S.; Ishiyama, S.; Fukaya, K.; Eto, M.; Oda, T.; Hirohata, Y.; Hino, T.; Tsai, H

    2000-12-01

    A long-term test has been conducted in the JFT-2M tokamak fusion device to determine the effects of environmental exposure on the mechanical and chemical behavior of a V-4Cr-4Ti alloy. Test specimens of the alloy were exposed in the outward lower divertor chamber of JFT-2M in a region away from direct contact with the plasma and were preheated to 300 deg. C just prior to and during selected plasma discharges. During their nine-month residence time in JFT-2M, the specimens experienced approximately 200 lower-single-null divertor shots at 300 deg. C, during which high energy particle fluxes to the preheated test specimens were significant, and approximately 2010 upper-single-null divertor shots and non-divertor shots at room temperature, for which high energy particle fluxes to and expected particle retention in the test specimens were very low. Data from post-exposure tests have indicated that the performance of the V-4Cr-4Ti alloy would not be significantly affected by environmental exposure to gaseous species at partial pressures typical for tokamak operation. Deuterium retention in the exposed alloy was also low (<2 ppm). Absorption of interstitials by the alloy was limited to the very near surface, and neither the strength nor the Charpy impact properties of the alloy appeared to be significantly changed from the exposure to the JFT-2M tokamak environment.

  20. Performance of V-4Cr-4Ti Alloy Exposed to the JFT-2M Tokamak Environment

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.R.; Trester, P.W.; Sengoku, S.; Ishiyama, S.; Fukaya, K.; Eto, M.; Oda, T.; Hirohata, Y.; Hino, T.; Tsai, H.

    1999-10-01

    A long-term test has been conducted in the JFT-2M tokamak fusion device to determine the effects of environmental exposure on the mechanical and chemical behavior of a V-4Cr-4Ti alloy. Test specimens of the alloy were exposed in the outward lower divertor chamber of JFT-2M in a region away from direct contact with the plasma and were preheated to 300 C just prior to and during selected plasma discharges. During their nine-month residence time in JFT-2M, the specimens experienced approximately 200 lower single-null divertor shots at 300 C, during which high energy particle fluxes to the preheated test specimens were significant, and approximately 2,010 upper single-null divertor shots and non-diverter shots at room temperature, for which high energy particle fluxes to and expected particle retention in the test specimens were very low. Data from post-exposure tests have indicated that the performance of the V-4Cr-4Ti alloy would not be significantly affected by environmental exposure to gaseous species at partial pressures typical for tokamak operation. Deuterium retention in the exposed alloy was also low (<2 ppm). Absorption of interstitial by the alloy was limited to the very near surface, and neither the strength nor the Charpy impact properties of the alloy appeared to be significantly changed from the exposure to the JFT-2M tokamak environment.

  1. Corrosion Performance of Fe-Based Alloys in Simulated Oxy-Fuel Environment

    Science.gov (United States)

    Zeng, Zuotao; Natesan, Ken; Cai, Zhonghou; Rink, David L.

    2016-09-01

    The long-term corrosion of Fe-based alloys in simulated oxy-fuel environment at 1023 K (750 °C) was studied. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of the corrosion products, and the cracking of scales for the alloys after exposure at 1023 K (750 °C) for up to 3600 hours. An incubation period during which the corrosion rate was low was observed for the alloys. After the incubation period, the corrosion accelerated, and the corrosion process followed linear kinetics. Effects of alloy, CaO-containing ash, and gas composition on the corrosion rate were also studied. In addition, synchrotron nanobeam X-ray analysis was employed to determine the phase and chemical composition of the oxide layers on the alloy surface. Results from these studies are being used to address the long-term corrosion performance of Fe-based alloys in various coal-ash combustion environments and to develop methods to mitigate high-temperature ash corrosion.

  2. Electrochemical performance of alloys Ho_5Fe_3Co_(12) and Ho_(33.3)Co_(66.7)

    Institute of Scientific and Technical Information of China (English)

    赵允红; 何维; 张永志; 曾令民

    2010-01-01

    Alloys with composition Ho5Fe3Co12 and Ho33.3Co66.7 were prepared and examined by X-ray diffractometer and automatic battery testing instrument. The electrochemical properties of these alloys such as discharge capacity, cycling performance and high rate dischargeability were investigated by battery testing instruments in alkaline electrolyte. A comparison of the electrochemical performance of the Ho5Fe3Co12 and Ho33.3Co66.7 alloys revealed that alloy Ho5Fe3Co12 possessed a better electrochemical performance...

  3. Effect of Cerium on Microstructure and Electrochemical Performance of Ti-V-Cr-Ni Electrode Alloy

    Institute of Scientific and Technical Information of China (English)

    Qiao Yuqing; Zhao Minshou; Zhu Xinjian; Cao Guangyi

    2007-01-01

    Effect of cerium on the microstructure and electrochemical performance of the Ti0.25V0.35-xCexCr0.1Ni0.3 (x=0, 0.005) electrode alloy was investigated by X-ray diffraction (XRD), field emission scanning electron microscopy/energy dispersive X-ray spectrometry (FESEM-EDS), and electrochemical impedance spectroscopy (EIS) measurements. On the basis of XRD and FESEM-EDS analysis, the alloy was mainly composed of V-based solid solution with body-centered-cubic structure and TiNi-based secondary phase. Ce did not exist in two phases, instead, it existed as Ce-rich small white particles, with irregular edges, distributed near the grain boundaries of the V-based solid solution phase. Discharge capacity, cycle stability, and high-rate discharge ability of the alloy electrode were effectively improved with the addition of Ce at 293 K. It was very surprising that the charge retention was abnormal with larger discharge capacity after standing at the open circuit for 24 h. EIS indicated that addition of Ce improved the dynamic performance, which caused the charge transfer resistance (RT) to decrease and exchange current density (I0) to increase markedly. The exchange current density of the electrochemical reaction on the alloy surface with Ce addition was about 2.07 and 3.10 times larger than that of the alloy without Ce at 303 and 343 K, respectively. The diffusion coefficient of hydrogen (D) in the bulk alloy electrode decreased with addition of Ce, but it did not decrease so much, and the apparent activation energy (△rH) was far higher than that of the AB5 type alloy.

  4. Electrochemical Performance Estimation of Anodized AZ31B Magnesium Alloy as Function of Change in the Current Density

    Science.gov (United States)

    Girón, L.; Aperador, W.; Tirado, L.; Franco, F.; Caicedo, J. C.

    2017-08-01

    The anodized AZ31B magnesium alloys were synthesized via electrodeposition processes. The aim of this work was to determine the electrochemical behavior of magnesium alloys by using anodized alloys as a protective coating. The anodized alloys were characterized by x-ray diffraction, exhibiting the crystallography orientation for Mg and MgO phases. The x-ray photoelectron spectroscopy was used to determine the chemical composition of anodized magnesium alloys. By using electrochemical impedance spectroscopy and Tafel curves, it was possible to estimate the electrochemical behavior of anodized AZ31B magnesium alloys in Hank's balanced salt solution (HBSS). Scanning electron microscopy was performed to analyze chemical changes and morphological surface changes on anodized Mg alloys due to the reaction in HBSS/anodized magnesium surface interface. Electrochemical behavior in HBSS indicates that the coatings may be a promising material for biomedical industry.

  5. Oxidation Behavior of a Refractory NbCrMo0.5Ta0.5TiZr Alloy (Preprint)

    Science.gov (United States)

    2012-03-01

    smaller than the atomic radii of other elements in the fourth alloy, causes additional formation of a minor FCC Laves phase [10]. Due to strongly...pattern of the HIPd NbCrMo0.5Ta0.5TiZr alloy. A major BCC1 phase and two minor phases , BCC2 and FCC ( Laves ), were identified [10]. The lattice parameters...parallel to the sample surface develop in the regions of former BCC2 and Laves phases (between former BCC1 particles). The cracks are also extended

  6. Fracture performance of high strength steels, aluminium and magnesium alloys during plastic deformation

    Directory of Open Access Journals (Sweden)

    Yu Haiyan

    2015-01-01

    Full Text Available A series of uniaxial tension tests were performed for 5052 and 6061 aluminum alloys, AZ31B magnesium alloy, TRIP600 and DP600 steels, to obtain a better understanding of their fracture performance. Scanning electron microscope (SEM observation of the microstructure evolution was conducted. The dimple structure, orientation relationship between the fracture surface and tensile direction, necking behavior were analyzed. The fracture mechanism and fracture mode of each material was discussed in detail. The results show that TRIP600 steel is subject to a typical inter-granular ductile fracture combined by shear fracture. DP600 steel belongs to mainly ductility mixed with normal fracture. Both 5052 and 6061 aluminum alloys are subject to a mixed ductility fracture and brittle fracture. AA5052 and AA6061 belong to a typical shear fracture and a normal fracture, respectively. Magnesium AZ31B is typical of a brittle fracture combined with normal fracture.

  7. Study on hydrogen evolution performance of the carbon supported PtRu alloy film electrodes

    Institute of Scientific and Technical Information of China (English)

    YANG; Bin; LI; Yang; ZAN; Lin-han

    2005-01-01

    The carbon supported PtRu alloy film electrodes having Pt about 0.10 mg/cm2 or even less were prepared by ion beam sputtering method (IBSM). It was valued on the hydrogen analyse performance, the temperature influence factor and the stability by electroanalysis hydrogen analyse method. It was found that the carbon supported PtRu alloy film electrodes had higher hydrogen evolution performance and stability, such as the hydrogen evolution exchange current density (j0) was increase as the temperature (T) rised, and it overrun 150 mA/cm2 as the trough voltage in about 0.68V, and it only had about 2.8% decline in 500 h electrolytic process. The results demonstrated that the carbon supported PtRu alloy film electrodes kept highly catalytic activity and stability, and it were successfully used in pilot plant for producing H2 on electrolysis of H2S.

  8. Chromia refractory brick with carbon treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, James P.; Kwong, Kyei-Sing

    2017-03-21

    The disclosure provides a refractory brick system comprising a chromia refractory brick for operation in the slagging environment of an air-cooled gasifier. The chromia refractory brick comprises a ceramically-bonded porous chromia refractory having a porosity greater than 9% and having carbon deposits residing within the pores. The brick may be further comprised of Al.sub.2O.sub.3. The air-cooled gasifier generates a liquefied slag in contact with the refractory brick and generally operates at temperatures between 1250.degree. C. and 1575.degree. C. and pressures between 300 psi to 1000 psi, with oxygen partial pressures generally between 10.sup.-4 and 10.sup.-10 atm. The refractory brick performs without substantial chromium carbide or chromium metal formation in the low oxygen partial pressure environment. The inclusion of carbon without chromium carbide formation provides for significant mitigation of slag penetration and significantly reduced refractory wear.

  9. Production of small diameter high-temperature-strength refractory metal wires

    Science.gov (United States)

    Petrasek, D. W.; Signorelli, R. A.; King, G. W.

    1973-01-01

    Special thermomechanical techniques (schedules) have been developed to produce small diameter wire from three refractory metal alloys: colombian base alloy, tantalum base alloy, and tungsten base alloy. High strengths of these wires indicate their potential for contributing increased strength to metallic composites.

  10. Fracture performance of computer-aided manufactured zirconia and alloy crowns

    NARCIS (Netherlands)

    Rosentritt, M.; Behr, M.; Thaller, C.; Rudolph, H.; Feilzer, A.J.

    2009-01-01

    Objective: To compare the fracture resistance and fracture performance of CAD/CAM zirconia and alloy crowns. Method and Materials: One electrophoretic deposition alumina ceramic (Wolceram, Wolceram) and 4 zirconia-based systems (ce.novation, ce.novation; Cercon, DeguDent; Digizon, Amann Girrbach; an

  11. Ultrahigh performance of Ti-based glassy alloy tube sensor for Coriolis mass flowmeter

    Institute of Scientific and Technical Information of China (English)

    MA Chao-li; A. INOUE; ZHANG Tao

    2006-01-01

    Bulk metallic glasses (BMGs) have potential applications for both structural and functional components owing to their good mechanical properties. With the aim of demonstrating great engineering value of BMGs, a direct melt-forming technique based on suction casting for the production of glassy alloy tubes was developed. The fabrication, structure, geometry, properties and sensor performance of the tubes were examined. The results show that the Coriolis mass flowmeters using the Ti-based glassy alloy sensor tube exhibit excellent measurement sensitivity, viz. 28.5 times higher than that of the conventional flowmeter manufactured using stainless steel (SUS316) tube.

  12. Pd-Pt Alloy with Coral-Like Nanostructures Showing High Performance for Oxygen Electrocatalytic Reduction.

    Science.gov (United States)

    Liu, Xing-Quan; Chen, Xue-Song; Wu, Jian; Yao, Lei

    2016-03-01

    Three-dimensional (3D) Pd-Pt alloy with coral-like nanostructures were synthesized via bubble dynamic templated electrodeposition method at room temperature. The morphology of the as-prepared nanostructures was characterized using scanning electron microscopy (SEM), EDS, high-resolution transmission electron microscopy (HRTEM), respectively. Cyclic voltammetry method was adopted to evaluate the electrocatalytic activities of the synthesized electrodes toward oxygen reduction in KCl solution. The electrochemical results indicated that the Pd-Pt alloy with coral-like nanostructures hold the high performance for oxygen reduction.

  13. Microstructure and magnetostrictive performance of NbC-dopedoriented Fe-Ga alloys

    Institute of Scientific and Technical Information of China (English)

    Xue-xu Gao

    2015-01-01

    Theoriented Fe83Ga17 alloy rods with various NbC contents less than 1at%were prepared by the directional solidification method at a growth rate of 720 mm⋅h−1. Low NbC-content was found to affect the oriented grain growth and slightly improve theori-entation. Flat grain boundaries in the alloys with low NbC contents less than 0.2at%became greatly curved at higher NbC contents, and a large amount of Nb-rich precipitates were observed in the alloys with high NbC contents. Small amounts of NbC, less than 0.2at%, resulted in an increase in magnetostrictive strain due to the improvement of theorientation, and a high magnetostrictive strain value of 335 × 10−6 under a pre-stress of 15 MPa was obtained in the 0.1at%NbC-doped alloys. The magnetostrictive performance obviously decreased with the NbC addition higher than 0.5at%, and the strain sensitivity under no pre-stress was lower than that in the binary Fe−Ga alloy.

  14. Effect of cooling rate on microstructure and compressive performance of AZ91 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; FENG Hui; QIU Ke-qiang; CHEN Li-jia; LIU Zheng

    2006-01-01

    Effect of cooling rate on both microstructure and room temperature compressive performance of the AZ91 magnesium alloy was investigated. The experimental results show that with increasing cooling rate, the quantity of the solid solution phase increases and the fraction of secondary phase Mg17Al12 decreases. The almost single solid solution phase can be obtained with using liquid nitrogen as a coolant. The compressive strengths of the rapid solidified AZ91 magnesium alloys are higher than those of normal cast alloy, and decrease with increasing cooling rate. After artificial aging treatment for 14 h at 168 ℃, the compressive strength of the rapidly solidified AZ91 magnesium alloy cooled in liquid nitrogen increases from 253.5 to 335.3 MPa, while the compressive yield strength increases from 138.1 to 225.91 MPa. The improvement in the compressive strength of the rapidly solidified AZ91magnesium alloys can be attributed to the hardening effect from fine secondary phase.

  15. Thermal storage/discharge performances of Cu-Si alloy for solar thermochemical process

    Science.gov (United States)

    Gokon, Nobuyuki; Yamaguchi, Tomoya; Cho, Hyun-seok; Bellan, Selvan; Hatamachi, Tsuyoshi; Kodama, Tatsuya

    2017-06-01

    The present authors (Niigata University, Japan) have developed a tubular reactor system using novel "double-walled" reactor/receiver tubes with carbonate molten-salt thermal storage as a phase change material (PCM) for solar reforming of natural gas and with Al-Si alloy thermal storage as a PCM for solar air receiver to produce high-temperature air. For both of the cases, the high heat capacity and large latent heat (heat of solidification) of the PCM phase circumvents the rapid temperature change of the reactor/receiver tubes at high temperatures under variable and uncontinuous characteristics of solar radiation. In this study, we examined cyclic properties of thermal storage/discharge for Cu-Si alloy in air stream in order to evaluate a potentiality of Cu-Si alloy as a PCM thermal storage material. Temperature-increasing performances of Cu-Si alloy are measured during thermal storage (or heat-charge) mode and during cooling (or heat-discharge) mode. A oxidation state of the Cu-Si alloy after the cyclic reaction was evaluated by using electron probe micro analyzer (EPMA).

  16. Boundary Engineering for the Thermoelectric Performance of Bulk Alloys Based on Bismuth Telluride.

    Science.gov (United States)

    Mun, Hyeona; Choi, Soon-Mok; Lee, Kyu Hyoung; Kim, Sung Wng

    2015-07-20

    Thermoelectrics, which transports heat for refrigeration or converts heat into electricity directly, is a key technology for renewable energy harvesting and solid-state refrigeration. Despite its importance, the widespread use of thermoelectric devices is constrained because of the low efficiency of thermoelectric bulk alloys. However, boundary engineering has been demonstrated as one of the most effective ways to enhance the thermoelectric performance of conventional thermoelectric materials such as Bi2 Te3 , PbTe, and SiGe alloys because their thermal and electronic transport properties can be manipulated separately by this approach. We review our recent progress on the enhancement of the thermoelectric figure of merit through boundary engineering together with the processing technologies for boundary engineering developed most recently using Bi2 Te3 -based bulk alloys. A brief discussion of the principles and current status of boundary-engineered bulk alloys for the enhancement of the thermoelectric figure of merit is presented. We focus mainly on (1) the reduction of the thermal conductivity by grain boundary engineering and (2) the reduction of thermal conductivity without deterioration of the electrical conductivity by phase boundary engineering. We also discuss the next potential approach using two boundary engineering strategies for a breakthrough in the area of bulk thermoelectric alloys.

  17. Effect of coatings on oxidation resistance and mechanical performance of Ti60 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tang Zhaolin; Wang Fuhui; Wu Weitao [Academia Sinica, Shenyang, LN (China). Inst. of Corrosion and Protection of Metals; Wang Qingjiang; Li Dong [Institute of Metals Research, The Chinese Academy of Sciences, Shenyang 110015 (China)

    1998-10-31

    The effect of several sputtered coatings on oxidation resistance and mechanical performance of Ti60 alloy was investigated. Sputtered pure Al, Ti-36Al, Ni-16Cr-2.5Al(wt%) coatings and reactively-sputtered Al{sub 2}O{sub 3} film were effective in inhibiting the oxidation and oxygen-embrittlement of Ti60 alloy at 600-700 C, while Al{sub 2}O{sub 3} and TiAl coatings exhibited a better effect than Al and NiCrAl coatings from the point of view of coating-substrate compatibility. The tensile test after 100h exposure at 600 C in air also showed that Ti60 alloy with Al{sub 2}O{sub 3} and TiAl coatings exhibited a higher ductility than that with Al and NiCrAl coatings, which exhibited a good correlation with coating-substrate compatibility. (orig.) 17 refs.

  18. Effect of Multi-repair Welding on Fatigue Performance of Aluminum Alloy Profile Welded Joint

    Science.gov (United States)

    Diao, You-De; Shi, Chun-Yuan; Tian, Hong-Lei

    2016-05-01

    Aluminum alloy profile has been widely used in the manufacture of the rail vehicles. But it's necessary for the repair welding of the welded joints to be conducted because some defects exist in the weld such as porosity, inclusions and incomplete penetrations in the welding processes. In this paper, the influence of the multi-repair welding of 6005A aluminum alloy profile butt welded joints on the fatigue performance are investigated based on the results of fatigue tests. The parameters of curves and the fatigue strength of the welded joints are calculated, and Goodman fatigue limit diagram is also obtained. The results show that fatigue strength of aluminum alloy profile butt welded joints, in condition of 107 cycle life, meet the standard requirement for the as-welded, repair welded state one time or two times respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

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

  1. Mechanical Properties of Low-Density, Refractory Multi-Principal Element Alloys of the Cr-Nb-Ti-V-Zr System (Postprint)

    Science.gov (United States)

    2014-04-01

    these faces were lubricated with boron nitride. The specimen’s dimensions were 4.7 mm4.7 mm7.7 mm. Com pression tests were conducted at 298 K, 873 K...characteristic vein patterns and spherical particles in these regions. Melting of this type has been observed during fracture of amorphous and nano ...of nano or submicron size particles. This work thus suggests a reasoned approach for developing high entropy alloys with both solid solution and

  2. Design and identification of high performance steel alloys for structures subjected to underwater impulsive loading

    Science.gov (United States)

    Wei, Xiaoding; Latourte, Felix; Feinberg, Zack; Olson, Gregory; Espinosa, Horacio; Micro; Nanomechanics Laboratory Team; Olson Group Team

    2011-06-01

    To characterize the performance of naval structures, underwater blast experiments have been developed. Martensitic and austenitic steel alloys were designed to optimize the performance of structures subjected to impulsive loads. The deformation and fracture characteristics of the designed steel alloys were investigated experimentally and computationally. The experiments were based on an instrumented fluid structure interaction apparatus, in which deflection profiles were recorded. The computational study was based on a modified Gurson damage model able to accurately describe ductile failure under various loading paths. The model was calibrated for two high performance martensitic steels (HSLA-100 and BA-160) and an austenitic steel (TRIP-120). The martensitic steel (BA-160) was designed to maximize strength and fracture toughness while the austenitic steel (TRIP-120) was designed to maximize uniform ductility. The combined experimental-computational approach provided insight into the relationships between material properties and blast resistance of structures.

  3. In vitro performance assessment of new beta Ti–Mo–Nb alloy compositions

    Energy Technology Data Exchange (ETDEWEB)

    Neacsu, Patricia [University of Bucharest, Department of Biochemistry and Molecular Biology, 91–95 Spl. Independentei, 050095 Bucharest (Romania); Gordin, Doina-Margareta [INSA Rennes, UMR CNRS 6226 ISCR/Chimie-Métallurgie, 20 avenue des Buttes de Coësmes, F-35043 Rennes, Cedex (France); Mitran, Valentina [University of Bucharest, Department of Biochemistry and Molecular Biology, 91–95 Spl. Independentei, 050095 Bucharest (Romania); Gloriant, Thierry [INSA Rennes, UMR CNRS 6226 ISCR/Chimie-Métallurgie, 20 avenue des Buttes de Coësmes, F-35043 Rennes, Cedex (France); Costache, Marieta [University of Bucharest, Department of Biochemistry and Molecular Biology, 91–95 Spl. Independentei, 050095 Bucharest (Romania); Cimpean, Anisoara, E-mail: anisoara.cimpean@bio.unibuc.ro [University of Bucharest, Department of Biochemistry and Molecular Biology, 91–95 Spl. Independentei, 050095 Bucharest (Romania)

    2015-02-01

    New β-titanium based alloys with low Young's modulus are currently required for the next generation of metallic implant materials to ensure good mechanical compatibility with bone. Several of these are representatives of the ternary Ti–Mo–Nb system. The aim of this paper is to assess the in vitro biological performance of five new low modulus alloy compositions, namely Ti12Mo, Ti4Mo32Nb, Ti6Mo24Nb, Ti8Mo16Nb and Ti10Mo8Nb. Commercially pure titanium (cpTi) was used as a reference material. Comparative studies of cell activity exhibited by MC3T3-E1 pre-osteoblasts over short- and long-term culture periods demonstrated that these newly-developed metallic substrates exhibited an increased biocompatibility in terms of osteoblast proliferation, collagen production and extracellular matrix mineralization. Furthermore, all analyzed biomaterials elicited an almost identical cell response. Considering that macrophages play a pivotal role in bone remodeling, the behavior of a monocyte-macrophage cell line, RAW 264.7, was also investigated showing a slightly lower inflammatory response to Ti–Mo–Nb biomaterials as compared with cpTi. Thus, the biological performances together with the superior mechanical properties recommend these alloys for bone implant applications. - Highlights: • Ti–Mo–Nb compositions show a fully β-microstructural state by XRD analysis. • Similar osteoblast growth and differentiation is displayed by β-Ti alloys and cpTi. • Ti–Mo–Nb alloys elicit a slightly lower inflammatory response than cpTi.

  4. Effect of cobalt content on electrochemical performance of La-Mg-Ni system (Ce2Ni7-type) electrode alloys

    Institute of Scientific and Technical Information of China (English)

    WANG Xinlin; DONG Xiaoping; ZHANG Yanghuan; GUO Shihai; Lü Fanxiu

    2008-01-01

    In order to improve the cyclic stability of La-Mg-Ni system (Ce2Ni7-type) alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure of the alloys were investigated in detail. XRD results showed that the alloys had multiphase structure composed of (La, Mg)2Ni7, LaNi5 and small amount of LaNi2 phases. The discharge capacity of the alloys first increased and then decreased with increasing Co content. At a discharge current density of 900 mA/g, the HRD of the alloy electrodes increased from 81.3% (x=0) to 89.2 % (x=0.2), and then reduced to 87.8 % (x=0.6). After 60 charge/discharge cycles, the capacity retention rate of the alloys enhanced from 52.67% to 61.32%, and the capacity decay rate of the alloys decreased from 2.60 to 2.05 mAh/g per cycle with increasing Co content. The obtained results by XPS and XRD showed that the fundamental reasons for the capacity decay of the La-Mg-Ni system (Ce2Ni7-type) alloy electrodes were corrosion and oxidation as well as passivation of Mg and La in alkaline solution.

  5. Performance Comparison of Al–Ti Master Alloys with Different Microstructures in Grain Refinement of Commercial Purity Aluminum

    Directory of Open Access Journals (Sweden)

    Wanwu Ding

    2014-05-01

    Full Text Available Three types of Al–5Ti master alloys were synthesized by a method of thermal explosion reaction in pure molten aluminum. Performance comparison of Al–5Ti master alloy in grain refinement of commercial purity Al with different additions (0.6%, 1.0%, 1.6%, 2.0%, and 3.0% and holding time (10, 30, 60 and 120 min were investigated. The results show that Al–5Ti master alloy with blocky TiAl3 particles clearly has better refining efficiency than the master alloy with mixed TiAl3 particles and the master alloy with needle-like TiAl3 particles. The structures of master alloys, differing by sizes, morphologies and quantities of TiAl3 crystals, were found to affect the pattern of the grain refining properties with the holding time. The grain refinement effect was revealed to reduce markedly for master alloys with needle–like TiAl3 crystals and to show the further significant improvement at a longer holding time for the master alloy containing both larger needle–like and blocky TiAl3 particles. For the master alloy with finer blocky particles, the grain refining effect did not obviously decrease during the whole studied range of the holding time.

  6. Performance Comparison of Al–Ti Master Alloys with Different Microstructures in Grain Refinement of Commercial Purity Aluminum

    Science.gov (United States)

    Ding, Wanwu; Xia, Tiandong; Zhao, Wenjun

    2014-01-01

    Three types of Al–5Ti master alloys were synthesized by a method of thermal explosion reaction in pure molten aluminum. Performance comparison of Al–5Ti master alloy in grain refinement of commercial purity Al with different additions (0.6%, 1.0%, 1.6%, 2.0%, and 3.0%) and holding time (10, 30, 60 and 120 min) were investigated. The results show that Al–5Ti master alloy with blocky TiAl3 particles clearly has better refining efficiency than the master alloy with mixed TiAl3 particles and the master alloy with needle-like TiAl3 particles. The structures of master alloys, differing by sizes, morphologies and quantities of TiAl3 crystals, were found to affect the pattern of the grain refining properties with the holding time. The grain refinement effect was revealed to reduce markedly for master alloys with needle–like TiAl3 crystals and to show the further significant improvement at a longer holding time for the master alloy containing both larger needle–like and blocky TiAl3 particles. For the master alloy with finer blocky particles, the grain refining effect did not obviously decrease during the whole studied range of the holding time. PMID:28788642

  7. On the performance of surface plasmon resonance based fibre optic sensor with different bimetallic nanoparticle alloy combinations

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Anuj K; Mohr, Gerhard J [Institute of Physical Chemistry, Friedrich-Schiller University, Lessingstrasse 10, 07743 Jena (Germany)], E-mail: anuj.sharma@uni-jena.de

    2008-03-07

    In this work, we have investigated the capability of different bimetallic nanoparticle alloy combinations to be used in fibre optic sensors based on the technique of surface plasmon resonance. The metals considered for this analysis are silver, gold, copper and aluminium. The performance of the sensor with different bimetallic nanoparticle alloy combinations is evaluated and compared numerically. The performance is analysed in terms of three parameters: sensitivity, signal-to-noise ratio (SNR) and operating range for the sensing layer refractive index values. On the basis of the comparison and some logistic criteria, the best possible bimetallic alloy combinations along with a requisite alloy composition ratio are predicted. The bimetallic nanoparticle alloy combination is capable of simultaneously providing larger values of sensitivity, SNR and operating range, which is not possible with any single metallic nanoparticle layer.

  8. Fabricating high performance tungsten alloys through zirconium micro-alloying and nano-sized yttria dispersion strengthening

    Science.gov (United States)

    Liu, R.; Xie, Z. M.; Hao, T.; Zhou, Y.; Wang, X. P.; Fang, Q. F.; Liu, C. S.

    2014-08-01

    Pure W, W-0.2wt%Zr (WZ), and W-0.2wt%Zr-1.0wt%Y2O3 (WZY) with a relative density of above 97% were fabricated by spark-plasma-sintering method. The tensile tests indicated that the WZ and WZY alloys exhibited a DBTT between 400 and 500 °C, about 200 °C lower than pure W. The ultimate tensile strength of WZY alloy at 700 °C is 534 MPa, which is 81% and 58% higher than those of WZ alloy (295 MPa) and pure W (337 MPa), respectively. The grain size of WZY alloy is about 3.2 μm, smaller than that of WZ alloy and pure W. Besides, at room temperature the fracture strength and hardness of the WZY alloy is higher than that of pure W. The improved mechanical property of the WZY alloy was suggested to be originated from the enhanced grain boundaries cohesion by Zr micro-alloying and nano-sized yttria dispersion strengthening.

  9. Enhancement of the electrochemical behaviour and biological performance of Ti–25Ta–5Zr alloy by thermo-mechanical processing

    Energy Technology Data Exchange (ETDEWEB)

    Cimpean, Anisoara [Department of Biochemistry and Molecular Biology, University of Bucharest, Spl. Independentei, 91-95, 050095 Bucharest (Romania); Vasilescu, Ecaterina; Drob, Paula [Department of Electrochemistry and Corrosion, Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Cinca, Ion, E-mail: ion_cinca@hotmail.com [Faculty of Material Science and Engineering, Politehnica University, Spl. Independentei 313, 060042 Bucharest (Romania); Vasilescu, Cora; Anastasescu, Mihai [Department of Electrochemistry and Corrosion, Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Mitran, Valentina [Department of Biochemistry and Molecular Biology, University of Bucharest, Spl. Independentei, 91-95, 050095 Bucharest (Romania); Drob, Silviu Iulian [Department of Electrochemistry and Corrosion, Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania)

    2014-05-01

    A new Ti–25Ta–5Zr alloy based only on non-toxic and non-allergic elements was elaborated in as-cast and thermo-mechanical processed, recrystallized states (XRD and SEM) in order to be used as candidate material for implant applications. Its long-term interactions with Ringer–Brown and Ringer solutions of different pH values and its cytocompatibility were determined. The thermo-mechanically processed alloy has nobler electrochemical behaviour than as-cast alloy due to finer microstructure obtained after the applied treatment. Corrosion and ion release rates presented the lowest values for the treated alloy. Nyquist and Bode plots displayed higher impedance values and phase angles for the processed alloy, denoting a more protective passive film. SEM micrographs revealed depositions from solutions that contain calcium, phosphorous and oxygen ions (EDX analysis), namely calcium phosphate. An electric equivalent circuit with two time constants was modelled. Cell culture experiments with MC3T3-E1 pre-osteoblasts demonstrated that thermo-mechanically processed Ti–25Ta–5Zr alloy supports a better cell adhesion and spreading, and enhanced cell proliferation. Altogether, these data indicate that thermo-mechanical treatment endows the alloy with improved anticorrosion and biological performances. - Highlights: • Ti–25Ta–5Zr alloy exhibited noble electrochemical, passive behaviour in simulated biofluids. • An electric equivalent circuit with two time constants was modelled. • Corrosion rates show the lowest values for the recrystallized Ti–25Ta–5Zr alloy. • In vitro tests revealed good cytocompatibility of as-cast and processed alloy. • Recrystallized treatment endows the alloy with superior biological performances.

  10. ANN-based wear performance prediction for plasma nitrided Ti6Al4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kahraman, Fatih; Karadeniz, Sueleyman; Durmus, Izmir; Durmus, Huelya

    2012-07-01

    Surface modification of a Ti6Al4V titanium alloy was made by the plasma nitriding process. Plasma nitriding was performed in a constant gas mixture of 20% H{sub 2} -80% N{sub 2} at temperatures between 700 and 1000 C and process times between 2 and 15 h. Samples nitrided at different treatment times and temperatures were subjected to the dry sliding wear test using the pin-on-disc set up under 80N normal load with rotational speed of counter face disc of 0.8 m/s at room conditions. An artificial neural network (ANN) model of was developed for prediction of wear performance of the plasma nitrided Ti6Al4V alloy. The inputs of the ANN model were processing times and temperatures, diffusion layer thickness, Ti{sub 2}N thickness, TiN thickness and hardness. The output of the ANN model was wear loss. The model is based on the multilayer backpropagation neural technique. The ANN was trained with a comprehensive dataset collected from experimental conditions and results of authors. The model can be used for the prediction of wear properties of Ti6Al4V alloys nitrided at different parameters. The ANN model demonstrated the best statistical performance with the experimental results.

  11. SISGR: Theoretically relating the surface composition of Pt alloys to their performance as the electrocatalysts of low-temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guofeng

    2010-12-31

    The main goal of this project is to gain fundamental knowledge about the relation between surface composition and catalytic performance of Pt alloy catalysts for oxygen reduction reaction (ORR). Specific objectives are: to develop and improve a first-principles based multiscale computation approach to simulating surface segregation phenomena in Pt alloy surfaces; to evaluate the surface electronic structure and catalytic activity of Pt alloy catalysts and; to relate the surface composition to the catalytic performance of Pt alloy catalysts.

  12. Research on low strain magnetic mechanical hysteresis damping performance of Fe-15Cr-3Mo-0.5Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui, E-mail: qinghe5525@163.com; Huang, Huawei; Hong, Xiaofeng; Yin, Changgeng; Huang, Zhaohua; Chen, Le

    2015-02-15

    Highlights: • Heat treatment system has a great effect on the alloy damping performance. • Damping performance does not improve monotonously with temperature. • Furnace cooling is higher than that of alloy after air cooling. • There is an optimum annealing temperature and grain size to obtain high damping. - Abstract: This paper studies the preparation of Fe-15Cr-3Mo-0.5Si alloy by using vacuum induction melting furnace and vacuum annealing furnace, the damping performance of which in different heat treatment states is tested with dynamic mechanical thermal analyzer (DMA). Through microstructure observation with metallographic microscope (OM), grain boundary observation with scanning electron microscopy (SEM), phase structure analysis with X-ray diffraction (XRD) and internal stress of S-B model analysis, the effect law of annealing temperature, types of cooling, holding time and grain sizes on the damping performance of alloy and the related mechanism can be concluded as follows. The annealing temperature and grain sizes have a significant impact on the damping strain amplitude as well as the magnetic and mechanical damping performance of this ferromagnetic alloy. Proper annealing temperature and grain size is the necessary condition to get high damping performance of the alloy. It is not conducive to improvement of the damping performance if the annealing temperature is too high or too low and the grain size is too small or too large. For Fe-15Cr-3Mo-0.5Si alloy, within the range of the low strain amplitude, alloy damping performance does not improve monotonously with the increase of the annealing temperature and grain size. The maximum value appears at the annealing temperature of 1100 °C/1 h with the grain size of about 300 μm. At high annealing temperature of 1100 °C, the damping performance of alloy in the slow cooling furnace is higher than that with air cooling treatment. The extension or shortening of the holding time, to a certain extent

  13. Grain Refinement and High-Performance of Equal-Channel Angular Pressed Cu-Mg Alloy for Electrical Contact Wire

    Directory of Open Access Journals (Sweden)

    Aibin Ma

    2014-12-01

    Full Text Available Multi-pass equal-channel angular pressing (EACP was applied to produce ultrafine-grained (UFG Cu-0.2wt%Mg alloy contact wire with high mechanical/electric performance, aim to overcome the catenary barrier of high-speed trains by maximizing the tension and improving the power delivery. Microstructure evolution and overall properties of the Cu-Mg alloy after different severe-plastic-deformation (SPD routes were investigated by microscopic observation, tensile and electric tests. The results show that the Cu-Mg alloy after multi-pass ECAP at 473 K obtains ultrafine grains, higher strength and desired conductivity. More passes of ECAP leads to finer grains and higher strength, but increasing ECAP temperature significantly lower the strength increment of the UFG alloy. Grain refinement via continuous SPD processing can endow the Cu-Mg alloy superior strength and good conductivity characteristics, which are advantageous to high-speed electrification railway systems.

  14. Electrochemical performances of hydrogen storage alloys treated using a new milling technique

    Institute of Scientific and Technical Information of China (English)

    LIU Kaiyu; ZHANG Ying; ZHANG Wei; HE Yuehui

    2008-01-01

    A new self-made additive of amidocyanogen-acetic salt was used in wet bail-grind technique (WBGT) for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge (HRD) ability, and good stability. The first discharge capacitance at 0.2 C (throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy (full capacity) is charged or discharged completely in 1/n h) reached 278mAh.g-1 and the discharge capacitance reached the maximum of 322mAh·g-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge (HRD) values (C5C/C0.2C ratio) were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275mAh·g-1 (dry method) to 295mAh·g-1 (WBGT).

  15. Microstructure evolution and lubricant wear performance of laser alloyed layers on automobile engine chains

    Science.gov (United States)

    Sun, G. F.; Zhou, R.; Zhang, Y. K.; Yuan, G. D.; Wang, K.; Ren, X. D.; Wen, D. P.

    2014-10-01

    Wear resistant layers on nodular cast iron chains with C-B-W-Cr powders were fabricated by laser surface alloying (LSA). Microstructure, phases and lattice parameters, were investigated by means of optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. Micro-, nano-hardness and elastic modulus were measured with a Vickers microhardness tester and a nano-indendation tester. Lubricant sliding wear performance was performed on a ball-on-disk apparatus in ambient air using the straight line reciprocating wear form. Results indicate that microstructure of the alloyed layers changes from hyper-eutectic to hypo-eutectic, varing with laser specific energy. Nano-grain size and micro-hardness decrease while martensite lattice parameters increase with laser specific energy. Existence of graphite in the substrate increases the carbon content in the retained austenite to 1.59 wt%. Nano-hardness and elastic modulus of the alloyed layers are close. Friction and wear properties of the layers are improved by LSA compared with the substrate. Wear mechanism of them is illustrated.

  16. High performance low alloy steels: Up date; Aceros de baja aleacion y alto rendimiento

    Energy Technology Data Exchange (ETDEWEB)

    Campos, M.; Blanco, L.; Sicre-Artalejo, J.; Torralba, J. M.

    2008-07-01

    A highly demanding automobile market requires an intensification of the efforts on increasing the performance and reducing costs of sintered steels, in order to stay in such a competitive market. final properties of sintered parts and their cost depend on two main factors, density and the alloying system. The growing interest for Cr and Mn as alloying elements is due to both price, more suitable than Mo, and the excellent level of properties which are achieved in as sintered parts as well as after the heat treatments. In this work, the possible techniques which lead to an enhancement of density are discussed, such as warm and high velocity compaction, or high temperature sintering moreover it is important to study the synergy between the proposed techniques which may be compatible. (Author) 70 refs.

  17. The Analysis of the General Performance and Mechanical Behavior of Unirradiated FeCrAl Alloys Before and After Welding

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-03

    The present report summarizes and discusses the preliminary results for the in-depth characterization of the modern, nuclear-grade FeCrAl alloys currently under development. The alloys were designed for enhanced radiation tolerance and weldability, and the research is currently being pursued by the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program. Last year, seven candidate FeCrAl alloys with well-controlled chemistry and microstructures were designed and produced; welding was performed under well-controlled conditions. The structure and general performance of unirradiated alloys were assessed using standardized and advanced microstructural characterization techniques and mechanical testing. The primary objective is to identify the best candidate alloy, or at a minimum to identify the contributing factors that increase the weldability and radiation tolerance of FeCrAl alloys, therefore enabling future generations of FeCrAl alloys to deliver better performance parameters. This report is structured so as to describe these critical assessments of the weldability; radiation tolerance will be reported on in later reports from this program.

  18. Effect of rapid solidification treatment on structure and electrochemical performance of low-Co AB5-type hydrogen storage alloy

    Institute of Scientific and Technical Information of China (English)

    姚青荣; 唐莹; 周怀营; 邓健秋; 王仲民; 潘顺康; 饶光辉; 朱其明

    2014-01-01

    The effect of rapid solidification on structure and electrochemical performance of the LaNi4.5Co0.25Al0.25 hydrogen storage alloy was investigated by X-ray powder diffraction and a simulated battery test, including maximum capacity, cycling stability, self-discharge, and high-rate discharge ability (HRD). All the melt-spun alloys were single-phase with the CaCu5-type structure (space groupP6/mmm). In comparison to the as-cast alloy, the rapidly quenched alloys manifested an improved homogeneity of com-position and expanded lattice parameters. The electrochemical measurements showed that the activation property, cycling stability and self-discharge of the alloy electrodes were also improved for the rapid solidified alloys. The HRDof the as-cast alloy was better than those of all the rapidly solidified alloys. As the quenching rate increased, the HRD and exchange current density first decreased and then increased.

  19. Electrochemical performance and capacity degradation mechanism of single-phase La-Mg-Ni-based hydrogen storage alloys

    Science.gov (United States)

    Liu, Jingjing; Li, Yuan; Han, Da; Yang, Shuqin; Chen, Xiaocui; Zhang, Lu; Han, Shumin

    2015-12-01

    La-Mg-Ni-based hydrogen storage alloys are a promising candidate for the negative electrode materials of nickel metal hydride batteries. However, their fast capacity degradation hinders them from more extensive application. In this study, the electrochemical performance and capacity degradation mechanism of single-phase La2MgNi9, La3MgNi14 and La4MgNi19 alloys are studied from the perspective of their constituent subunits. It is found that the rate capability and cycling stability of the alloy electrodes increase with higher [LaNi5]/[LaMgNi4] subunit ratio, while the discharge capacity shows a reverse trend. Degradation study shows that the inter-molecular strains in the alloys are the main reason that leads to the fast capacity degradation of La-Mg-Ni-based alloys. The strains are caused by the difference in the expansion/contraction properties between [LaNi5] and [LaMgNi4] subunits during charge/discharge which is mainly observed in the H-dissolved solid solution instead of hydride. It is also found that the strains can be relieved by adjusting [LaNi5]/[LaMgNi4] subunit ratio of the alloys, thus achieving less pulverization and oxidation, and better cycling stability. We expect our findings can inspire new thoughts on improving the electrochemical performance of La-Mg-Ni-based alloys by tuning their superlattice structures.

  20. Experimental investigation on effective thermal conductivities of refractory alloy honeycomb cores%耐热合金蜂窝等效热导率的实验研究

    Institute of Scientific and Technical Information of China (English)

    赵剑; 谢宗蕻; 李玮; 田江

    2011-01-01

    耐热合金蜂窝夹芯结构是高超音速飞行器热防护系统外面板的理想候选方案.针对Hastelloy X耐热合金蜂窝夹芯结构开展了稳态传热实验,通过控制加热板温度,获得了一组热平衡时蜂窝夹芯结构的热、冷面温度,结合Stefan-Boltzmann定律和大空间自然对流实验关联式,采用热阻分析方法得到了Hastelloy X耐热合金蜂窝随温度变化的宏观等效热导率,并采用Swan-Pittman半经验模型预测了该蜂窝的等效热导率,与实验结果对比一致性较好.%The honeycomb sandwich structures made of heat resistant alloy are suitable for the outer panels of thermal protection system used in hypersonic applications. Static heat transfer experiment was conducted on the Hastelloy X honeycomb sandwich structure, and both the upper and lower face sheet temperatures at steady state were obtained. The macroscopic effective thermal conductivities varying with different temperatures were acquired based on the thermal resistance analytical method, in combination with Stefan-Boltzmanns law and experimental correlation formula for natural convection in infinite space. Swan-Pittman semi-empirical model was adopted to predict the effective thermal conductivities of the Hastelloy X honeycomb sandwich structure, and the comparison between experimental results and predicted results shows good conformity.

  1. Effects of Flux Precoating and Process Parameter on Welding Performance of Inconel 718 Alloy TIG Welds

    Science.gov (United States)

    Lin, Hsuan-Liang; Wu, Tong-Min; Cheng, Ching-Min

    2014-01-01

    The purpose of this study is to investigate the effect of activating flux on the depth-to-width ratio (DWR) and hot cracking susceptibility of Inconel 718 alloy tungsten inert gas (TIG) welds. The Taguchi method is employed to investigate the welding parameters that affect the DWR of weld bead and to achieve optimal conditions in the TIG welds that are coated with activating flux in TIG (A-TIG) process. There are eight single-component fluxes used in the initial experiment to evaluate the penetration capability of A-TIG welds. The experimental results show that the Inconel 718 alloy welds precoated with 50% SiO2 and 50% MoO3 flux were provided with better welding performance such as DWR and hot cracking susceptibility. The experimental procedure of TIG welding process using mixed-component flux and optimal conditions not only produces a significant increase in DWR of weld bead, but also decreases the hot cracking susceptibility of Inconel 718 alloy welds.

  2. Influence of Al on the microstructure and carburization performance of a Ni-based alloy coating

    Energy Technology Data Exchange (ETDEWEB)

    Cangue, Feliciano Jose Ricardo, E-mail: fcangue@yahoo.com [Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil); D' Oliveira, Ana Sofia Climaco Monteiro, E-mail: sofmat@ufpr.br [Mechanical Engineering Department, Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil)

    2010-04-15

    Carburization is a degradation mechanism involving the diffusion of carbon into a metal alloy and its accumulation on the surface. Coke forms on the internal walls of crude oil refining equipment and adversely affects its efficiency and service life. In an attempt to enhance the service life of materials exposed to these aggressive environments, this work investigated the development of a protective coating to reduce the diffusion of carbon into the surfaces of components. Coatings were tailored by mixing the atomized Ni alloy (Hastealloy C) with 5 wt% and 15 wt% Al powders and deposited by Plasma Transferred Arc hardfacing. Pack carburizing was carried out at 650 deg. C and 850 deg. C for 6 h, and temperature stability was tested in an air furnace to evaluate the performance of the coatings. Characterization included measurement of Vickers microhardness profiles and microstructure analysis by optical and scanning electron microscopy and X-ray diffraction. The good weldability of the original Ni-based alloy was not altered by the presence of Al. Richer Al coatings developed ordered aluminide compounds in a Ni matrix and exhibited increased hardness and dilution. Exposure to temperatures of 650 deg. C and 850 deg. C in an air furnace and to a carburizing environment neither compromised coating hardness nor produced a carburizing layer, although carbides were identified at the top surface. Our results will be of benefit in the development of an alternative solution for the protection of components operating in carburizing environments.

  3. Preparation and Performance of Rare Earths Chemical Conversion Film on Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.

  4. Extracorporeal photopheresis performed on the CELLEX® compared with the UVAR-XTS® instrument is more efficient and better tolerated in children with steroid-refractory graft-versus-host disease.

    Science.gov (United States)

    Kapadia, Ekta; Wong, Edward; Perez-Albuerne, Evelio; Jacobsohn, David

    2015-08-01

    Extracorporeal photopheresis (ECP) is an effective therapy in children with refractory graft-versus-host disease (GVHD). The two most frequently used instruments are UVAR-XTS® and CELLEX®. We performed a retrospective chart review of ten patients who underwent ECP with both UVAR-XTS® and CELLEX® instruments for steroid-refractory acute or chronic GVHD to compare instrument run times, percentages of cells treated, and complication rates. We found that compared to the UVAR-XTS® instrument, use of the CELLEX® instrument resulted in shorter run times, increased percentage of mononuclear cells treated, reduced incidence of line occlusions requiring TPA treatment, and decreased incidence of patient-related complications.

  5. Approaches to refractory epilepsy

    Directory of Open Access Journals (Sweden)

    Jerome Engel

    2014-01-01

    Full Text Available Epilepsy is one of the most common serious neurological conditions, and 30 to 40% of people with epilepsy have seizures that are not controlled by medication. Patients are considered to have refractory epilepsy if disabling seizures continue despite appropriate trials of two antiseizure drugs, either alone or in combination. At this point, patients should be referred to multidisciplinary epilepsy centers that perform specialized diagnostic testing to first determine whether they are, in fact, pharmacoresistant, and then, if so, offer alternative treatments. Apparent pharmacoresistance can result from a variety of situations, including noncompliance, seizures that are not epileptic, misdiagnosis of the seizure type or epilepsy syndrome, inappropriate use of medication, and lifestyle issues. For patients who are pharmacoresistant, surgical treatment offers the best opportunity for complete freedom from seizures. Surgically remediable epilepsy syndromes have been identified, but patients with more complicated epilepsy can also benefit from surgical treatment and require more specialized evaluation, including intracranial EEG monitoring. For patients who are not surgical candidates, or who are unwilling to consider surgery, a variety of other alternative treatments can be considered, including peripheral or central neurostimulation, ketogenic diet, and complementary and alternative approaches. When such alternative treatments are not appropriate or effective, quality of life can still be greatly improved by the psychological and social support services offered by multidisciplinary epilepsy centers. A major obstacle remains the fact that only a small proportion of patients with refractory epilepsy are referred for expert evaluation and treatment.

  6. Investigation of Material Performance Degradation for High-Strength Aluminum Alloy Using Acoustic Emission Method

    Directory of Open Access Journals (Sweden)

    Yibo Ai

    2015-02-01

    Full Text Available Structural materials damages are always in the form of micro-defects or cracks. Traditional or conventional methods such as micro and macro examination, tensile, bend, impact and hardness tests can be used to detect the micro damage or defects. However, these tests are destructive in nature and not in real-time, thus a non-destructive and real-time monitoring and characterization of the material damage is needed. This study is focused on the application of a non-destructive and real-time acoustic emission (AE method to study material performance degradation of a high-strength aluminum alloy of high-speed train gearbox shell. By applying data relative analysis and interpretation of AE signals, the characteristic parameters of materials performance were achieved and the failure criteria of the characteristic parameters for the material tensile damage process were established. The results show that the AE method and signal analysis can be used to accomplish the non-destructive and real-time detection of the material performance degradation process of the high-strength aluminum alloy. This technique can be extended to other engineering materials.

  7. RESEARCH ON REFRACTORY SUPERALLOYS IN THE HTM 21 PROJECT

    Institute of Scientific and Technical Information of China (English)

    Y.F.Gu; Y.Yamabe-Mitarai; C.Huang; H.Harada

    2005-01-01

    It was proposed that a new class of alloys based on platinum group metals (PGMs) were called refractory superalloys.These refractory superalloys have an fcc and LI2 coherent two-phase structure (similar to that of Ni-based superalloys), high melting temperatures and good potential as structural materials used at temperatures up to 1800℃.Our recent results on the microstructure evolution, deformation and fracture behavior of some of these refracotry superalloys, especial Ir- and Rh-base refractory superalloys were reported.

  8. Computational dynamics of laser alloyed metallic materials for improved corrosion performance: computational dynamics of laser alloyed metallic materials

    CSIR Research Space (South Africa)

    Fatoba, OS

    2016-04-01

    Full Text Available Laser alloying is a material processing method which utilizes the high power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. Since melting occur solitary at the surface, large...

  9. Emergency coronary angioplasty in refractory unstable angina

    NARCIS (Netherlands)

    P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); M.J.B.M. van den Brand (Marcel); K. Balakumaran (Kulasekaram); A.L. Soward; P.G. Hugenholtz (Paul); A.E.R. Arnold (Alfred); B. Mochtar (Bas)

    1985-01-01

    textabstractWe performed percutaneous transluminal coronary angioplasty as an emergency procedure in 60 patients with unstable angina pectoris that was refractory to treatment with maximally tolerated doses of beta-blockers, calcium antagonists, and intravenous nitroglycerin. The initial success

  10. Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance

    Directory of Open Access Journals (Sweden)

    Tom Grossfeld

    2017-09-01

    Full Text Available We investigate the microstructure evolution of Ag-alloyed PbTe compounds for thermoelectric (TE applications with or without additions of 0.04 at. % Bi. We control the nucleation and temporal evolution of Ag2Te-precipitates in the PbTe-matrix applying designated aging heat treatments, aiming to achieve homogeneous dispersion of precipitates with high number density values, hypothesizing that they act as phonon scattering centers, thereby reducing lattice thermal conductivity. We measure the temperature dependence of the Seebeck coefficient and electrical and thermal conductivities, and correlate them with the microstructure. It is found that lattice thermal conductivity of PbTe-based compounds is reduced by controlled nucleation of Ag2Te-precipitates, exhibiting a number density value as high as 2.7 × 1020 m−3 upon 6 h aging at 380 °C. This yields a TE figure of merit value of ca. 1.4 at 450 °C, which is one on the largest values reported for n-type PbTe compounds. Subsequent aging leads to precipitate coarsening and deterioration of TE performance. Interestingly, we find that Bi-alloying improves the alloys’ thermal stability by suppressing microstructure evolution, besides the role of Bi-atoms as electron donors, thereby maintaining high TE performance that is stable at elevated service temperatures. The latter has prime technological significance for TE energy conversion.

  11. Improvement on the Fatigue Performance of 2024-T4 Alloy by Synergistic Coating Technology

    Directory of Open Access Journals (Sweden)

    Xi-Shu Wang

    2014-05-01

    Full Text Available In this paper, rotating bending fatigue tests of 2024-T4 Al alloy with different oxide coatings were carried out. Compared to the uncoated and previously reported oxide coatings of aluminum alloys, the fatigue strength is able to be enhanced by using a novel oxide coating with sealing pore technology. These results indicate that the better the coating surface quality is, the more excellent the fatigue performance under rotating bending fatigue loading is. The improvement on the fatigue performance is mainly because the fatigue crack initiation and the early stage of fatigue crack growth at the coating layer can be delayed after PEO coating with pore sealing. Therefore, it is a so-called synergistic coating technology for various uses, including welding thermal cracks and filling micro-pores. The effects of different oxide coatings on surface hardness, compressive residual stress, morphology and fatigue fracture morphology are discussed. A critical compressive residual stress of about 95–100 MPa is proposed.

  12. Reaction-Forming Method for Producing Near Net-Shape Refractory Metal Carbides

    Energy Technology Data Exchange (ETDEWEB)

    Palmisiano, Marc N.; Jakubenas, Kevin J.; Baranwal, Rita

    2004-07-20

    A method for reaction forming refractory metal carbides. The method involves the fabrication of a glassy carbon preform by casting an organic, resin-based liquid mixture into a mold and subsequently heat treating it in two steps, which cures and pyrolizes the resin resulting in a porous carbon preform. By varying the amounts of the constituents in the organic, resin-based liquid mixture, control over the density of the carbon preform is obtained. Control of the density and microstructure of the carbon preform allows for determination of the microstructure and properties of the refractory metal carbide material produced. The glassy carbon preform is placed on a bed of refractory metal or refractory metal--silicon alloy. The pieces are heated above the melting point of the metal or alloy. The molten metal wicks inside the porous carbon preform and reacts, forming the refractory metal carbide or refractory metal carbide plus a minor secondary phase.

  13. Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness

    Directory of Open Access Journals (Sweden)

    Adak Tridibesh

    2008-04-01

    Full Text Available Abstract Background The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO synthesis. NO metabolites, nitrite (NO2- and nitrate (NO3- are produced by the action of an inducible Anopheles culicifacies NO synthase (AcNOS in mosquito mid-guts and may be central to anti-parasitic arsenal of these mosquitoes. Method While exploring a plausible mechanism of refractoriness based on nitric oxide synthase physiology among the sibling species of An. culicifacies, a sensitive, specific and cost effective high performance liquid chromatography (HPLC method was developed, which is not influenced by the presence of biogenic amines, for the determination of NO2- and NO3- from mosquito mid-guts and haemolymph. Results This method is based on extraction, efficiency, assay reproducibility and contaminant minimization. It entails de-proteinization by centrifugal ultra filtration through ultracel 3 K filter and analysis by high performance anion exchange liquid chromatography (Sphereclone, 5 μ SAX column with UV detection at 214 nm. The lower detection limit of the assay procedure is 50 pmoles in all midgut and haemolymph samples. Retention times for NO2- and NO3- in standards and in mid-gut samples were 3.42 and 4.53 min. respectively. Assay linearity for standards ranged between 50 nM and 1 mM. Recoveries of NO2- and NO3- from spiked samples (1–100 μM and from the extracted standards (1–100 μM were calculated to be 100%. Intra-assay and inter assay variations and relative standard deviations (RSDs for NO2- and NO3- in spiked and un-spiked midgut samples were 5.7% or less. Increased levels NO2- and NO3- in midguts and haemolymph of An. culicifacies sibling species B in comparison to species A reflect towards a mechanism of refractoriness based on AcNOS physiology. Conclusion HPLC is a sensitive

  14. Accelerated growth of oxide film on aluminium alloys under steam: Part II: Effects of alloy chemistry and steam vapour pressure on corrosion and adhesion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Bordo, Kirill; Jellesen, Morten Stendahl

    2015-01-01

    The steam treatment of aluminium alloys with varying vapour pressure of steamresulted in the growth of aluminium oxyhydroxide films of thickness range between 450 - 825nm. The surface composition, corrosion resistance, and adhesion of the produced films was characterised by XPS, potentiodynamic...... of the vapour pressure of the steam. The accelerated corrosion and adhesion tests on steam generated oxide films with commercial powder coating verified that the performance of the oxide coating is highly dependent on the vapour pressure of the steam....

  15. Accelerated growth of oxide film on aluminium alloys under steam: Part II: Effects of alloy chemistry and steam vapour pressure on corrosion and adhesion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Bordo, Kirill; Jellesen, Morten Stendahl;

    2015-01-01

    The steam treatment of aluminium alloys with varying vapour pressure of steamresulted in the growth of aluminium oxyhydroxide films of thickness range between 450 - 825nm. The surface composition, corrosion resistance, and adhesion of the produced films was characterised by XPS, potentiodynamic...... of the vapour pressure of the steam. The accelerated corrosion and adhesion tests on steam generated oxide films with commercial powder coating verified that the performance of the oxide coating is highly dependent on the vapour pressure of the steam....

  16. Refractory status epilepticus.

    Science.gov (United States)

    Fernandez, Andres; Claassen, Jan

    2012-04-01

    Refractory status epilepticus (RSE) has a high morbidity and mortality. There are currently no definitive data to guide both the optimal choice of therapy and treatment goals. This review focuses on RSE diagnosis and outcome and discusses both commonly used and anecdotal therapies for RSE. The challenges in performing randomized controlled trials (RCTs) in neurocritical care and more specifically for the treatment of RSE are illustrated by the early termination of the first RCT of RSE due to low recruitment that compared propofol to barbiturates. Recent case series include the successful treatment of recurrent RSE with ketamine, intravenous lacosamide as an add-on treatment, the use of combination antiepileptics (phenytoin, levetiracetam, and pregabalin), and surgical treatments (vagal nerve and deep brain stimulation) for the control of RSE. A number of different therapeutic options are available for the treatment of RSE but none have been shown to be superior to others at this point.

  17. Nonlinear Analysis of Actuation Performance of Shape Memory Alloy Composite Film Based on Silicon Substrate

    Directory of Open Access Journals (Sweden)

    Shuangshuang Sun

    2014-01-01

    Full Text Available The mechanical model of the shape memory alloy (SMA composite film with silicon (Si substrate was established by the method of mechanics of composite materials. The coupled action between the SMA film and Si substrate under thermal loads was analyzed by combining static equilibrium equations, geometric equations, and physical equations. The material nonlinearity of SMA and the geometric nonlinearity of bending deformation were both considered. By simulating and analyzing the actuation performance of the SMA composite film during one cooling-heating thermal cycle, it is found that the final cooling temperature, boundary condition, and the thickness of SMA film have significant effects on the actuation performance of the SMA composite film. Besides, the maximum deflection of the SMA composite film is affected obviously by the geometric nonlinearity of bending deformation when the thickness of SMA film is very large.

  18. Fuel Performance Experiments and Modeling: Fission Gas Bubble Nucleation and Growth in Alloy Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    McDeavitt, Sean [Texas A & M Univ., College Station, TX (United States); Shao, Lin [Texas A & M Univ., College Station, TX (United States); Tsvetkov, Pavel [Texas A & M Univ., College Station, TX (United States); Wirth, Brian [Univ. of Tennessee, Knoxville, TN (United States); Kennedy, Rory [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-04-07

    Advanced fast reactor systems being developed under the DOE's Advanced Fuel Cycle Initiative are designed to destroy TRU isotopes generated in existing and future nuclear energy systems. Over the past 40 years, multiple experiments and demonstrations have been completed using U-Zr, U-Pu-Zr, U-Mo and other metal alloys. As a result, multiple empirical and semi-empirical relationships have been established to develop empirical performance modeling codes. Many mechanistic questions about fission as mobility, bubble coalescience, and gas release have been answered through industrial experience, research, and empirical understanding. The advent of modern computational materials science, however, opens new doors of development such that physics-based multi-scale models may be developed to enable a new generation of predictive fuel performance codes that are not limited by empiricism.

  19. Fatigue Performance of Friction-Stir-Welded Al-Mg-Sc Alloy

    Science.gov (United States)

    Zhemchuzhnikova, Daria; Mironov, Sergey; Kaibyshev, Rustam

    2017-01-01

    Fatigue behavior of a friction-stir-welded Al-Mg-Sc alloy was examined in cast and hot-rolled conditions. In both cases, the joints failed in the base material region and therefore the joint efficiency was 100 pct. The specimens machined entirely from the stir zone demonstrated fatigue strength superior to that of the base material in both preprocessed tempers. It was shown that the excellent fatigue performance of friction-stir joints was attributable to the ultra-fine-grained microstructure, the low dislocation density evolved in the stir zone, and the preservation of Al3Sc coherent dispersoids during welding. The formation of such structure hinders the initiation and growth of fatigue microcracks that provides superior fatigue performance of friction-stir welds.

  20. Hot corrosion performance of a NiCr coated Ni-based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, T.S.; Prakash, S.; Agrawal, R.D. [Indian Institute of Technology, Roorkee (India)

    2006-07-15

    The hot corrosion performance of high velocity oxy-fuel sprayed Ni-20Cr wire coating on a Ni-based superalloy is evaluated for 1000 h at 900{sup o}C under cyclic conditions in a coal-fired boiler. The performance of bare and Ni-20Cr coated Superni 75 is assessed via thermogravimetric data, metal thickness loss corresponding to the corrosion scale formation, scale thickness loss and the depth of internal corrosion attack. The better hot corrosion resistance of the coated alloy is mainly attributed to the formation of a thick band of chromium oxide just above the scale-substrate interface and chromium oxide stringers along the splat boundaries, as well as to the nickel oxide and the dense and uniform fine grain structure of the as sprayed coating.

  1. Corrosion Performance of Fe-Cr-Ni Alloys in Artificial Saliva and Mouthwash Solution

    Science.gov (United States)

    Porcayo-Calderon, J.; Casales-Diaz, M.; Salinas-Bravo, V. M.; Martinez-Gomez, L.

    2015-01-01

    Several austenitic stainless steels suitable for high temperature applications because of their high corrosion resistance and excellent mechanical properties were investigated as biomaterials for dental use. The steels were evaluated by electrochemical techniques such as potentiodynamic polarization curves, cyclic polarization curves, measurements of open circuit potential, and linear polarization resistance. The performance of steels was evaluated in two types of environments: artificial saliva and mouthwash solution at 37°C for 48 hours. In order to compare the behavior of steels, titanium a material commonly used in dental applications was also tested in the same conditions. Results show that tested steels have characteristics that may make them attractive as biomaterials for dental applications. Contents of Cr, Ni, and other minor alloying elements (Mo, Ti, and Nb) determine the performance of stainless steels. In artificial saliva steels show a corrosion rate of the same order of magnitude as titanium and in mouthwash have greater corrosion resistance than titanium. PMID:26064083

  2. High-performance Copper Alloy QBD-6%高性能铜合金QBD-6

    Institute of Scientific and Technical Information of China (English)

    曾力维; 张舟逸; 蒋中华

    2015-01-01

    Use electromagnetic stirring, horizontal continuous casting to break casting structure and refine casting the precipitates "Ni - P" compounds by high temperature annealing. After 20 finished rolling mills, the production of QBD - 6 high-performance copper alloy plate strips has high strength, high elasticity, high conductivity, high finish and other characteristics which can replace imported alloy, such as: MF202, CAC5 and some low-intensity C7025. This can be successfully applied to the lead frame materials, connectors, terminals, and motor brush components in power tools.%采用电磁搅拌水平连铸,破碎铸造组织并通过高温退火细化铸造组织中的析出物"Ni-P"化合物,经过20辊轧机的成品轧制,生产的QBD-6高性能铜合金板带材具有高强度、高弹性、高导电和高光洁度等特性,可替代进口合金,如:M F202、C A C5以及部分低强度的C7025.成功应用于引线框架材料、连接器、端子以及电动工具中的电机电刷部件.

  3. Wear-Resistance Performance of ZA-27 Alloys Reinforced by Rare Earth Compounds

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The morphology of ZA-27 alloy reinforced by RE compounds and its wear-resistance were studied. It is found that some nodular second phases appear due to the addition of Si and RE, which can disperse in grain boundaries or between dendrite crystals so that the alloy has been refined. Energy spectrum analysis of scanning electron microscope shows that the second phases are complex compounds containing RE, Al, Zn and Si. The micro-hardness test indicates that micro-hardness values of the compounds are higher than those of the matrix. The wear-resistance of ZA-27 alloy reinforced by RE compounds is 4 times as high as that of ZA-27 alloy and also higher than that of ZA-27 alloy containing Si phase. The impact toughness of the alloy containing RE and Si is higher than that of the alloy containing Si.

  4. Developing Refractories for Exporting

    Institute of Scientific and Technical Information of China (English)

    PANShang-xin

    1996-01-01

    The total output of China refractory products and export volume of China refractory raw materials rank the first in the world,In future the task is to improve the quality of the products to enlarge the variety and to expand export.

  5. Silica Refractory Bricks

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan; Peng Xigao

    2011-01-01

    @@ 1.Scope This standard specifies the classification,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of silica refractory bricks.This standard is applicable to silica refractory bricks with single weight≤40 kg.

  6. Development of improved refractories

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, A.A.; Ferber, M.K.; Liu, K.C. [Oak Ridge National Lab., TN (United States); Moore, R.E. [Univ. of Missouri, Rolla, MO (United States)

    1997-04-01

    The goal of the proposed project is to provide expertise and facilities for the high temperature mechanical properties characterization of refractory materials which are of interest to the US DOE`s Office of Industrial Technologies Advanced Industrial Materials Project. Initially the project would establish dedicated refractory testing facilities which would be capable of generating representative engineering creep and high temperature modulus of elasticity (MOE) data to a temperature of 3300{degrees}F (1815{degrees}C) in ambient air. The generated engineering creep and MOE data would serve R&D requirements of refractories-manufacturers and its glass-manufacturer end-users and designers. The relevance of this effort to the refractory and glass-making industries would be ensured by coordinating the research activities through a membership with Alfred University`s Center for Glass Research (CGR) Satellite Center at the University of Missouri-Rolla (UMR), an NSF Center. Valid engineering creep and high temperature MOE data currently do not exist for almost all commercial refractories. Refractory end-users such as glass-manufacturers require such data for efficient and economical design of their various glass-melting furnace superstructures (e.g., furnace crowns). Refractories in glass production furnaces may be subjected to extreme temperatures as high as 3200{degrees}F (1760{degrees}C). With the simultaneous imposition of mechanical and thermal stresses, creep deformation of the refractory material will assuredly occur as a consequence. Designers must ensure that the structural integrity is maintained, so these high temperature deformations must be considered for successful glass furnace superstructure design. These criteria can only be satisfied with the utilization of representative engineering creep and high temperature MOE data for the refractory materials that are chosen for the design of the refractory superstructures.

  7. A new strategy to improve the high-rate performance of hydrogen storage alloys with MoS2 nanosheets

    Science.gov (United States)

    Chen, L. X.; Zhu, Y. F.; Yang, C. C.; Chen, Z. W.; Zhang, D. M.; Jiang, Q.

    2016-11-01

    The poor high-rate dischargeability of negative electrode materials (hydrogen storage alloys) has hindered applications of nickel metal hydride batteries in high-power fields, new-energy vehicles, power tools, military devices, etc. In this work, a new strategy is developed to improve the high-rate performance of hydrogen storage alloys by coating MoS2 nanosheets on alloy surfaces. The capacity retention rate of the composite electrode reaches 50.5% at a discharge current density of 3000 mA g-1, which is 2.7 times that of bare alloy (18.4%). The density functional theory simulations indicate that such an outstanding performance is derived from adjustments of ion concentrations at the electrode/electrolyte interface by MoS2 nanosheets: (1) the higher OH- concentration facilitates the electrochemical reaction of MHads + OH- - e- → M + H2O; and (2) the lower H+ concentration leads to a large gradient between the electrode/electrolyte interface and interior of alloys, which is beneficial for the diffusion of atomic hydrogen during the discharging process.

  8. Microstructures and Hardness/Wear Performance of High-Carbon Stellite Alloys Containing Molybdenum

    Science.gov (United States)

    Liu, Rong; Yao, J. H.; Zhang, Q. L.; Yao, M. X.; Collier, Rachel

    2015-12-01

    Conventional high-carbon Stellite alloys contain a certain amount of tungsten which mainly serves to provide strengthening to the solid solution matrix. These alloys are designed for combating severe wear. High-carbon molybdenum-containing Stellite alloys are newly developed 700 series of Stellite family, with molybdenum replacing tungsten, which are particularly employed in severe wear condition with corrosion also involved. Three high-carbon Stellite alloys, designated as Stellite 706, Stellite 712, and Stellite 720, with different carbon and molybdenum contents, are studied experimentally in this research, focusing on microstructure and phases, hardness, and wear resistance, using SEM/EDX/XRD techniques, a Rockwell hardness tester, and a pin-on-disk tribometer. It is found that both carbon and molybdenum contents influence the microstructures of these alloys significantly. The former determines the volume fraction of carbides in the alloys, and the latter governs the amount of molybdenum-rich carbides precipitated in the alloys. The hardness and wear resistance of these alloys are increased with the carbide volume fraction. However, with the same or similar carbon content, high-carbon CoCrMo Stellite alloys exhibit worse wear resistance than high-carbon CoCrW Stellite alloys.

  9. Brazing Refractory Metals Used In High-Temperature Nuclear Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    A. J. Palmer; C. J. Woolstenhulme

    2009-06-01

    As part of the U. S. Department of Energy (DOE) sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL’s Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR 1) experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed.

  10. Refractory metals fabrication technology as applied to fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    1976-07-01

    Activities are reported in research programs on inspection and fabricion of refractory metals and alloys including those of Mo, Nb, Ta, and V. Progress is summarized in sections on blanking, edge preparation, machining, forming, joining, cleaning, thermal processing, and coating. (JRD)

  11. Experimental research on refractory performance of reinforced concrete beams strengthened with CFRP sheets bonded with an inorganic adhesive

    Institute of Scientific and Technical Information of China (English)

    ZHENG Wen-zhong; WAN Fu-xiong; LI Shi-guang

    2010-01-01

    To meet the requirement of fire endurance for concrete structures strengthened with CFRP sheets,this study develops an inorganic adhesive whose strength at 600℃ is not lower than that at normal room temper ature.The inorganic adhesive is then used to bond CFRP sheets on reinforced concrete beams in order to strengthen them.The fire protection of the CFRP sheets is done using the thick-type fireproofing coatings for tunnel(TFCT)and steel structure(TFCSS)respectively.Four specimens are tested in the furnace together.Specimens are exposed to fire for 1.5 h in according to the ISO834 standard fire curve,and then naturally cooled for 1 h.In the tests,the largest displacements at the mid-span positions of specimens are only from1/1400 to 1/318 of actual span corresponding to the highest temperatures from 300 ℃ to 470 ℃.After the specimens are naturally cooled to the normal temperature and the fireproofing coatings are then removed,it can be seen that the CFRP sheets keep in a good state,which indicates that CFRP sheets can be tightly bonded on the concrete and work well together with the concrete beams during and after fire.Besides,the tests also verify that the fire performance of TFCT is superior to TFCSS for the strengthened beams.

  12. Extraction of beryllium from refractory beryllium oxide with dilute ammonium bifluoride and determination by fluorescence: a multiparameter performance evaluation.

    Science.gov (United States)

    Goldcamp, Michael J; Goldcamp, Diane M; Ashley, Kevin; Fernback, Joseph E; Agrawal, Anoop; Millson, Mark; Marlow, David; Harrison, Kenneth

    2009-12-01

    Beryllium exposure can cause a number of deleterious health effects, including beryllium sensitization and the potentially fatal chronic beryllium disease. Efficient methods for monitoring beryllium contamination in workplaces are valuable to help prevent dangerous exposures to this element. In this work, performance data on the extraction of beryllium from various size fractions of high-fired beryllium oxide (BeO) particles (from Beryllium concentrations were determined by fluorescence using a hydroxybenzoquinoline fluorophore. The effects of ABF concentration and volume, extraction temperature, sample tube types, and presence of filter or wipe media were examined. Three percent ABF extracts beryllium nearly twice as quickly as 1% ABF; extraction solution volume has minimal influence. Elevated temperatures increase the rate of extraction dramatically compared with room temperature extraction. Sample tubes with constricted tips yield poor extraction rates owing to the inability of the extraction medium to access the undissolved particles. The relative rates of extraction of Be from BeO of varying particle sizes were examined. Beryllium from BeO particles in fractions ranging from less than 32 microm up to 212 microm were subjected to various extraction schemes. The smallest BeO particles are extracted more quickly than the largest particles, although at 90 degrees C even the largest BeO particles reach nearly quantitative extraction within 4 hr in 3% ABF. Extraction from mixed cellulosic-ester filters, cellulosic surface-sampling filters, wetted cellulosic dust wipes, and cotton gloves yielded 90% or greater recoveries. Scanning electron microscopy of BeO particles, including partially dissolved particles, shows that dissolution in dilute ABF occurs not just on the exterior surface but also via accessing particles' interiors due to porosity of the BeO material. Comparison of dissolution kinetics data shows that as particle diameter approximately doubles, extraction

  13. Preliminary Analysis of the General Performance and Mechanical Behavior of Irradiated FeCrAl Base Alloys and Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-30

    The iron-based, iron-chromium-aluminum (FeCrAl) alloys are promising, robust materials for deployment in current and future nuclear power plants. This class of alloys demonstrates excellent performance in a range of environments and conditions, including high-temperature steam (>1000°C). Furthermore, these alloys have the potential to have prolonged survival under loss-of-coolant accident (LOCA) conditions compared to the more traditional cladding materials that are either Zr-based alloys or austenitic steels. However, one of the issues associated with FeCrAl alloys is cracking during welding. The present project investigates the possibility of mitigating welding-induced cracking via alloying and precise structure control of the weldments; in the frame work of the project, several advanced alloys were developed and are being investigated prior to and after neutron irradiation to provide insight into the radiation tolerance and mechanical performance of the weldments. The present report provides preliminary results on the post-irradiation characterization and mechanical tests performed during United States Fiscal Year (FY) 2016. Chapter 1 provides a general introduction, and Chapter 2 describes the alloy compositions, welding procedure, specimen geometry and manufacturing parameters. Also, a brief discussion of the irradiation at the High Flux Isotope Reactor (HFIR) is provided. Chapter 3 is devoted to the analysis of mechanical tests performed at the hot cell facility; tensile curves and mechanical properties are discussed in detail focusing on the irradiation temperature. Limited fractography results are also presented and analyzed. The discussion highlights the limitations of the testing within a hot cell. Chapter 4 underlines the advantages of in-situ testing and discusses the preliminary results obtained with newly developed miniature specimens. Specimens were moved to the Low Activation Materials Development and Analysis (LAMDA) laboratory and prepared for

  14. Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars

    Directory of Open Access Journals (Sweden)

    de Rincón, O.

    2003-12-01

    Full Text Available This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermosprayed aluminum (3-year evaluation and conventional Al/Zn/In anocies in an epoxy-painted steel bracelet (12-year evaluation, indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermosprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials ( < -1100 mV vs. Cu/CuSO4 they supply to the reinforcement could lead to hydrogen embrittlement.

    Este trabajo presenta la realización de varios diseños de protección catódica utilizando aleaciones de aluminio para la protección de pilotes pretensados. Los resultados obtenidos con diferentes diseños (aleación de Al/Zn/In, tipo brazalete y aluminio termorociado (3 años de evaluación y ánodos convencionales de Al/Zn/In colocados en un brazalete de acero pintado con epoxy (12 años de evaluación, indicaron que todos estos sistemas pueden ser utilizados como ánodos de sacrificio para la protección de los pilotes. Sin embargo, el sistema con aluminio termorociado no puede ser utilizado en pilotes de acero pretensado debido al potencial muy negativo alcanzado por la armadura (<-1100 mV vs Cu/CuSO4, lo cual podría inducir a daños por hidrógeno.

  15. Development of wire drawing processes for refractory metal fibers

    Science.gov (United States)

    King, G. W.

    1972-01-01

    Fabrication schedules were developed for producing wire, 0.25 mm to 0.51 mm diameter, from the refractory metal alloys ASTAR-811C, B-88 and W-Hf-C. Tensile properties were evaluated at room temperature and up to 1204 C. Also, the stress rupture properties of the alloys at 1093 C were determined. W-Hf-C and B-88 were found to have the best mechanical properties on a strength to density basis. The fabrication schedules for producing wire from these two alloys were further improved with regards to the wire quality and material yield under the optimization of fabrication schedule.

  16. Fatigue performance of medical Ti6Al4V alloy after mechanical surface treatments.

    Directory of Open Access Journals (Sweden)

    Robert Sonntag

    Full Text Available Mechanical surface treatments have a long history in traditional engineering disciplines, such as the automotive or aerospace industries. Today, they are widely applied to metal components to increase the mechanical performance of these. However, their application in the medical field is rather rare. The present study aims to compare the potential of relevant mechanical surface treatments on the high cycle fatigue (R = 0.1 for a maximum of 10 million cycles performance of a Ti6Al4V standard alloy for orthopedic, spinal, dental and trauma surgical implants: shot peening, deep rolling, ultrasonic shot peening and laser shock peening. Hour-glass shaped Ti6Al4V specimens were treated and analyzed with regard to the material's microstructure, microhardness, residual stress depth profiles and the mechanical behavior during fatigue testing. All treatments introduced substantial compressive residual stresses and exhibited considerable potential for increasing fatigue performance from 10% to 17.2% after laser shock peening compared to non-treated samples. It is assumed that final mechanical surface treatments may also increase fretting wear resistance in the modular connection of total hip and knee replacements.

  17. Fatigue performance of medical Ti6Al4V alloy after mechanical surface treatments.

    Science.gov (United States)

    Sonntag, Robert; Reinders, Jörn; Gibmeier, Jens; Kretzer, J Philippe

    2015-01-01

    Mechanical surface treatments have a long history in traditional engineering disciplines, such as the automotive or aerospace industries. Today, they are widely applied to metal components to increase the mechanical performance of these. However, their application in the medical field is rather rare. The present study aims to compare the potential of relevant mechanical surface treatments on the high cycle fatigue (R = 0.1 for a maximum of 10 million cycles) performance of a Ti6Al4V standard alloy for orthopedic, spinal, dental and trauma surgical implants: shot peening, deep rolling, ultrasonic shot peening and laser shock peening. Hour-glass shaped Ti6Al4V specimens were treated and analyzed with regard to the material's microstructure, microhardness, residual stress depth profiles and the mechanical behavior during fatigue testing. All treatments introduced substantial compressive residual stresses and exhibited considerable potential for increasing fatigue performance from 10% to 17.2% after laser shock peening compared to non-treated samples. It is assumed that final mechanical surface treatments may also increase fretting wear resistance in the modular connection of total hip and knee replacements.

  18. Fireclay Refractory Bricks

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaohui

    2010-01-01

    @@ 1 Scope This standard specifies the classification,brand,shape,dimension,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of fireclay refractory bricks.

  19. Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Ashdown, B.G. (comp.)

    1980-04-01

    Progress is reported concerning preparation of a materials handbook for fusion, creep-fatigue of first-wall structural materials, test results on miniature compact tension fracture toughness specimens, austenitic stainless steels, Fe-Ni-Cr alloys, iron-base alloys with long-range crystal structure, ferritic steels, irradiation experiments, corrosion testing, and hydrogen permeation studies. (FS)

  20. Refractory duodenal ulcer

    Directory of Open Access Journals (Sweden)

    Al Freihi Hussein

    1995-01-01

    Full Text Available Refractory or intractable ulcer is defined as an ulcer that fails to heal completely after eight to twelve weeks, despite appropriate treatment with a modern antiulcer therapy in a compliant patient. Refractory ulcer should be suspected in individuals diagnosed to have peptic ulcer if their symptoms persist longer than usual: occurrence of complications or simply their ulcers fail to heal, since up to 25% of such patients remain asymptomatic. Conditions associated with refractory ulcer include noncompliance, continuous consumption of nonsteroidal anti-inflam-matory drugs, acid hypersecretion, smoking. male gender and other factors with questionable role like advanced age, large ulcer size, prolonged duration of symptoms and the presence of complication like bleeding. Nonpeptic ulcers like tuberculosis, malignancy, Crohn′s disease and primary intestinal lymphoma should always be considered in the differential diagnosis. Colonization with H. pylori which is well-known as a cause of frequent recurrences, has not been linked with refractoriness. Patients with refractory ulcers must undergo thorough re-evaluation including repeated endoscopies, obtaining biopsies for microbiology and histology and determination of serum-gastrin level. Once diseases with identifiable etiologies have been ruled out, aggressive medical management with single or multiple antiulcer drugs should be instituted. Such treatments will virtually heal all refractory ulcers. Surgery should be reserved for patients whose ulcers fail to respond to optimal medical therapy or those who develop com-plications necessitating surgical intervention.

  1. Considerations on the performance and fabrication of candidate materials for the Yucca Mountain repository waste packages highly corrosion resistant nickel-base and titanium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dalder, E; Goldberg, A

    1995-11-30

    Among the metallurgical factors that affect the performance of a material in a given environment are alloy composition, alloy segregation, depletion of alloying elements, non-uniform microstructures, precipitation leading to an increase in susceptibility to corrosion as well as decreases in ductility, residual plastic deformation, and residual stresses. Precipitation often occurs preferentially at grain boundaries, causing depletion of critical elements in regions adjacent to these boundaries. Continuous grain-boundary precipitates can lead to drops in ductility and toughness. The presence of non-metallic inclusions, if excessive and/or segregated, can also cause embrittlement. Segregation of alloying elements can result in localized galvanic action. Depletion of alloying elements as well as segregation can result in reductions in the concentrations of critical elements below those necessary to resist localized corrosion. Segregation and alloy depletion can also facilitate precipitation that could lead to embrittlement.

  2. Technology Progress of Refractories for Iron Making in China

    Institute of Scientific and Technical Information of China (English)

    CHAI Junlan; CHENG Qingxian; SHEN Keyin

    2005-01-01

    This paper reviews the present development situation of refractories for iron making system in China, which includes blast furnace, hot blast stove and coke dry quenching, etc. Varieties and performances of refractories used by the top steel and iron groups such as Baosteel, Wuhan I&S Group and Anshan I&S Group for iron making were exemplified and concerned problems were analyzed,together with solutions and suggestions for future refractories R&D work.

  3. Preliminary Analysis of the General Performance and Mechanical Behavior of Irradiated FeCrAl Base Alloys and Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N [ORNL; Field, Kevin G [ORNL; Yamamoto, Yukinori [ORNL

    2016-09-01

    The iron-based, iron-chromium-aluminum (FeCrAl) alloys are promising, robust materials for deployment in current and future nuclear power plants. This class of alloys demonstrates excellent performance in a range of environments and conditions, including high-temperature steam (>1000 C). Furthermore, these alloys have the potential to survive greater durations under lost-of-coolant incident (LOCA) conditions compared to the more traditional cladding materials that are Zr-based or austenitic steels. However, one of the issues associated with FeCrAl alloys is cracking during welding. The present project investigates the possibility to mitigate welding-induced cracking via alloying and precise structure control of the weldments; in the frame work of the project, several advanced alloys were developed and are being investigated prior to and after neutron irradiation to provide insight into the radiation tolerance and mechanical performance of the weldments. The present report provides preliminary, working results on the post-irradiation characterization and mechanical tests performed during United States Fiscal Year (FY) 2016. Chapter 1 provides a general introduction, and Chapter 2 describes the alloy compositions, welding procedure, specimen geometry and manufacturing. Also, a brief discussion of the irradiation at the High-Flux Isotope Reactor (HFIR) is provided. Chapter 3 is devoted to the analysis of mechanical tests performed at the hot cell facility; tensile curves and mechanical properties are discussed in details focusing on the irradiation temperature role. Limited fractography results are also given and analyzed. The discussion highlights the limitations of the testing at the hot cell. Chapter 4 underlines the advantages of in-situ testing and discusses the preliminary results obtained with newly developed miniature specimens. Specimens were moved to the Low Activation Materials Development Laboratory (LAMDA) and prepared for mechanical tests. Follow-on SEM

  4. Pulsed-mode operation and performance of a ferromagnetic shape memory alloy actuator

    Science.gov (United States)

    Asua, E.; García-Arribas, A.; Etxebarria, V.; Feuchtwanger, J.

    2014-02-01

    The actuation capabilities and positioning performance of a single crystal ferromagnetic shape memory alloy (FSMA) operated in pulsed mode are evaluated in a prototype device. It consists of two orthogonal coil pairs that produce the magnetic fields necessary for the non-contact deformation of the material. The position of the top of the crystal after actuation is measured by a capacitive sensor. A specifically designed power module drives the discharge of a set of capacitors through the coils, producing fast current pulses of large amplitudes (about 250 A), the coil pairs are driven independently to control the direction of actuation. Open-loop experiments demonstrate that successive pulses of increasing magnitude successfully produced the desired expansion and contraction of the crystal, depending on the pair of coils that is activated. The deformation achieved is maintained after the pulses, highlighting the advantageous set-and-forget operation of the device. Closed-loop experiments are performed using a double proportional-integral-derivative controller, designed to take advantage of the energy-saving quality of the set-and-forget operation. Despite the nonlinear response and hysteric response of FSMA materials, a reference position can be reached and maintained with a maximum error of 0.5 μm.

  5. Two-Dimensional Atomic-Layered Alloy Junctions for High-Performance Wearable Chemical Sensor.

    Science.gov (United States)

    Cho, Byungjin; Kim, Ah Ra; Kim, Dong Jae; Chung, Hee-Suk; Choi, Sun Young; Kwon, Jung-Dae; Park, Sang Won; Kim, Yonghun; Lee, Byoung Hun; Lee, Kyu Hwan; Kim, Dong-Ho; Nam, Jaewook; Hahm, Myung Gwan

    2016-08-03

    We first report that two-dimensional (2D) metal (NbSe2)-semiconductor (WSe2)-based flexible, wearable, and launderable gas sensors can be prepared through simple one-step chemical vapor deposition of prepatterned WO3 and Nb2O5. Compared to a control device with a Au/WSe2 junction, gas-sensing performance of the 2D NbSe2/WSe2 device was significantly enhanced, which might have resulted from the formation of a NbxW1-xSe2 transition alloy junction lowering the Schottky barrier height. This would make it easier to collect charges of channels induced by molecule adsorption, improving gas response characteristics toward chemical species including NO2 and NH3. 2D NbSe2/WSe2 devices on a flexible substrate provide gas-sensing properties with excellent durability under harsh bending. Furthermore, the device stitched on a T-shirt still performed well even after conventional cleaning with a laundry machine, enabling wearable and launderable chemical sensors. These results could pave a road toward futuristic gas-sensing platforms based on only 2D materials.

  6. REFRACTORY THROMBOCYTOPENIA AND NEUTROPENIA: A DIAGNOSTIC CHALLENGE

    Directory of Open Access Journals (Sweden)

    Emmanuel Gyan

    2015-02-01

    Full Text Available Background. The 2008 WHO classification identified refractory cytopenia with unilineage dysplasia (RCUD as a composite entity encompassing refractory anemia, refractory thrombocytopenia (RT, and refractory neutropenia (RN, characterized by 10% or more dysplastic cells in the bone marrow respective lineage. The diagnosis of RT and RN is complicated by several factors.  Diagnosing RT first requires exclusion of familial thrombocytopenia, chronic auto-immune thrombocytopenia, concomitant medications, viral infections, or hypersplenism. Diagnosis of RN should also be made after ruling out differential diagnoses such as ethnic or familial neutropenia, as well as acquired, drug-induced, infection-related or malignancy-related neutropenia. An accurate quantification of dysplasia should be performed in order to distinguish RT or RN from the provisional entity named idiopathic cytopenia of unknown significance (ICUS. Cytogenetic analysis, and possibly in the future somatic mutation analysis (of genes most frequently mutated in MDS, and flow cytometry analysis aberrant antigen expression on myeloid cells may help in this differential diagnosis. Importantly, we and others found that, while isolated neutropenia and thrombocytopenia are not rare in MDS, those patients can generally be classified (according to WHO 2008 classification as refractory cytopenia with multilineage dysplasia or refractory anemia with excess blasts, while RT and RN (according to WHO 2008 are quite rare.These results suggest in particular that identification of RT and RN as distinct entities could be reconsidered in future WHO classification updates.

  7. Phosphatizing of Mg particles to improve the protective performance of Mg-rich primer on A2024 Al alloy

    Science.gov (United States)

    Wang, Jianguo; Zuo, Yu; Tang, Yuming; Lu, Xiangyu

    2014-02-01

    Mg-rich primer as a new type protective coating provides cathodic protection for Al alloy. In this paper, a kind of phosphatizing surface treatment on Mg particles was studied in order to improve the protective performance of Mg-rich primer. After treated with phosphoric acid, a protective magnesium phosphate layer was formed on the surface of Mg particles, which had no negative influence on the cathodic protection of the Mg-rich primer for Al alloy. The coating resistance of the treated Mg-rich primer was bigger than that of untreated primer, meanwhile the coating capacitance of the treated Mg-rich primer was smaller than that of untreated primer, suggesting that the barrier effect of the primer was improved and the lifetime was extended. The magnesium phosphate layer could reduce the consumption rate of Mg particles. Meanwhile, the phosphate radicals transported to Al alloy substrate to form a product layer composed of magnesium phosphate and aluminum phosphate on the substrate surface, which decreased the corrosion rate of Al alloy and improved the protective performance of the primer.

  8. Hydrogen storage performances of LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) alloys prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Wang, Haitao [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Zhai, Tingting; Yang, Tai; Yuan, Zeming; Zhao, Dongliang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China)

    2015-10-05

    Highlights: • Amorphous and nanostructured alloys were prepared by mechanical milling. • The maximum discharge capacity of ball milled alloys reaches to 1053.5 mA h/g. • The addition of Ni significantly increases the discharge capacity. • Increasing milling time reduces the kinetic performances of ball milled alloys. - Abstract: In order to improve the hydrogen storage performances of Mg-based materials, LaMg{sub 11}Ni alloy was prepared by vacuum induction melting. Then the nanocrystalline/amorphous LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) hydrogen storage alloys were synthesized by ball milling technology. The structure characterizations of the alloys were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical hydrogen storage characteristics were tested by using programmed control battery testing system. The electrochemical impedance spectra (EIS), potentiodynamic polarization curves and potential-step curves were also plotted by an electrochemical workstation (PARSTAT 2273). The results indicate that the as-milled alloys exhibit a nanocrystalline and amorphous structure, and the amorphization degree of the alloys visibly increases with extending milling time. Prolonging the milling duration markedly enhances the electrochemical discharge capacity and cyclic stability of the alloys. The electrochemical kinetics, including high rate discharge ability (HRD), charge transfer rate, limiting current density (I{sub L}), hydrogen diffusion coefficient (D), monotonously decrease with milling time prolonging.

  9. Damping performance of Cu-Zn-Al shape memory alloys in engineering structures

    Institute of Scientific and Technical Information of China (English)

    司乃潮; 孙克庆; 孙少纯; 刘海霞

    2004-01-01

    The stress strain curves of two CuZnAl shape memory alloys which have the martensitic transformation temperatures of 50 ℃ and -10 ℃ respectively, were measured by using electronic material tester after treated by different heat-treatment conditions. The results show that the area enclosed by hysteresis loop of the CuZnAl shape memory alloy in martensitic state is much larger than that of the alloy in austenitic state with super-elasticity at room temperature. Therefore, the former has better vibration attenuation effect. After being oil-quenched, waterquenched, and step-quenched, the CuZnAl alloy takes on more stable shape memory effect, better super-plasticity and superelasticity (pseudoelasticity). A CuZnAl shape memory alloy damper was designed, produced and installed to a 2-layer frame structure. In addition, the vibration experiments were made by dynamic data collecting analysis meter. The velocity of vibration attenuation of frame structure with CuZnAl shape memory alloy damper is much faster than that without it. And with the help of CuZnAl shape memory alloy damper, the attenuation period reduces to 1/10 of the original.

  10. Refractory Materials for Flame Deflector Protection System Corrosion Control: Refractory Ceramics Literature Survey

    Science.gov (United States)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.; Coffman, Brekke E.

    2009-01-01

    . Figure 2 shows many ofthese applications, their life expectancy or requirement, and the exposure temperature for the refractory ceramic. Note that the exposure temperatures for refractory ceramics are very similar to the exposure conditions for specialty ceramics (rocket nozzles, space vehicle re-entry fields, etc.) and yet the life expectancy or requirement is relatively low. Currently NASA is repairing the refractory lining in the flame trench after every launch - although this is not a direct indication of low life expectancy, it does indicate that the current system may not be sufficiently durable to maximize economy. Better performing refractory ceramics are needed to improve the performance, economy, and safety during and after launches at the flame trenches at Kennedy Space Center (KSC). To achieve this goal a current study is underway to assess different refractory systems for possible use in the flame trenches at KSC. This report will target the potential applicability of refractory ceramics for use in the flame trenches. An overview of the different refractory ceramics will be provided (see Figure I). This will be followed with a brief description of the structure of refractory products, the properties and characteristics of different systems, the methodology for selecting refractories, and then a general design methodology. Based on these sections, future challenges and opportunities will be identified with the objective of improving the durability, performance, economy, and safety of the launch complex. Refractory ceramics are used for a wide variety of applications. Figure 2 shows many ofthese applications, their life expectancy or requirement, and the exposure temperature for the refractory ceramic. Note that the exposure temperatures for refractory ceramics are very similar to the exposure conditions for specialty ceramics (rocket nozzles, space vehicle re-entry fields, etc.) and yet the life expectancy or requirement is relatively low. Currently NASA is

  11. Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor

    Science.gov (United States)

    Übeyli, Mustafa; Tel, Eyyüp

    2003-06-01

    Selection of structural material for a fusion-fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic/martensitic steels, vanadium alloys and SiC/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory alloys, namely, W-5Re, T111, TZM and Nb-1Zr on neutronic performance of the hybrid reactor was investigated. Neutron transport calculations were conducted with the help of SCALE 4.3 System by solving the Boltzmann transport equation with code XSDRNPM. Among the investigated structural materials, tantalum had the worst performance due to the fact that it has higher neutron absorption cross section than others. And W-5Re and TZM having similar results showed the best performance.

  12. Aspects of high-cycle fatigue performance in a Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, B.L.; Campbell, J.P.; Roder, O.; Thompson, A.W.; Ritchie, R.O.

    1999-07-01

    Determination of critical levels of microstructural damage that can lead to fatigue crack propagation under high-cycle fatigue loading conditions is a major concern for the aircraft industry regarding structural integrity of turbine engine components. The cyclic frequencies characteristic of service loading spectra are extremely high and appear to require a damage-tolerant design approach. One idea for such an approach is to attempt to define a practical, appropriate crack-propagation threshold, {Delta}K{sub TH}. The present study identifies a practical lower-bound large-crack threshold under high-cycle fatigue conditions in a Ti-6 Al-4V blade alloy (with {approximately}60% primary {alpha} in a matrix of lamellar {alpha}+{beta}). The authors suggest that lower-bound thresholds can be determined by modifying standard large-crack propagation tests to simulate small-crack behavior. Modification techniques include high load-ratio testing under both constant-R and constant-K{sub max} conditions, performed at cyclic loading frequencies up to 1 kHz and R ratios up to 0.95. The results of these tests are compared to the near-threshold behavior of naturally-initiated small cracks, and to the crack initiation and early growth behavior of small cracks emanating from sites of simulated foreign object damage.

  13. Development of diamond coated tool and its performance in machining Al–11%Si alloy

    Indian Academy of Sciences (India)

    B Sahoo; A K Chattopadhyay; A B Chattopadhyay

    2002-11-01

    An attempt has been made to deposit CVD diamond coating on conventional carbide tool using hot filament CVD process. ISO grade K10 turning inserts with SPGN 120308 geometry were used to deposit diamond coating. This diamond coating well covering the rake surface, cutting edges and flank surfaces could be successfully deposited. The coatings were characterized by SEM, XRD and Raman spectroscopy for coating quality, morphology etc. Performance of diamond coated tool relative to that of uncoated carbide tool was evaluated in turning Al–11%Si alloy under dry environment. The diamond coated tool outperformed the uncoated carbide tool which severely suffered from sizeable built-up edge formation leading not only to escalation of cutting forces but also poorer surface finish. In contrast, the diamond coated tool, owing to chemical inertness of diamond coating towards the work material, did not show any trace of edge built-up even in dry environment and could maintain low level of cutting forces and remarkably improved surface finish. It has been further revealed that success of the diamond coated tool depends primarily on adhesion of the diamond coating with the carbide substrate and this is strongly influenced by the pre-treatment of the carbide substrate surface before coating.

  14. Evaluation of the mechanical and corrosion protection performance of electrodeposited hydroxyapatite on the high energy electron beam treated titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gopi, D., E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011,Tamil Nadu (India); Sherif, El-Sayed M. [Center of Excellence for Research in Engineering Materials (CEREM), Advanced Manufacturing Institute, King Saud University, P.O. Box 800, Al-Riyadh 11421 (Saudi Arabia); Electrochemistry and Corrosion Laboratory, Department of Physical Chemistry, National Research Centre (NRC), Dokki, 12622 Cairo (Egypt); Rajeswari, D. [Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu (India); Department of Physics, Periyar University, Salem 636 011, Tamil Nadu (India); Kavitha, L. [Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Thiruvarur 610 101, Tamil Nadu (India); Pramod, R.; Dwivedi, Jishnu [Industrial Accelerator Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013, Madhya Pradesh (India); Polaki, S.R. [Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

    2014-12-15

    Graphical abstract: - Highlights: • Ti–6Al–4V alloy was surface treated by high energy low current DC electron beam. • Successful electrodeposition of HAP was achieved on surface treated Ti–6Al–4V. • The as-formed coating possessed improved surface wettability and adhesion strength. • Maximum corrosion protection performance was exhibited by the as-formed coating. - Abstract: In our present study, the Ti–6Al–4V alloy surface was modified by irradiating with the high energy low current DC electron beam (HELCDEB) using 700 keV DC accelerator. Following this, the HELCDEB treated surface was coated with hydroxyapatite by adopting electrodeposition method. The microstructure and hardness of HELCDEB treated Ti–6A1–4V alloy with and without electrodeposited hydroxyapatite were investigated. Also, the electrochemical corrosion characteristics of the samples in simulated body fluid (SBF) was studied by potentiodynamic polarisation and electrochemical impedence techniques (EIS) which showed an enhanced corrosion resistance and revealed an improved life time for the hydroxyapatite coating developed on the HELCDEB treated Ti–6A1–4V alloy than the untreated sample.

  15. Effects of Stoichiometry on Transformation Temperatures and Actuator-Type Performance of NiTiPd and NiTiPdX High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Bigelow, Glen S.; Gaydosh, Darrell; Garg, Anita; Padula, Santo A., II; Noebe, Ronald D.

    2007-01-01

    High-temperature shape memory NiTiPd and NiTiPdX (X=Au, Pt, Hf) alloys were produced with titanium equivalent (Ti+Hf) compositions of 50.5, 50.0, 49.5, and 49.0 at.%. Thermo-mechanical testing in compression was used to evaluate the transformation temperatures, transformation strain, work output, and permanent deformation behavior of each alloy to study the effects of quaternary alloying and stoichiometry on high-temperature shape memory alloy behavior. Microstructural evaluation showed the presence of second phases for all alloy compositions. No load transformation temperatures in the stoichiometric alloys were relatively unchanged by Au and Pt substitutions, while the substitution of Hf for Ti causes a drop in transformation temperatures. The NiTiPd, NiTiPdAu and NiTiPdHf alloys exhibited transformation temperatures that were highest in the Ti-rich compositions, slightly lower at stoichiometry, and significantly reduced when the Ti equivalent composition was less than 50 at.%. For the NiTiPdPt alloy, transformation temperatures were highest for the Ti-rich compositions, lowest at stoichiometry, and slightly higher in the Ni-rich composition. When thermally cycled under constant stresses of up to 300 MPa, all of the alloys had transformation strains, and therefore work outputs, which increased with increasing stress. In each series of alloys, the transformation strain and thus work output was highest for stoichiometric or Ti-rich compositions while permanent strain associated with the constant-load thermal cycling was lowest for alloys with Ni-equivalent-rich compositions. Based on these results, basic rules for optimizing the composition of NiTiPd alloys for actuator performance will be discussed.

  16. RHI Refractories Opens Dalian Plant

    Institute of Scientific and Technical Information of China (English)

    Stefan Pirker

    2004-01-01

    @@ End of November the opening ceremony of the RHI Refractories Dalian plant took place in the presence of 250 guests from China and Europe. RHI Refractories welcomed highly official guests from the Dalian City and the Dalian Development Area, the Supervisory Board of RHI, the company's biggest shareholder, the Board of Management, representatives of customers in China as well as Professors of China's refractory academic field. The ceremony' s highlight was the speech of Professor Zhong Xiangchong from Zhengzhou University, member of the China Academy of Science, who pointed out RHI Refractories' long and successful history of refractory innovations during the last decades and the future possibilities of collaboration with RHI Refractories.

  17. Enhanced electrocatalytic performance of Pt monolayer on nanoporous PdCu alloy for oxygen reduction

    Science.gov (United States)

    Hou, Linxi; Qiu, Huajun

    2012-10-01

    By selectively dealloying Al from PdxCu20-xAl80 ternary alloys in 1.0 M NaOH solution, nanoporous PdCu (np-PdCu) alloys with different Pd:Cu ratios are obtained. By a mild electrochemical dealloying treatment, the np-PdCu alloys are facilely converted into np-PdCu near-surface alloys with a nearly pure-Pd surface and PdCu alloy core. The np-PdCu near-surface alloys are then used as substrates to fabricate core-shell catalysts with a Pt monolayer as shell and np-PdCu as core by a Cu-underpotential deposition-Pt displacement strategy. Electrochemical measurements demonstrate that the Pt monolayer on np-Pd1Cu1 (Pt/np-Pd1Cu1) exhibits the highest Pt surface-specific activity towards oxygen reduction, which is ˜5.8-fold that of state-of-the-art Pt/C catalyst. The Pt/np-Pd1Cu1 also shows much enhanced stability with ˜78% active surface retained after 10,000 cycles (0.6-1.2 V vs. RHE). Under the same condition, the active surface of Pt/C drops to ˜28%.

  18. Modification Performance of WC Nanoparticles in Aluminum and an Al-Si Casting Alloy

    Science.gov (United States)

    Borodianskiy, Konstantin; Zinigrad, Michael

    2016-04-01

    The influence of a modifier based on tungsten carbide (WC) nanoparticles is investigated first using 1 kg of bulk aluminum and then in a real industrial process using a commercial Al-Si casting alloy. The modifier is prepared by two different approaches, and its influence is investigated in pure aluminum and in commercial aluminum alloy A356. Microstructural studies show that the mean grain size in pure aluminum is reduced by 11.5 pct. Such a change usually causes an improvement in the mechanical properties of metals. Accordingly, the mechanical properties of the A356 alloy modified with WC nanoparticles are determined after T6 heat treatment and compared with unmodified specimens of the same alloy. The results obtained in the modified A356 alloy reveal unusual behavior of the mechanical properties, where the elongation of the alloys improved by 32 to 64 pct, while the tensile strength and yield strength remained unchanged. This behavior is attributable to a grain-size strengthening mechanism, where strengthening occurs due to the high concentration of grain boundaries, which act as obstacles to the motion of dislocations in the lattice.

  19. Performance Enhancement of Silicon Alloy-Based Anodes Using Thermally Treated Poly(amide imide) as a Polymer Binder for High Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Yang, Hwi Soo; Kim, Sang-Hyung; Kannan, Aravindaraj G; Kim, Seon Kyung; Park, Cheolho; Kim, Dong-Won

    2016-04-05

    The development of silicon-based anodes with high capacity and good cycling stability for next-generation lithium-ion batteries is a very challenging task due to the large volume changes in the electrodes during repeated cycling, which results in capacity fading. In this work, we synthesized silicon alloy as an active anode material, which was composed of silicon nanoparticles embedded in Cu-Al-Fe matrix phases. Poly(amide imide)s, (PAI)s, with different thermal treatments were used as polymer binders in the silicon alloy-based electrodes. A systematic study demonstrated that the thermal treatment of the silicon alloy electrodes at high temperature made the electrodes mechanically strong and remarkably enhanced the cycling stability compared to electrodes without thermal treatment. The silicon alloy electrode thermally treated at 400 °C initially delivered a discharge capacity of 1084 mAh g(-1) with good capacity retention and high Coulombic efficiency. This superior cycling performance was attributed to the strong adhesion of the PAI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. These findings are supported by results from X-ray photoelectron spectroscopy, scanning electron microscopy, and a surface and interfacial cutting analysis system.

  20. A Probabilistic Performance Assessment Model for General Corrosion of Alloy 22 for High Level Nuclear Waste Disposal Container

    Energy Technology Data Exchange (ETDEWEB)

    J. H. Lee; H. A. Elayat

    2003-12-11

    Alloy 22 (UNS N06022) is the candidate material for the corrosion barrier of the double-wall waste package (WP) for the disposal of high-Gel nuclear waste at the proposed Yucca Mountain repository. A probabilistic temperature-dependent general corrosion model for the WP outer barrier (WPOB) was developed based on the 5-year weight-loss measurements of Alloy 22 crevice samples. The 5-year corrosion rate distribution is represented by a Weibull distribution, with scale factors = 8.88, shape factor b = 1.62, and location factor l = 0. The temperature-dependence of the general corrosion rate was modeled using an Arrhenius relation. An activation energy of 25.91 {+-} 2.46 kJ/mol was determined from the corrosion rates obtained from the short-term polarization resistance data for Alloy 22 specimens tested for a wide range of sample configurations, metallurgical conditions, and exposure conditions (temperature and water chemistry). Analysis of the data from the current study and the literature indicates that the activation energies of general corrosion rate of highly corrosion resistant Ni-Cr-Mo alloys including Alloy 22 are similar and do not change significantly, as the general corrosion rate decreases with the exposure time. The 5-year corrosion rates were conservatively selected for extrapolation over the repository time scale. Because of very low general corrosion rates of the WPOB for the conditions expected in the proposed repository, the WP performance will not be limited by general corrosion for the repository regulatory time period. The current conservative approach for the constant (time-independent) general corrosion rate at a given temperature provides an additional confidence for the general corrosion model.

  1. Microstructure and performance of solid TC4 titanium alloy subjected to the high pulsed magnetic field treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.R., E-mail: liguirong@ujs.edu.cn; Li, Y.M.; Wang, F.F.; Wang, H.M.

    2015-09-25

    Highlights: • A high pulsed magnetic field was introduced to process the solid titanium alloy. • The phase transition from beta to alpha in processed alloy was discovered. • The magneto-plasticity effect was found and highlighted. • The strength and toughness of treated alloy were enhanced synchronously. - Abstract: The effect of high pulsed magnetic field with different magnetic induced intensity (B) on the microstructure and mechanical performance of solid TC4 titanium alloy was investigated. The microstructure morphology was characterized by metallographic microscope, scanning electronic microscopy and transmission electronic microscopy. The results show that the magnetic has induced the phase transformation from β to α. At 4 T the volume fraction of α phase has increased from 49% (B = 0) to 59%. Meanwhile, compared to that of original sample the dislocation density at 3 T is 4.8 times, which was the result of magneto-plasticity effect. However, the dislocation density will not always increase with B due to the dislocation pile-up effect. The mechanical properties tests show that the strength of materials is enhanced with the B increase within a certain scope. The strength and elongation of processed TC4 alloy exhibit the obvious changes: when B = 3 T the maximum strength reaches 1330 MPa which ascribes to the dislocation strengthening. It is enhanced by 7.6% compared to that of original sample. It is noted that when B = 4 T the strength and toughness are improved simultaneously which are attributed to not only the dislocation strengthening but also the amount, distribution and morphology of α phase.

  2. Refractory peptic ulcer disease.

    Science.gov (United States)

    Napolitano, Lena

    2009-06-01

    Refractory PUD is a diagnostic and therapeutic challenge. Optimal management of severe or refractory PUD requires a multidisciplinary team approach, using primary care providers, gastroenterologists, and general surgeons. Medical management has become the cornerstone of therapy. Identification and eradication of H pylori infection combined with acid reduction regimens can heal ulceration and also prevent recurrence. Severe, intractable or recurrent PUD and associated complications mandates a careful and methodical evaluation and management strategy to determine the potential etiologies and necessary treatment (medical or surgical) required.

  3. ZrO2-Containing Refractories for Cement Rotary Kilns

    Institute of Scientific and Technical Information of China (English)

    YE Guotian; XU Yanqing

    2002-01-01

    ZrO2-containing refractories have been increasingly used for cement rotary kilns. This paper discusses how the properties and performance of ZrO2-containing. Refractories are inwroved in terms of chemical attack resistance, thermal shock resistance, thermal conductivity and mechanical stress.

  4. Barrier Coatings for Refractory Metals and Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-02-23

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  5. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

    Gilliland, R.G.; Patriarca, P.; Slaughter, G.M.; Williams, L.C.

    1962-06-12

    A new and improved ternary alloy is described which is of particular utility in braze-bonding parts made of a refractory metal selected from Group IV, V, and VI of the periodic table and alloys containing said metal as a predominating alloying ingredient. The brazing alloy contains, by weight, 40 to 50 per cent zirconium, 40 to 50 per cent titanium, and the balance beryllium in amounts ranging from 1 to 20 per cent, said alloy having a melting point in the range 950 to 1400 deg C. (AEC)

  6. Microstructure and degradation performance of biodegradable Mg-Si-Sr implant alloys.

    Science.gov (United States)

    Gil-Santos, Andrea; Marco, Iñigo; Moelans, Nele; Hort, Norbert; Van der Biest, Omer

    2017-02-01

    In this work the microstructure and degradation behavior of several as-cast alloy compositions belonging to the Mg rich corner of the Mg-Si-Sr system are presented and related. The intermetallic phases are identified and analyzed describing the microstructure evolution during solidification. It is intended in this work to obtain insight in the behavior of the ternary alloys in in vitro tests and to analyze the degradation behavior of the alloys under physiologically relevant conditions. The as-cast specimens have been exposed to immersion tests, both mass loss (ML) and potentiodynamic polarization (PDP). The degradation rate (DR) have been assessed and correlated to microstructure features, impurity levels and alloy composition. The initial reactions resulted to be more severe while the degradation stabilizes with time. A higher DR is related with a high content of the Mg17Sr2 phase and with the presence of coarse particles of the intermetallics Mg2Si, MgSiSr and MgSi2Sr. Specimens with a higher DR typically have higher levels of impurities and alloy contents.

  7. Refractory Minerals in Henan Province

    Institute of Scientific and Technical Information of China (English)

    JIN Qinguo; LI Jing; LIU Jiehua; LIU Yanjun

    2004-01-01

    Henan province is very rich in refractory minerals of many varieties including silica, dolomite, graphite,pearlite, sepiolite, olivine, and sillimanite group minerals, besides the abundant reserves of fireclay and bauxite,which lay a good foundation for the development of the refractories industry of the province. The paper introduces the reserves, distribution and character of the refractory minerals in Henan province.

  8. Preparation technology and anti-corrosion performances of black ceramic coatings formed by micro-arc oxidation on aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    CHEN Ling; HAN Jing; YU Shengxue

    2006-01-01

    In order to prepare ornamental and anti-corrosive coating on aluminum alloys, preparation technology of black micro-arc ceramic coatings on Al alloys in silicate based electrolyte was studied.The influence of content of Na2WO4 and combination additive in solution on the performance of black ceramic coatings was studied; the anticorrosion performances of black ceramic coatings were evaluated through whole-immersion test and electrochemical method in 3.5% NaCl solution at different pH value; SEM and XRD were used to analyze the surface morphology and phase constitutes of the black ceramic coatings.Experimental results indicated that, without combination additives, with the increasing of Na2WO4 content in the electrolyte, ceramic coating became darker and thicker, but the color was not black; after adding combination additive, the coating turned to be black; the black ceramic coating was multi-hole form in surface.There was a small quantity of tungsten existing in the black ceramic coating beside α-Al2O3 phase and β-Al2O3 phase.And aluminum alloy with black ceramic coating exhibited excellent anti-corrosion property in acid, basic and neutral 3.5% NaCl solution.

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

    Science.gov (United States)

    Zhang, Jialei; Gu, Changdong; Tu, Jiangping

    2017-03-29

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

  10. Corrosion Inhibition Performance of Triazole Derivatives on Copper-Nickel Alloy in 3.5 wt.% NaCl Solution

    Science.gov (United States)

    Jiang, B.; Jiang, S. L.; Liu, X.; Ma, A. L.; Zheng, Y. G.

    2015-12-01

    This study investigates the performance of three triazole derivatives with different molecular structures as corrosion inhibitors for the copper-nickel alloy CuNi 90/10 in 3.5 wt.% NaCl solution. Inhibition behavior was systematically determined through electrochemical measurements, scanning electron microscopy, energy-dispersive spectroscopy, and Fourier transform infrared spectroscopy. In addition, adsorption behavior and the inhibition mechanism were investigated via quantum chemical calculation and molecular dynamic simulation. Experimental results indicate that the three inhibitors with triazole rings and heteroatoms exhibited excellent corrosion inhibition capabilities on the copper-nickel alloy surface through physisorption and chemisorption. In particular, 3-amino-5-mercapto-1,2,4-triazole showed the best inhibition capability according to the concentration ranges considered in the experiments. The results of quantum chemical calculation agreed with the experimental findings.

  11. Analysis on the Causes for Refractory GERD

    Institute of Scientific and Technical Information of China (English)

    陈婕; 许军英; 徐勇; 谢小平; 易粹琼; 侯晓华

    2002-01-01

    To analyze the causes of failure in conventional treatment to refractory gastroesophageal reflux diseases (GERD) patients, 16 refractory GERD patients (group R) and 16 eases of GERD primarily diagnosed (group P) were studied. Endoscopy, pathologic examination and 14C urea breath test were conducted in every patient. 24 h ambulatory pH and bilirubin monitoring were performed with Digitrapper MI Ⅲ and Synetics Bilitec 2000. It was found that esophagitis in group R was more severe than in group P. The rate of Helicobacter pylori infection in group R was significantly lower than in group P. Fraction time pH below 4. 00 was not longer while the bile reflux represented by fraction time abs above 0. 14 was greater for patients in the group R as compared with those in the group P. The mixed refluxes and pure bile refluxes between the two groups had significant difference. The reflux episodes in the group R mainly occurred during nights. These results indicated that severe esophagitis, especially Barrett's esophagus with complications makes it difficult to control GERD. Severe duodenogastroesophageal refluxes (DGER) are often accompanied by refractory GERD. Mixed refluxes aggravate the esophageal injuries. Pure bile refluxes and nocturnal refluxes may cause failure of administration of proton pump inhibitors (PPI) in the morning. Helicobacter pylori infection and acid refluxes may not be the direct cause of refractoriness. Individual refractory GERD patient without abnormal results on pH or bile reflux recently should be diagnosed again.

  12. Alloy development for irradiation performance. Quarterly progress report for period ending March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Ashdown, B.G. (comp.)

    1980-06-01

    This report is organized along topical lines in parallel to a Program Plan of the same title so that activities and accomplishments may be followed readily relative to that Program Plan. Thus, the work of a given laboratory may appear throughout the report. Chapters 1, 2, 8, and 9 review activities on analysis and evaluation, test methods development, status of irradiation experiments, and corrosion testing and hydrogen permeation studies, respectively. These activities relate to each of the alloy development paths. Chapters 3, 4, 5, 6, and 7 present the ongoing work on each alloy development path. The Table of Contents is annotated for the convenience of the reader.

  13. Development of Low Cost, High Performance AlZn4.5Mg1 Alloy 7020

    Science.gov (United States)

    2009-02-01

    MPa) U.T.S. (MPa) El. (%) Data Reference 7005-T651 290 (42) 370 (54) 15 typical [6] 6061 -T651 300 (44) 337 (49) 19 experiment [15] 7018...Aluminum Association chemical composition limits [14]. Alloy Si Fe Cu Mn Mg Cr Ni Zn Ti V Zr Date 6061 0.40 0.8 0.7 0.15 0.40 0.15...Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys, (www.eaa.net/en/about- aluminium /standards/international-registration), The Aluminum

  14. Alloy development for irradiation performance. Quarterly progress report for period ending June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Ashdown, B.G. (ed.)

    1980-10-01

    This report is organized along topical lines in parallel to a Program Plan of the same title so that activities and accomplishments may be followed readily relative to that Program Plan. Thus, the work of a given laboratory may appear throughout the report. Chapters 1, 2, 8, and 9 review activities on analysis and evaluation, test methods development, status of irradiation experiments, and corrosion testing and hydrogen permeation studies, respectively. These activities relate to each of the alloy development paths. Chapters 3, 4, 5, 6, and 7 present the ongoing work on each alloy development path. The Table of Contents is annotated for the convenience of the reader.

  15. Critical evaluations of lead-free solder alloys and performance comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Hitch, T.T.; Palit, K.; Prabhu, A.N. [David Sarnoff Research Center, Princeton, NJ (United States)

    1996-12-31

    This paper discusses the methodology for solder alloy selection, solder preparation processes, test selection, results, and conclusions. The conclusions from this phase of study were that: (1). Solders containing significant amounts of bismuth exhibit poor fatigue life. (2). The Sn-Ag-Cu alloy was the best solder we studied for use as a replacement for Sn-Pb eutectic. A second phase of the work involved detailed study of the Sn-Ag-Cu system with other additions to determine the optimum lead-free solder compositions in terms of melting point, solderability, and mechanical properties.

  16. Alloy development for irradiation performance. Quarterly progress report for period ending September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    This report is organized along topical lines in parallel to a Program Plan of the same title so that activities and accomplishments may be followed readily relative to that Program Plan. Thus, the work of a given laboratory may appear throughout the report. Chapters 1, 2, 8, and 9 review activities on analysis and evaluation, test methods development, status of irradiation experiments, and corrosion testing and hydrogen permeation studies, respectively. These activities relate to each of the alloy development paths. Chapters 3, 4, 5, 6, and 7 present the ongoing work on each alloy development path. The Table of Contents is annotated for the convenience of the reader.

  17. Status epilepticus: Refractory and super-refractory.

    Science.gov (United States)

    Dubey, Deepanshu; Kalita, Jayantee; Misra, Usha K

    2017-01-01

    Status epilepticus (SE) is an important neurological emergency. It is defined as seizures lasting for 5 minutes or more or recurrent seizures without recovery of consciousness to baseline between the attacks. Refractory SE (RSE) is defined as SE persisting despite sufficient dose of benzodiazepines and at least one antiepileptic drug (AED), irrespective of time. Super refractory SE (SRSE) is defined as SE that continues for 24 hours or more after the use of anesthetic therapy, including cases that recur on weaning of the anesthestic agent. RSE occurs in 23%-48% of the patients and SRSE in approximately 22% of the patients with SE. In general, RSE occurs in patients with new-onset seizures rather than in patients with chronic epilepsy. The etiology of RSE in developing countries is dominated by central nervous system (CNS) infections and head injury compared to stroke and drug withdrawal in the developed countries. The treatment of RSE and SRSE is not evidence based. Following benzodiazepines, the second line antiepileptic drugs include sodium valproate, phenytoin, levetiracetam, and anesthetic drugs such as midazolam, phenobarbital, and propofol. Most intravenous anesthetic drugs produce hypotension and respiratory suppression; therefore, patients with RSE are managed in intensive care units (ICUs). In RSE patients, electroencephalogram (EEG) burst suppression with interburst interval of 2-20 s or even flat EEG has been tried. Recently, concerns have been raised on the safety of burst suppression in RSE and SRSE. The paucity of ICUs in developing countries limits the use of these management protocols. There is a need to explore intravenous AEDs with safer cardiovascular and respiratory profile for the management of SE.

  18. Refractory headache: classification and nomenclature.

    Science.gov (United States)

    Levin, Morris

    2008-06-01

    There are a number of reasons to attempt to define and classify refractory headache disorders. Particularly important are the potential benefits in the areas of research, treatment, and medical cost reimbursement. There are challenges in attempting to classify refractory forms of headaches, including the lack of biological or other objective markers and a lack of consensus among practitioners as to what qualifies as refractoriness, or even if a separate category for refractory migraine and other refractory headaches needs to be established. A definition of refractory migraine has been proposed by Schulman et al in this issue ("Defining Refractory Migraine [RM] and Refractory Chronic Migraine [RCM]: Proposed Criteria for the Refractory Headache Special Interests Section of the American Headache Society"), which should be tested for validity and usefulness. It seems reasonable to consider adding this defined syndrome to the International Classification of Headache Disorders, second edition (ICHD-II). In this article, options for adding refractory headache syndromes to the ICHD are discussed with pros and cons for each. Two "best" options for adding the disorder "refractory migraine" to the ICHD are presented along with an illustrative case example.

  19. Investigation of Appropriate Refractory Material for Laboratory Electritic Resistrance Furnance

    Directory of Open Access Journals (Sweden)

    J.B Agboola

    2009-07-01

    Full Text Available There have been numerous efforts to increase the local content of furnaces; hence the choice of appropriate refractory material for lining of locally manufactured furnaces has remained a major concern. This research work investigates the choice of appropriate local refractory material for the lining of laboratory electric resistance furnace.Electric resistance furnaces are extensively used in the laboratory for heat treatment of metals and alloys. Refractory binders such as silicon carbide were experimented upon for strength and resistance to high temperature.The results obtained showed that Kankara fireclay containing 15% SiC ( 5.70 % linear shrinkage , 46.2% apparent porosity, 1.77gkm³ Bulk density, 18 cycles of spalling tests at 1300°C, 5.253KN/m² of cold strength has appropriate properties for producing grooved bricks for lining of laboratory electric resistance Furnace.

  20. Tempering effect on corrosion performance of magnesium alloys for biomedical applications

    NARCIS (Netherlands)

    Zhang, X.; Ferrari, G.M.; Erinc, M.; Sillekens, W.H.

    2010-01-01

    The corrosion resistances for magnesium alloys AZ80, AE82 and ZM21 treated at 200 and 330°C for 2 hours, and for AZ80 and AE82 at 415°C for 8 hours were investigated using potentiodynamic polarization measurements in simulated body fluid (SBF) solution at 37°C. The morphology and the Volta potential

  1. Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires

    Directory of Open Access Journals (Sweden)

    Jing Bai

    2014-10-01

    Full Text Available With the development of new biodegradable Mg alloy implant devices, the potential applications of biomedical Mg alloy fine wires are realized and explored gradually. In this study, we prepared three kinds of Mg alloy fine wires containing 4 wt% RE(Gd/Y/Nd and 0.4 wt% Zn with the diameter less than 0.4 μm through casting, hot extruding and multi-pass cold drawing combined with intermediated annealing process. Their microstructures, mechanical and degradation properties were investigated. In comparison with the corresponding as-extruded alloy, the final fine wire has significantly refined grain with an average size of 3–4 μm, and meanwhile shows higher yield strength but lower ductility at room temperature. The degradation tests results and surface morphologies observations indicate that Mg–4Gd–0.4Zn and Mg–4Nd–0.4Zn fine wires have similar good corrosion resistance and the uniform corrosion behavior in SBF solution. By contrast, Mg–4Y–0.4Zn fine wire shows a poor corrosion resistance and the pitting corrosion behavior.

  2. Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14

    Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening) .

  3. Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires

    Institute of Scientific and Technical Information of China (English)

    Jing Bai; Zhejun Tang; Lingling Yin; Ye Lu; Yiwei Gan; Feng Xue; Chenglin Chu; Jingli Yan; Kai Yan; Xiaofeng Wan

    2014-01-01

    With the development of new biodegradable Mg alloy implant devices, the potential applications of biomedical Mg alloy fine wires are realized and explored gradually. In this study, we prepared three kinds of Mg alloy fine wires containing 4 wt%RE(Gd/Y/Nd) and 0.4 wt%Zn with the diameter less than 0.4μm through casting, hot extruding and multi-pass cold drawing combined with intermediated annealing process. Their microstructures, mechanical and degradation properties were investigated. In comparison with the corresponding as-extruded alloy, the final fine wire has significantly refined grain with an average size of 3–4μm, and meanwhile shows higher yield strength but lower ductility at room temperature. The degradation tests results and surface morphologies observations indicate that Mg–4Gd–0.4Zn and Mg–4Nd–0.4Zn fine wires have similar good corrosion resistance and the uniform corrosion behavior in SBF solution. By contrast, Mg–4Y–0.4Zn fine wire shows a poor corrosion resistance and the pitting corrosion behavior.

  4. Performance Comparison of Steam-Based and Chromate Conversion Coatings on Aluminum Alloy 6060

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    In this study, oxide layers generated on aluminum alloy 6060(UNS A96060) using a steam-based process were compared with conventional chromate and chromate-phosphate conversion coatings. Chemical composition and microstructure of the conversion coatings were investigated and their corrosion perfor...

  5. The role of microstructural aspects on the performance of coarse-grained superplastic Al alloys

    NARCIS (Netherlands)

    Chezan, AR; De Hosson, JTM; Houtte, PV; Kestens, L

    2005-01-01

    Deformed under optimum conditions of temperature and strain rate, coarse-grained aluminum alloys show elongation to failure in excess of 300%. The strain rate sensitivity index and the activation energy point to solute drag creep as the principal mechanism, a mechanism that has virtually no grain si

  6. PERFORMANCE IMPROVEMENT OF CREEP-RESISTANT FERRITIC STEEL WELDMENTS THROUGH THERMO-MECHANICAL TREATMENT AND ALLOY DESIGN

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yukinori [ORNL; Babu, Prof. Sudarsanam Suresh [University of Tennessee, Knoxville (UTK); Shassere, Benjamin [ORNL; Yu, Xinghua [ORNL

    2016-01-01

    Two different approaches have been proposed for improvement of cross-weld creep properties of the high temperature ferrous structural materials for fossil-fired energy applications. The traditional creep strength-enhanced ferritic (CSEF) steel weldments suffer from Type IV failures which occur at the fine-grained heat affected zone (FGHAZ). In order to minimize the premature failure at FGHAZ in the existing CSEF steels, such as modified 9Cr-1Mo ferritic-martensitic steels (Grade 91), a thermo-mechanical treatment consisting of aus-forging/rolling and subsequent aus-aging is proposed which promotes the formation of stable MX carbonitrides prior to martensitic transformation. Such MX remains undissolved during welding process, even in FGHAZ, which successfully improves the cross-weld creep properties. Another approach is to develop a new fully ferrtic, creep-resistant FeCrAl alloy which is essentially free from Type IV failure issues. Fe-30Cr-3Al base alloys with minor alloying additions were developed which achieved a combination of good oxidation/corrosion resistance and improved tensile and creep performance comparable or superior to Grade 92 steel.

  7. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Terry, Brandon C., E-mail: terry13@purdue.edu [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Sippel, Travis R. [Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011 (United States); Pfeil, Mark A. [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Gunduz, I.Emre; Son, Steven F. [School of Mechanical Engineering, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States)

    2016-11-05

    Highlights: • Al-Li alloy propellant has increased ideal specific impulse over neat aluminum. • Al-Li alloy propellant has a near complete reduction in HCl acid formation. • Reduction in HCl was verified with wet bomb experiments and DSC/TGA-MS/FTIR. - Abstract: Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (I{sub SP}). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal I{sub SP} by ∼7 s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5 ± 4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

  8. The results of the space technological experiments performed with the suprconducting and magnetic alloys

    Science.gov (United States)

    Michailov, B. P.; Torchinova, R. S.; Bychkova, M. I.

    On board the orbital complex "Salyut-6-Soyuz" during long-term near 0-gravity space flight the technological experiments on synthesis of the superconducting MoGa 5, MO 3Ga and Nb 3Sn intermetallic compounds by means of liquid-phase diffusion and on bulk crystallization of the hypoeutectic superconducting Pb-Sn alloy and magnetically ordered Gd 3Co and (Gd 0.2Tb 0.8) 3Co compounds have been performed. During the process of the liquid-phase diffusion considerable changes of the formation of the reaction layers (mechanisms, phase composition, thickness, etc.) in the superconducting Mo-Ga and Nb-Sn systems were observed. MoGa 5, Nb 6Sn 5 and NbSn 2 phases were found in the ground-based samples while in the flight samples the formation of MoGa 5, Mo 3Ga, Nb 3Sn and Nb 6Sn 5 phases was observed. As a result of the changes of the phase composition of the diffusion layers in the flight samples two superconducting transitions at 18.3 and 5.7 K were established (only one transition at 6.9K was measured for the ground-based sample) (Savitsky et al., Izv. Akad. Nauk SSSR, Metals5, 224-232, 1982; Zemskov et al., Izv. Akad. Nauk SSSR, Physics49, 673-680, 1985). Considerable increasing of the critical current measured for the Pb-Sn flight sample has been observed (Savitsky et al., Dokl. Akad. Nauk SSSR257, 102-104, 1981; Zemskov et al., 1985). Better homogeneity and crystal structure perfection of the flight Gd 3Co and (Gd 0.2Tb 0.8) 3Co samples have been established by means of the micro-zonde and low-temperature X-ray technique (Savitsky et al., Acta Astronautica11, 691-696, 1984; Zemskov et al., 1985). Different behaviour of the ground-based and flight samples in the process of magnetization and the displacements of the temperatures of the magnetic phase transitions have been observed.

  9. Artigo revisão: atuação dos antioxidantes em refratários contendo carbono Review article: performance of the antioxidants in carbon containing refractories

    Directory of Open Access Journals (Sweden)

    A. P. Luz

    2007-12-01

    Full Text Available Os materiais refratários contendo carbono têm despertado grande atenção nos últimos anos, uma vez que são amplamente utilizados na indústria siderúrgica em virtude de suas excelentes propriedades. A presença do carbono nos refratários contribui para o aumento da resistência ao choque térmico, da energia de fratura e da resistência ao ataque por escória. Entretanto, a principal desvantagem do seu uso é a sua alta susceptibilidade a oxidação. Com o objetivo de manter o carbono presente na estrutura do material refratário o maior tempo possível, algumas medidas são requeridas para reduzir sua oxidação sob condições operacionais. Desta forma, o uso de substâncias conhecidas como antioxidantes tem sido extensivamente estudado. Os principais antioxidantes, suas características e formas de atuação são abordados nesta revisão. A formação de novos compostos devido à reação entre os antioxidantes com o carbono, nitrogênio, oxigênio e o próprio material refratário pode provocar um preenchimento parcial dos poros e redução da taxa de interdifusão dos gases, havendo assim a prevenção da oxidação do carbono presente no refratário.Carbon containing refractories have received great attention over the last years, as they are widely used in the steel making industry due to their better properties, such as: higher thermal shock resistance, fracture energy and slag resistance. However, their main disadvantage is the carbon oxidation. Aiming to keep carbon in the structure of the refractory material some actions are required in order to reduce its oxidation under operational conditions. Therefore, the use of materials known as antioxidants has been extensively studied. The main antioxidants, their characteristics and performance are discussed in the present review article. The formation of new compounds due to the reaction of the antioxidants with carbon, nitrogen, oxygen and the refractory material can induce a pore

  10. Refractory gastroesophageal reflux disease

    OpenAIRE

    Joaquim Prado P. Moraes-Filho

    2012-01-01

    CONTEXT: Gastroesophageal reflux disease (GERD) is a condition which develops when the reflux of stomach contents causes troublesome symptoms and/or complications. Its pathophysiology, diagnosis and treatment have frequently been analyzed but it is interesting to review some aspects of the GERD refractory patients to the proton pump inhibitors treatment. The treatment encompasses behavioral measures and pharmacological therapy. The majority of the patients respond well to proton pump inhibito...

  11. Colectomy for refractory constipation

    DEFF Research Database (Denmark)

    Raahave, Dennis; Loud, Franck Bjørn; Christensen, Elsebeth;

    2010-01-01

    OBJECTIVE: This study evaluated the type of colectomy, postoperative complications, functional results, and satisfaction in patients with constipation refractory to conservative therapy. Further, colonic transit time (CTT), faecal load (coprostasis), and colon length (redundancies) were compared...... had at hemicolectomy, 11 patients a subtotal colectomy and 3 patients an ileostomy. Two patients had an anastomotic leak and one died. In 11 patients, further surgery was necessary, because of recurrent constipation. Abdominal pain disappeared and defecation patterns improved significantly to 1-4 per...

  12. High-Density Infrared Surface Treatments of Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Tiegs, T.N.

    2005-03-31

    Refractory materials play a crucial role in all energy-intensive industries and are truly a crosscutting technology for the Industries of the Future (IOF). One of the major mechanisms for the degradation of refractories and a general decrease in their performance has been the penetration and corrosion by molten metals or glass. Methods and materials that would reduce the penetration, wetting, and corrosive chemistry would significantly improve refractory performance and also maintain the quality of the processed liquid, be it metal or glass. This report presents the results of an R&D project aimed at investigating the use of high-density infrared (HDI) heating to surface treat refractories to improve their performance. The project was a joint effort between Oak Ridge National Laboratory (ORNL) and the University of Missouri-Rolla (UMR). HDI is capable of heating the near-surface region of materials to very high temperatures where sintering, diffusion, and melting can occur. The intended benefits of HDI processing of refractories were to (1) reduce surface porosity (by essentially sealing the surface to prevent liquid penetration), (2) allow surface chemistry changes to be performed by bonding an adherent coating onto the underlying refractory (in order to inhibit wetting and/or improve corrosion resistance), and (3) produce noncontact refractories with high-emissivity surface coatings.

  13. Refractory status epilepticus

    Directory of Open Access Journals (Sweden)

    Sanjay P Singh

    2014-01-01

    Full Text Available Refractory status epilepticus is a potentially life-threatening medical emergency. It requires early diagnosis and treatment. There is a lack of consensus upon its semantic definition of whether it is status epilepticus that continues despite treatment with benzodiazepine and one antiepileptic medication (AED, i.e., Lorazepam + phenytoin. Others regard refractory status epilepticus as failure of benzodiazepine and 2 antiepileptic medications, i.e., Lorazepam + phenytoin + phenobarb. Up to 30% patients in SE fail to respond to two antiepileptic drugs (AEDs and 15% continue to have seizure activity despite use of three drugs. Mechanisms that have made the treatment even more challenging are GABA-R that is internalized during status epilepticus and upregulation of multidrug transporter proteins. All patients of refractory status epilepticus require continuous EEG monitoring. There are three main agents used in the treatment of RSE. These include pentobarbital or thiopental, midazolam and propofol. RSE was shown to result in mortality in 35% cases, 39.13% of patients were left with severe neurological deficits, while another 13% had mild neurological deficits.

  14. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Jun Wei

    2005-03-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  15. Evidence for a response preparation bottleneck during dual-task performance: effect of a startling acoustic stimulus on the psychological refractory period.

    Science.gov (United States)

    Maslovat, Dana; Chua, Romeo; Spencer, Hunter C; Forgaard, Christopher J; Carlsen, Anthony N; Franks, Ian M

    2013-11-01

    The present study was designed to investigate the mechanism associated with dual-task interference in a psychological refractory period (PRP) paradigm. We used a simple reaction time paradigm consisting of a vocal response (R1) and key-lift task (R2) with a stimulus onset asynchrony (SOA) between 100ms and 1500ms. On selected trials we implemented a startling acoustic stimulus concurrent with the second stimulus to determine if we could involuntarily trigger the second response. Our results indicated that the PRP delay in the second response was present for both control and startle trials at short SOAs, suggesting the second response was not prepared in advance. These results support a response preparation bottleneck and can be explained via a neural activation model of preparation. In addition, we found that the reflexive startle activation was reduced in the dual-task condition for all SOAs, a result we attribute to prepulse inhibition associated with dual-task processing.

  16. High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

    Directory of Open Access Journals (Sweden)

    Michał Tacikowski

    2014-09-01

    Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

  17. Performance of Integrated Fiber Optic, Piezoelectric, and Shape Memory Alloy Actuators/Sensors in Thermoset Composites

    Science.gov (United States)

    Trottier, C. Michael

    1996-01-01

    Recently, scientists and engineers have investigated the advantages of smart materials and structures by including actuators in material systems for controlling and altering the response of structural environments. Applications of these materials systems include vibration suppression/isolation, precision positioning, damage detection and tunable devices. Some of the embedded materials being investigated for accomplishing these tasks include piezoelectric ceramics, shape memory alloys, and fiber optics. These materials have some benefits and some shortcomings; each is being studied for use in active material design in the SPICES (Synthesis and Processing of Intelligent Cost Effective Structures) Consortium. The focus of this paper concerns the manufacturing aspects of smart structures by incorporating piezoelectric ceramics, shape memory alloys and fiber optics in a reinforced thermoset matrix via resin transfer molding (RTM).

  18. Performance Investigation of Nanoscale Strained Ge pMOSFETs with a GeSn Alloy Stressor.

    Science.gov (United States)

    Lee, Chang-Chun; Chang, Shu-Tong; Cheng, Sen-Wen; Chian, Bow-Tsin

    2015-11-01

    A germanium (Ge)-based substrate combined with germanium-tin (GeSn) alloy embedded in source/drain (S/D) regions has attracted significant attention because of its ability to satisfy the requirements of a high-mobility channel. Devices are shrunk in their geometries to meet the target of superior density in layout arrangement. Thus, determining the influences of devices on mobility gain is important. Accordingly, several designed factors, including gate width, S/D length, and Sn concentration of the GeSn stressor, are systematically analyzed in this study. A second-order formula composed of piezoresistance coefficients is derived and adopted to achieve a precise mobility gain estimation. A peak of the carrier mobility gain appears when a nanoscale geometry combination of 20 nm gate length and -200 nm gate width is used in the Ge channel, and 10% of the Sn mole proportion of the GeSn alloy is applied.

  19. Characterization of the Corrosion Behavior of Alloy 22 Regarding its Lifetime Performance as a Potential Nuclear Waste Container Material

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; McCright, D

    2002-06-04

    Alloy 22 (UNS N06022) was proposed for the corrosion resistant outer barrier of a two-layer waste package container for nuclear waste at the potential repository site at Yucca Mountain in Nevada (USA). A testing program is underway to characterize and quantify three main modes of corrosion that may occur at the site. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

  20. Wetting and Reaction Characteristics of Al2O3/SiC Composite Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jing [ORNL; Hemrick, James Gordon [ORNL; Peters, Klaus-Markus [ORNL; Liu, Xingbo [ORNL; Barbero, Ever J [ORNL

    2007-01-01

    The reactive wetting behavior of three types of alumina-silicon carbide composite refractory materials was investigated in contact with molten aluminum (Al) and Al alloy using an optimized sessile drop method at 900oC in a purified Ar-4% H2 atmosphere. The time dependent behavior of contact angle and droplet geometry was monitored and the wetting kinetics was identified. The initial contact angle between the liquid Al/Al alloy and two of the refractory substrates was found to be an obtuse angle, which gradually changed to a 90o angle and then eventually to an acute angle with time. However, the wetting angle for the third refractory substrate was found to stay at an obtuse angle for the entire two-hour duration of the experiment. The difference in wetting properties among three types of refractories is attributed to be due to their microstructural and compositional variations. The significant effect of the alloying magnesium added to the molten Al alloy droplets in regard to the wetting kinetics and the influence on the reaction with the refractory substrates is discussed. The results obtained provide important understanding on the wetting and corrosion mechanisms of alumina and silicon carbide materials in contact with molten aluminum.

  1. The influence of the chemical composition and type of alloy on corrosion performances of some medium strength Al-Mg-Si series of alloys

    Directory of Open Access Journals (Sweden)

    Kemal Delijić

    2014-07-01

    Full Text Available The effect of the chemical composition, i.e. content of silicone (Si and other alloying elements (Zr, Mn, etc on the corrosion behaviour and mechanical properties of Al-Mg-Si (6xxx type alloys was investigated in this paper. Open circuit corrosion potential (OCP measurements, linear polarization and potentiodynamic anodic/cathodic polarization were employed in order to determine the corrosion behaviour of artificially aged Al-Mg-Si samples in the chloride ions containing aqueous corrosion solutions. The difference in OCPs for the tested 6xxx type alloys in relation to the standard AA1020 alloy was observed to be between 1-4%, except for the AlMg0.65Si0.76Zr0.1 alloy when the difference was 14% (about 100 mV. The presence of zirconium and manganese in AlMgSi0.7 base alloy, that contains small excess of Si, shifts the OCPs to more negative values for -15 mV (~2% and -88 mV (~11% in natural water and 0,51 mol NaCl, respectively. All the tested 6xxx type alloys, except AlMg0.7Si1.2Mn0.8, show almost the same corrosion rates and other corrosion characteristics in chloride solution, with mass loss per year between 2.3-3 g/m2 .

  2. Composition and Performance of Nanostructured Zirconium Titanium Conversion Coating on Aluminum-Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Sheng-xue Yu

    2013-01-01

    Full Text Available Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF6 0.75 g·L−1, NaF 1.25 g·L−1, MgSO4 1.0 g/L, and tetra-n-butyl titanate (TBT 0.08 g·L−1. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM and scanning electron microscopy (SEM. Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS. Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is 9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.

  3. Preparation and performance of fluorescent sensing coating for monitoring corrosion of Al alloy 2024

    Institute of Scientific and Technical Information of China (English)

    LI Song-mei; ZHANG Hong-rui; LIU Jian-hua

    2006-01-01

    A kind of fluorescent sensing coating was prepared for monitoring corrosion of aluminum alloys by incorporating phenylfluorone(PF) into acrylic paint as sensing material. The fluorescent dye PF reacts with aluminum ions on corroded aluminum substrate to occur fluorescence quenching observed in UV light. This paint system is sensitive to underlying corrosion processes through reacting with the Al3+ produced by anodic reaction accompanying corrosion. After a certain time,when the samples of Al alloy 2024 coated with PF-acrylic paint were immersed in 1 mol/L NaCl solution,fluorescence quenching spots can be seen with unaided eyes. With the development of corrosion process,the size of fluorescence quenching spots increases. Active corrosion areas on the sample surface were found under the fluorescence quenching spots by optical microscope. The corrosion areas can be observed more clearly by SEM,and many pits are found. This suggests that the fluorescence quenching spots are the sites of produced Al3+ by the anodic reaction of the local attack of the coated Al alloy substrate in the chloride solution and the corrosion process of the coated Al alloy can be monitored on-line by the sensing coating. The sensitivity of this coating system for detection of anodic reaction associated with corrosion was determined by applying constant charge current and measuring the charge,at which fluorescence quenching is detected in the coating with unaided eyes. Visual observation of coated samples can detect fluorescence change resulting from a charge corresponding to an equivalent hemispherical pit with approximate depth of 50 μm.

  4. Therapeutic drug monitoring of levetiracetam by high-performance liquid chromatography with photodiode array ultraviolet detection: preliminary observations on correlation between plasma concentration and clinical response in patients with refractory epilepsy.

    Science.gov (United States)

    Lancelin, Frédérique; Franchon, Emilie; Kraoul, Linda; Garciau, Isabelle; Brovedani, Sophie; Tabaouti, Khalid; Landré, Elisabeth; Chassoux, Francine; Paubel, Pascal; Piketty, Marie-Liesse

    2007-10-01

    Levetiracetam is a new antiepileptic drug prescribed for the treatment of patients with refractory partial seizures with or without secondary generalization as well as for the treatment of juvenile myoclonic epilepsy. A rapid and specific method by high-performance liquid chromatography diode array detection was developed to measure the concentration of levetiracetam in human plasma. The trough plasma concentrations measured in 69 epileptic patients treated with 500 to 3000 mg/d of levetiracetam ranged from 1.1 to 33.5 microg/mL. The mean (range) levetiracetam plasma concentrations in responders and nonresponders were 12.9 microg/mL (4.6-21 microg/mL) and 9.5 microg/mL (1.1-20.9 microg/mL), respectively. A wide variability in concentration-response relationships was observed in patients. Using a receiver operating characteristic curve, the threshold levetiracetam concentration for a therapeutic response was 11 microg/mL. The sensitivity and specificity for this threshold levetiracetam concentration were 73% and 71%, respectively. According to chi analysis, this finding was not significant probably because of the small number of patients and because of their refractory seizure type. Nevertheless, the levetiracetam plasma concentration could be used to help clinicians detect severe intoxication or to verify compliance by repeating the measurement in patients.

  5. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

    Science.gov (United States)

    Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

    2016-11-05

    Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Preparation and Oxidation Performance of Y and Ce-Modified Cr Coating on open-cell Ni-Cr-Fe Alloy Foam by the Pack Cementation

    Science.gov (United States)

    Pang, Q.; Hu, Z. L.; Wu, G. H.

    2016-10-01

    Metallic foams with a high fraction of porosity, low density and high-energy absorption capacity are a rapidly emerging class of novel ultralight weight materials for various engineering applications. In this study, Y-Cr and Ce-Cr-coated Ni-Cr-Fe alloy foams were prepared via the pack cementation method, and the effects of Y and Ce addition on the coating microstructure and oxidation performance were analyzed in order to improve the oxidation resistance of open-cell nickel-based alloy foams. The results show that the Ce-Cr coating is relatively more uniform and has a denser distribution on the surface of the nickel-based alloy foam. The surface grains of the Ce-Cr-coated alloy foam are finer compared to those of the Y-Cr-coated alloy foam. An obvious Ce peak appears on the interface between the coating and the alloy foam strut, which gives rise to a "site-blocking" effect for the short-circuit transport of the cation in the substrate. X-ray diffraction analysis shows that the Y-Cr-coated alloy foam mainly consists of Cr, (Fe, Ni) and (Ni, Cr) phases in the surface layer. The Ce-Cr-coated alloy foam is mainly composed of Cr and (Ni, Cr) phases. Furthermore, the addition of Y and Ce clearly lead to an improvement in the oxidation resistance of the coated alloy foams in the temperature range of 900-1000 °C. The addition of Ce is especially effective in enhancing the diffusion of chromium to the oxidation front, thus, accelerating the formation of a Cr2O3 layer.

  7. How Social and Refractory Is the Social Psychological Refractory Period?

    Science.gov (United States)

    Wühr, Peter; Heuer, Herbert

    2017-07-01

    The social psychological refractory period (PRP) effect refers to an increase in RT to the second of two successive stimuli when another person responds to the first stimulus (shared dual-task condition) rather than when a single person responds to both stimuli (individual dual-task condition). We investigated (a) whether a social PRP effect would occur without explicit instruction concerning task priority and (b) whether there are crosstalk effects in the shared dual-task situation. We observed a strong PRP effect together with a small crosstalk effect in the individual dual-task condition, but in the shared dual-task condition both effects were absent. These findings suggest that the explicit instruction to perform responses in a fixed order is necessary to obtain the social PRP effect. In the individual dual-task condition, sequential processing can be seen as a means to reduce or prevent crosstalk effects, which is not necessary in the shared dual-task condition.

  8. Development of Ion-Plasma Refractory Metallic Layers of Heat-Insulating Coatings for Cooled Turbine Rotor Blades

    Science.gov (United States)

    Budinovskii, S. A.; Muboyadzhyan, S. A.; Gayamov, A. M.; Matveev, P. V.

    2014-03-01

    Alloys ZhS32 and ZhS36 with heat-protection coatings (HPC) consisting of external ceramic layers and internal refractory metallic layers are studied. The coated alloys are tested for heat fastness and high-temperature strength at 1100 - 1150°C. The HPC with a metallic layer of the (Ni - Cr - Al - Hf) + Al system are shown to be more advantageous than similar HPC based on an SPD-2 + VSDP-16 commercial refractory coating. The effect of the HPC on the characteristics of high-temperature strength and fatigue resistance of alloys ZhS32 and ZhS36 is investigated.

  9. Fracture and fatigue properties of Mo-Mo{sub 3}Si-Mo{sub 5}SiB{sub 2} refractory intermetallic alloys at ambient to elevated temperatures (25-1300 degrees Centigrade)

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Heeman; Schneibel, J.H.; Ritchie, R.O.

    2002-08-01

    The need for structural materials with high-temperature strength and oxidation resistance coupled with adequate lower-temperature toughness for potential use at temperatures above {approx} 1000 degrees C has remained a persistent challenge in materials science. In this work, one promising class of intermetallic alloys is examined, namely boron-containing molybdenum silicides, with compositions in the range Mo (bal), 12-17 at. percentSi, 8.5 at. percentB, processed using both ingot (I/M) and powder (P/M) metallurgy methods. Specifically, the oxidation (''pesting''), fracture toughness and fatigue-crack propagation resistance of four such alloys, which consisted of {approx}21 to 38 vol. percent a-Mo phase in an intermetallic matrix of Mo3Si and Mo5SiB2 (T2), were characterized at temperatures between 25 degrees and 1300 degrees C. The boron additions were found to confer superior ''pest'' resistance (at 400 degrees to 900 degrees C) as compared to unmodified molybdenum silicides, such as Mo5Si3. Moreover , although the fracture and fatigue properties of the finer-scale P/M alloys were only marginally better than those of MoSi2, for the I/M processed microstructures with coarse distributions of the a-Mo phase, fracture toughness properties were far superior, rising from values above 7 MPa sqrt m at ambient temperatures to almost 12 MPa sqrt m at 1300 degrees C.

  10. Performance evaluation of shape memory alloy/rubber-based isolation systems for seismic response mitigation of bridges

    Science.gov (United States)

    Ozbulut, Osman E.; Hurlebaus, Stefan

    2010-04-01

    Base isolation is an effective method of reducing seismic response of bridges during an earthquake. Rubber isolators are one of the most common types of base isolation systems. As an alternative to conventional rubber isolators such as high damping rubber bearing and lead rubber bearing, smart rubber bearing systems with shape memory alloys (SMAs) have been proposed in recent years. As a class of smart materials, shape memory alloys shows excellent re-centering and considerable damping capabilities which can be exploited to obtain an efficient seismic isolation system. This paper explores effectiveness of shape memory alloy/rubber-based isolation systems for protecting bridges against seismic loads by performing a sensitivity analysis. The isolation system considered in this study consists of a laminated rubber bearing which provides lateral flexibility while supplying high vertical load-carrying capacity and an auxiliary device made of multiple loops SMA wires. The SMA device offers additional energy dissipating and re-centering capability. A threespan continuous bridge is modeled with SMA/rubber-based isolation system. Numerical simulations of the bridge are conducted for various historical ground motions that are spectrally matched to a target design spectrum. The normalized yield strength, yield displacement and pre-stress level of the SMA device and ambient temperature are selected as parameters of the sensitivity study. The variation of seismic response of the bridge with considered parameters is assessed. The optimum values of the normalized yield strength and the yield displacement of the SMA device is found to be in the range of 0.20-0.25 and 40-50 mm, respectively. Also, the SMA/rubber-based isolation system is observed to be more effective when the SMA device is pre-stressed. In addition, it is found that ambient temperature considerably affects the performance of the bridge isolated by SMA/rubber-based isolators.

  11. Influences of Preparation Conditions and Melt Treatment Procedures on Melt Treatment Performance of Al-5Ti-B and Al-10Sr Master Alloys

    Institute of Scientific and Technical Information of China (English)

    Pengfa FENG; Jinglin TANG; Xinyan JIN; Shuangshou LI; Daben ZENG

    2006-01-01

    The influences of preparation conditions of Al-5Ti-B (as-cast and hot-rolled) and Al-10Sr (as-cast and hotextruded) and melt treatment procedures on the grain refinement and modification performance of A356 alloy are experimentally studied. For the two master alloys, the 50% reduction is sufficient to meet the demands of the efficient grain refinement and modification of A356 alloy. When Al-5Ti-B is introduced into the melt prior to degassing, the grain refinement efficiency of Al-5Ti-B will be greatly increased due to the better dispersity of TiB2 particles. Al-5Ti-B master alloy is less prone to affect the modification effect of Al-10Sr when they are used together.

  12. In vitro performance characteristics of a high-flux hemodialyzer with a novel polyester-polymer-alloy (PEPA) membrane.

    Science.gov (United States)

    Smith, M D; Mahiout, A

    2002-05-01

    Despite improvements in hemodialyzers with respect to their clearance of middle and high molecular mass molecules, accumulation of specific solutes in the circulation of dialysis patients continues to be a medical problem. A new membrane material, polyester-polymer alloy (PEPA) which has been developed to have a filtration profile akin to that of the natural kidney, is now being used in hemodialyzers. This study evaluates the performance of a PEPA-based hemodialyzer alongside a selection of available competing high-flux dialyzers using official standardized methods. The new membrane material appears to be a viable alternative which offers performance at least as good as that of the competition. The promising results obtained with the PEPA membrane suggest that a detailed clinical performance study should be undertaken.

  13. Hydrogen storage and low-temperature electrochemical performances of A2B7 type La-Mg-Ni-Co-Al-Mo alloys

    Directory of Open Access Journals (Sweden)

    Jianguang Yuan

    2017-04-01

    Full Text Available The effect of Mo-addition on hydrogen storage and low-temperature electrochemical performances of La-Mg-Ni-Co-Al alloys is investigated. The alloys were synthetized via vacuum induction melting followed by annealing treatment at 1123 K for 8 h. The major phases in the annealed alloys are consisted of (La, Mg2Ni7, (La, Mg5Ni19 and LaNi5 phases. Mo-addition facilitates phase transformation of LaNi5 into (La, Mg2Ni7 and (La, Mg5Ni19 phases. Hydrogen absorption/desorption PCI curves indicates that the hydrogen storage capacity of the alloy increases remarkably with the addition of Mo. Furthermore, the La0.75Mg0.25Ni3.05Co0.2Al0.05Mo0.2 alloy shows excellent hydriding/dehydriding kinetics with a higher capacity, requiring only 100 s to reach its saturated hydrogen capacity of 1.58 wt% at low temperature of 303 K, and releasing 1.57 wt% hydrogen within 400 s at 338 K. Electrochemical experiments manifest that the Mo-added alloy electrode has perfect activation properties and the maximum discharge capacity. The low-temperature dischargeability shows that the La0.75Mg0.25Ni3.05Co0.2Al0.05Mo0.2 alloy exhibits the excellent low-temperature discharge performance, and the maximum discharge capacity is improved from 231.0 to 334.6 mAh/g at 253 K. The HRD property of the alloy electrode is enhanced, suggesting that Mo enhances the kinetic ability at low-temperature.

  14. Passivation and corrosion of the high performance materials alloy 33, alloy 31 and nickel in LiBr solution at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Igual Munoz, A.; Garcia Anton, J.; Guinon, J.L.; Perez Herranz, V. [Departamento de Ingenieria Quimica y Nuclear. E.T.S. Industriales, Universidad Politecnica de Valencia, P.O. Box 22012, E-46071 Valencia (Spain)

    2004-07-01

    Aqueous solutions containing high concentrations of Lithium Bromide are employed as absorbent solutions for almost all types of heating and refrigerating absorption systems that use natural gas or steam as energy sources. LiBr solutions can cause serious corrosion problems in common metallic components. The objective of the present work was to study the corrosion resistance of new high alloyed materials in commercial LiBr heavy brine solution (which contains chromate as inhibitor), at different temperatures (25, 30, 40, 50, 60, 70 and 80 deg. C). The materials tested were stainless steels Alloy 33 (UNS R20033), a new corrosion resistant austenitic material alloyed with nominally (wt%) 33 Cr, 32 Fe, 31 Ni; Nicrofer 3127 hMo-alloy 31 (UNS N08031), an iron-nickel-chromium-molybdenum alloy with nitrogen; and pure Nickel. Corrosion resistance was estimated from the cyclic potentiodynamic polarization curves, comparing OCP values, calculating corrosion potentials and current rates from Tafel analysis; in order to characterize the passivating behaviour of the alloys the study was completed with the analysis of the pitting potentials, passivating current and re-passivating properties at the temperatures under study. Passivating properties are well observed in all the samples in commercial LiBr solution at all temperatures. In these cases, passivation properties decrease with temperature. (authors)

  15. Irradiation Performance of U-Mo Alloy Based ‘Monolithic’ Plate-Type Fuel – Design Selection

    Energy Technology Data Exchange (ETDEWEB)

    A. B. Robinson; G. S. Chang; D. D. Keiser, Jr.; D. M. Wachs; D. L. Porter

    2009-08-01

    A down-selection process has been applied to the U-Mo fuel alloy based monolithic plate fuel design, supported by irradiation testing of small fuel plates containing various design parameters. The irradiation testing provided data on fuel performance issues such as swelling, fuel-cladding interaction (interdiffusion), blister formation at elevated temperatures, and fuel/cladding bond quality and effectiveness. U-10Mo (wt%) was selected as the fuel alloy of choice, accepting a somewhat lower uranium density for the benefits of phase stability. U-7Mo could be used, with a barrier, where the trade-off for uranium density is critical to nuclear performance. A zirconium foil barrier between fuel and cladding was chosen to provide a predictable, well-bonded, fuel-cladding interface, allowing little or no fuel-cladding interaction. The fuel plate testing conducted to inform this selection was based on the use of U-10Mo foils fabricated by hot co-rolling with a Zr foil. The foils were subsequently bonded to Al-6061 cladding by hot isostatic pressing or friction stir bonding.

  16. Evaluating the effects of PIRAC nitrogen-diffusion treatments on the mechanical performance of Ti–6Al–4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Bonello, T. [Department of Metallurgy and Materials Engineering, University of Malta, MSD 2080 (Malta); Avelar-Batista Wilson, J.C.; Housden, J. [Wallwork Tecvac R and D, Buckingway Business Park, Swavesey, Cambridge CB24 4UG (United Kingdom); Gutmanas, E.Y.; Gotman, I. [Department of Materials Science and Engineering, Technion – Israel Institute of Technology, Haifa 32000 (Israel); Matthews, A.; Leyland, A. [Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin St., Sheffield S1 3JD (United Kingdom); Cassar, G., E-mail: glenn.cassar@um.edu.mt [Department of Metallurgy and Materials Engineering, University of Malta, MSD 2080 (Malta)

    2014-12-01

    Powder Immersion Reaction Assisted Coating (PIRAC) is a relatively simple nitrogen diffusion based process which has been proposed as a technique capable of considerable improvements in the tribological performance of ceramics and metals alike; however, the necessary exposure of the substrate material to high temperatures for several hours may have an adverse effect on the bulk properties of materials such as titanium alloys. The effect of PIRAC treatments on the bulk metallography and mechanical properties of Ti–6Al–4V has been studied. Following PIRAC nitrogen-diffusion treatment, studies using X-ray diffraction and cross-sectional microscopy have shown evidence of the formation of a thin (∼1.4 µm) TiN/Ti{sub 2}N layer, together with the presence of some Ti{sub 3}Al intermetallic phase. Semi-logarithmic S–N plots show a deleterious effect after PIRAC treatment in terms of material cyclic fatigue strength, particularly at higher treatment temperatures. Samples processed at 800 °C for 4 h however exhibit better fatigue performance than others treated at lower temperatures for longer nitriding times. Fractographic inspection has shown that fatigue cracks originate at (or near) the surface for the untreated Ti-alloy and from the subsurface regions following diffusion treatment, owing to the build-up of compressive stresses in the latter, which hinder crack propagation.

  17. Composition, Compatibility, and the Functional Performances of Ternary NiTiX High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Bucsek, Ashley N.; Hudish, Grant A.; Bigelow, Glen S.; Noebe, Ronald D.; Stebner, Aaron P.

    2016-03-01

    A general procedure to optimize shape memory alloys (SMAs) for specific engineering performance metrics is outlined and demonstrated through a study of ternary, NiTiX high-temperature SMAs, where X = Pd, Hf, Zr. Transformation strains are calculated using the crystallographic theory of martensite and compared to the cofactor conditions, both requiring only lattice parameters as inputs. Measurements of transformation temperatures and hysteresis provide additional comparisons between microstructural-based and transformation properties. The relationships between microstructural-based properties and engineering performance metrics are then thoroughly explored. Use of this procedure demonstrates that SMAs can be tuned for specific applications using relatively simple, fast, and inexpensive measurements and theoretical calculations. The results also indicate an overall trade-off between compatibility and strains, suggesting that alloys may be optimized for either minimal hysteresis or large transformation strains and work output. However, further analysis of the effects of aging shows that better combinations of uncompromised properties are possible through solid solution strengthening.

  18. Orind Refractories Limited

    Institute of Scientific and Technical Information of China (English)

    Mr R. Mishra; Group Manging Director

    2005-01-01

    @@ "Sight can be acquired, Vision cannot". Orind Refractories Limited (ORIND), China was formed with this rare vision. At a time when the world was testing the tepid waters of China; Mr. Ravin Jhunjhunwala, Chairman of ORIND and the management of ORIND India had looked over the Great Wall to begin a journey of success. Incorported on 18th August 1994 with an initial investment of USD 5 million, ORL caters to the ever-demanding needs of the steel industry and beyond. Incidentally ORIND was the first wholly owned India company to set up base in China. Pesently, ORIND China has a 616 strong work force including 23 expatriates.

  19. Refractoriness in human atria

    DEFF Research Database (Denmark)

    Skibsbye, Lasse; Jespersen, Thomas; Christ, Torsten

    2016-01-01

    drugs. Cardiomyocyte excitability depends on availability of sodium channels, which involves both time- and voltage-dependent recovery from inactivation. This study therefore aims to characterise how sodium channel inactivation affects refractoriness in human atria. METHODS AND RESULTS: Steady......-state activation and inactivation parameters of sodium channels measured in vitro in isolated human atrial cardiomyocytes were used to parameterise a mathematical human atrial cell model. Action potential data were acquired from human atrial trabeculae of patients in either sinus rhythm or chronic atrial...... in pharmacological management of chronic atrial fibrillation....

  20. Effect of Rapid Quenching on Microstructures and Electrochemical Performances of La2Mg(Ni0.85Co0.15)9M0.1(M=B, Cr) Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhang Yanghuan; Dong Xiaoping; Wang Guoqing; Feng Meng; Ren Jiangyuan; Wang Xinlin

    2005-01-01

    The La-Mg-Ni-system (PuNi3-type) La2Mg(Ni0.85Co0.15)9M0.1 (M=B, Cr) hydrogen storage electrode alloys were prepared by casting and rapid quenching. The electrochemical performances and microstructures of the as-cast and quenched alloys were determined and measured. The effects of rapid quenching on the microstructures and electrochemical properties of the alloys were investigated in detail. The obtained results show that the alloys are composed of the (La, Mg)Ni3 phase (PuNi3-type structure) and the LaNi5 phase, as well as the small amount of the LaNi2 phase. A trace of the Ni2B phase exists in the as-cast alloy containing boron, and the Ni2B phase in the alloy nearly disappears after rapid quenching. The relative amount of each phase in the alloys depends on the quenching rate. The rapid quenching technique can greatly improve the electrochemical performance of the alloy, and the effect of rapid quenching on the activation performances of the alloys is minor. Rapid quenching enhances the cycle stability of the alloy, and the cycle life of the alloy increases with the increase of the quenching rate.

  1. Obtaining Multiple Metals Through Electron Beam Melting of Refractory Metal Wastes

    Science.gov (United States)

    Vutova, Katia; Vassileva, Vania

    Investigations and results on the refining of tungsten scrap applying electron beam melting (EBM) in vacuum are presented and discussed. In this work EB melting experiments were performed in single or double-melt operations with different power inputs and refining times for tungsten purification and recovery of multiple metals (including refractory and other metals such as Mo, Nb, Cu, Zn, etc.), which are alloyed elements or impurities with high concentrations in the initial materials. Evaluations for extraction of some valuable metals, generated in the condensate at their removal from the liquid metal during the refining process are provided. Efficient technological regimes for e-beam melting and refining that enable the simultaneous production of pure metal ingots and condensates that can be used directly or can be used for subsequent extraction of expensive and valuable metals are presented.

  2. Development of Refractories for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    TIAN Shouxin; JIN Congjin; YAO Jinfu; LI Zeya

    2004-01-01

    The paper introduces refractories for continuous casting, especially, refractories for continuous casting for clean steel in baosteel. Developing direction of refractories for continuous casting has been pointed out to satisfy the new metallurgical operating practice.

  3. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Laing

    2005-10-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  4. Microstructure and Mechanical Performance of Cu-Sn-Ti-Based Active Braze Alloy Containing In Situ Formed Nano-Sized TiC Particles

    Science.gov (United States)

    Leinenbach, Christian; Transchel, Robert; Gorgievski, Klea; Kuster, Friedrich; Elsener, Hans Rudolf; Wegener, Konrad

    2015-05-01

    A Cu-Sn-Ti-based active brazing filler alloy was in situ reinforced with nanosized TiC particles by adding different amounts of a cellulose nitride-based binder. The TiC particles emanate from a reaction of the Ti within the filler alloy with the carbon from the binder that does not decompose completely during heating. The correlation between the microstructure and mechanical performance was studied. In addition, the effect of different binder amounts on the shear strength and cutting performance of brazed diamond grains was studied in shear tests and single grain cutting tests. The results clearly show that the mechanical performance of the brazed diamond grains can be improved by the formation of TiC particles. This is attributed to particle strengthening of the filler alloy matrix as well as to the decreasing grain size and more homogeneous distribution of the (Cu,Sn)3Ti5 phase with increasing amount of binder.

  5. Joint performance of CO2 laser beam welding 5083-H321 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Qi Junfeng; Zhang Dongyun; Xiao Rongshi; Chen Kai; Zuo Tiechuan

    2007-01-01

    Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam autogenous welding and wire feed welding are conducted on 4mm thick 5083-H321 aluminum alloy sheets at different welding variables. The mechanical properties and microstructure characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Experimental results indicate that both the tensile strength and hardness of laser beam welds are affected by the constitution of filler material, except the yield strength. The soften region of laser beam welds is not in the heat-affected zone (HAZ). The tensile fracture of laser beam welded specimens takes place in the weld zone and close to the weld boundary because of different filler materials. Some pores are found on the fracture face, including hydrogen porosities and blow holes, but these pores have no influence on the tensile strength of laser beam welds. Tensile strength values of laser beam welds with filler wire are up to 345.57MPa, 93% of base material values, and yield strengths of laser beam welds are equivalent to those of base metal (264.50MPa).

  6. Development of a Refractory High Entropy Superalloy

    Directory of Open Access Journals (Sweden)

    Oleg N. Senkov

    2016-03-01

    Full Text Available Microstructure, phase composition and mechanical properties of a refractory high entropy superalloy, AlMo0.5NbTa0.5TiZr, are reported in this work. The alloy consists of a nano-scale mixture of two phases produced by the decomposition from a high temperature body-centered cubic (BCC phase. The first phase is present in the form of cuboidal-shaped nano-precipitates aligned in rows along <100>-type directions, has a disordered BCC crystal structure with the lattice parameter a1 = 326.9 ± 0.5 pm and is rich in Mo, Nb and Ta. The second phase is present in the form of channels between the cuboidal nano-precipitates, has an ordered B2 crystal structure with the lattice parameter a2 = 330.4 ± 0.5 pm and is rich in Al, Ti and Zr. Both phases are coherent and have the same crystallographic orientation within the former grains. The formation of this modulated nano-phase structure is discussed in the framework of nucleation-and-growth and spinodal decomposition mechanisms. The yield strength of this refractory high entropy superalloy is superior to the yield strength of Ni-based superalloys in the temperature range of 20 °C to 1200 °C.

  7. EFFECT OF ELECTROLESS DEPOSITION CONDITIONS ON THE STRUCTURES AND THE MAGNETIC PERFORMANCES OF THE Co-Fe-P ALLOY

    Institute of Scientific and Technical Information of China (English)

    S.L. Wang; F.Q. Zeng

    2006-01-01

    Electroless Co-Fe-P alloys were deposited from an alkaline bath, containing boric acid as a buffer agent and sodium citrate as a complexing agent. As a result, with the increase of pH of the bath, the iron content of the deposit increased, whereas the cobalt and phosphorus contents decreased. The structure of the deposit was investigated using X-ray diffraction (XRD) and transmission electron microscope (TEM). The deposit consisted of hexahedron phase Co, cubic phase Fe-Co, and amorphous phase (crystalline). The magnetic performances of the deposit were studied using vibrating sample magnetometer (VSM). The more the content of Fe and the less the content of P (the content of Co being less), the better the magnetic performances of the deposit. The Co-Fe-P deposit was suitable for use as soft magnetic material.

  8. Refractory Celiac Disease

    Directory of Open Access Journals (Sweden)

    K Khatami

    2014-04-01

    Full Text Available Refractory celiac disease (RCD is when malabsorption symptoms and villous atrophy persist despite strict adherence to a gluten free diet (GFD for more than 12 months and other causes of villous atrophy have been ruled out.  RCD is considered a rare disease and almost exclusively occurs in adults. Persistent diarrhea, abdominal pain, weight loss are the most common symptoms in RCD. Also, anemia, fatigue, malaise, thromboembolic events and coexisting autoimmune disorders are frequent. Diagnosis of RCD is based on other causes of unresponsiveness to the GFD, particularly collagenous sprue, ulcerative jejunitis, and enteropathy-associated T-cell lymphoma. Many disorders such as autoimmune enteropathy, tropical sprue, common variable immunodeficiency, and intolerance to non-gluten dietary proteins may have similar histological findings but not necessarily identical with CD and therefore should be excluded. Repeat intestinal biopsy may help to differentiate causes of non-responsive CD associated with ongoing villous atrophy (e.g., gluten contamination, small-bowel bacterial overgrowth, RCD. There are 2 subtypes of RCD according to absence (type I or presence (type II of an abnormal intraepithelial lymphocyte population. RCD type 1 usually becomes better with a combination of aggressive nutritional support, adherence to GFD, and pharmacologic therapies such as prednisone, budesonide and azathioprine. For RCD type 2, more aggressive therapeutic approach is needed since clinical response to therapies is less certain and may evolve into aggressive enteropathy associated T-cell lymphoma and the prognosis is poor.   Key words: Celiac Disease, Refractory.  

  9. Microstructure Modeling of 3rd Generation Disk Alloy

    Science.gov (United States)

    Jou, Herng-Jeng

    2008-01-01

    The objective of this initiative, funded by NASA's Aviation Safety Program, is to model, validate, and predict, with high fidelity, the microstructural evolution of third-generation high-refractory Ni-based disc superalloys during heat treating and service conditions. This initiative is a natural extension of the DARPA-AIM (Accelerated Insertion of Materials) initiative with GE/Pratt-Whitney and with other process simulation tools. Strong collaboration with the NASA Glenn Research Center (GRC) is a key component of this initiative and the focus of this program is on industrially relevant disk alloys and heat treatment processes identified by GRC. Employing QuesTek s Computational Materials Dynamics technology and PrecipiCalc precipitation simulator, physics-based models are being used to achieve high predictive accuracy and precision. Combining these models with experimental data and probabilistic analysis, "virtual alloy design" can be performed. The predicted microstructures can be optimized to promote desirable features and concurrently eliminate nondesirable phases that can limit the reliability and durability of the alloys. The well-calibrated and well-integrated software tools that are being applied under the proposed program will help gas turbine disk alloy manufacturers, processing facilities, and NASA, to efficiently and effectively improve the performance of current and future disk materials.

  10. Effect of Cr content on the corrosion performance of low-Cr alloy steel in a CO2 environment

    Science.gov (United States)

    Xu, Lining; Wang, Bei; Zhu, Jinyang; Li, Wei; Zheng, Ziyi

    2016-08-01

    Low-Cr alloy steel demonstrates lower corrosion rate than does C steel in a high-temperature and high-pressure CO2-containing environment. This study aimed to clarify the role of the Cr content in mitigating corrosion and reports the performance of 1%Cr, 2%Cr, 3%Cr, 4%Cr, 5%Cr, and 6.5%Cr steels. The results show that low-Cr alloy steel in CO2 at 80 °C and 0.8 MPa possesses spontaneous prepassivation characteristics when the Cr content is 3% or higher. Furthermore, the formation and peel-off of a prepassivation film on 3%Cr-6.5%Cr steels surfaces during polarization demonstrate that adequate amount of Cr in the steel substrate can cause protective layer. The main component of prepassivation film on 3%Cr steel is Cr(OH)3. Thus, the role of Cr is revealed. An adequate amount of Cr in the steel substrate causes the formation of protective Cr(OH)3 layer, which helps low-Cr steel to possess prepassivation characteristics. Prepassivation is the reason why low-Cr steel has a lower corrosion rate than C steel.

  11. 合金元素对K白金首饰合金性能影响的探讨%Investigation of Alloy Elements on Influence of Karat White Gold Jewelry Alloy Performance

    Institute of Scientific and Technical Information of China (English)

    申柯娅

    2011-01-01

    K白金的强度高、铸造性能好,在首饰业被广泛用作铂金的替代品.但K白金的合金成分对K白金首饰的合金性能会产生很大的影响,通过实验研究了不同成分和含量的合金元素对K白金的密度、颜色、硬度和加工硬化的影响,提出了K白金补口材料的性能要求.%Karat white gold is widely used as a substitute of platinum because of its high strength and good cast ability, but alloy elements within Karat white gold have obvious influence upon jewelry alloy performance. The influence of different alloy elements and different contents upon density, color, hardness, work hardening behaviour was studied through experimentats, and then the performance of master alloys was recommended.

  12. High-temperature electrochemical performance of low-cost La–Ni–Fe based hydrogen storage alloys with different preparation methods

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiannan [Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Zhu, Ding [Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065 (China); Zhou, Wanhai; Zhong, Chenglin; Wu, Chaoling [Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Chen, Yungui, E-mail: ygchen60@aliyun.com [Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065 (China)

    2016-04-15

    Highlights: • Effects of four different preparation processes were studied at 20/60 °C. • All NS + HT, RS and RS + HT processes can optimize the thermodynamic performance. • The HT process can provoke the precipitation of A{sub 2}B{sub 7} and leads to a poor cycling life. • Al exhibits the most remarkable dissolution for all the alloys, especially at 60 °C. - Abstract: In order to optimize the microstructure and high temperature electrochemical performances of low-cost AB{sub 5}-type Ml(NiMnAl){sub 4.2}Co{sub 0.3}Fe{sub 0.5} hydrogen storage electrode alloys, four different preparation methods including normal solidification (NS), normal solidification and 900 °C heat treatment (NS + HT), rapid solidification (RS), rapid solidification and 900 °C heat treatment (RS + HT) were adopted in this work. All alloys exhibit CaCu{sub 5} type hexagonal structure and there is a small amount of A{sub 2}B{sub 7} phase in NS + HT and RS + HT alloys. It is found the using of HT process can decrease the hydrogen equilibrium plateau pressure, the plateau slope and hysteresis at 40, 60 and 80 °C. The NS + HT and RS + HT alloys also possess better activation, high rate discharge performance, larger discharge capacity, but poor cycling performance due to the existence of A{sub 2}B{sub 7} phase which can accelerate dissolution of Ni, Mn and Fe elements in KOH alkaline electrolyte. The RS process can make alloy exhibit the best cycling performance especially at 60 °C.

  13. Joint performance of laser-TIG double-side welded 5A06 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Yan-bin; MIAO Yu-gang; LI Li-qun; WU Lin

    2009-01-01

    The influence of welding parameters on mechanical properties and microstructure of the welds of laser-TIG double-side welded 5A06 aluminum alloy was investigated. The results show that the weld cross-sectional shape has an intimate relation with the mechanical properties and microstructure of the welds. The symmetrical "X" cross-section possesses a relatively higher tensile strength and elongation than the others, about 91% and 58% of those of base metal, respectively. The good weld profiles and free defects are responsible for the improvement of tensile properties. Due to low hardness of the fusion zone, this region is the weakest area in the tensile test and much easier to fracture. The loss of Mg element is responsible for the decrease of mechanical properties of the joints. The microstructure of "X" cross-section has an obvious difference along the direction of weld depth, and that of the "H" cross-section is consistent and coarse.

  14. In Vivo Neural Recording and Electrochemical Performance of Microelectrode Arrays Modified by Rough-Surfaced AuPt Alloy Nanoparticles with Nanoporosity

    Directory of Open Access Journals (Sweden)

    Zongya Zhao

    2016-11-01

    Full Text Available In order to reduce the impedance and improve in vivo neural recording performance of our developed Michigan type silicon electrodes, rough-surfaced AuPt alloy nanoparticles with nanoporosity were deposited on gold microelectrode sites through electro-co-deposition of Au-Pt-Cu alloy nanoparticles, followed by chemical dealloying Cu. The AuPt alloy nanoparticles modified gold microelectrode sites were characterized by scanning electron microscopy (SEM, electrochemical impedance spectroscopy (EIS, cyclic voltammetry (CV and in vivo neural recording experiment. The SEM images showed that the prepared AuPt alloy nanoparticles exhibited cauliflower-like shapes and possessed very rough surfaces with many different sizes of pores. Average impedance of rough-surfaced AuPt alloy nanoparticles modified sites was 0.23 MΩ at 1 kHz, which was only 4.7% of that of bare gold microelectrode sites (4.9 MΩ, and corresponding in vitro background noise in the range of 1 Hz to 7500 Hz decreased to 7.5 μ V rms from 34.1 μ V rms at bare gold microelectrode sites. Spontaneous spike signal recording was used to evaluate in vivo neural recording performance of modified microelectrode sites, and results showed that rough-surfaced AuPt alloy nanoparticles modified microelectrode sites exhibited higher average spike signal-to-noise ratio (SNR of 4.8 in lateral globus pallidus (GPe due to lower background noise compared to control microelectrodes. Electro-co-deposition of Au-Pt-Cu alloy nanoparticles combined with chemical dealloying Cu was a convenient way for increasing the effective surface area of microelectrode sites, which could reduce electrode impedance and improve the quality of in vivo spike signal recording.

  15. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang; Alireza Rezaie

    2004-10-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  16. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang; Jun Wei

    2005-04-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  17. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang; Jun Wei

    2005-01-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  18. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang

    2005-10-01

    The University of Missouri-Rolla identified materials that permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project was to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study attempted to define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials were selected/developed that either react with the gasifier environment to form protective surfaces in

  19. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang

    2005-07-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  20. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Alireza Rezaie; Xiaoting Liang; Musa Karakus; Jun Wei

    2005-12-01

    The University of Missouri-Rolla identified materials that permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project was to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study attempted to define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials were selected or developed that reacted with the gasifier environment to form protective surfaces in

  1. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick; Musa Karakus; Alireza Rezaie

    2004-03-30

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  2. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Alireza Rezaie

    2003-08-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the materials problems encountered during the operation of low-pressure high-temperature (LFHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  3. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Alireza Rezaie

    2003-12-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the materials problems encountered during the operation of low-pressure high-temperature (LFHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  4. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Xiaoting Liang; Alireza Rezaie

    2004-07-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the material problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  5. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr.; Alireza Rezaie

    2004-04-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the materials problems encountered during the operation of low-pressure high-temperature (LPHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  6. Refractory for Black Liquor Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Robert E. Moore; William L. Headrick; Alireza Rezaie

    2003-03-31

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the materials problems encountered during the operation of low-pressure high-temperature (LFHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  7. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr.; Alireza Rezaie

    2003-12-01

    The University of Missouri-Rolla will identify materials that will permit the safe, reliable and economical operation of combined cycle gasifiers by the pulp and paper industry. The primary emphasis of this project will be to resolve the materials problems encountered during the operation of low-pressure high-temperature (LFHT) and low-pressure low-temperature (LPLT) gasifiers while simultaneously understanding the materials barriers to the successful demonstration of high-pressure high-temperature (HPHT) black liquor gasifiers. This study will define the chemical, thermal and physical conditions in current and proposed gasifier designs and then modify existing materials and develop new materials to successfully meet the formidable material challenges. Resolving the material challenges of black liquor gasification combined cycle technology will provide energy, environmental, and economic benefits that include higher thermal efficiencies, up to three times greater electrical output per unit of fuel, and lower emissions. In the near term, adoption of this technology will allow the pulp and paper industry greater capital effectiveness and flexibility, as gasifiers are added to increase mill capacity. In the long term, combined-cycle gasification will lessen the industry's environmental impact while increasing its potential for energy production, allowing the production of all the mill's heat and power needs along with surplus electricity being returned to the grid. An added benefit will be the potential elimination of the possibility of smelt-water explosions, which constitute an important safety concern wherever conventional Tomlinson recovery boilers are operated. Developing cost-effective materials with improved performance in gasifier environments may be the best answer to the material challenges presented by black liquor gasification. Refractory materials may be selected/developed that either react with the gasifier environment to form protective

  8. Thoughts on Strategic Development of China's Refractories Industry

    Institute of Scientific and Technical Information of China (English)

    ZHONG Xiangchong

    2003-01-01

    For China' s refractories industry, the first two decades in the new century would be a period of structural optimization with reorganization of refractories enterprises,reconstruction of manufacturing plants and restructuring of product varieties. An important strategic measure should be to develop high quality synthetic raw materials and high performance functional products mainly based on our rich natural resources to cope with new demands of advanced high temperature technologies.

  9. Performance comparison of AlTiC and AlTiB master alloys in grain refinement of commercial and high purity aluminum

    Institute of Scientific and Technical Information of China (English)

    LI Jian-guo; HUANG Min; MA Mo; YE Wei; LIU Dong-yu; SONG Dong-ming; BAI Bing-zhe; FANG Hong-sheng

    2006-01-01

    For further knowledge about the refining performance of AlTiC master alloys, Al5.5Ti0.25C and Al6.5Ti0.5C master alloys containing high Ti and C content were prepared and used in grain refining experiments of 99.8% commercial pure aluminum(CPAl). Their performance was compared with two types of Al5TilB refiners whose performance was nowadays considered to be the best. These two types of master alloys show similar refining efficiency at the addition level of 0.2%. However, at the addition level of 0.5%, there still exists great performance difference between AlTiC and Al5TiB alloys in grain refinement of 99.98% and 99.995% high purity aluminum(HPAl). The growth of columnar grains is fully suppressed due to the refinement of AlTiC at the addition level of 0.5%. Also, at the same addition level, the grain refining experiments of Al3Ti0.15C and Al5Ti0.2C master alloys which have found initial commercial applications are conducted in the above-mentioned three types of pure aluminum.According to the experimental results, these two refiners of different compositions are both nonideal. The second phase particles extracted from each refiner were observed through TEM, while the nuclei of grains after grain refinement were observed through SEM. The results were analyzed through computation and comparison of the constitutional-supercooling parameter and the growth-restriction parameter whose values were determined by solute element in aluminum melt with different purity. Apparently,AlTiC master alloys with high content of Ti and C element have great refining potential.

  10. Refractory chronic migraine

    DEFF Research Database (Denmark)

    Martelletti, Paolo; Katsarava, Zaza; Lampl, Christian

    2014-01-01

    and in the uncontrolled application of therapeutic techniques not yet validated.The European Headache Federation Expert Group on rCM presents hereby the updated definition criteria for this harmful subset of headache disorders. This attempt wants to be the first impulse towards the correct identification......The debate on the clinical definition of refractory Chronic Migraine (rCM) is still far to be concluded. The importance to create a clinical framing of these rCM patients resides in the complete disability they show, in the high risk of serious adverse events from acute and preventative drugs...... of these patients, the correct application of innovative therapeutic techniques and lastly aim to be acknowledged as clinical entity in the next definitive version of the International Classification of Headache Disorders 3 (ICHD-3 beta)....

  11. Refractory chronic cluster headache

    DEFF Research Database (Denmark)

    Mitsikostas, Dimos D; Edvinsson, Lars; Jensen, Rigmor H

    2014-01-01

    Chronic cluster headache (CCH) often resists to prophylactic pharmaceutical treatments resulting in patients' life damage. In this rare but pragmatic situation escalation to invasive management is needed but framing criteria are lacking. We aimed to reach a consensus for refractory CCH definition...... for clinical and research use. The preparation of the final consensus followed three stages. Internal between authors, a larger between all European Headache Federation members and finally an international one among all investigators that have published clinical studies on cluster headache the last five years....... Eighty-five investigators reached by email. Proposed criteria were in the format of the International Classification of Headache Disorders III-beta (description, criteria, notes, comments and references). Following this evaluation eight drafts were prepared before the final. Twenty-four (28...

  12. The performances of proto-type Ni/MH secondary batteries using Zr-based hydrogen storage alloys and filamentary type Ni

    Science.gov (United States)

    Lee, Sang-Min; Lee, Ho; Kim, Jin-Ho; Lee, Paul S.; Lee, Jai-Young

    2001-04-01

    For the purpose of developing a Zr-based Laves phase alloy with higher capacity and better performance for electrochemical application, extensive work has been carried out. After careful alloy design of ZrMn2-based hydrogen storage alloys through varying their stoichiometry by means of substituting or adding alloying elements, the Zr0.9Ti0.1(Mn0.7V0.5Ni1.4)0.92 with high capacity (392 mAh/g at the 0.25C) and improved performance (comparable to that of commercialized AB5 type alloy) was developed. Another endeavor was made to improve the poor activation property and the low rate capability of the developed Zr-based Laves phase alloy for commercialization. The combination method of hot-immersion and slow-charging was introduced. It was found that electrode activation was greatly improved after hot immersion at 80°C for 12h followed by charging at 0.05C. The effects of this method are discussed in comparison with other activation methods. The combination method was successfully applied to the formation process of 80 Ah Ni/MH cells. A series of systematic investigations has been rendered to analyze the inner cell pressure characteristics of a sealed type Ni-MH battery. It was found that the increase of inner cell pressure in the sealed type Ni/MH battery of the above-mentioned Zr-Ti-Mn-V-Ni alloy was mainly due to the accumulation of oxygen gas during charge/discharge cycling. The fact identified that the surface catalytic activity was affected more dominantly by the oxygen recombination reaction than the reaction surface area was also identified. In order to improve the surface catalytic activity of a Zr-Ti-Mn-V-Ni alloy, which is closely related to the inner pressure behavior in a sealed cell, the electrode was fabricated by mixing the alloy with Cu powder and a filamentary type of Ni and replacing 75% of the carbon black with them; thus, the inner cell pressure rarely increases with cycles due to the active gas recombination reaction. Measurements of the surface

  13. Guide for Recommended Practices to Perform Crack Tip Opening Displacement Tests in High Strength Low Alloy Steels

    Directory of Open Access Journals (Sweden)

    Julián A. Ávila

    Full Text Available Abstract: Fracture mechanics approach is important for all mechanical and civil projects that might involve cracks in metallic materials, and especially for those using welding as a structural joining process. This methodology can enhance not only the design but also the service life of the structures being constructed. This paper includes detailed consideration of several practical issues related to the experimental procedures to assess the fracture toughness in high strength low alloy steels (HSLA using the crack tip opening displacement (CTOD parameter, specifically pipeline steels for oil and gas transportation. These considerations are important for engineers who are new in the field, or for those looking for guidelines performing different procedures during the experimentation, which usually are difficult to understand from the conventional standards. We discuss on topics including geometry selection, number of replicate tests, fatigue precracking, test procedure selection and realization, reports of results and other aspects.

  14. Effects of Different Processes on Phases and Service Performance of FeSiMg8RE5 Alloy

    Institute of Scientific and Technical Information of China (English)

    Jia Yanhua; Zhang Hong; Wang Zidong; Xue Shouhong; Qiao Zhen; Zhang Xianheng

    2004-01-01

    The difference of nodularizer in phase morphology and service performance by three processes was introduced.The three processes include directly pressing magnesium into molten alloy stirring by nitrogen gas and no stirring from 5 t arc furnace and melting magnesium in the intermediate frequency furnace.The microstructure patterns were observed by scanning electron microscope, and composition of phases was measured by energy dispersive spectrometer method.X-ray diffraction method was used to determine the phase structure of the nodularizer.The results show that spheroidizing reaction time and violent degree of nodularizers are influenced by grain size and distribution uniformity of siliconizing magnesium phase; spheroidizing reaction degree can be mitigated and spheroidizing time be increased by using N2 stirring in pressing magnesium from arc furnace.

  15. PC/ASA合金的研发%Research on PC/ASA Alloy Performance and Preparation Process

    Institute of Scientific and Technical Information of China (English)

    黄李胜; 李景; 麦伟宗; 赖世亮

    2016-01-01

    利用双螺杆挤出机制备PC/ASA合金,探讨了不同PC与ASA配比对性能的影响。结果表明:在PC/ASA体系中,PC与ASA的配比为70∶30,添加4%的相容剂SMA以及0.8%的抗氧剂、润滑剂,能获得最优的性能:悬臂梁缺口冲击强度达66.7kJ/m2,拉伸强度达56.1MPa,弯曲强度达82.3MPa,热变形温度达105.6℃;同时比同等条件下制备出来的PC/ABS合金拥有更好的耐光性。%Using a twin-screw extruder equipment,PC/ASA alloy was prepared,the effects of different ratio of PC and ASA on performance were investigated. The results showed that:in PC/ASA system,PC and ASA ratio is 70∶30,adding compatibility agent SMA 4% and 0. 8% of antioxidant and lubricant,can achieve optimal perform-ance:Izod notched impact strength of 66. 7kJ/m2 , the tensile strength of 56. 1MPa, the bending strength of 82. 3MPa,heat distortion temperature of 105. 6℃;while PC/ABS was prepared under the same conditions,PC/ASA alloy has better lightfastness than PC/ABS.

  16. Sample Preparation for Monolithic Refractories Part 1: Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaohui; Peng Xigao

    2010-01-01

    @@ 1 Scope This standard specifies the definition and test methods of flowability of dense and insulating refractory castables,and moulding equipment,moulding methods,curing and drying conditions of castables samples.

  17. Preparation and Performance of Plasma/Polymer Composite Coatings on Magnesium Alloy

    DEFF Research Database (Denmark)

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Bagheriyan, S.

    2016-01-01

    , globular porosities, and micro-cracks with a thickness of 40-50 μm, while the Al2O3·13%TiO2 coating, as the second layer, presented a unique bimodal microstructure with a thickness of 70-80 μm. The top layer was a hydrophobic polymer, which effectively sealed the porosities of plasma layers. The results......A triplex plasma (NiCoCrAlHfYSi/Al2O3·13%TiO2)/polycaprolactone composite coating was successfully deposited on a Mg-1.2Ca alloy by a combination of atmospheric plasma spraying and dip-coating techniques. The NiCoCrAlHfYSi (MCrAlHYS) coating, as the first layer, contained a large number of voids...... of micro-hardness and bonding strength tests showed that the plasma coating presented excellent hardness (870 HV) and good bonding strength (14.8 MPa). However, the plasma/polymer coatings interface exhibited low bonding strength (8.6 MPa). The polymer coating formed thick layer (100-110 μm...

  18. Present Situation of Refractories for Baosteel

    Institute of Scientific and Technical Information of China (English)

    TAI Li; SHEN Keyin

    2004-01-01

    The paper reviews the present situation of refractories for Baosteel, including refractories for iron-making system, converters, ladles and tundishes. Descriptions have been also conducted on the environment protection and reutilization of refractories in Baosteel, together with somesuggestions for refractories suppliers to meet the advancement in iron and steel making technology of Baosteel.

  19. Performance of NiB inhibitor for PbSCC of alloy 600 in Pb-contaminated water and caustic solutions

    Science.gov (United States)

    Kim, Joung Soo; Yi, Yong-Sun; Kwon, Oh Chul; Kim, Mi-Ae; Kim, Hong Pyo

    2008-06-01

    Nickel-based iron-chromium alloys are used as steam generator (SG) tubing materials in nuclear power plants (NPPs) but experience intergranular stress corrosion cracking (IGSCC) and lead stress corrosion cracking (PbSCC) due to the harsh operating conditions of NPPs. In order to improve the integrity of SGs, many studies have sought suitable inhibitors for IGSCC, while those for PbSCC have been sought to a limited extent. In this study, the performance of nickel boride (NiB) as an inhibitor for PbSCC was evaluated. Nickel boride has been shown to be a good inhibitor for IGSCC of Alloy (or Inconel) 600 in a caustic aqueous solution containing no lead (Pb). No significant SCC was observed to occur in Alloy 600 tested in pure water under the slow strain rate test (SSRT) condition in this study. A mixed mode of IGSCC and TGSCC, however, occurred relatively easily in Alloy 600 tested in pure water containing lead oxide (PbO) at 315 °C. The susceptibility of Alloy 600 to SCC decreased with the addition of NiB, implying that NiB can be used as an inhibitor for PbSCC in Pb-contaminated water.

  20. Fabrication and electromagnetic interference shielding performance of open-cell foam of a Cu–Ni alloy integrated with CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Keju; Zhao, Huihui; Zhang, Jun; Chen, Jia; Dai, Zhendong, E-mail: zddai@nuaa.edu.cn

    2014-08-30

    Highlights: • Cu–Ni alloy open-cell foam integrated with CNTs was used for EMI shielding. • The composite was prepared by electroless, electro-, and electrophoretic deposition. • The main shielding mechanism was multiple reflections and absorptions of microwaves. • The composite had a porous structure, large surface area, and inherent permeability. - Abstract: A lightweight multi-layered electromagnetic interference (EMI) shielding material made of open-cell foam of a Cu–Ni alloy integrated with carbon nanotubes (CNTs) was prepared by electroless copper plating, then nickel electroplating, and finally electrophoretic deposition of CNTs. The foamed Cu–Ni–CNT composite comprises, from inside to outside, Cu, Ni, and CNT layers. Scanning electron microscopy, energy dispersive spectroscopy, and EMI tests were employed to characterize the morphology, composition, and EMI performance of the composite, respectively. The results indicated that the shielding effectiveness (SE) of the composite increased with increasing pore density (indicated as pores per inch (PPI)) and increasing thickness. A specimen with a PPI of 110 and a 1.5-mm thickness had a maximum SE of up to 54.6 dB, and a SE as high as 47.5 dB on average in the 8–12 GHz range. Integrating the inherent superiority of Cu, Ni, and CNTs, the porous structure of the composite can attenuate the incident electromagnetic microwaves by reflecting, scattering, and absorbing them between the metallic skeleton and the CNT layer. The multiple reflections and absorptions make it difficult for the microwaves to escape from the composite before being absorbed, thereby making the composite a potential shielding material.

  1. Self-flow Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaohui; Peng Xigao

    2010-01-01

    @@ 1 Scope This standard specifies the term and definition,classification, technical requirements, test methods,quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of self-flow refractory castables.

  2. Alumina-magnesia Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Wang Jing

    2010-01-01

    @@ 1 Scope This standard specifies the classification,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of alumina-magnesia refractory castables.

  3. Preparation and Performance of Plasma/Polymer Composite Coatings on Magnesium Alloy

    Science.gov (United States)

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Bagheriyan, S.; Daroonparvar, M.; Kasiri-Asgarani, M.; Shah, A. M.; Medraj, M.

    2016-09-01

    A triplex plasma (NiCoCrAlHfYSi/Al2O3·13%TiO2)/polycaprolactone composite coating was successfully deposited on a Mg-1.2Ca alloy by a combination of atmospheric plasma spraying and dip-coating techniques. The NiCoCrAlHfYSi (MCrAlHYS) coating, as the first layer, contained a large number of voids, globular porosities, and micro-cracks with a thickness of 40-50 μm, while the Al2O3·13%TiO2 coating, as the second layer, presented a unique bimodal microstructure with a thickness of 70-80 μm. The top layer was a hydrophobic polymer, which effectively sealed the porosities of plasma layers. The results of micro-hardness and bonding strength tests showed that the plasma coating presented excellent hardness (870 HV) and good bonding strength (14.8 MPa). However, the plasma/polymer coatings interface exhibited low bonding strength (8.6 MPa). The polymer coating formed thick layer (100-110 μm) that homogeneously covered the surface of the plasma layers. Contact angle measurement showed that polymer coating over plasma layers significantly decreased surface wettability. The corrosion current density ( i corr) of an uncoated sample (262.7 µA/cm2) decreased to 76.9 µA/cm2 after plasma coatings were applied. However, it was found that the i corr decreased significantly to 0.002 µA/cm2 after polymer sealing of the porous plasma layers.

  4. A novel Nickel-Aluminum alloy with Titanium for improved anode performance and properties in Molten Carbonate Fuel Cells

    Science.gov (United States)

    Frattini, Domenico; Accardo, Grazia; Moreno, Angelo; Yoon, Sung Pil; Han, Jong Hee; Nam, Suk Woo

    2017-06-01

    The anode materials of MCFC require more investigations in order to boost performances at long term. In literature, many NiAl modified alloys have been proposed but not always enhanced cell performance and improved mechanical properties are achieved together. In this work, differently from previous literature, the use of Ti in a NiAl/Ti system is proposed as an effective strategy to enhance both mechanical and electrochemical properties. Results show that bending strength and stiffness increase whereas creep deformation under high pressure-temperature is lower, i.e. around 5-6%, compared to 7.5% of the standard benchmark. The preliminary cell tests carried out show also how the performance, in terms of current and voltage output, is better for anodes with Ti addition with a maximum power density of 165 mW cm-2 at 300 mA cm-2 for Ti 5% compared to 149 mW cm-2 of Ni5Al at the same current density. Finally, the best electrochemical behavior is found for the Ti 5% sample as it achieved the lowest internal and charge transfer resistance at the end of tests. These results suggest that NiAl/Ti systems can be eligible anode materials and are worthy to be investigated more in order to attract a renewed interest for development of MCFCs.

  5. Effect of Heat Treatment on Structure and Magnetic Performance of Ni-Fe-P Alloy Obtained by Electroless Plating

    Institute of Scientific and Technical Information of China (English)

    WANG Sen-lin; ZHANG Yong

    2005-01-01

    The electroless deposition of Ni68-Fe10.5-P21.5 alloy has been investigated. The crystallization behavior of the deposit was comparatively studied by using differential scanning calorimetry and X-ray diffractometry. The deposit transforms into a square Ni3P phase at 380.0 ℃, then changes into a cubic FeNi3 phase at 490.0 ℃. The microhardness,the size of the formed grains and the magnetic performance of the deposit increase with the increase of the heat treatment temperature below 500 ℃, then they decrease after this temperature. The effect of heat treatment time at 500 ℃on the surface micromorphology, the structure and the magnetic performance of the deposit were also studied. The resuIts show that with the increase of heat treatment time, the extent of crystallization of the deposit increases and the size of the formed grains becomes uniform. The results also show that the magnetic performance of the deposit under heat treatment for 40 min is maximal and then decreases with the increase of heat treatment time. The property change of the deposit is related to the crystal structure and the size of the formed grains of the deposit.

  6. EFFECT OF CHEMISTRY VARIATIONS IN PLATE AND WELD FILLER METAL ON THE CORROSION PERFORMANCE OF NI-CR-MO ALLOYS

    Energy Technology Data Exchange (ETDEWEB)

    D.V. Fix

    2006-02-07

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials in the range of the standards.

  7. Effect of Chemistry Variations in Plate and Weld Filler Metal on the Corrosion Performance of Ni-Cr-Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fix, D V; Rebak, R B

    2006-02-05

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials in the range of the standards.

  8. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  9. VNS for refractory status epilepticus.

    Science.gov (United States)

    Zeiler, F A; Zeiler, K J; Teitelbaum, J; Gillman, L M; West, M

    2015-05-01

    Our goal was to perform a systematic review of the literature on the insertion of vagal nerve stimulators (VNS) for refractory status epilepticus (RSE) and its impact on the control of RSE. All articles from MEDLINE, BIOSIS, EMBASE, Global Health, HealthStar, Scopus, Cochrane Library, the International Clinical Trials Registry Platform, clinicaltrials.gov (inception to June 2014), reference lists of relevant articles, and gray literature were searched. The strength of evidence was adjudicated using both the Oxford and GRADE methodology by two independent reviewers (FZ and MW). Overall, 17 studies were identified, with 7 manuscripts and 10 meeting abstracts. A total of 28 patients were treated. In those with generalized RSE, 76% displayed cessation of RSE with VNS insertion. In cases of focal RSE, 25% responded to VNS insertion. Few adverse effects related to VNS insertion were described. We currently cannot recommend the use of VNS for RSE. Oxford level 4, GRADE D evidence exists to suggest improvement in seizure control with the use of urgent VNS in generalized RSE. No comments can be made on the utility of VNS in focal RSE. Further prospective study is warranted. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Impact of alternate fuels on industrial refractories and refractory insulation applications. An Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G.C.; Tennery, V.J.

    1976-09-01

    The effects of use of alternate fuels such as distillate oils, residual oils, coal, producer gas, and electricity on refractory insulation are evaluated. Sections are included on alternate fuels for 1976 to 1980, assessment by industry of fuel conversion impact on industrial refractories in the period 1976 to 1980, interactions of alternate fuel combustion products with refractories and refractory insulation, and analysis of degradation mechanisms in refractories and refractory materials. (JRD)

  11. Development of a Refractory High Entropy Superalloy (Postprint)

    Science.gov (United States)

    2016-03-17

    primary phase . RHEAs with a low density and high strength are among the most promising recent achievements in this field [19–23]. In particular, the...after annealing at 1400 °C for 24 h. Second- phase precipitates (which are dark) are present at grain boundaries. (a) (b) Figure 4. High magnification...Microstructure, phase composition and mechanical properties of a refractory high entropy super alloy, AlMo0.5NbTa0.5TiZr, are reported in this work. The

  12. Preparation of Permanent Mold Coating Using Magnesia Powder for Magnesium Alloys

    Science.gov (United States)

    Guo, Guangsi; Wang, Guangtai; Yu, Haifeng; Ye, Sheng

    A kind of permanent mold coating for magnesium alloy was developed using magnesia powder and diatomite as refractory aggregate. The properties of the coating were tested and analyzed by various ingredients. The final ingredient was determined through the tests which are to find out the optimal proportion of two kinds of aggregate and the influences to coating properties by changing the proportion of binder and suspending agents. The experimental results shown that the permanent mold coating performed good properties on magnesium alloys when the optimized ratio of magnesia powder and diatomite was 6: 4, and the integrated property is very excellent when the coating was prepared with 2 percent of sodium bentonite, 0.4 percent of CMC, 7 percent of sodium hexametaphosphate, and 7 percent of sodium silicate. The excellent performance has also been proved by actual casting test.

  13. Enhancing catalytic performance of palladium in gold and palladium alloy nanoparticles for organic synthesis reactions through visible light irradiation at ambient temperatures.

    Science.gov (United States)

    Sarina, Sarina; Zhu, Huaiyong; Jaatinen, Esa; Xiao, Qi; Liu, Hongwei; Jia, Jianfeng; Chen, Chao; Zhao, Jian

    2013-04-17

    The intrinsic catalytic activity of palladium (Pd) is significantly enhanced in gold (Au)-Pd alloy nanoparticles (NPs) under visible light irradiation at ambient temperatures. The alloy NPs strongly absorb light and efficiently enhance the conversion of several reactions, including Suzuki-Miyaura cross coupling, oxidative addition of benzylamine, selective oxidation of aromatic alcohols to corresponding aldehydes and ketones, and phenol oxidation. The Au/Pd molar ratio of the alloy NPs has an important impact on performance of the catalysts since it determines both the electronic heterogeneity and the distribution of Pd sites at the NP surface, with these two factors playing key roles in the catalytic activity. Irradiating with light produces an even more profound enhancement in the catalytic performance of the NPs. For example, the best conversion rate achieved thermally at 30 °C for Suzuki-Miyaura cross coupling was 37% at a Au/Pd ratio of 1:1.86, while under light illumination the yield increased to 96% under the same conditions. The catalytic activity of the alloy NPs depends on the intensity and wavelength of incident light. Light absorption due to the Localized Surface Plasmon Resonance of gold nanocrystals plays an important role in enhancing catalyst performance. We believe that the conduction electrons of the NPs gain the light absorbed energy producing energetic electrons at the surface Pd sites, which enhances the sites' intrinsic catalytic ability. These findings provide useful guidelines for designing efficient catalysts composed of alloys of a plasmonic metal and a catalytically active transition metal for various organic syntheses driven by sunlight.

  14. Nasogastric tube-administered alectinib achieved long-term survival in a crizotinib-refractory nonsmall cell lung cancer patient with a poor performance status.

    Science.gov (United States)

    Kanai, Osamu; Kim, Young Hak; Nakatani, Koichi; Fujita, Kohei; Mio, Tadashi

    2017-06-01

    Alectinib shows remarkable efficacy against anaplastic lymphoma kinase (ALK)-positive nonsmall cell lung cancer (NSCLC), with minimal adverse effects. Therefore, alectinib may provide a survival benefit to ALK-positive NSCLC patients with a poor performance status. If the medication cannot be taken by mouth, the patient may be given alectinib through a nasogastric tube.

  15. Effect of cobalt alloying on the electrochemical performance of manganese oxide nanoparticles nucleated on multiwalled carbon nanotubes

    Science.gov (United States)

    Yazdani, Sajad; Kashfi-Sadabad, Raana; Palmieri, Alessandro; Mustain, William E.; Thompson Pettes, Michael

    2017-04-01

    MnO is an electrically insulating material which limits its usefulness in lithium ion batteries. We demonstrate that the electrochemical performance of MnO can be greatly improved by using oxygen-functional groups created on the outer walls of multiwalled carbon nanotubes (MWCNTs) as nucleation sites for metal oxide nanoparticles. Based on the mass of the active material used in the preparation of electrodes, the composite conversion-reaction anode material Mn1‑x Co x O/MWCNT with x = 0.2 exhibited the highest reversible specific capacity, 790 and 553 mAhg‑1 at current densities of 40 and 1600 mAg‑1, respectively. This is 3.1 times higher than that of MnO/MWCNT at a charge rate of 1600 mAg‑1. Phase segregation in the {{{Mn}}}1-x{{{Co}}}x{{O}} nanoparticles was not observed for x ≤ 0.15. Capacity retention in x = 0, 0.2, and 1 electrodes showed that the corresponding specific capacities were stabilized at 478, 709 and 602 mAhg‑1 respectively, after 55 cycles at a current density of 400 mAg‑1. As both MnO and CoO exhibit similar theoretical capacities and MnO/MWCNT and CoO/MWCNT anodes both exhibit lower performance than Mn0.8Co0.2O/MWCNT, the improved performance of the {{{Mn}}}1-x{{{Co}}}x{{O}}/{{MWCNT}} alloy likely arises from beneficial synergistic interactions in the bimetallic system.

  16. Effectiveness and resolution of tests for evaluating the performance of cutting fluids in machining aerospace alloys

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Axinte, Dragos A.

    2008-01-01

    The paper discusses effectiveness and resolution of five cutting tests (turning, milling, drilling, tapping, VIPER grinding) and their quality output measures used in a multi-task procedure for evaluating the performance of cutting fluids when machining aerospace materials. The evaluation takes...

  17. Innovative surface modification of Ti–6Al–4V alloy with a positive effect on osteoblast proliferation and fatigue performance

    Energy Technology Data Exchange (ETDEWEB)

    Havlikova, Jana, E-mail: havlikova@biomed.cas.cz [Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4 (Czech Republic); Strasky, Josef, E-mail: josef.strasky@gmail.com [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Vandrovcova, Marta, E-mail: vandrovcova@biomed.cas.cz [Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4 (Czech Republic); Harcuba, Petr, E-mail: harcuba.p@seznam.cz [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Mhaede, Mansour, E-mail: mansour.mhaede@tu-clausthal.de [Institute of Materials Science and Engineering, Clausthal University of Technology, Agricolastraße 2/6, 38678 Clausthal-Zellerfeld (Germany); Faculty of Engineering, Zagazig University, Zagazig (Egypt); Janecek, Milos, E-mail: janecek@met.mff.cuni.cz [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Bacakova, Lucie, E-mail: lucy@biomed.cas.cz [Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4 (Czech Republic)

    2014-06-01

    A novel approach of surface treatment of orthopaedic implants combining electric discharge machining (EDM), chemical milling (etching) and shot peening is presented in this study. Each of the three techniques have been used or proposed to be used as a favourable surface treatment of biomedical titanium alloys. But to our knowledge, the three techniques have not yet been used in combination. Surface morphology and chemistry were studied by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Fatigue life of the material was determined and finally several in-vitro biocompatibility tests have been performed. EDM and subsequent chemical milling leads to a significant improvement of osteoblast proliferation and viability thanks to favourable surface morphology and increased oxygen content on the surface. Subsequent shot-peening significantly improves the fatigue endurance of the material. Material after proposed combined surface treatment possesses favourable mechanical properties and enhanced osteoblast proliferation. EDM treatment and EDM with shot peening also supported early osteogenic cell differentiation, manifested by a higher expression of collagen type I. The combined surface treatment is therefore promising for a range of applications in orthopaedics. - Highlights: • Surface modification combining EDM, chemical milling and shot-peening was developed. • Fatigue endurance was improved when high Almen intensity and small shots were used. • Chemical milling creates favourable surface morphology and increases oxygen content. • The three-step surface modification has a positive effect on the osteoblast growth. • EDM and EDM with shot peening supported early osteogenic cell differentiation.

  18. The Influence of High Temperature Exposure on the Wear Performance of a Ni Based Alloy PTA Coating

    Institute of Scientific and Technical Information of China (English)

    Karin Graf; Ana Sofia C.M. d'Oliveira

    2004-01-01

    Degradation phenomena like wear and corrosion, may have their effects accelerated as components operate at high temperature. The aim of this work is to make an indirect evaluation of the influence of high temperature exposure on wear behavior of Ni coatings. A Ni-Cr-Mo-W alloy, was deposited with Plasma Transferred Arc (PTA) process. An indirect approach based on the Ahrrenius relationship was used to evaluated long time exposures at high temperatures. To simulate longer exposures at lower temperatures, coatings were exposed to higher temperatures for the same time interval. So coatings were soaked in an air furnace at 650℃, 1000℃ and 1200℃. Metal/metal wear behavior was evaluated by pin-on-disc tests. Pins were removed from the coatings by eletrodischarge machining and rubbed against a VC31 quenched and tempered tool steel. Two sets of wear tests were run at 2m/s, for different loads (0.5, 1.0, 2.0 and 3.0Kg) and for different sliding distances (120, 720, 1080, 1440 and 1800m).Coatings characterization was done by scanning electronic microscopy and Vickers microhardness. Results showed as temperature is increased, coatings wear performance is altered,and this is associated with microstructural changes.

  19. Long - range foundry Al composite alloys

    Directory of Open Access Journals (Sweden)

    A. D. Mekhtiev

    2014-10-01

    Full Text Available The technology of obtaining nanostructural composite aluminum alloys consists in the plasma injection of refractory nanometric particles with simultaneous two-plane magnetic dynamic mixing of the melt. Particularly important in obtaining composite aluminum matrix alloys is the provision of the introduced particles wettability with the matrix melt for forming stable adhesive bonds. Nanostructured powder components can be considered not only to be a starting product for producing nanostructural composite aluminum alloys but as an independent commerce product. Nanostructural composite metal matrix alloys make one of the most prospective structural materials of the future, and liquid-phase technologies of their obtaining are the most competitive in producing products of nanostructural composite aluminum alloys in the industrial scale.

  20. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  1. Performance analysis of STT-RAM with cross shaped free layer using Heusler alloys

    Science.gov (United States)

    Bharat Kumary, Tangudu; Ghosh, Bahniman; Awadhiya, Bhaskar; Verma, Ankit Kumar

    2016-01-01

    We have investigated the performance of a spin transfer torque random access memory (STT-RAM) cell with a cross shaped Heusler compound based free layer using micromagnetic simulations. We have designed a free layer using a Cobalt based Heusler compound. Simulation results clearly show that the switching time from one state to the other state has been reduced, also it has been found that the critical switching current density (to switch the magnetization of the free layer of the STT RAM cell) is reduced.

  2. High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

    Directory of Open Access Journals (Sweden)

    Rafik Abbas

    2017-01-01

    Full Text Available A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

  3. Company Profile Dengfeng Chunsheng Refractories Co., Ltd.

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Dengfeng Chunsheng Refractories Co., Ltd. is an industrial enterprise integrating refractories research, design, manufacturing and engineering service into one and was entitled as one of China's high-quality silica bricks production and export bases.

  4. ZrO2—Containing Refractories for Cement Rotary Kilns

    Institute of Scientific and Technical Information of China (English)

    YEGuotian; XUYanqing

    2002-01-01

    ZrO2-Containing Refractories have been increasingly used for cement rotary kilns,This paper discusses how the properties and performance of ZrO2-Containing Refractories are improved in terms of chemical attack resistance,thermal shock resistance,thermal conductivity and mechanical stress.

  5. Espinelização in-situ e seu efeito na resistência ao choque térmico de concretos refratários In-situ spinelization and thermal shock performance of refractory castables

    Directory of Open Access Journals (Sweden)

    G. B. Cintra

    2008-09-01

    Full Text Available O desempenho de uma panela siderúrgica está atrelado ao seu revestimento refratário. Devido à elevada agressividade da escória presente no aço fundido, é fundamental a utilização de revestimentos de alta resistência à corrosão. Concretos refratários aluminosos contendo espinélio são amplamente utilizados em tal aplicação por apresentarem esta característica. Neste contexto, destacam-se os concretos refratários do sistema alumina-magnésia, uma vez que a formação de espinélio in-situ é benéfica em termos termodinâmicos e microestruturais. Considerando-se que as panelas sofrem constantemente variações bruscas de temperatura, devido à ciclagem térmica, a análise da resistência ao choque térmico é um parâmetro fundamental para a correta seleção do revestimento refratário. Sendo assim, o objetivo deste trabalho é caracterizar o efeito das variações dos componentes da matriz dos concretos Al2O3-MgO e suas conseqüências nos danos causados por choque térmico. Os resultados mostraram que os concretos com espinelização in-situ apresentaram desempenho inferior àqueles com adição de espinélio pré-formado em ambientes sem constrição. Adicionalmente, a presença de microssílica aumentou o dano sofrido pelos concretos. Porém, deve-se considerar que o ensaio de caracterização foi realizado em temperaturas inferiores às de transição vítrea, podendo influenciar no resultado. A associação destes conhecimentos possibilita encontrar a melhor solução termomecânica associada a uma elevada resistência à corrosão química, resultando em maior vida útil e superior desempenho das panelas siderúrgicas.The steel ladle working life is directly related with the refractory lining performance. Considering the great corrosion promoted by basic slags in the secondary steelmaking industry, the use of a high quality material is essential. The corrosion resistance is attained by the use of alumina

  6. Electrochemical Performance of Alloy 690 Under ETA and AVT Water Chemistry Condition%690合金在ETA和AVT水工况下的电化学特性

    Institute of Scientific and Technical Information of China (English)

    朱志平; 赵永福; 周瑜; 郭小翠; 邓奕鹏

    2012-01-01

    采用Tafel极化曲线法和电化学阻抗法研究了690合金在乙醇胺(ETA)和全挥发处理(AVT)两种水工况下的电化学行为,并着重考察了pH值、温度、Cl-和SO42-对690合金电化学性能的影响.结果表明,在两种不同水工况下,pH值升高会提高690合金的耐蚀性,而温度升高和Cl-,SO42-的加入则均会加速690合金的腐蚀.在相同条件下,690合金与ETA水工况有更好的兼容性,ETA的缓蚀性能优于NH3.%The electrochemical corrosion behavior of alloy 690 in environments of ethanolamine(ETA) and all volatile treatment(AVT) water chemistry was studied by means of Tafel polarization curves and electrochemical impedance spectroscopy(EIS) with a particular emphasis on the effect of pH,temperature,Cl-and SO42-on the electrochemical performance of alloy 690.The results showed that under the two different water chemistry conditions,the increase of pH value would enhance the corrosion resistance of the alloy while the elevation of the temperature and the addition Cl-and SO42-would accelerate the corrosion of alloy 690.Under the same conditions,ETA water chemistry environment had a better compatibility with alloy 690 and ETA exhibited better inhibition efficiency than NH3.

  7. Magnesia-Chrome Refractories for Flash Furnace

    Institute of Scientific and Technical Information of China (English)

    LI Yong; CHEN Kaixian; LU Xinghua; LIU Jianlong; SUN Jialin; HONG Yanruo

    2002-01-01

    The rapid development of our country's heavy nonferrous metallurgical technology and the revolution in new type of heavynon-ferrous metallurgical furnace have imposed more critical demand on the refractory materials ,i. e. high quality and long service life. This paper presents the domestic status of the refractories for flash furnace , briefly describes the wear of the refractory used , and it is considered that the domestic in refractories for flashfurnace can be surely realized.

  8. Reuse and Reproduction of Used Refractories

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The paper analyzed the recycle condition and developing trend of used refractories China and other countries, including research achievements of recycles of used refractories such as MgO-C bricks, Al2O3-MgO-C bricks, Al2O3-SiC-C castable and MgO-Cr2O3 bricks. Recycled refractories exhibit the same or even better properties as compared with the original. In addition, prospects for recycle of used refractories are also discusseded.

  9. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  10. Numerical analysis of static performance comparison of friction stir welded versus riveted 2024-T3 aluminum alloy stiffened panels

    Science.gov (United States)

    Shao, Qing; He, Yuting; Zhang, Teng; Wu, Liming

    2014-07-01

    Most researches on the static performance of stiffened panel joined by friction stir welding(FSW) mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method(FEM) is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted

  11. Tungsten joining with copper alloy and its high heat load performance

    Science.gov (United States)

    Liu, Xiang; Lian, Youyun; Chen, Lei; Cheng, Zengkui; Chen, Jiming; Duan, Xuru; Song, Jioupeng; Yu, Yang

    2014-12-01

    W-CuCrZr joining technology by using low activation Cu-Mn filler metal was developed at Southwestern Institute of Physics (SWIP) for the manufacturing of divertor components of fusion experiment devices. In addition, a fast W coating technology by chemical vapor deposition (CVD) was also developed and CVD-W/CuCrZr and CVD-W/C mockups with a W coating thickness of 2 mm were prepared. In order to assess their high heat flux (HHF) performances, a 60 kW Electron-beam Material testing Scenario (EMS-60) equipped with a 150 keV electron beam welding gun was constructed at SWIP. Experimental results indicated that brazed W/CuCrZr mockups can withstand 8 MW/m2 heat flux for 1000 cycles without visible damages and CVD-W/CuCrZr mockups with W-Cu gradient interface can survive 1000 cycles under 11 MW/m2 heat flux. An ultrasonic inspection method for non-destructive tests (NDT) of brazed W/CuCrZr mockups was established and 2 mm defect can be detected. Infinite element analysis and heat load tests indicated that 5 mm defect had less noticeable influence on the heat transfer.

  12. Management of chronic refractory cough.

    Science.gov (United States)

    Gibson, Peter G; Vertigan, Anne E

    2015-12-14

    Chronic refractory cough (CRC) is defined as a cough that persists despite guideline based treatment. It is seen in 20-46% of patients presenting to specialist cough clinics and it has a substantial impact on quality of life and healthcare utilization. Several terms have been used to describe this condition, including the recently introduced term cough hypersensitivity syndrome. Key symptoms include a dry irritated cough localized around the laryngeal region. Symptoms are not restricted to cough and can include globus, dyspnea, and dysphonia. Chronic refractory cough has factors in common with laryngeal hypersensitivity syndromes and chronic pain syndromes, and these similarities help to shed light on the pathophysiology of the condition. Its pathophysiology is complex and includes cough reflex sensitivity, central sensitization, peripheral sensitization, and paradoxical vocal fold movement. Chronic refractory cough often occurs after a viral infection. The diagnosis is made once the main diseases that cause chronic cough have been excluded (or treated) and cough remains refractory to medical treatment. Several treatments have been developed over the past decade. These include speech pathology interventions using techniques adapted from the treatment of hyperfunctional voice disorders, as well as the use of centrally acting neuromodulators such as gabapentin and pregabalin. Potential new treatments in development also show promise.

  13. Refractory disease in autoimmune diseases

    NARCIS (Netherlands)

    Vasconcelos, Carlos; Kallenberg, Cees; Shoenfeld, Yehuda

    2011-01-01

    Refractory disease (RD) definition has different meanings but it is dynamic, according to knowledge and the availability of new drugs. It should be differentiated from severe disease and damage definitions and it must take into account duration of adequate therapy and compliance of the patient. It c

  14. Effects of cerium on performance of Al-Zn-Sn sacrificial anode alloy%Ce对Al-Zn-Sn牺牲阳极合金性能的影响

    Institute of Scientific and Technical Information of China (English)

    贺俊光; 文九巴; 孙乐民; 高军伟; 李登辉

    2015-01-01

    采用扫描电镜(SEM)、X射线衍射(XRD)、动电位极化、电化学阻抗等方法研究了Ce含量对Al-7Zn-0.1Sn(质量分数,%)合金显微组织和电化学性能的影响。结果表明:Ce可明显细化晶粒,使Al-7Zn-0.1Sn合金从粗大枝状晶向细小等轴晶转变;适量的Ce可有效改善Al-7Zn-0.1Sn合金的电化学性能;随着Ce含量增加,合金电位负移、电流效率逐步提高;当 Ce 含量(质量分数)为0.5%时,合金具有最好的电化学性能,其电流效率相比Al-7Zn-0.1Sn 合金的提高10%。%The effects of cerium content on the microstructure and electrochemical performance of Al-7Zn-0.1Sn (mass fraction, %) alloy were investigated by scanning electron microscopy (SEM), X-ray diffractometry (XRD), potentiodynamic polarization and electrochemical impedance spectra measurements. The results show that cerium can refine the crystalline structure and make the microstructure of Al-7Zn-0.1Sn alloy transform from bulky dendrite grain to fine equiaxed grain. Proper cerium addition is effective on improving the electrochemical properties of Al-7Zn-0.1Sn alloy. The corrosion potential shifts negatively and the current efficiency increases with increasing the cerium content. The optimal electrochemical performance can be obtained when the Ce content in the alloy is 0.5%. The current efficiency of the Al-7Zn-0.1Sn-0.5Ce alloy increases by 10% than that of Al-7Zn-0.1Sn alloy.

  15. Commercial off-the-Shelf (COTS) Refractory Material Evaluation

    Science.gov (United States)

    Calle, Luz Marina; Kolody, Mark R.; Curran, Jerome P.; Back, Teddy; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Perusich, Stephen; Bucherl, Cori

    2009-01-01

    Fondu Fyre (FF) is currently the only refractory material qualified for use in the flame trench at KSC's Shuttle Launch Pads 39A and 39B. However, the material is not used as it was qualified and has undergone increasingly frequent and severe degradation due to the launch blasts. This degradation is costly as well as dangerous for launch infrastructure, crew and vehicle. FF is applied at the pad via the gunnite process, where wetted refractory material is sprayed onto a steel grid mounted on a support structure. The water content in this process can be manually adjusted by operators, causing distinct visual and physical discrepancies among repair areas. Since the application process is unlikely to change for new refractory materials, it is important to understand the effects of water content on commercial off-the-shelf (COTS) refractory materials. The purpose of this study was to evaluate the performance of the FF with respect to various water contents as well as heat treatments, to simulate aging and exposure to the blast. Initial results indicated that different water contents and heat treatments result in distinct differences in crushing strength, apparent porosity and bulk density. However, water content became an insignificant factor in both crush strength and porosity when FF was cured to at least 1500 deg. Additionally, inspection of the material's surface microstructure by scanning electron microscopy indicated distinguishable characteristics for different heat treatment levels. Results from this study will help guide future studies on the development and identification of new refractory materials.

  16. Radiosurgery for the management of refractory trigeminal neuralgia

    Directory of Open Access Journals (Sweden)

    Ajay Niranjan

    2016-01-01

    Full Text Available Gamma Knife stereotactic radiosurgery (SRS is a minimally invasive surgical approach for managing medically refractory trigeminal neuralgia (TN. The goal of trigeminal neuralgia SRS is to eliminate or reduce the facial pain in order to improve the quality of life. Over the past 28 years, 1250 patients have undergone gamma knife SRS for TN at our institution. In our retrospective review of 503 patients who underwent SRS for management of refractory TN, 449 patients (89% experienced initial pain relief at a median latency of 1 month. At the one year mark, 73% patients were pain free (with or without medications and 80% had pain control. Repeat radiosurgery was performed for 193 patients (43%. At the one year mark, 26% of these patients were completely pain free and 78% were pain free with or without medications. The role of gamma Knife SRS in the management of medically refractory trigeminal neuralgia has evolved over the past two decades. SRS is a minimally invasive procedure and is associated with 60-90% rate of pain relief in patents with medical refractory trigeminal neuralgia. Early intervention with SRS as the initial surgical procedure for management of refractory trigeminal neuralgia is associated with faster, better, and longer pain relief. As SRS is the least invasive procedure for TN, it is a good treatment option for patients with other high-risk medical conditions. SRS is an attractive alternative especially to those who do not want to accept the greater risk associated with other surgical procedures.

  17. Effect of the addition CNTs on performance of CaP/chitosan/coating deposited on magnesium alloy by electrophoretic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [Department of Neuro Intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Pharmaceutical Research Institute in Heilongjiang Province, Jiamusi University, Jiamusi 154007 (China); Wen, Zhaohui, E-mail: wenzhaohui1968@163.com [Department of Neuro Intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Zhao, Meng [Department of Neuro Intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Li, Guozhong, E-mail: hydlgz1962@163.com [Department of Neuro Intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Dai, Changsong, E-mail: changsd@hit.edu.cn [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2016-01-01

    CaP/chitosan/carbon nanotubes (CNTs) coating on AZ91D magnesium alloy was prepared via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The bonding between the layer and the substrate was studied by an automatic scratch instrument. The phase compositions and microstructures of the composite coatings were determined by using X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscope (SEM). The element concentration and gentamicin concentration were respectively determined by inductively coupled plasma optical emission spectrometer (ICP-OES) test and ultraviolet spectrophotometer (UV). The cell counting kit (CCK) assay was used to evaluate the cytotoxicity of samples to SaOS-2 cells. The results showed that a few CNTs with their original tubular morphology could be found in the CaP/chitosan coating and they were beneficial for the crystal growth of phosphate and improvement of the coating bonding when the addition amount of CNTs in 500 ml of electrophoretic solution was from 0.05 g to 0.125 g. The loading amount of gentamicin increased and the releasing speed of gentamicin decreased after CNTs was added into the CaP/chitosan coating for immersion loading and EPD loading. The cell viability of Mg based CaP/chitosan/CNTs was higher than that of Mg based CaP/chitosan from 16 days to 90 days. - Highlights: • CaP/chitosan/CNTs coating on AZ91D was prepared. • The addition of CNTs could improve the performance of CaP/chitosan coating. • A new method of loading gentamicin by EPD was proposed.

  18. Launch Pad Flame Trench Refractory Materials

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Bucherl, Cori; Sampson, Jeffrey W.; Curran, Jerome P.; Kolody, Mark; Perusich, Steve; Whitten, Mary

    2010-01-01

    The launch complexes at NASA's John F. Kennedy Space Center (KSC) are critical support facilities for the successful launch of space-based vehicles. These facilities include a flame trench that bisects the pad at ground level. This trench includes a flame deflector system that consists of an inverted, V-shaped steel structure covered with a high temperature concrete material five inches thick that extends across the center of the flame trench. One side of the "V11 receives and deflects the flames from the orbiter main engines; the opposite side deflects the flames from the solid rocket boosters. There are also two movable deflectors at the top of the trench to provide additional protection to shuttle hardware from the solid rocket booster flames. These facilities are over 40 years old and are experiencing constant deterioration from launch heat/blast effects and environmental exposure. The refractory material currently used in launch pad flame deflectors has become susceptible to failure, resulting in large sections of the material breaking away from the steel base structure and creating high-speed projectiles during launch. These projectiles jeopardize the safety of the launch complex, crew, and vehicle. Post launch inspections have revealed that the number and frequency of repairs, as well as the area and size of the damage, is increasing with the number of launches. The Space Shuttle Program has accepted the extensive ground processing costs for post launch repair of damaged areas and investigations of future launch related failures for the remainder of the program. There currently are no long term solutions available for Constellation Program ground operations to address the poor performance and subsequent failures of the refractory materials. Over the last three years, significant liberation of refractory material in the flame trench and fire bricks along the adjacent trench walls following Space Shuttle launches have resulted in extensive investigations of

  19. Performance of Semi-solid Slurry Produced by Twin-screw Stirring Mixer and Rheo-diecasting Process of AZ91D Alloy

    Institute of Scientific and Technical Information of China (English)

    XIAO Ze-hui; LUO Ji-rong; WU Shu-sen; LI Dong-nan

    2004-01-01

    The microstructure of semi-solid slurry of AZ91D alloy, which was produced by twin-screw stirring mixer under the different parameters, was investigated.Rheoforming by cold chamber die casting process was performed thereafter. The results indicate that with decreasing of the barrel temperature of the mixer and the pouring temperature of molten Mg alloy, the solid fraction of semi-solid slurry increases and the size of non-dendritic grains becomes smaller. While the shear rate increases, the solid fraction of semi-solid slurry decreases. The tensile strength and elongation of metal rheoformed by die casting are higher by about 37% and 44% respectively than those produced by conventional liquid die casting.

  20. Optimization of thermoelectric performance of SrSi2-based alloys via the modification in band structure and phonon-point-defect scattering

    Directory of Open Access Journals (Sweden)

    Yung-Kang eKuo

    2014-11-01

    Full Text Available Thermoelectric properties of alkaline-earth-metal disilicides are strongly dependent on their electronic band structure in the vicinity of the Fermi level. In particular, the strontium disilicide SrSi2 with a narrow band gap of about few tens of meV is composed of non-toxic, naturally abundant elements, and its thermoelectric properties are very sensitive to the substitution/alloying with third elements. In this article, we summarize the thermoelectric performance of substituted and Sr-deficient/Sr-rich SrSi2 alloys to realize the high thermoelectric figure-of-merit (ZT for practical applications in the electronic and thermoelectric aspects, and also to explore the alternative routes to further improve its ZT value.

  1. A study of the performance of tight-binding models for silicon and silicon-germanium alloys

    Science.gov (United States)

    Roberts, Amanda Killen

    1998-11-01

    resulted in a superior reproduction of a wide variety of physical properties of these systems, which is particularly evident in improved defect formation energies. We have also found that our SiGe model gives a good reproduction of Vegard's law for SiGe alloys containing up to 50% Ge. Given these results, we expect our Si, Ge, and SiGe models to perform well in dynamical studies of dopants and defects.

  2. Refractory carcinoid syndrome: a review of treatment options

    Science.gov (United States)

    Riechelmann, Rachel P.; Pereira, Allan A.; Rego, Juliana F. M.; Costa, Frederico P.

    2016-01-01

    Carcinoid syndrome (CSy) is a constellation of symptoms that may commonly present in patients with well differentiated neuroendocrine tumors (NETs), with somatostatin analogs (SSAs) being the first-line option for symptom management. However, symptomatic progression eventually occurs and in this scenario of a refractory CSy; several treatment options have been studied such as dose escalation of SSA, interferon and liver-directed therapies. Nevertheless, recent phase III trials have contributed to the understanding and management of this condition. We performed a comprehensive review of interventional studies examining refractory CSy to provide the evidence for current treatment options and propose a treatment sequence. PMID:28203303

  3. Neuroimaging in refractory epilepsy. Current practice and evolving trends

    Energy Technology Data Exchange (ETDEWEB)

    Ramli, N. [Department of Biomedical Imaging, University Malaya Research Imaging Centre (Malaysia); Rahmat, K., E-mail: katt_xr2000@yahoo.com [Department of Biomedical Imaging, University Malaya Research Imaging Centre (Malaysia); Lim, K.S.; Tan, C.T. [Neurology Unit, Department of Medicine, University Malaya, Kuala Lumpur (Malaysia)

    2015-09-15

    Highlights: • Neuroimaging is imperative in diagnostic work up and therapeutic assessment of refractory epilepsy. • Identification of epileptogenic zone on EEG, MRI and functional imaging improves the success of surgery. • High performance MRI greatly enhanced metabolic information and elucidate brain functions. • Optimisation of epilepsy protocols in structural and functional MRI are presented in this article. - Abstract: Identification of the epileptogenic zone is of paramount importance in refractory epilepsy as the success of surgical treatment depends on complete resection of the epileptogenic zone. Imaging plays an important role in the locating and defining anatomic epileptogenic abnormalities in patients with medically refractory epilepsy. The aim of this article is to present an overview of the current MRI sequences used in epilepsy imaging with special emphasis of lesion seen in our practices. Optimisation of epilepsy imaging protocols are addressed and current trends in functional MRI sequences including MR spectroscopy, diffusion tensor imaging and fusion MR with PET and SPECT are discussed.

  4. IMPROVED FURNACE EFFICIENCY THROUGH THE USE OF REFRACTORY MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL

    2011-01-01

    This paper describes efforts performed at Oak Ridge National Laboratory (ORNL), in collaboration with industrial refractory manufacturers, refractory users, and academic institutions, to improve energy efficiency of U.S. industry through increased furnace efficiency brought about by the employment of novel refractory systems and techniques. Work in furnace applications related to aluminum, gasification, and lime are discussed. The energy savings strategies discussed are achieved through reduction of chemical reactions, elimination of mechanical degradation caused by the service environment, reduction of temperature limitations of materials, and elimination of costly installation and repair needs. Key results of several case studies resulting from a US Department of Energy (DOE) funded research program are discussed with emphasis on applicability of these results to high temperature furnace applications.

  5. Arthroscopic capsular release for refractory shoulder stiffness.

    Science.gov (United States)

    Fernandes, Marcos Rassi

    2013-01-01

    To evaluate the results of the arthroscopic treatment of refractory adhesive capsulitis of the shoulder with two to nine years of follow-up, comparing the pre- and postoperative range of motion. This was an observational study (case series) of 18 patients who underwent arthroscopic capsular release for refractory shoulder stiffness. The mean age was of 53.6 years (range: 39 to 68), with female predominance (77.77%) and nine cases left shoulders. There were 6 primary (33.33%) and 12 secondary cases (66.67%). Arthroscopic capsular release was performed in all patients after a mean of 9.33 months of physical therapy (range: 6 to 20 months) with a minimum follow-up of two years (range: 26 to 110 months). The mean active and passive forward flexion, external rotation and internal rotation increased from 94.4°/103.3°, 11.9°/21.9°, and S1/L5 vertebral level, respectively, to 151.1°/153.8°, 57.2°/64.4°, and T12/T10 vertebral level, respectively. There was a significant difference between the pre- and postoperative range of motion (p < 0.001). According to the Constant-Murley functional score (ROM), the value increased from 14 (preoperative mean) to 30 points (postoperative mean). Postoperatively, all patients showed diminished shoulder pain (none or mild/15 or 10 points in the Constant-Murley score). Arthroscopic treatment is an effective treatment for refractory shoulder stiffness. Copyright © 2013 Elsevier Editora Ltda. All rights reserved.

  6. Gastroesophageal Reflux in Children with Refractory Asthma

    Directory of Open Access Journals (Sweden)

    Alaa S. Deeb

    2010-07-01

    Full Text Available Objectives: To investigate the association between clinical and macroscopic findings of GER and severity of refractory asthma (statistical study.Methods: A prospective study in a university-based practice of 75 children who were diagnosed with refractory asthma because they exhibited no satisfactory response for at least three months of treatment. Medical history, physical examination, spirometrical measurements and prick skin test were conducted on all patients. Endoscopic and macroscopic evaluations for esophagitis were performed on all patients regardless of the presence of GER symptoms.Results: Endoscopy was done for 75 children with refractory asthma. GER was symptomatic in 65% of all patients with no statistical significance (p>0.05 and the most frequent symptom was abdominal pain (67%. The frequency of these symptoms was 50% in mild asthma, 58% in moderate asthma and 72% in severe asthma with no statistical significance (p>0.05. The frequency of macroscopic esophagitis was 71%, distributed in three asthmatic groups as in order of 75% in mild asthma, 58.3% in moderate asthma and 76.6% in severe asthma (p>0.05. Regarding the relationship between GER and nocturnal attacks or spasmodic cough, the frequency of the latest was 66.7%. The differences have no statistical significance regarding GER symptoms (p>0.05, but they are statistically significant regarding the reflux esophagitis (p<0.05. Also endoscopic reflux was as frequent as76.3% in non allergic patients, and this result is statistically significant (p<0.05.Conclusion: In spite of the fact that there was no relationship between the severity of asthma and the symptoms of GER, or its endoscopic findings, the frequency of GER in asthmatic children was higher than its frequency in other children.

  7. Ictal PET in presurgical workup of refractory extratemporal epilepsy

    Directory of Open Access Journals (Sweden)

    Javeria Nooraine

    2013-01-01

    Full Text Available Ictal Pet in presurgical workup of refractory epilepsy is seldom performed and limited due to technical difficulties. In carefully selected patient subset with frequent extratemporal seizures, ictal PET depicts ′seizure onset zone′ with high spatial resolution even within a widespread pathology. We here depict a four year old with posterior quadrant dysplasia evaluated with ictal PET.

  8. Refractory strictures despite steroid injection after esophageal endoscopic resection

    Science.gov (United States)

    Hanaoka, Noboru; Ishihara, Ryu; Uedo, Noriya; Takeuchi, Yoji; Higashino, Koji; Akasaka, Tomofumi; Kanesaka, Takashi; Matsuura, Noriko; Yamasaki, Yasushi; Hamada, Kenta; Iishi, Hiroyasu

    2016-01-01

    Background: Although steroid injection prevents stricture after esophageal endoscopic submucosal dissection (ESD), some patients require repeated sessions of endoscopic balloon dilation (EBD). We investigated the risk for refractory stricture despite the administration of steroid injections to prevent stricture in patients undergoing esophageal ESD. Refractory stricture was defined as the requirement for more than three sessions of EBD to resolve the stricture. In addition, the safety of steroid injections was assessed based on the rate of complications. Patients and methods: We analyzed data from 127 consecutive patients who underwent esophageal ESD and had mucosal defects with a circumferential extent greater than three-quarters of the esophagus. To prevent stricture, steroid injection was performed. EBD was performed whenever a patient had symptoms of dysphagia. Results: The percentage of patients with a tumor circumferential extent greater than 75 % was significantly higher in those with refractory stricture than in those without stricture (P = 0.001). Multivariate analysis adjusted for age, sex, history of radiation therapy, tumor location, and tumor diameter showed that a tumor circumferential extent greater than 75 % was an independent risk factor for refractory stricture (adjusted odds ratio [OR] 5.49 [95 %CI 1.91 – 15.84], P = 0.002). Major adverse events occurred in 3 patients (2.4 %): perforation during EBD in 2 patients and delayed perforation after EBD in 1 patient. The patient with delayed perforation underwent esophagectomy because of mediastinitis. Conclusions: A tumor circumferential extent greater than 75 % is an independent risk factor for refractory stricture despite steroid injections. The development of more extensive interventions is warranted to prevent refractory stricture. PMID:27004256

  9. Refractory overactive bladder: Beyond oral anticholinergic therapy

    Directory of Open Access Journals (Sweden)

    Ronald W Glinski

    2007-01-01

    Full Text Available Objectives: In this review, we discuss the treatment of refractory overactive bladder (OAB that has not adequately responded to medication therapy and we propose an appropriate care pathway to the treatment of OAB. We also attempt to address the cost of OAB treatments. Materials and Methods: A selective expert review of the current literature on the subject of refractory OAB using MEDLINE was performed and the data is summarized. We also review our experience in treating refractory OAB. The role and outcomes of various treatment options for refractory OAB are discussed and combined therapy with oral anticholinergics is explored. Emerging remedies including intravesical botulinum toxin injection and pudendal neuromodulation are also reviewed, along with conventional surgical options. Results: In general behavioral therapy, pelvic floor electrical stimulation, magnetic therapy and posterior tibial nerve stimulation (PTNS, have shown symptom decreases in 50-80% of patients with OAB. Depending on the study, combination therapy with oral anticholinergics seems to improve efficacy of behavioral therapy and PTNS in approximately 10-30%. In multicenter, long-term randomized controlled trials, sacral neuromodulation has been shown to improve symptoms of OAB and OAB incontinence in up to 80% of the patients treated. Studies involving emerging therapies such as pudendal serve stimulation suggest that there may be a 15-20% increase in efficacy over sacral neuromodulation, but long-term studies are not yet available. Another emerging therapy, botulinum toxin, is also showing similar success in reducing OAB symptoms in 80-90% of patients. Surgical approaches, such as bladder augmentation, are a last resort in the treatment of OAB and are rarely used at this point unless upper tract damage is a concern and all other treatment options have been exhausted. Conclusion: The vast majority of OAB patients can be managed successfully by behavioral options with or

  10. Correlation between Mechanical Behavior and Actuator-type Performance of Ni-Ti-Pd High-temperature Shape Memory Alloys

    Science.gov (United States)

    Bigelow, Glen S.; Padula, Santo A., II; Garg, Anita; Noebe, Ronald D.

    2007-01-01

    High-temperature shape memory alloys in the NiTiPd system are being investigated as lower cost alternatives to NiTiPt alloys for use in compact solid-state actuators for the aerospace, automotive, and power generation industries. A range of ternary NiTiPd alloys containing 15 to 46 at.% Pd has been processed and actuator mimicking tests (thermal cycling under load) were used to measure transformation temperatures, work behavior, and dimensional stability. With increasing Pd content, the work output of the material decreased, while the amount of permanent strain resulting from each load-biased thermal cycle increased. Monotonic isothermal tension testing of the high-temperature austenite and low temperature martensite phases was used to partially explain these behaviors, where a mismatch in yield strength between the austenite and martensite phases was observed at high Pd levels. Moreover, to further understand the source of the permanent strain at lower Pd levels, strain recovery tests were conducted to determine the onset of plastic deformation in the martensite phase. Consequently, the work behavior and dimensional stability during thermal cycling under load of the various NiTiPd alloys is discussed in relation to the deformation behavior of the materials as revealed by the strain recovery and monotonic tension tests.

  11. Preparation of Uniform Ni-B Amorphous Alloy Catalyst on CNTs and its Performance for Acetylene Selective Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Chang Yuan HU; Feng Yi LI; Rong Bin ZHANG; Li HUA

    2006-01-01

    Uniform Ni-B amorphous alloys about 14 nm have been prepared on CNTs-A support,named Ni-B/CNTs-A. In comparison with the Ni-B/CNTs amorphous catalyst, Ni-B/CNTs-A showed higher nickel loading, determined by ICP and better catalytic activity and ethylene selectivity in the acetylene hydrogenation reaction.

  12. Mechanical properties of Mo-Si-B alloys fabricated by using core-shell powder with dispersion of yttria nanoparticles

    Science.gov (United States)

    Byun, Jong Min; Bang, Su-Ryong; Choi, Won June; Kim, Min Sang; Noh, Goo Won; Kim, Young Do

    2017-01-01

    In recent years, refractory materials with excellent high-temperature properties have been in the spotlight as a next generation's high-temperature materials. Among these, Mo-Si-B alloys composed of two intermetallic compound phases (Mo5SiB2 and Mo3Si) and a ductile α-Mo phase have shown an outstanding thermal properties. However, due to the brittleness of the intermetallic compound phases, Mo-Si-B alloys were restricted to apply for the structural materials. So, to enhance the mechanical properties of Mo-Si-B alloys, many efforts to add rare-earth oxide particles in the Mo-Si-B alloy were performed to induce the improvement of strength and fracture toughness. In this study, to investigate the effect of adding nano-sized Y2O3 particles in Mo-Si-B alloy, a core-shell powder consisting of intermetallic compound phases as the core and nano-sized α-Mo and Y2O3 particles surrounding the core was fabricated. Then pressureless sintering was carried out at 1400 °C for 3 h, and the mechanical properties of sintered bodies with different amounts of Y2O3 particles were evaluated by Vickers hardness and 3-point bending test. Vickers hardness was improved by dispersed Y2O3 particles in the Mo-Si-B alloy. Especially, Mo-3Si-1B-1.5Y2O3 alloy had the highest value, 589 Hv. The fracture toughness was measured using Mo-3Si-1B-1.5Y2O3 alloy and the value indicated as 13.5 MPa·√m.

  13. Development and Processing of Nickel Aluminide-Carbide Alloys

    Science.gov (United States)

    Newport, Timothy Scott

    1996-01-01

    With the upper temperature limit of the Ni-based superalloys attained, a new class of materials is required. Intermetallics appear as likely candidates because of their attractive physical properties. With a relatively low density, high thermal conductivity, excellent oxidation resistance, high melting point, and simple crystal structure, nickel aluminide (NiAl) appears to be a potential candidate. However, NiAl is limited in structural applications due to its low room temperature fracture toughness and poor elevated temperature strength. One approach to improving these properties has been through the application of eutectic composites. Researchers have shown that containerless directional solidification of NiAl-based eutectic alloys can provide improvement in both the creep strength and fracture toughness. Although these systems have shown improvements in the mechanical properties, the presence of refractory metals increases the density significantly in some alloys. Lower density systems, such as the carbides, nitrides, and borides, may provide NiAl-based eutectic structure. With little or no information available on these systems, experimental investigation is required. The objective of this research was to locate and develop NiAl-carbide eutectic alloys. Exploratory arc-melts were performed in NiAl-refractory metal-C systems. Refractory metal systems investigated included Co, Cr, Fe, Hf, Mo, Nb, Ta, Ti, W, and Zr. Systems containing carbides with excellent stability (i.e.,HfC, NbC, TaC, TiC, and ZrC) produced large blocky cubic carbides in an NiAl matrix. The carbides appeared to have formed in the liquid state and were randomly distributed throughout the polycrystalline NiAl. The Co, Cr, Fe, Mo, and W systems contained NiAl dendrites with a two-phase interdendritic microconstituent present. Of these systems, the NiAl-Mo-C system had the most promising microstructure for in-situ composites. Three processing techniques were used to evaluate the NiAl-Mo-C system

  14. Formation of Refractory Metal Alloys and Their Occurrence in CAIs

    Science.gov (United States)

    Schwander, D.; Berg, T.; Ott, U.; Schönhense, G.; Palme, H.

    2012-09-01

    At the conference we will give an overview of the current state of our research of RMN from Murchison, Allende and Acfer 094 including statistical analysis of their compositions and structures in relation to condensation calculations.

  15. Alloimmune refractoriness to platelet transfusions.

    Science.gov (United States)

    Sandler, S G

    1997-11-01

    Patients who are transfused on multiple occasions with red cells or platelets may develop platelet-reactive alloantibodies and experience decreased clinical responsiveness to platelet transfusion. This situation, conventionally described as "refractoriness to platelet transfusions," is defined by an unsatisfactory low post-transfusion platelet count increment. If antibodies to HLAs are detected, improved clinical outcomes may result from transfusions of HLA-matched or donor-recipient cross-matched platelets. Because refractoriness is an expected, frequently occurring phenomenon, prevention of HLA alloimmunization is an important management strategy. Prevention strategies include efforts to decrease the number of transfusions, filtration of cellular components to reduce the number of HLA-bearing leukocytes, or pretransfusion ultraviolet B irradiation of cellular components to decrease their immunogenicity. Other investigational approaches include reducing the expression of HLAs on transfused platelets, inducing a transient reticuloendothelial system blockade by infusions of specialized immunoglobulin products, or transfusing semisynthetic platelet substitutes (thromboerythrocytes, thrombospheres) or modified platelets (infusible platelet membranes, lyophilized platelets).

  16. Iron refractory iron deficiency anemia

    OpenAIRE

    De Falco, Luigia; Sanchez, Mayka; Silvestri, Laura; Kannengiesser, Caroline; Muckenthaler, Martina U; Iolascon, Achille; Gouya, Laurent; Camaschella, Clara; Beaumont, Carole

    2013-01-01

    Iron refractory iron deficiency anemia is a hereditary recessive anemia due to a defect in the TMPRSS6 gene encoding Matriptase-2. This protein is a transmembrane serine protease that plays an essential role in down-regulating hepcidin, the key regulator of iron homeostasis. Hallmarks of this disease are microcytic hypochromic anemia, low transferrin saturation and normal/high serum hepcidin values. The anemia appears in the post-natal period, although in some cases it is only diagnosed in ad...

  17. NOVEL SPINEL-FAMILY REFRACTORIES FOR HIGH-TEMPERATURE, HIGH-ALKALINE ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Armstrong, Beth L [ORNL; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.

    2012-01-01

    Work was performed by Oak Ridge National Laboratory (ORNL), in collaboration with the industrial refractory manufacturer Minteq International, Inc. (MINTEQ), academic research partner Missouri University of Science and Technology (MS&T) and end users to employ novel refractory systems and techniques to reduce energy consumption of refractory lined vessels found in industries such as aluminum, chemical, glass, and pulp and paper. The project aim was to address factors which limit the applicability of currently available refractory materials such as chemical attack, mechanical degradation, use temperature, and installation or repair issues. To this end, new innovative unshaped refractory compositions (gunnables) were developed based on MgO-Al 2O3 spinel and alumino-silicate based structures utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Development efforts, materials validation, and results to date of current industrial validation trials a discussed.

  18. DEVELOPMENT AND DEPLOYMENT OF SHOTCRETE REFRACTORIES FOR ALUMINUM ROTARY FURNACE APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2013-01-01

    Work was performed by Oak Ridge National Laboratory (ORNL) in the United States, in collaboration with the industrial refractory manufacturer Minteq International, Inc. (MINTEQ), academic research partner Missouri University of Science and Technology (MS&T) and end users to employ novel refractory systems and techniques to reduce energy consumption of refractory lined vessels found in the aluminum industry. The project aim was to address factors that limit the applicability of currently available refractory materials such as chemical attack, mechanical degradation, use temperature, and installation or repair issues. To this end, as part of the overall project, shotcretable refractory compositions were developed based on alumino-silicate based structures utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques for use in rotary dross furnaces. Additionally a shotcretable high strength insulating back-up lining material was also developed for use in this and other applications. Development efforts, materials validation, and results from industrial validation trials are discussed.

  19. Failure Mechanisms in High Chrome Oxide Gasifier Refractories

    Science.gov (United States)

    Bennett, James P.; Kwong, Kyei-Sing

    2011-04-01

    Gasification is a high-temperature, high-pressure chemical process used to convert a carbon feedstock into CO and H2 (syngas) for use in power generation and the production of chemicals. It is also a leading candidate as a source of hydrogen in a hydrogen economy and is one of several technologies expected to see increased use in advanced fossil fuel power systems in the future. Gasification is being evaluated because of its high efficiency, its ability to capture CO2 for sequestration or reuse in other applications, and its potential for carbon feedstock fuel flexibility. At the heart of the gasification process is a gasifier, a high pressure chemical reaction vessel used to contain the interactions between carbon and water in a shortage of oxygen, producing syngas. The gasifier is lined with high chrome oxide materials to protect the containment vessel. Gasifiers are complex systems, and failure of the refractories used to line them was identified by industry as a limitation to their reliability and availability and to their increased use. NETL researchers have examined spent high-Cr2O3 (over 90 pct Cr2O3) refractories from numerous gasifiers to determine in-service failure mechanisms. This analysis revealed that premature failure of the high chrome oxide refractories was related to ash in the carbon feedstock, which liquefies during gasification and interacts with the refractories, leading to wear by chemical dissolution or spalling (structural and chemical). A discussion of this postmortem wear of spent refractory materials and of thermodynamic modeling used to explain microstructural changes leading to wear are explained in this article. This information will serve the basis to develop improved performance refractory materials.

  20. Ketogenic diet treatment for pediatric super-refractory status epilepticus.

    Science.gov (United States)

    Appavu, Brian; Vanatta, Lisa; Condie, John; Kerrigan, John F; Jarrar, Randa

    2016-10-01

    We aimed to study whether ketogenic diet (KD) therapy leads to resolution of super-refractory status epilepticus in pediatric patients without significant harm. A retrospective review was performed at Phoenix Children's Hospital on patients with super-refractory status epilepticus undergoing ketogenic diet therapy from 2011 to 2015. Ten children with super-refractory status epilepticus, ages 2-16 years, were identified. 4/10 patients had immune mediated encephalitis, including Rasmussen encephalitis, anti-N-methyl-d-aspartate receptor encephalitis, and post-infectious mycoplasma encephalitis. Other etiologies included Lennox Gastaut Syndrome, non-ketotic hyperglycinemia, PCDH19 and GABRG2 genetic epilepsy, New Onset Refractory Status Epilepticus, and Febrile Infection-Related Epilepsy Syndrome. 4/10 patients' EEG features suggested focal with status epilepticus, and 6/10 suggested generalized with status epilepticus. Median hospital length was 61days and median ICU length was 27days. The median number of antiepileptic medications prior to diet initiation was 3.0 drugs, and the median after ketogenic diet treatment was 3.5 drugs. Median duration of status epilepticus prior to KD was 18days. 9/10 patients had resolution of super-refractory status epilepticus in a median of 7days after diet initiation. 8/9 patients were weaned off anesthesia within 15days of diet initiation, and within 1day of achieving ketonuria. 1/10 patients experienced side effects on the diet requiring supplementation. Most patients achieved resolution of status epilepticus on KD therapy, suggesting it could be an effective therapy that can be utilized early in the treatment of children with super refractory status epilepticus. Copyright © 2016. Published by Elsevier Ltd.

  1. Understanding and treating refractory constipation

    Institute of Scientific and Technical Information of China (English)

    Gabrio; Bassotti; Corrado; Blandizzi

    2014-01-01

    Chronic constipation is a frequently encountered disorder in clinical practice. Most constipated patients benefit from standard medical approaches. However, current therapies may fail in a proportion of patients. These patients deserve better evaluation and thorough investigations before their labeling as refractory to treatment. Indeed, several cases of apparent refractoriness are actually due to misconceptions about constipation, poor basal evaluation (inability to recognize secondary causes of constipation, use of constipating drugs) or inadequate therapeutic regimens. After a careful reevaluation that takes into account the above factors, a certain percentage of patients can be defined as being actually resistant to first-line medical treatments. These subjects should firstly undergo specific diagnostic examination to ascertain the subtype of constipation. The subsequent therapeutic approach should be then tailored according to their underlying dysfunction. Slow transit patients could benefit from a more robust medical treatment, based on stimulant laxatives (or their combination with osmotic laxatives, particularly over the short-term), enterokinetics (such as prucalopride) or secretagogues (such as lubiprostone or linaclotide). Patients complaining of obstructed defecation are less likely to show a response to medical treatment and might benefit from biofeedback, when available. When all medical treatments prove to be unsatisfactory, other approaches may be attempted in selected patients (sacral neuromodulation, local injection of botulinum toxin, anterograde continence enemas), although with largely unpredictable outcomes. A further although irreversible step is surgery (subtotal colectomy with ileorectal anastomosis or stapled transanal rectal resection), which may confer some benefit to a few patients with refractoriness to medical treatments.

  2. Electrochemical hydrogen storage performances of the nanocrystalline and amorphous (Mg24Ni10Cu2)100-xNdx (x=0-20) alloys applied to Ni-MH battery

    Institute of Scientific and Technical Information of China (English)

    张羊换; 王海涛; 杨泰; 翟亭亭; 张国芳; 赵栋梁

    2013-01-01

    Melt spinning technology was used to prepare the Mg2Ni-type (Mg24Ni10Cu2)100-xNdx (x=0, 5, 10, 15, 20) alloys in order to obtain a nanocrystalline and amorphous structure. The effects of Nd content and spinning rate on the structures and electrochemical hydrogen storage performances of the alloys were investigated. The structure characterizations of X-ray diffraction (XRD), transmis-sion electron microscopy (TEM) and scanning electron microscopy (SEM) linked with energy dispersive spectroscopy (EDS) re-vealed that the as-spun Nd-free alloy displayed an entire nanocrystalline structure, whereas the as-spun Nd-added alloys held a nanocrystalline and amorphous structure and the degree of amorphization visibly increased with the rising of Nd content and spinning rate, suggesting that the addition of Nd facilitated the glass forming of the Mg2Ni-type alloy. The electrochemical measurements in-dicated that the addition of Nd and melt spinning improved the electrochemical hydrogen storage performances of the alloys signifi-cantly. The discharge capacities of the as-cast and spun alloys exhibited maximum values when Nd content was x=10, which were 86.4, 200.5, 266.3, 402.5 and 452.8 mAh/g corresponding to the spinning rate of 0 (As-cast was defined as the spinning rate of 0 m/s), 10, 20, 30 and 40 m/s, respectively. The cycle stability (S20, the capacity maintain rate at 20th cycle) of the as-cast alloy always rose with the increasing of Nd content, and those of the as-spun alloys exhibited the maximum values for Nd content x=10, which were 77.9%, 83.4%89.2%and 89.7%, corresponding to the spinning rate of 10, 20, 30 and 40 m/s, respectively.

  3. Development and Application of Al2O3 - Si3N4 Refractories Used in Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    LI Xianming; LI Yong; KANG Huarong; DONG Shengying; XUE Wendong; SONG Wen

    2008-01-01

    Newly developed Al2O3-Si3N4 composite refracto-ries used for blast furnace is introduced in this work.Al2O3-Si3N4 composite refractories attacked by alkali vapor and blast Jhrnace slag was investigated. High per-formance Al2O3 -Si3N4 composite refractories was pro-duced and used at both 2 560 m3 blast furnaces of Tan-gsteel and No. 5 blast furnace of Shaosteel.

  4. 钒铁冶炼炉氧化铝渣用于耐火材料的性能分析%Analysis on performances of melting furnace alumina slag used for refractory material

    Institute of Scientific and Technical Information of China (English)

    吴胜利

    2014-01-01

    通过选取完整的氧化铝渣饼,进行物理化学性能测试,来探索钒铁冶炼炉氧化铝渣用于耐火材料的可能性。测试结果显示,氧化铝渣的主要成分为 Al2 O3、MgO 和 CaO,且以镁铝尖晶石、铝酸钙为主;耐火度大于1790℃,体积密度大于3.0g·cm-3,吸水率小于3.0%;氧化铝渣具有水硬性,可替代高铝水泥;其颗粒强度与焦宝石接近,可用作耐火骨料。综合各项指标,氧化铝渣可用于耐火材料。%To explore the usability of vanadium iron smelting furnace slag for refractory alumina,this paper introduces a physical chemistry experiment with an unbroken alumina slag cake. The result shows that the major constituents of the alumina slag are Al2 O3 ,MgO and CaO,and the major compo-sitions are spinel and calcium aluminate;its refractoriness is over 1 790 ℃ ,the bulk density is higher than 3. 0g·cm -3 ,the water absorption is 3. 0% . Alumina slag can be uesd to replace high alumina cement for its hydraulicity. Its particle strength is similar with flint,so it can be used as refractory ag-gregate. In conclusion,the alumina slag can be used for refractory material.

  5. The effect of microstructure on fatigue performance of Ti-6Al-4V alloy after EDM surface treatment for application in orthopaedics.

    Science.gov (United States)

    Stráský, Josef; Janeček, Miloš; Harcuba, Petr; Bukovina, Michal; Wagner, Lothar

    2011-11-01

    Three different microstructures--equiaxed, bi-modal and coarse lamellar--are prepared from Ti-6Al-4V alloy. Electric discharge machining (EDM) with a high peak current (29 A) is performed in order to impose surface roughness and modify the chemical composition of the surface. Detailed scanning electron microscopy (SEM) investigation revealed a martensitic surface layer and subsurface heat affected zone (HAZ). EDX measurements showed carbon enriched remnants of the EDM process on the material surface. Rotating bending fatigue tests are undertaken for EDM processed samples for all three microstructures and also for electropolished-benchmark-samples. The fatigue performance is found to be rather poor and not particularly dependent on microstructure. The bi-modal microstructure shows a slightly superior high cycle fatigue performance. This performance can be further improved by a suitable heat treatment to an endurance limit of 200 MPa.

  6. Facile synthesis of Pd-Pt alloy nanocages and their enhanced performance for preferential oxidation of CO in excess hydrogen.

    Science.gov (United States)

    Zhang, Hui; Jin, Mingshang; Liu, Hongyang; Wang, Jinguo; Kim, Moon J; Yang, Deren; Xie, Zhaoxiong; Liu, Jingyue; Xia, Younan

    2011-10-25

    This article describes a new method for the facile synthesis of Pd-Pt alloy nanocages with hollow interiors and porous walls by using Pd nanocubes as sacrificial templates. Differing from our previous work (Zhang, H.; Jin, M. S.; Wang, J. G.; Li, W. Y.; Camargo, P. H. C.; Kim, M. J.; Yang, D. R.; Xie, Z. X.; Xia, Y. Synthesis of Pd-Pt Bimetallic Nanocrystals with a Concave Structure through a Bromide-Induced Galvanic Replacement Reaction. J. Am. Chem. Soc.2011, 133, 6078-6079), we complemented the galvanic replacement (between Pd nanocubes and PtCl(4)(2-)) with a coreduction process (for PdCl(4)(2-) from the galvanic reaction and PtCl(4)(2-) from the feeding) to generate Pd-Pt alloy nanocages in one step. We found that the rate of galvanic replacement (as determined by the concentrations of Br(-) and PtCl(4)(2-) and temperature) and the rates of coreduction (as determined by the type of reductant and temperature) played important roles in controlling the morphology of resultant Pd-Pt alloy nanocages. The Pd-Pt nanocages exhibited both enhanced activity and selectivity for the preferential oxidation (PROX) of CO in excess hydrogen than those of Pd nanocubes and the commercial Pt/C thanks to the alloy composition and hollow structure. In addition, as the sizes of the Pd-Pt nanocages decreased, they exhibited higher CO conversion rates and lower maximum conversion temperatures due to the increase in specific surface area.

  7. Refractories Quality Improvement for Glass Industry Upgrading

    Institute of Scientific and Technical Information of China (English)

    ZENG Dafan

    2009-01-01

    @@ 1 Glass Industry and Refractories Industry Closely Connect 1.1 Glass Development Drives Refractories Progress Refractories are indispensable to glass industry; the rapid development of glass industry drives the growth of refractories industry. China's glass industry developed slowly before the mid 1980s. The kilns and furnaces were backward and small-scale with furnace life of only 2-3 years; glass was produced with extremely low efficiency and poor quality. During that period, refractories for glass melting furnaces had very limited varieties and inferior quality. The fused cast refractories for advanced glass melting furnaces were imported, for the materials made in China could not meet the requirements, which seriously restrained the technical progress of China's glass industry.

  8. Post-annealing effects on the electrochemical performance of a Si/TiSi2 heteronanostructured anode material prepared by mechanical alloying

    Science.gov (United States)

    Shin, Min-Seon; Lee, Taeg-Woo; Park, Jung-Bae; Lim, Sung-Hwan; Lee, Sung-Man

    2017-03-01

    A change in the microstructure of Ti-Si alloys synthesized by high-energy mechanical milling through post-annealing significantly enhances their electrochemical performances as anode materials for lithium-ion batteries (LIBs). The microstructures of ball-milled and post-annealed powders are investigated using high-resolution transmission electron microscopy (HR-TEM). The Si phase is uniformly distributed on the silicide (TiSi2) matrix. The individual Si domains of the mechanical alloying (MA) sample consist of amorphous and crystalline regions with a diffuse interface between the two phases. When MA powder is annealed at 600 °C, the Si phase has a well-developed nanocrystalline microstructure: a multi-grain structure with random orientation of nanometric crystal domains. Annealing at 600 °C causes a significant improvement in electrochemical performance parameters like cycling stability and rate capability. However, when annealed at 800 °C, the electrochemical performances deteriorate due to an increase in the size of Si domains.

  9. Refractory, Abrasive and Other Industrial Mineral Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes refractory, abrasive, and other industrial minerals operations in the United States. The data represent commodities covered by the Minerals...

  10. Individual differences effects on the psychological refractory period

    OpenAIRE

    Laguë-Beauvais, Maude; Gagnon, Christine; Castonguay, Nathalie; Bherer, Louis

    2013-01-01

    The goal of this study was to assess the impact of individual neuropsychological differences on the ability to share attention between concurrent tasks. Participants (n = 20) were trained on six single task practice sessions and dual-task was assessed with reaction time performance on a psychological refractory period (PRP) paradigm. Neuropsychological test scores were also acquired. Furthermore, one of the known variables that can influence performances on neuropsychological tests is gender,...

  11. The Electrochemical Performance of Ml0.7Mm0.3Ni3.7Co0.7Mn0.4Al0.2 Nanocrystalline Hydrogen Storage Alloy as Metal Hydride Electrode

    Institute of Scientific and Technical Information of China (English)

    方守狮; 熊义辉; 等

    2002-01-01

    Ml0.7Mm0.3Ni3.7Co0.7Mn0.4Al0.2 nanocrystalline hydrogen storage materials are prepared by melt-spinning(MS).X-ray diffraction is used for the measurement of the nanocrystalline size.Compared to the electrode of polycrystalline alloys,the property of activation MH9metal hydride)electrode of the alloys with nanometer scale became worse and the inital discharge capacity decreased.It may be ascribed to the decrease of the total amount of rare earth metals and the increase of oxygen on the surface from the analysis of components of the alloys.After heat-treatment,the electrochemical performance of MH electrode of as-spun alloys could be improved,which could be attributed to the alleviation of the lattice strain.

  12. Hypothermia for pediatric refractory status epilepticus.

    Science.gov (United States)

    Guilliams, Kristin; Rosen, Max; Buttram, Sandra; Zempel, John; Pineda, Jose; Miller, Barbara; Shoykhet, Michael

    2013-09-01

    Refractory status epilepticus (RSE) is a life-threatening emergency, demonstrating, by definition, significant pharmacoresistance. We describe five cases of pediatric RSE treated with mild hypothermia. Retrospective chart review was performed of records of children who received hypothermia for RSE at two tertiary-care pediatric hospitals between 2009 and 2012. Five children with RSE received mild hypothermia (32-35°C). Hypothermia reduced seizure burden during and after treatment in all cases. Prior to initiation of hypothermia, four children (80%) received pentobarbital infusions to treat RSE, but relapsed after pentobarbital discontinuation. No child relapsed after treatment with hypothermia. One child died after redirection of care. Remaining four children were discharged. This is the largest pediatric case series reporting treatment of RSE with mild hypothermia. Hypothermia decreased seizure burden during and after pediatric RSE and may prevent RSE relapse. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

  13. Relation of Engine Turbine-blade Life to Stress-rupture Properties of the Alloys, Stellite 21, Hastelloy B, Cast S-816, Forged S-816, X-40, Nimonic 80, Refractaloy 26, N-155, and Inconel X

    Science.gov (United States)

    Garrett, F B; Yaker, C

    1951-01-01

    An investigation was conducted to relate the engine performance of the heat-resistant alloys, Stellite 21, Hastelloy B, cast S-816, forged S-816, X-40, Nimonic 80, Refractory 26, N-155, and Iconel X to their stress-rupture properties. The engine test consisted of the repetition of a 20-minute cycle, 15 minutes at rated speed and approximately 5 minutes at idle. The results of the investigation indicated a direct correlation between stress-rupture life and blade life for the relatively low-strength alloys. The stress-rupture life and blade life for the relatively high-strength alloys did not correlate because of the effects of the vibratory stresses and the corrosive-gas atmosphere.

  14. DEVELOPMENT OF NOVEL SPINEL REFRACTORIES FOR USE IN COAL GASIFICATION ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Armstrong, Beth L [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2011-01-01

    Work has been performed by Oak Ridge National Laboratory (ORNL), in collaboration with industrial refractory manufacturer (Minteq International, Inc.), academic research partner (Missouri University of Science and Technology) and end users to employ novel refractory systems and techniques to reduce energy consumption of refractory lined vessels found in industries such as aluminum, chemical, glass, and pulp and paper. The objective of the project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al 2O3 spinel structured unshaped refractory compositions (castables, gunnables, shotcretes, etc) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. As part of the four-year project funded by the U.S. Department of Energy (DOE), materials have been developed specifically for coal gasification environments. Additionally, work has been performed to develop and apply low cost coatings using a colloidal approach for protection against corrosion attack of the refractory brick and to develop a light-weight back-up refractory system to help offset the high thermal conductivity inherent in spinel materials. This paper discusses the development of these materials, along with preliminary results achieved toward the reduction of chemical reactions and mechanical degradation by the service environment.

  15. DEVELOPMENT AND APPLICATION OF IMPROVED SHOTCTRETE REFRACTORY FOR ALUMINUM ROTARY FURNACE APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2013-01-01

    Oak Ridge National Laboratory, in collaboration with refractory manufacturer Minteq International, Inc., academic partner Missouri University of Science and Technology and refractory end users have developed novel refractory systems and techniques to reduce energy consumption of refractory lined vessels. The objective of this U.S. DOE funded project was to address the need for innovative refractory compositions by developing novel gunnable refractory compositions for use in high temperature and high alkali environments. Developed materials utilized new aggregate materials, bond systems, protective coatings, and phase formation techniques. Under this project, materials were developed specifically for aluminum rotary dross furnace applications and a light-weight back-up refractory system was also developed to improve the thermal efficiency of the installed lining system. This paper discusses the systematic development of these materials, laboratory testing and evaluation of these materials, and the performance of several industrial trials performed using these newly developed materials. The success of the industrial trials will be highlighted and future areas of application of these materials discussed.

  16. USE OF STRUCTURAL MRI IN PATIENTS WITH MEDICALLY REFRACTORY SEIZURES

    Directory of Open Access Journals (Sweden)

    Ara G. Kaprelyan

    2012-12-01

    Full Text Available Introduction: Refractory epilepsy is common in patients with structural brain lesions including acquired disorders and genetic abnormalities. Recently, MRI is a precise diagnostic tool for recognition of different structural causes underlying medically intractable seizures.Objective: To evaluate the usefulness of MRI for detection of brain lesions associated with refractory epilepsy.Material and methods: 49 patients (20M and 29F; aged 48.6±24.7 years with refractory epilepsy were included in the study. They presented with partial (46.0%, secondary (31.0% or primary (23.0% generalized tonic-clonic seizures. Clinical diagnosis was based on the revised criteria of ILAE. Structural neuroimaging (MRI, EEG recording, and neurological examination were performed.Results: MRI detected different structural brain abnormalities totally in 36 (73.5% patients, including cerebral tumors (21p, cerebrovascular accidents (5p, hyppocampal sclerosis (3p, developmental malformations (2p, postencephalitic lesions (2p, arachnoid cysts (2p, and tuberous sclerosis (1p. Neuroimaging revealed normal findings in 13 (27.5% cases. EEG recordings showed focal epileptic activity in 38 (77.6% patients, including 33 cases with and 5 without structural brain abnormalities.Conclusion: This study revealed that structural brain lesions are commonly associated with refractory epilepsy. We suggested that MRI is a useful diagnostic method for assessment of patients with uncontrolled seizures or altered epileptic pattern.

  17. Penetration and Effectiveness of Micronized Copper in Refractory Wood Species

    Science.gov (United States)

    Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N.; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W. M. R.

    2016-01-01

    The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect. PMID:27649315

  18. Penetration and Effectiveness of Micronized Copper in Refractory Wood Species.

    Science.gov (United States)

    Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W M R

    2016-01-01

    The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect.

  19. Thermal Transport in Refractory Carbides.

    Science.gov (United States)

    Thermal energy transport mechanisms in titanium carbide and zirconium carbide have been studied. Several compositions of vanadium carbide alloyed...with titanium carbide were used. The electronic component of the thermal conductivity exceeded the values computed using the classical value for L in

  20. 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

  1. Genetics Home Reference: iron-refractory iron deficiency anemia

    Science.gov (United States)

    ... refractory iron deficiency anemia iron-refractory iron deficiency anemia Enable Javascript to view the expand/collapse boxes. ... All Close All Description Iron-refractory iron deficiency anemia is one of many types of anemia , which ...

  2. Management of refractory cardiogenic shock.

    Science.gov (United States)

    Reyentovich, Alex; Barghash, Maya H; Hochman, Judith S

    2016-08-01

    Cardiogenic shock is a life-threatening condition that occurs in response to reduced cardiac output in the presence of adequate intravascular volume and results in tissue hypoxia. Cardiogenic shock has several underlying aetiologies, with the most common being acute myocardial infarction (AMI). Refractory cardiogenic shock presents as persistent tissue hypoperfusion despite administration of adequate doses of two vasoactive medications and treatment of the underlying aetiology. Investigators of the SHOCK trial reported a long-term mortality benefit of emergency revascularization for shock complicating AMI. Since the publication of the SHOCK trial and subsequent guideline recommendations, the increase in community-based use of percutaneous coronary intervention for this condition has resulted in a significant decline in mortality. Despite these successes in the past 15 years, mortality still remains exceptionally high, particularly in patients with refractory cardiogenic shock. In this Review, we discuss the aetiology and pathophysiology of cardiogenic shock and summarize the data on the available therapeutics and their limitations. Although new mechanical circulatory support devices have been shown to improve haemodynamic variables in patients with shock complicating AMI, they did not improve clinical outcomes and are associated with high costs and complications.

  3. Impact toughness of laser surface alloyed Aluminium

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-03-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and the impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  4. Refractory Pellet for Hot Blast Stove

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Peng Xigao

    2011-01-01

    1 Scope This standard specifies the term,definition,classification,specification,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of refractory pellet for hot blast stove.This standard is applicable to refractory pellet for hot blast stove.

  5. Spectral reflecting characteristics of dinas refractory

    Energy Technology Data Exchange (ETDEWEB)

    Zapechnikov, V.N.; Pushkin, V.T.; Zen' kovskii, A.G.

    1987-09-01

    This article outlines a nondestructive testing format which uses spectral reflectance to assess the remaining service life, the thermal degradation, and the insulating effectiveness of refractories used as insulating liners in glass melters. Thermal as well as mechanical influences on the reflectance behavior of several refractories are discussed.

  6. Modern technologies of refractory glaucoma treatment. Review

    Directory of Open Access Journals (Sweden)

    A. Yu. Rascheskov

    2014-07-01

    Full Text Available this article presents a review of available literature concerning basic directions of refractory glaucoma treatment. the surgical management of refractory glaucoma is presented by two main groups of surgical techniques: filtering surgery (including surgery with the use of antimetabolites and implants and cyclodestructive procederes. types of glaucoma drainages are described, modern valve drainage system is presented.

  7. Case 40. Misdiagnosis of refractory macrocytic anemia.

    Science.gov (United States)

    Stringaris, Kate; Bain, Barbara

    2008-11-01

    A diagnosis of myelodysplastic syndrome, refractory anemia subtype, was made in an elderly Indian woman on the basis of a refractory macrocytic anemia with normal vitamin B(12) and folate assays, normal thyroid function, essentially normal liver function and normal cytogenetic analysis. Disease evolution revealed that the diagnosis was erroneous.

  8. Effect of annealing temperature on microstructure and electrochemical performance of La0.75Mg0.25Ni3.5Co0.2 hydrogen storage electrode alloy

    Institute of Scientific and Technical Information of China (English)

    DONG Xiaoping; L(U) Fanxiu; ZHANG Yanghuan; YANG Liying; WANG Xinlin

    2008-01-01

    To improve the cyclic stability of La-Mg-Ni system alloy, as-cast La0.75Mg0.25Ni3.5Co0.2 alloy was annealed at 1123, 1223, and 1323 K for 10 h in 0.3 MPa argon. The microstructure and electrochemical performance of different annealed alloys were investigated systematically by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and electrochemical experiments. The results obtained by XRD and SEM showed that the as-cast and annealed (1123 K) alloys had multiphase structure containing LaNi5, (La, Mg)2(Ni, Co)7 and few LaNi2 phases. When annealing temperatures approached 1223 and 1323 K, LaNi2 phase disappeared. The annealed alloys at 1223 and 1323 K were composed of LaNi5, (La, Mg)2(Ni, Co)7 and (La, Mg)(Ni, Co)3 phases. With increasing annealing temperature, the maximum discharge capacity of the alloy decreased monotonously, but the cyclic stability was improved owing to structure homogeneity and grain growth after annealing, as well as the enhancement of anti-oxidation/corrosion ability and the suppression of pulverization during cycling in KOH electrolyte.

  9. Brain stimulation for treatment of refractory epilepsy

    Institute of Scientific and Technical Information of China (English)

    GE Yan; HU Wei; LIU Chong; ZHANG Jian-guo; MENG Fan-gang

    2013-01-01

    Objective We review the targets of the deep brain and the responsive neurostimulation system (RNS) to identify the best optimal stimulation parameters and the best mode of stimulation,whether cyclical,continuous,or smarter.Data sources This review is based on data obtained from published articles from 1950 to 2013.To perform the PubMed literature search,the following keywords were input:deep brain stimulation (DBS),RNS,and refractory epilepsy.Study selection Articles containing information related to brain stimulation or RNS for the treatment of refractory epilepsy were selected.Results The currently available treatment options for those patients who resist multiple antiepileptic medications and surgical procedures include electric stimulation,both direct and indirect,of brain nuclei thought to be involved in epileptogenesis.The number of potential targets has increased over the years to include the anterior nucleus of the thalamus,the centromedian nucleus of the thalamus,the hippocampus,the subthalamic nucleus,the caudate nucleus,and the cerebellum,among others.The results of a randomized controlled trial and the RNS trial were published to reveal the effectiveness.Conclusions Although statistically significant reductions in seizures have been observed using several different stimulation techniques,including vagus nerve stimulation,DBS,and RNS,these effects are currently only palliative and do not approach the efficacy comparable with that seen in resection in appropriately selected patients.More research is needed to determine optimal stimulation targets and techniques as well as to determine which epilepsy patients will benefit most from this technology.

  10. Zinc alloy enhances strength and creep resistance

    Energy Technology Data Exchange (ETDEWEB)

    Machler, M. [Fisher Gauge Ltd., Peterborough, Ontario (Canada). Fishercast Div.

    1996-10-01

    A family of high-performance ternary zinc-copper-aluminum alloys has been developed that provides higher strength, hardness, and creep resistance than the traditional zinc-aluminum alloys Zamak 3, Zamak 5, and ZA-8. Designated ACuZinc, mechanical properties comparable to those of more expensive materials make it suitable for high-load applications and those at elevated temperatures. This article describes the alloy`s composition, properties, and historical development.

  11. 低成色白色金合金的性能试验%Test on performance of low karat white gold alloy

    Institute of Scientific and Technical Information of China (English)

    袁军平; 陈德东; 陈令霞; 陈绍兴; 王昶

    2016-01-01

    With the change of the age structure of consumers and the sales mode,the low karat gold alloy is grad-ually becoming a new trend of the karat gold jewelry market. In this paper,10K white gold alloy was chosen as the ex-perimental material,its physical,chemical and processing performances were detected by methods of casting filling, DTA,Archimedes flotage, colourmetry, accelerated corrosion, high temperature oxidization and cold working. The re-sults show that when the alloy contains 41. 7% to 42% Au,11% to 14% Ni,33% to 36% Cu,9% to 13% Zn, 0. 05 % to 0. 3 % Si,0. 005 % to 0. 05 % B,its melting temperature range is below 37 ℃ and the castability is per-fect,with the sieve filling rate of 98%;the alloy''s yellowness index is below 19 while its whiteness reaches level 1,and it has excellent sulphide discoloration resistance and resistance to high temperature oxidization; the alloy has high o-riginal hardness,while its work-hardening rate is moderate,which is beneficial for cold working production and wear resistance of jewelry surface.%随着消费群体年龄结构和销售模式的变化,低成色金合金逐渐成为K金首饰市场的一个新方向. 该文以10 K白色金合金为研究材料,采用铸造充填法、差热分析法、静水密度法、测色法、加速腐蚀法、高温氧化法、冷变形法等检测了试验合金的物理性能、化学性能及加工制作性能. 试验结果表明:当合金中有41 . 7 % ~42 %金、11 % ~14 %镍、33 % ~36 %铜、9 % ~13 %锌、0 . 05 % ~0 . 3 %硅、0 . 005 % ~0 . 05 %硼时,其熔化温度变化范围在37 ℃以下,筛网充填率达到98 %,有较好的铸造性能;合金的黄度指数低于19 ,达到1级白色,具有优良的抗硫化变色性能及抗高温氧化性能;合金的初始硬度较高,加工硬化速率适中,有利于进行冷加工生产和首饰表面耐磨损.

  12. Prefabricated Refractory Panels for Use in KSC's Flame Deflectors: A Feasibility Study

    Science.gov (United States)

    Calle, Luz Maria; Trejo, David

    2010-01-01

    The launch complexes at the John F. Kennedy Space Center (KSC) have been used to launch space vehicles for the Apollo and Space Shuttle programs. NASA is currently designing and developing a new space vehicle. The launch complexes have been in service for a significant duration and the aggressive conditions of the Florida coast and the launches have resulted in failures within the launch complexes. Of particular interests is the performance of the refractory lining that covers the steel base structure for the diversion of the exhaust from the launched vehicles (i.e., the flame deflectors). An unprotected steel base structure would likely experience loss of strength and possible failure when subjected to the high temperatures during launches. The refractory lining is critical for successful launches. The refractory material currently used in the flame trenches was developed in 1959 and is the only refractory material approved for use in these facilities. Significant effort and costs are expended in repairing the lining system after each launch. NASA is currently performing a comprehensive research program to assess and develop refractory materials for improved performance in the flame trenches. However, one challenge associated with the use of refractory materials in the flame trench is that the materials should be cured, dried, and fired to maximize their properties and characteristics. Because of the large size of the deflectors and trenches, drying and firing of the lining system is difficult, if not impossible. Most refractory materials are dried and fired before use. Because the refractory materials used for the deflector lining cannot be dried and fired, the full potential of the materials are not being realized. A system that could use refractory materials that could be cured, dried, and sintered in a controlled environment would likely improve the performance of the lining system. This report evaluates the feasibility of fabricating and placing prefabricated

  13. Oxidation Protection of MgO-C Monolithic Refractories with Tar-Resin Binder and Metal Antioxidants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The development of efficient bonding agents is one aspect of the advancement of refractories. Based on a newly developed binder system, a new generation of tar-resin bonded magnesia carbon products with high performance has been developed. Furthermore, the binder system characterized by high carbon yield after carbonization results in forming an extremely strong carbon bonding. It can improve refractories properties to get new product with more advantages than old refractories: more economic, lower cost and low toxicity. Tar-resin is not only used in shaped refractories, but also in more refractories types, such as monolithic refractories. Immersion experiments of MgO-C monolithic refractories samples in liquid steel at 1600℃ have been carried out for steel making industry.These experiments showed the formation of a dense and continuous MgO rich layer, on the interface between refractory and steel, and the possible formation of inclusions as large clusters protruding from the refractory surface. For the mechanical properties, the powder was heated up to 1400℃ in air to remove carbon, and was subsequently formed into brick shape. Standard ASTM was used to determine the MOR, porosity and density. It is found that antioxidantmaterials play an important role in improving the mechanical properties.

  14. Hydrogen adsorption on hydrogen storage alloy surface and electrochemical performances of the M1Ni{sub 4.0}Co{sub 0.6}Al{sub 0.4} alloy electrodes before and after surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.X.; Xu, Z.D. [Zhejiang Univ., Hangzhou (China). Dept. of Chemistry; Tu, J.P. [Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering; Li, H.Y.; Chen, S.; Bao, S.N. [Zhejiang Univ., Hangzhou (China). Dept. of Physics; Yuan, J. [Zhejiang Univ., Hangzhou (China). State Key Lab. of Si Material Science

    2001-07-01

    The surfaces of the hydrogen storage alloy powders (MlNi{sub 4.0}Co{sub 0.6}Al{sub 0.4}) before and after surface treating were analyzed by X-ray photoelectron spectroscopy (XPS), electron probe micro-analysis (EPMA), inductively coupled plasma spectroscopy (ICP). It was found that a Ni-rich surface layer was produced and the specific surface area was augmented by the surface treatment with a hot 6 MKOH or 6 MKOH+0.02 MKBH{sub 4} solution due to the preferential dissolution of Al and the etching of the hot alkaline solution. The effect of the surface treatments on the hydrogen adsorption on the alloy surface was for the first time evaluated by means of the thermal desorption spectroscopy (TDS). It was found that the surface treatments enhanced the hydrogen adsorption on the alloy surfaces and produced new adsorption states. The untreated alloy had only one hydrogen adsorption peak at about 400 K. There were two hydrogen adsorption states at about 540 and 630 K on the surface of the alloy treated with 6 MKOH. In the case of the alloy treated with 6 MKOH+0.02 MKBH{sub 4} three hydrogen adsorption peaks were observed at about 390, 540 and 630 K, respectively. The results of electrochemical measurements showed that the treated alloy electrodes exhibited higher exchange current density for the hydrogen electrode reaction than the untreated hydrogen alloy. After the surface treatment, the hydrogen adsorption enhancement on the treated alloy surface facilitated the hydrogen electrode reaction process on the alloy electrodes and results in good activation and low polarization resistance. (author)

  15. Effect of overheating degree of molten alloy on material reliability and performance stability of AlSi17CuNiMg silumin castings

    Directory of Open Access Journals (Sweden)

    J. Szymszal

    2010-10-01

    Full Text Available The article discusses the effect of overheating degree (above the casting temperature on material reliability of AlSi17 silumin. Theexamined alloys was poured at temperatures, 760; 870 and 980oC, holding the melt for 40 minutes and casting from the temperature of760oC. The assessment of the impact of the degree of overheating was to analysis the tensile strength. From the results of the static tensile test, the main estimators of the descriptive statistics, and coefficients of variation. Having determined the boundary value sO for Weibull distribution, the value of „m” modulus was computed along with other coefficients of material reliability, proposed formerly by the authors. Basing on the obtained results, a model of Weibull distribution function was developed for the tensile strength with respective graphic interpretation. The time-temperature parameters of the melting and casting technology have been chosen to determine the scatter of resultant parameter (Rm in function of overheating degree. The time-temperature treatment of hypereutectic AlSi17CuNiMg silumin, through its effect on the cluster structure of molten alloy, is shaping the material reliability and performance stability of castings.

  16. Structural Evolution and Performance Changes in FeCoCrNiAlNb x High-Entropy Alloy Coatings Cladded by Laser

    Science.gov (United States)

    Lin, Danyang; Zhang, Nannan; He, Bin; Gong, Xue; Zhang, Yue; Li, Deyuan; Dong, Fuyu

    2017-09-01

    FeCoCrNiAlNb x (x = 0, 0.25, 0.5, 0.75, and 1) high-entropy alloy (HEA) coatings were prepared by laser cladding to explore the effects of the addition of Nb on the microstructure and wear resistance properties of FeCoCrNiAlNb x HEAs. These effects were analyzed by microstructure and wear performance tests. The experimental results show that the structure of FeCoCrNiAlNb x consists of BCC and FCC phases at x = 0, 0.25, and 0.5. FCC2 formed at x = 0.75, and Fe2Nb was detected at x = 1. The content of FCC phase increased with the increasing content of Nb. At x = 0, 0.25, 0.5, 0.75, and 1, the average hardness values were 439, 685, 773, 672, and 561 HV, whereas the mass losses were 3.4, 1.9, 1.6, 2.3, and 2.5 mg after a sliding wear test against a WC ball, respectively. The hardness and wear resistance clearly increased initially and then decreased with the continuous addition of Nb. The wear resistance is highest for the alloy with x = 0.5. Thus, the effect of the addition of Nb should be considered and rationally determined before the preparation of FeCoCrNiAlNb x HEA to improve the wear resistance.

  17. Influence of Zr Addition on Structure and Performance of Rare Earth Mg-Based Alloys as Anodes in Ni/MH Battery

    Directory of Open Access Journals (Sweden)

    Shujun Qiu

    2015-04-01

    Full Text Available In this study, the substitution of Mg with Zr in La0.7Mg0.3(Ni0.85Co0.153.5 was carried out with the purpose of improving the electrochemical performances. The structural and hydrogen storage properties in both gas-solid reaction and the electrochemical system were systematically studied on La0.7(Mg0.3−xZrx(Ni0.85Co0.153.5 (x = 0.05, 0.1, 0.2, 0.3 alloys. Each tested alloy is composed of LaNi3 phase, LaNi5 phase and ZrNi3 phase with different phase abundances. The electrochemical studies indicated that all Zr-substituted anodes possessed a much higher cycling capacity retention than pristine La0.7Mg0.3(Ni0.85Co0.153.5. However, the maximum discharge capacity was reduced with the increase of Zr content. The potential-step tests showed that the diffusion of hydrogen atoms inside the anodes was decelerated after the introduction of Zr.

  18. Creep in refractory materials; Fluencia en materiales refractarios

    Energy Technology Data Exchange (ETDEWEB)

    Tomba Martinez, A. G.; Luz, A. P.; Pandolfelli, V. C.

    2013-10-01

    Refractory materials are widely used in various industrial fields due to their outstanding properties and performance in aggressive environments. However, although creep resistance is one of the most important properties for the selection of these materials, few researches were carried out focused on the fundamentals and technological understanding of their performance at high temperatures. In this context, this work addresses: 1) the creep mechanisms, 2) the mathematical models proposed for the analysis and to forecast the creep deformation at high temperature, 3) technical procedures and experimental testing, and 4) a critical analysis of some basic and practical aspects considering the literature available on this issue. Based on the collected information, mathematical models (such as the Projection concept) were considered as a powerful tool for the prediction of the refractories creep behavior, helping to identify the main creep mechanisms in these materials and to induce the development of optimized compositions able to attend the end-users requirements. (Author)

  19. Characterization of the Ti-10Nb-10Zr-5Ta Alloy for Biomedical Applications. Part 2: Wettability, Tribological Performance and Biocompatibility

    Science.gov (United States)

    Braic, V.; Balaceanu, M.; Braic, M.; Vitelaru, C.; Titorencu, I.; Pruna, V.; Parau, A. C.; Fanara, C.; Vladescu, A.

    2014-01-01

    The Ti-10Nb-10Zr-5Ta alloy, prepared in a levitation melting furnace, was investigated as a possible candidate for replacing Ti6Al4V alloy in medical applications. The sessile drop method, pin-on-disc and in vitro tests were used to analyze wettability, wear resistance, and biocompatibility of the new alloy. The characteristics of the Ti-10Nb-10Zr-5Ta alloy were assessed in comparison to those of the Ti6Al4V alloy. The Ti-10Nb-10Zr-5Ta system was found to have hydrophilic characteristics with similar contact angle as the Ti6Al4V alloy. In all environments (deionized water, simulated body fluid and Fusayama Meyer artificial saliva), the friction coefficient showed a stable evolution versus sliding distance, being similar for both alloys. On overall, the wear resistance of Ti-10Nb-10Zr-5Ta alloy was lower than that of Ti6Al4V for all testing environments. The Ti-10Nb-10Zr-5Ta alloy exhibited good biocompatibility characteristics at in vitro test compared to Ti6Al4V alloy. The cell viability on Ti-10Nb-10Zr-5Ta surfaces was higher than the one observed on Ti6Al4V samples, regardless the number of days spent in osteoblast-like cells culture. A high degree of cell attachment and spreading was observed on both alloys.

  20. Effects of Pd substitution for Ni on corrosion performances of Mg0.9Ti0.1Ni1-xPdx hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    TIAN Qi-feng; ZHANG Yao; TAN Zhi-cheng; XU Fen; SUN Li-xian; ZHANG Tao; Yuan Hua-tang

    2006-01-01

    The Mg0.9Ti0.1Ni1-xPdx (x= 0,0.05, 0.1, 0.15) hydrogen storage electrode alloys were prepared by mechanical alloying. The main phases of the alloys were determined as amorphous by X-ray diffraction(XRD). The corrosion potentials of the alloys were measured by open circuit potential measurements and the values are -0.478, -0.473, -0.473 and -0.471 V (vs Hg/HgO electrode) for x=0, 0.05, 0.1, 0.15, respectively. The corrosion currents of the studied alloys were obtained by non-linear fitting of the anodic polarization curve using Bulter-Volmer equation and Levenberg-Marquardt algorithm, which were obtained after different cycles.The initial corrosion currents of the alloys are decreased with the increasing of Pd content. The increasing of Pd content in the alloys inhibits the corrosion rates of the electrode alloys with the progress of cycle number. The electrochemical impedance spectroscopy(EIS) was conducted after open circuit potential of the alloys stabilizing. The impedance data fit well with the theoretical values obtained by the proposed equivalent circuit model. The corrosion resistances and the thickness of surface passive film of the alloys, which were deduced by the analyses of EIS, are enhanced with the increasing of Pd content in the alloys, which are consistent with the results of corrosion rates obtained from anodic polarization measurements.

  1. Plasma Surface Cu Alloyed Layer as a Lubricant on Stainless Steel Sheet:Wear Characteristics and On-job Performance in Incremental Forming

    Institute of Scientific and Technical Information of China (English)

    WU Hongyan; WEI Hongyu; Ghulam Hussain; TAO Kemei; Asif Iqbal; RAO Weifeng

    2016-01-01

    To solve the problems of poor forming and easy adhesion of the stainless steel, Cu alloyed layer on the stainless steels was prepared by the double glow plasma surface alloying technique. The experimental results indicated that the supersaturated copper dispersedly precipitated in grain interior and crystal boundaries and formed the vermicular structure. The tribological tests indicated that the friction coefifcient of the Cu alloyed layer was lower than that of the stainless steels. The wear rate of stainless steel in the presence of Cu alloyed layer was approximately 2-fold lower than that in the absence of the alloyed layer. The results of the incremental forming indicated that the ploughing phenomenon was not observed on the stainless steel in the presence of Cu alloyed layer during the incremental forming, while the stainless steel presented the deep ploughing. Therefore, Cu alloyed layer on stainless steel exhibited excellent self-lubrication and forming properties.

  2. Research and Development of Bauxite—based Refractories

    Institute of Scientific and Technical Information of China (English)

    ZHONGXiang-chong

    1996-01-01

    The research work on the microstructure and high temperature mehanical properties of sintered Chinses bauxite(DK type) and the ef-fects of foreign oxide additions (K2O,CaO,TiO,Fe2O3,MgO,ZrO2·SiO2) carried out at our laboratories have been reviewed.Based on these basic research results,bauxite-based high performance refractories have been develped for high temperature applications with success-ful achievements.

  3. Preparation and Cycling Performance of Iron or Iron Oxide Containing Amorphous Al-Li Alloys as Electrodes

    Directory of Open Access Journals (Sweden)

    Franziska Thoss

    2014-12-01

    Full Text Available Crystalline phase transitions cause volume changes, which entails a fast destroying of the electrode. Non-crystalline states may avoid this circumstance. Herein we present structural and electrochemical investigations of pre-lithiated, amorphous Al39Li43Fe13Si5-powders, to be used as electrode material for Li-ion batteries. Powders of master alloys with the compositions Al39Li43Fe13Si5 and Al39Li43Fe13Si5 + 5 mass-% FeO were prepared via ball milling and achieved amorphous/nanocrystalline states after 56 and 21.6 h, respectively. In contrast to their Li-free amorphous pendant Al78Fe13Si9, both powders showed specific capacities of about 400 and 700 Ah/kgAl, respectively, after the third cycle.

  4. Performance of Pt-Co alloys and CoTPP catalysts for the reduction of oxygen in AFC

    Energy Technology Data Exchange (ETDEWEB)

    Kiros, Y. [Royal Institute of Technology, Stockholm (Sweden); Sampathrajan, A.; Ramanathan, M. [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1996-12-31

    One of the primary problems of the oxygen reduction reaction (ORR) for especially low and medium temperature fuel cells such as AFC, PEFC and PAFC is the high activation overpotential. This high overpotential is due to the complicated nature of the ORR and the morphological properties of the catalyst particles. High catalyst dispersion on the carbon support and small particle sizes, non-agglomeration and/or non-dissolution of the electrocatalyst is desired for the long-term operation of the electrodes. In this study electrodes were tested at different temperatures and concentrations in order to substantiate their influences on the activity and stability of the electrocatalysts, i.e.; cobalt tetraphenylporphyrin (CoTPP) and alloys of platinum and cobalt.

  5. Influence of phytic acid concentration on performance of phytic acid conversion coatings on the AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cui Xiufang [School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong Street, Harbin 150001 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang 110016 (China)], E-mail: cuixf97721@yahoo.com.cn; Li Ying [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang 110016 (China); Li Qingfen; Jin Guo; Ding Minghui [School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong Street, Harbin 150001 (China); Wang Fuhui [School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong Street, Harbin 150001 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang 110016 (China)

    2008-10-15

    In this study, the phytic acid conversion coating, a new environmentally friendly chemical protective coating for magnesium alloys, was prepared. The influences of phytic acid concentration on the formation process, microstructure, chemical state and corrosion resistance of the conversion coatings on AZ91D magnesium alloy were investigated by means of weight gain measurement, field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS), respectively. And the depth profile of all elements in the optimal conversion coatings was analyzed by auger electron spectroscopy (AES). The results show that the growth, microstructure, chemical state and corrosion resistance of the conversion coatings are all obviously affected by the phytic acid concentration. The concentration of 5 g l{sup -1} corresponds to the maximum weight gain. The main elements of the coating are Mg, Al, O, P, and C, which are distributed gradually in depth. The functional groups of conversion coatings formed in higher concentration phytic acid solution are closer to the constituent of phytic acid than those formed in lower concentration phytic acid solution. The coatings formed in 1-5 g l{sup -1} are integrated and uniform. However, those formed in 20-50 g l{sup -1} have some micro-cracks on the {alpha} phase. The coating formed in 5 g l{sup -1} has the best corrosion resistance, whose open circuit current density decreases about six orders than that of the untreated sample, although the coatings deposited in 1-20 g l{sup -1} can all improve the corrosion resistance of AZ91D.

  6. Surface coating from phosphonate ionic liquid electrolyte for the enhancement of the tribological performance of magnesium alloy.

    Science.gov (United States)

    Jiménez, Ana Eva; Rossi, Antonella; Fantauzzi, Marzia; Espinosa, Tulia; Arias-Pardilla, Joaquin; Martínez-Nicolás, Ginés; Bermúdez, María-Dolores

    2015-05-20

    A chronoamperometric method has been applied for the growth of a surface coating on AZ31B magnesium alloy, using the imidazolium alkylphosphonate room-temperature ionic liquid 1-ethyl-3-methylimidazolium ethylphosphonate ([EMIM][EtPO3H]) as electrolyte. A surface coating layer is obtained after 4 h under a constant voltage bias of -0.8 V with respect to the standard electrode. The coating nucleation and growth process correlates well with a 3D progressive mechanism. X-ray photoelectron spectrometry (XPS) analysis of [EMIM][EtPO3H] shows new P 2p and O 1s peaks after its use as electrolyte, as a consequence of reaction between the phosphonate anion and the magnesium substrate. Angle-resolved XPS (ARXPS) analysis of [EMIM][EtPO3H] did not show any change in the composition of the surface before and after chronoamperometry, since the sampling depth (1.5 nm at the highest emission angle) is larger than the cation and anion sizes (ca. 7 and 5 Å, respectively). Characterization of the coating was made by scanning electron microscopy (SEM), focussed ion beam SEM, energy dispersive X-ray spectroscopy, XPS, and ARXPS. FIB-SEM shows that the coating presents a mean thickness of 374 (±36) nm and contains magnesium and aluminum phosphates. Linear reciprocating tribological tests under variable load show that the presence of the coating can reduce friction coefficients of the coated AZ31B against steel up to 32% and wear rates up to 90%, with respect to the uncoated alloy.

  7. Effect of cerium content on microstructure and hydrogen storage performance of Ti24Cr17.5V50Fe8.5Cex (x=0-1.0) alloys

    Institute of Scientific and Technical Information of China (English)

    MI Jing; LIU Xiaopeng; LI Yan; JIANG Lijun; LI Zhinian; HUANG Zhuo; WANG Shumao

    2009-01-01

    Effect of Ce addition on microstructure and hydrogen storage performance of Ti24Cr17.5V50Fe8.5Cex (x=0, 0.5at.%, 0.8at.% and 1.0at.%) alloys was studied by X-ray diffraction, scanning electron microscopy and P-C-isotherm measurements. The results indicated that Ce addition was a useful way to improve the flatness of the plateau and increase hydrogen storage capacity of Ti24Cr17.5V50Fe8.5 alloy. It was indicated that both homogenization of composition and increase of hydrogen diffusion coefficient were the main reasons for improving the hydrogen storage performance of Ti24Cr17.5V50Fe8.5Cex alloys.

  8. Primordial Compositions of Refractory Inclusions

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, L; Simon, S B; Rai, V K; Thiemens, M H; Hutcheon, I D; Williams, R W; Galy, A; Ding, T; Fedkin, A V; Clayton, R N; Mayeda, T K

    2008-02-20

    Bulk chemical and oxygen, magnesium and silicon isotopic compositions were measured for each of 17 Types A and B refractory inclusions from CV3 chondrites. After bulk chemical compositions were corrected for non-representative sampling in the laboratory, the Mg and Si isotopic compositions of each inclusion were used to calculate its original chemical composition assuming that the heavy-isotope enrichments of these elements are due to Rayleigh fractionation that accompanied their evaporation from CMAS liquids. The resulting pre-evaporation chemical compositions are consistent with those predicted by equilibrium thermodynamic calculations for high-temperature nebular condensates but only if different inclusions condensed from nebular regions that ranged in total pressure from 10{sup -6} to 10{sup -1} bar, regardless of whether they formed in a system of solar composition or in one enriched in OC dust relative to gas by a factor of ten relative to solar composition. This is similar to the range of total pressures predicted by dynamic models of the solar nebula for regions whose temperatures are in the range of silicate condensation temperatures. Alternatively, if departure from equilibrium condensation and/or non-representative sampling of condensates in the nebula occurred, the inferred range of total pressure could be smaller. Simple kinetic modeling of evaporation successfully reproduces observed chemical compositions of most inclusions from their inferred pre-evaporation compositions, suggesting that closed-system isotopic exchange processes did not have a significant effect on their isotopic compositions. Comparison of pre-evaporation compositions with observed ones indicates that 80% of the enrichment in refractory CaO + Al{sub 2}O{sub 3} relative to more volatile MgO + SiO{sub 2} is due to initial condensation and 20% due to subsequent evaporation for both Type A and Type B inclusions.

  9. Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

    Science.gov (United States)

    Ma, Zheyuan

    Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM

  10. Aluminum alloy

    Science.gov (United States)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  11. Unusual cause of respiratory distress misdiagnosed as refractory asthma

    Directory of Open Access Journals (Sweden)

    Al-Otair Hadil

    2006-01-01

    Full Text Available We report a young lady, who was labeled as a case of refractory asthma for a few years, based on history of shortness of breath on minimal exertion, noisy breathing and normal chest radiograph. Repeated upper airway exam by an otolaryngologist and computerized tomography scan, were normal. On presentation to our hospital, she was diagnosed to have fixed upper airway obstruction, based on classical flow-volume loop findings. Fibroptic bronchoscopy revealed a web-shaped subglottic stenosis. The histopathology of a biopsy taken from that area, showed non-specific inflammation. No cause for this stenosis could be identified. The patient was managed with rigid bronchoscopy dilatation, without recurrence. We report this case as idiopathic subglottic stenosis, that was misdiagnosed as refractory bronchial asthma, stressing the importance of performing spirometry in the clinic.

  12. Refractory Research Group - U.S. DOE, Albany Research Center [Institution Profile

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, James P.

    2004-09-01

    The refractory research group at the Albany Research Center (ARC) has a long history of conducting materials research within the U.S. Bureau of Mines, and more recently, within the U.S. Dept. of Energy. When under the U.S. Bureau of Mines, research was driven by national needs to develop substitute materials and to conserve raw materials. This mission was accomplished by improving refractory material properties and/or by recycling refractories using critical and strategic materials. Currently, as a U.S. Dept of Energy Fossil Energy field site, research is driven primarily by the need to assist DOE in meeting its vision to develop economically and environmentally viable technologies for the production of electricity from fossil fuels. Research at ARC impacts this vision by: • Providing information on the performance characteristics of materials being specified for the current generation of power systems; • Developing cost-effective, high performance materials for inclusion in the next generation of fossil power systems; and • Solving environmental emission and waste problems related to fossil energy systems. A brief history of past refractory research within the U.S. Bureau of Mines, the current refractory research at ARC, and the equipment and capabilities used to conduct refractory research at ARC will be discussed.

  13. Status of Testing and Characterization of CMS Alloy 617 and Alloy 230

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)

    2006-08-01

    Status and progress in testing and characterizing CMS Alloy 617 and Alloy 230 tasks in FY06 at ORNL and INL are described. ORNL research has focused on CMS Alloy 617 development and creep and tensile properties of both alloys. In addition to refurbishing facilities to conduct tests, a significant amount of creep and tensile data on Alloy 230, worth several years of research funds and time, has been located and collected from private enterprise. INL research has focused on the creep-fatigue behavior of standard chemistry Alloy 617 base metal and fusion weldments. Creep-fatigue tests have been performed in air, vacuum, and purified Ar environments at 800 and 1000 C. Initial characterization and high-temperature joining work has also been performed on Alloy 230 and CCA Alloy 617 in preparation for creep-fatigue testing.

  14. Synthesis and Electrocatalytic Performance of Multi-Component Nanoporous PtRuCuW Alloy for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Xiaoting Chen

    2015-06-01

    Full Text Available We have prepared a multi-component nanoporous PtRuCuW (np-PtRuCuW electrocatalyst via a combined chemical dealloying and mechanical alloying process. The X-ray diffraction (XRD, transmission electron microscopy (TEM and electrochemical measurements have been applied to characterize the microstructure and electrocatalytic activities of the np-PtRuCuW. The np-PtRuCuW catalyst has a unique three-dimensional bi-continuous ligament structure and the length scale is 2.0 ± 0.3 nm. The np-PtRuCuW catalyst shows a relatively high level of activity normalized to mass (467.1 mA mgPt−1 and electrochemically active surface area (1.8 mA cm−2 compared to the state-of-the-art commercial PtC and PtRu catalyst at anode. Although the CO stripping peak of np-PtRuCuW 0.47 V (vs. saturated calomel electrode, SCE is more positive than PtRu, there is a 200 mV negative shift compared to PtC (0.67 V vs. SCE. In addition, the half-wave potential and specific activity towards oxygen reduction of np-PtRuCuW are 0.877 V (vs. reversible hydrogen electrode, RHE and 0.26 mA cm−2, indicating a great enhancement towards oxygen reduction than the commercial PtC.

  15. Structure and tribological performance by nitrogen and oxygen plasma based ion implantation on Ti6Al4V alloy

    Science.gov (United States)

    Feng, Xingguo; Sun, Mingren; Ma, Xinxin; Tang, Guangze

    2011-09-01

    Ti6Al4V alloy was implanted with nitrogen-oxygen mixture by using plasma based ion implantation (PBII) at pulsed voltage -10, -30 and -50 kV. The implantation was up to 6 × 1017 ions/cm2 fluence. The changes in chemical composition, structure and hardness of the modified surfaces were studied by XPS and nanoindentation measurements. According to XPS, it was found that the modified layer was predominantly TiO2, but contained small amounts of TiO, Ti2O3, TiN and Al2O3 between the outmost layer and metallic substrate. Surface hardness and wear resistance of the samples increased significantly after PBII treatment, the wear rate of the sample implanted N2-O2 mixture at -50 kV decreased eight times than the untreated one. The sample implanted N2-O2 mixture showed better wear resistance than that of the sample only implanted oxygen at - 50 kV. The wear mechanism of untreated sample was abrasive-dominated and adhesive, and the wear scar of the sample implanted at -50 kV was characterized by abrasive wear-type ploughing.

  16. High performance p-type segmented leg of misfit-layered cobaltite and half-Heusler alloy

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Van Nong, Ngo; Snyder, Gerald Jeffrey;

    2015-01-01

    In this study, a segmented p-type leg of doped misfit-layered cobaltite Ca2.8Lu0.15Ag0.05Co4O9+δ and half-Heusler Ti0.3Zr0.35Hf0.35CoSb0.8Sn0.2 alloy was fabricated and characterized. The thermoelectric properties of single components, segmented leg, and the electrical contact resistance...... of the joint part were measured as a function of temperature. The output power generation characteristics of segmented legs were characterized in air under various temperature gradients, DT, with the hot side temperature up to 1153 K. At ΔT ≈756 K, the maximum conversion efficiency reached a value of ∼5......%, which is about 65% of that expected from the materials without parasitic losses. The long-term stability investigation for two weeks at the hot and cold side temperatures of 1153/397 K shows that the segmented leg has good durability as a result of stable and low electrical resistance contacts. 2015...

  17. Performance of titanium oxide-polymer insulation in superconducting coils made of Bi-2212/Ag-alloy round wire

    Science.gov (United States)

    Chen, Peng; Trociewitz, Ulf P.; Dalban-Canassy, Matthieu; Jiang, Jianyi; Hellstrom, Eric E.; Larbalestier, David C.

    2013-07-01

    Conductor insulation is one of the key components needed to make Ag-alloy clad Bi2Sr2CaCu2O8+x (Bi-2212/Ag) superconducting round wire (RW) successful for high field magnet applications, as dielectric standoff and high winding current densities (Jw) directly depend on it. In this study, a TiO2-polymer insulation coating developed by nGimat LLC was applied to test samples and a high field test coil. The insulation was investigated by differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), dielectric property measurement, and transport critical current (Ic) property measurement. About 29% of the insulation by weight is polymer. When the Bi-2212/Ag wire is fully heat treated, this decomposes with slow heating to 400 ° C in pure O2. After the full reaction, we found that the TiO2 did not degrade the critical current properties, adhered well to the conductor, and provided a breakdown voltage of more than 100 V, which allowed the test coil to survive quenching in 31.2 T background field, while providing a 2.6 T field increment. For Bi-2212/Ag RW with a typical diameter of 1.0-1.5 mm, this ˜15 μm thick insulation allows a very high coil packing factor of ˜0.74, whereas earlier alumino-silicate braid insulation only allows packing factors of 0.38-0.48.

  18. Improved performance of Mg-Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Science.gov (United States)

    La, Mao; Zhou, Huaijuan; Li, Ning; Xin, Yunchuan; Sha, Ren; Bao, Shanhu; Jin, Ping

    2017-05-01

    The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium-yttrium (Mg-Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg-Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  19. Effect of CVD-Diamond on the Tribological and Mechanical Performance of Titanium Alloy (Ti6Al4V

    Directory of Open Access Journals (Sweden)

    S.H. Din

    2016-12-01

    Full Text Available Nano-crystalline diamond and microcrystalline diamond films have been separately deposited on chemically treated titanium alloy (Ti6Al4V substrates from methane/hydrogen (CH4/H2 gas mixture, using hot filament chemical vapor deposition technique. The coatings have architecture of Ti6Al4V/NCD and Ti6Al4V/MCD. The as grown nano-crystalline diamond and microcrystalline diamond films were characterized using high resolution scanning electron microscope and Raman’s spectroscopy. The residual stresses along the surface of nano-crystalline diamond coatings and micro-crystalline diamond coatings are compressive in nature as shown by the Raman spectroscopy. Nanoindentation tests were also conducted using Berkovich nanoindenter for the purpose of measurement of hardness and elastic modulus values. The indentation depth for microcrystalline diamond coating was 65 nm, whereas for nanocrystalline diamond coating, it was 72 nm. Microcrystalline diamond and nanocrystalline diamond coatings have yielded the super-hardness of ~55 G Pa and ~38 G Pa respectively. The average coefficient of friction of microcrystalline diamond and nanocrystalline diamond coatings decrease from 0.305-0.27 to 0.068-0.053, respectively, when the load is increased from 1 N to 10 N. However, for conventional Ti6Al4V substrate the average coefficient of friction changes from 0.625 to 0.38 under the same input conditions.

  20. Corrosion performance of atmospheric plasma sprayed alumina coatings on AZ31B magnesium alloy under immersion environment

    Directory of Open Access Journals (Sweden)

    D. Thirumalaikumarasamy

    2014-12-01

    Full Text Available Plasma sprayed ceramic coatings are successfully used in many industrial applications, where high wear and corrosion resistance with thermal insulation are required. The alumina powders were plasma sprayed on AZ31B magnesium alloy with three different plasma spraying parameters. In the present work, the influence of plasma spray parameters on the corrosion behavior of the coatings was investigated. The corrosion behavior of the coated samples was evaluated by immersion corrosion test in 3.5 wt% NaCl solution. Empirical relationship was established to predict the corrosion rate of plasma sprayed alumina coatings by incorporating process parameters. The experiments were conducted based on a three factor, five-level, central composite rotatable design matrix. The developed relationship can be effectively used to predict the corrosion rate of alumina coatings at 95% confidence level. The results indicate that the input power has the greatest influence on corrosion rate, followed by stand-off distance and powder feed rate.

  1. Alkaline sulfide pretreatment of an antimonial refractory Au-Ag ore for improved cyanidation

    Science.gov (United States)

    Alp, Ibrahim; Celep, Oktay; Deveci, Haci

    2010-11-01

    This paper presents the alkaline sulfide pretreatment of an antimonial refractory gold and silver ore. In the ore, gold occurs mainly as gold-silver alloys and as associated with quartz and framboidal pyrite grains, and, to a small extent, as the inclusions within antimonial sulfides. Silver is present extensively as antimonial sulfides such as andorite. Alkaline sulfide pretreatment was shown to allow the decomposition of the antimonial sulfide minerals (up to 98% Sb removal) and to remarkably improve the amenability of gold (e.g., from silver (e.g., from leaching. An increase in reagent concentration (1-4 mol/L Na2S or NaOH) and temperature (20-80°C), and a decrease in particle size seem to produce an enhancing effect on metal extraction. These findings suggest that alkaline sulfide leaching can be suitably used as a chemical pretreatment method prior to the conventional cyanidation for antimonial refractory gold and silver ores.

  2. Fireclay Refractory Bricks for Hot Blast Stove

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Zhang Yongfang; Chai Junlan

    2008-01-01

    @@ 1 Scope This standard specifies the classification, shape, dimension, technical requirements, test method,inspection rules, packing, marking,transportation,storage and quality certification of fireclay refractory bricks for hot blast stove.

  3. Spalling Resistance Fast-drying Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Peng Xigao

    2010-01-01

    @@ 1 Scope This standard specifies the term and definition,classification, technical requirements, test methods,quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of spalling resistance fast-drying refractory castables.

  4. Ultra High Temperature Refractory Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Legacy refractory materials that have origins dating to the original Saturn program are commonly used in current launch facilities. Although they failure to meet the...

  5. Ultra High Temperature Refractory Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Legacy refractory materials that have origins dating to the original Saturn program are commonly used in current launch facilities. Although they fail to meet the...

  6. Alumina Carbon Refractory Products for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 1 Scope This standard specifies the classification.techni-cal requirements,test methods,inspection rules,packing,marking,transportation,storage and quality certificate of alumina carbon refractory products for continuous casting.

  7. Testing Consent Order on Refractory Ceramic Fibers

    Science.gov (United States)

    This notice announces that EPA has signed signed an enforceable testing consent order under the Toxic Substances Control Act (TSCA), 15 U.S.C. section 2601 at seq., with three of the primary producers of refractory ceramic fibers (RCF).

  8. Prognostic Factors for Refractory Status Epilepticus

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2013-03-01

    Full Text Available Researchers at the Mayo Clinic, Rochester, MN studied the outcome and identified prognostic factors for refractory status epilepticus (RSE in 54 adult patients, median age 52 years [range 18-93].

  9. Neutron absorbing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masayuki

    1998-12-04

    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  10. Situation of China's Refractories Industry in Last Sixty Years

    Institute of Scientific and Technical Information of China (English)

    HUO Jiangping; PAN Shangxin; LI Chaowen

    2009-01-01

    The annual output of China's refractories in 1949 was 74 thousand tons, and was 29.11 million tons in 2007, which was 65% of the world total refractories output. The export of China's refractory products and raw materials in 2008 was 6.18 million tons, which were exported to hundreds of countries and regions in the world. China is a big country in the field of refractories production and refractories export, which has devoted a lot to relative high temperature industry.

  11. Method of making a composite refractory material

    Science.gov (United States)

    Morrow, Marvin S.; Holcombe, Cressie E.

    1995-01-01

    A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000.degree. C. to form a composite refractory material.

  12. The modified atkins diet in refractory epilepsy.

    Science.gov (United States)

    Sharma, Suvasini; Jain, Puneet

    2014-01-01

    The modified Atkins diet is a less restrictive variation of the ketogenic diet. This diet is started on an outpatient basis without a fast, allows unlimited protein and fat, and does not restrict calories or fluids. Recent studies have shown good efficacy and tolerability of this diet in refractory epilepsy. In this review, we discuss the use of the modified Atkins diet in refractory epilepsy.

  13. Neuromodulation in refractory epilepsy: Brazilian specialists consensus

    Directory of Open Access Journals (Sweden)

    Vera Cristina Terra

    Full Text Available ABSTRACT Epilepsy is a potentially devastating brain disorder characterized by a predisposition to spontaneous epileptic seizures. In patients with medically refractory epilepsy, new non-pharmacological therapeutic approaches may be considered. In this scenario, palliative surgery such as vagus nerve stimulation (VNS or deep brain stimulation (DBS may be indicated in a subset of patients. In this paper we make recommendations for the use of VNS and DBS in patients in Brazil with refractory epilepsy.

  14. The Modified Atkins Diet in Refractory Epilepsy

    Directory of Open Access Journals (Sweden)

    Suvasini Sharma

    2014-01-01

    Full Text Available The modified Atkins diet is a less restrictive variation of the ketogenic diet. This diet is started on an outpatient basis without a fast, allows unlimited protein and fat, and does not restrict calories or fluids. Recent studies have shown good efficacy and tolerability of this diet in refractory epilepsy. In this review, we discuss the use of the modified Atkins diet in refractory epilepsy.

  15. Refractory migraine in a headache clinic population

    Directory of Open Access Journals (Sweden)

    Fernandez-Torron Roberto

    2011-08-01

    Full Text Available Abstract Background Many migraineurs who seek care in headache clinics are refractory to treatment, despite advances in headache therapies. Epidemiology is poorly characterized, because diagnostic criteria for refractory migraine were not available until recently. We aimed to determine the frequency of refractory migraine in patients attended in the Headache Unit in a tertiary care center, according to recently proposed criteria. Methods The study population consisted of a consecutive sample of 370 patients (60.8% females with a mean age of 43 years (range 14-86 evaluated for the first time in our headache unit over a one-year period (between October 2008 and October 2009. We recorded information on clinical features, previous treatments, Migraine Disability Assessment Score (MIDAS, and final diagnosis. Results Overall migraine and tension-type headache were found in 46.4% and 20.5% of patients, respectively. Refractory migraine was found in 5.1% of patients. In refractory migraineurs, the mean MIDAS score was 96, and 36.8% were medication-overusers. Conclusions Refractory migraine is a relatively common and very disabling condition between the patients attended in a headache unit. The proposed operational criteria may be useful in identifying those patients who require care in headache units, the selection of candidates for combinations of prophylactic drugs or invasive treatments such as neurostimulation, but also to facilitate clinical studies in this patient group.

  16. Advances in Modern Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ningsheng; HU Shuhe; ZHANG Sanhua

    2004-01-01

    Recent developments in terms of binding system, new material system, installation method and pre-cast shapes of refractory castables are introduced and discussed. In authors view, binding system is advancing on the one hand towards "purification" to minimize impurity components from binder materials, and on the other hand "stabilization" to minimize the structure destroy by volatility and decomposition of binder materials. Challenges of higher service temperature, slag resistance, clean steel production and better thermal shock resistance have promoted the booming of new varieties of castables including MgObased, natural flake graphite containing and non-oxides like Si3 N4, AlON and SiAlON containing castables. Installation technique is developing towards convenience,simplification and high efficiency. Advancement in installation and dry-out is of an incentive to the boost of selfflow castables, shotcreting castables, infiltration casting,quick dry-out castables and pre-cast shapes. Along with the increased adoption of pre-cast shapes of castables, the boundary between "shaped" and "unshaped" is becoming vague.

  17. Advances in Modern Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    ZHOUNingsheng; HUShuhe; ZHANGSanhua

    2004-01-01

    Recent developments in terms of binding system, new material system, installation method and pre-cast shapes of refractory castables are introduced and discussed. In authors' view, binding system is advancing on the one hand towards "purification" to minimize impurity components from binder materials, and on the other hand "stabilization" to minimize the structure destroy by volatility and decomposition of binder materials. Challenges of higher service temperature, slag resistance, clean steel production and better thermal shock resistance have promoted the booming of new varieties of castables including MgO based, natural flake graphite containing and non-oxides like Sis N4, AION and SIMON containing castables. Installation technique is developing towards convenience, simplification and high efficiency. Advancement in installation and dry-out is of an incentive to the boost of selfflow castables, shotcreting castables, infiltration casting, quick dry-out castables and pre-cast shapes. Along wit hthe increased adoption of pre-cast shapes of castables, the boundary between "shaped" and " unshaped " is becoming vague.

  18. Corrosion and bioactivity performance of graphene oxide coating on TiNb shape memory alloys in simulated body fluid.

    Science.gov (United States)

    Saud, Safaa N; Hosseinian S, Raheleh; Bakhsheshi-Rad, H R; Yaghoubidoust, F; Iqbal, N; Hamzah, E; Ooi, C H Raymond

    2016-11-01

    In the present work, the microstructure, corrosion, and bioactivity of graphene oxide (GO) coating on the laser-modified and -unmodified surfaces of TiNb shape memory alloys (SMAs) were investigated. The surface morphology and chemical composition was examined using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The surface modification was carried out via a femtosecond laser with the aim to increase the surface roughness, and thus increase the adhesion property. FE-SEM analysis of the laser-treated Ti-30at.% Nb revealed the increase in surface roughness and oxygen/nitrogen containing groups on the Ti-30at.% Nb surface after being surface modified via a femtosecond laser. Furthermore, the thickness of GO was increased from 35μm to 45μm after the surface was modified. Potentiodynamic polarisation and electrochemical impedance spectroscopy studies revealed that both the GO and laser/GO-coated samples exhibited higher corrosion resistance than that of the uncoated TiNb SMA sample. However, the laser/GO-coated sample presented the highest corrosion resistance in SBF at 37°C. In addition, during soaking in the simulated body fluid (SBF), both the GO and laser/GO coating improved the formation of apatite layer. Based on the bioactivity results, the GO coating exhibited a remarkable antibacterial activity against gram-negative bacteria compared with the uncoated. In conclusion, the present results indicate that Ti-30at.% Nb SMAs may be promising alternatives to NiTi for certain biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Stress corrosion cracking tests for low and high alloy steels in sour oilfield service. Tests performed at VTT

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, K. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity; Haemaelaeinen, E. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Engineering Materials

    1996-10-01

    The purpose of the studies was to validate the usefulness of the proposed NACE slow strain rate testing method and compare it with the EFC document. In the NACE document the testing takes place at a temperature of 177 deg C, the test solution contains 20 wt% NaCl, the partial pressure of H{sub 2}S varies between 14 and 28 bar and the partial pressure of CO{sub 2} between 14 and 55 bar. In the NACE document the strain rate is determined as 4 x 10{sup -6} 1/s and in the EFC document 1 x 10{sup -6} 1/s. The results showed brittle behaviour for the test material in all of the test environments, and in each case the elongation was less than 5%. For comparison purposes the SSRT was conducted with the test material also in an inert environment (N{sub 2} gas), where the fracture was ductile and elongation 65%. The tests conducted with different strain rates gave the same result, which shows that the difference between EFC and NACE documents within the strain rate is not significant in the environments studied. However, since the alloy 654 SMO, which is considered to have a high resistance to corrosion, failed the SSRT test in the environments determined in the NACE document, the NACE document can be considered too severe for testing of austenitic stainless steels. Since contrary to the NACE document the EFC document does not determine levels for hydrogen sulphide and carbon dioxide, the EFC document can be considered more suitable than the NACE document for testing of austenitic stainless steels for sour service. (author)

  20. Experimental investigation with respect to the performance of deep submillimeter-scaled textured tools in dry turning titanium alloy Ti-6Al-4V

    Science.gov (United States)

    Li, Ning; Chen, Yongjie; Kong, Dongdong; Tan, Shenglin

    2017-05-01

    Titanium alloy Ti-6Al-4V falls under the category of the most difficult to machine materials due to its inherent high strength maintained at elevated temperature and low thermal conductivity. Based on size effect, the poor machinability may be improved by surface texturing on the tools. Thus, the effect of deep submillimeter-scaled textures on the cutting performance in Ti-6Al-4V turning was investigated. To this end, three kinds of surface textures with different sizes were fabricated using femtosecond laser on rake faces of the uncoated cemented carbide (WC/Co) inserts. Then, dry cutting experiments were conducted with these textured inserts and conventional inserts under the condition of cutting speed Vc = 50m/min, depth of cut ap = 2 mm, and feed rate f = 0.3 mm/rev. The cutting performance is evaluated in terms of cutting forces, coefficient of friction at the tool-chip interface. Results obtained in this work show the feasibility of fabricating deep submillimeter-scaled textures on tool rake face to improve the machinability of Ti-6Al-4V. The parallel type of textured tool P01 demonstrates the best performance in both reducing cutting force and improving the friction properties on the rake face. This result can be explained by the reduced tool-chip contact area and the ploughing effect.

  1. Successful rescue of refractory, severe antibody mediated rejection with splenectomy.

    Science.gov (United States)

    Kaplan, Bruce; Gangemi, Antonio; Thielke, James; Oberholzer, José; Sankary, Howard; Benedetti, Enrico

    2007-01-15

    Antibody-mediated rejection (AMR) commonly occurs after transplantation of ABO-incompatible and sensitized renal transplant. Treatment regimens commonly include a combination of plasmapheresis (PL) and intravenous immunoglobulin (IVIG). However, some cases of AMR remain refractory to treatment. We report a case series of four patients with AMR refractory to standard therapy (ST) who resolved after splenectomy. Four living donor kidney transplant recipients were diagnosed with AMR. Two patients were ABO incompatible, one was cross-match positive and one had no obvious predisposing factors. After failure of therapy with corticosteroids, PL, IVIG, Thymoglobulin, and Rituximab (three patients) or Campath (one patient), AMR was treated with laparoscopic splenectomy. After an average of 11 days of ST, laparoscopic splenectomy was performed for rescue. The urinary output improved immediately in all patients, serum creatinine levels decreased within 48 hr, and ABO titers fell in the ABO-incompatible patient and the cross-match became negative in the two sensitized patients. Splenectomy may play a role in the treatment of AMR refractory to ST.

  2. Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching

    Institute of Scientific and Technical Information of China (English)

    O. CELEP; (I).ALP; H. DEVEC(I); M. VICIL

    2009-01-01

    The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. <38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.

  3. Airway refractoriness to inhaled mannitol after repeated challenge.

    Science.gov (United States)

    Suh, Dong In; Lee, Ju Kyung; Kim, Jin-Tack; Koh, Young Yull

    2011-10-01

    Exercise and inhaled mannitol are thought to cause bronchoconstriction through a similar mechanism in asthma. The response to exercise becomes refractory with repeated challenges. This study aimed to investigate whether repeated challenge with mannitol induces refractoriness, as with exercise. Forty-one children with asthma underwent two consecutive dose-response mannitol challenges (Phase 1); the second challenge proceeded after recovery (FEV(1) : 95% or more of baseline value) from the first. The response to mannitol was expressed as a provocative dose causing a 15% fall in FEV(1) (PD(15) ) and the response-dose ratio (RDR) (% fall in FEV(1) /cumulative dose). In 18 subjects who were deemed to have mannitol refractoriness in Phase 1, a mannitol challenge was performed before and after a methacholine challenge (Phase 2). In Phase 1, the time taken for the FEV(1) to recover after the first mannitol challenge ranged from 20 to 100 min with a median of 50 min. In the 23 subjects with a measurable mannitol PD(15) in both challenges, the geometric mean (95%CI) PD(15) in the second challenge (163 mg [114-232]) was significantly higher than that in the first challenge (66 mg [50-88], P value of 0.083%/mg (0.055-0.125) in the first challenge to 0.029%/mg (0.017-0.048) in the second challenge (P challenge with methacholine or mannitol did not significantly alter subsequent bronchoconstriction to the opposite challenge. Repeated challenge with mannitol resulted in less bronchoconstriction when compared with the initial challenge. This refractoriness seems not to be attributable to functional loss of responsiveness or non-specific effect of prior bronchoconstriction.

  4. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...

  5. Electron microscopy study of refractory ceramic fibers.

    Science.gov (United States)

    MacKinnon, P A; Lentz, T J; Rice, C H; Lockey, J E; Lemasters, G K; Gartside, P S

    2001-10-01

    In epidemiological studies designed to identify potential health risks of exposures to synthetic vitreous fibers, the characterization of airborne fiber dimensions may be essential for assessing mechanisms of fiber toxicity. Toward this end, air sampling was conducted as part of an industry-wide study of workers potentially exposed to airborne fibrous dusts during the manufacture of refractory ceramic fibers (RCF) and RCF products. Analyses of a subset of samples obtained on the sample filter as well as on the conductive sampling cowl were performed using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to characterize dimensions of airborne fibers. Comparison was made of bivariate fiber size distributions (length and diameter) from air samples analyzed by SEM and by TEM techniques. Results of the analyses indicate that RCF size distributions include fibers small enough in diameter ( 60 microm) may go undetected by TEM, as evidenced by the proportion of fibers in this category for TEM and SEM analyses (1% and 5%, respectively). Limitations of the microscopic techniques and differences in fiber-sizing rules for each method are believed to have contributed to the variation among fiber-sizing results. It was concluded from these data that further attempts to characterize RCF exposure in manufacturing and related operations should include analysis by TEM and SEM, since the smallest diameter fibers are not resolved with SEM and the fibers of longer length are not sized by TEM.

  6. Phonon broadening in high entropy alloys

    Science.gov (United States)

    Körmann, Fritz; Ikeda, Yuji; Grabowski, Blazej; Sluiter, Marcel H. F.

    2017-09-01

    Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation high-temperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). Phonons critically influence thermal stability, thermodynamic and elastic properties, as well as thermal conductivity. In contrast to perfect crystals and ordered alloys, the inherently present mass and force constant fluctuations in multi-component random alloys (high entropy alloys) can induce significant phonon scattering and broadening. Despite their importance, phonon scattering and broadening have so far only scarcely been investigated for high entropy alloys. We tackle this challenge from a theoretical perspective and employ ab initio calculations to systematically study the impact of force constant and mass fluctuations on the phonon spectral functions of 12 body-centered cubic random alloys, from binaries up to 5-component high entropy alloys, addressing the key question of how chemical complexity impacts phonons. We find that it is crucial to include both mass and force constant fluctuations. If one or the other is neglected, qualitatively wrong results can be obtained such as artificial phonon band gaps. We analyze how the results obtained for the phonons translate into thermodynamically integrated quantities, specifically the vibrational entropy. Changes in the vibrational entropy with increasing the number of elements can be as large as changes in the configurational entropy and are thus important for phase stability considerations. The set of studied alloys includes MoTa, MoTaNb, MoTaNbW, MoTaNbWV, VW, VWNb, VWTa, VWNbTa, VTaNbTi, VWNbTaTi, HfZrNb, HfMoTaTiZr.

  7. The Influence of Zn Content on the Corrosion and Wear Performance of Mg-Zn-Ca Alloy in Simulated Body Fluid

    Science.gov (United States)

    Li, Hua; Liu, Debao; Zhao, Yue; Jin, Feng; Chen, Minfang

    2016-09-01

    Mg-Zn-Ca alloy has been attracting increasing attention as a potential biodegradable implant material. In this paper, Mg-3Zn-0.2Ca and Mg-4Zn-0.2Ca alloys were prepared by means of vacuum melting and subsequent hot extrusion process. The influences of Zn content on the microstructure, mechanical properties, and corrosion and wear behavior of Mg-Zn-Ca alloys in simulated body fluid (SBF) were studied. The results show that with increased Zn content, the grain size and corrosion resistance were decreased, while the mechanical strength and wear resistance were increased, under both dry sliding and SBF-lubricated conditions. For the same Mg-Zn-Ca alloy, the wear loss rate under SBF lubrication was higher than dry sliding condition, indicating a strong corrosion-assisted wear effect of SBF to the Mg-Zn-Ca alloy.

  8. Performance of high speed ball bearings with lead and lead alloy plated retainers in liquid hydrogen at 1.2 million DN

    Science.gov (United States)

    Brewe, D. E.; Scibbe, H. W.; Wisander, D. W.

    1973-01-01

    Ball bearings with lead- and lead-alloy-coated retainers were operated in liquid hydrogen at 30,000 rpm under a thrust load of 400 lb. Bearing lives were compared using different: (1) lead- and lead-alloy coatings, (2) coating thicknesses, (3) substrate materials, (4) retainer locating surfaces, and (5) plating techniques. Longer bearing run times were achieved using retainers with a lead-tin-copper alloy coating electroplated onto a leaded-bronze material and an aluminum-bronze alloy. Thirty percent of the bearings tested achieved the desired objective of 10 hours. All of the lead-alloy coated retainers exceeded this objective. A coating thickness of at least 0.0014 in. was used for all bearings exceeding the 10-hour goal.

  9. High temperature resistant cermet and ceramic compositions. [for thermal resistant insulators and refractory coatings

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1978-01-01

    High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.

  10. Grain refinement of AZ31 magnesium alloy by Al-Ti-C-Y master alloy

    Institute of Scientific and Technical Information of China (English)

    XU Chunxiang; LU Binfeng; L(U) Zhengling; LIANG Wei

    2008-01-01

    Al-Ti-C-Y master alloy was prepared by combining SHS technique and melting-casting method. The microstructure of master alloy and its grain-refining effect on AZ31 alloy were investigated by means of OM, XRD, SEM and EDS. Experimental results indicated that the prepared master alloy consisted of α-Al, TiAl3, TiC and Al3Y phases, and exhibited good grain-refining performance of AZ31 alloy. Morphology of α-Mg changed from coarse dendritic to fine equiaxed and the average grain size of α-Mg matrix reduced from the original 580 to 170 μm after adding 1.0 wt.% master alloy. The grain refining efficiency of Al-Ti-C-Y master alloy on AZ31 alloy was mainly attributed to heterogeneous nucleation of TiC particles and grain growth restriction of Al-Y compound or TiC at grain boundaries.

  11. Micro-Structures of Hard Coatings Deposited on Titanium Alloys by Laser Alloying Technique

    Science.gov (United States)

    Li, Wei; Yu, Huijun; Chen, Chuanzhong; Wang, Diangang; Weng, Fei

    2013-01-01

    This work is based on micro-structural performance of the Ti-B4C-C laser alloying coatings on Ti-6Al-4V titanium alloy. The test results indicated that laser alloying of the Ti-B4C-C pre-placed powders on the Ti-6Al-4V alloy substrate can form the ceramics reinforced hard alloying coatings, which increased the micro-hardness and wear resistance of substrate. The test result also indicated that the TiB phase was produced in alloying coating, which corresponded to its (101) crystal plane. In addition, yttria has a refining effect on micro-structures of the laser alloying coating, and its refinement mechanism was analyzed. This research provided essential experimental and theoretical basis to promote the applications of the laser alloying technique in manufacturing and repairing of the aerospace parts.

  12. Measurements of Total Hemispherical Emissivity of Several Stably Oxidized Metals and Some Refractory Oxide Coatings

    Science.gov (United States)

    Wade, William R.

    1959-01-01

    A description of the apparatus and methods used for obtaining total hemispherical emissivity is presented, and data for several stably oxidized metals are included. The metals which were tested included type 347 stainless steel, tungsten, and Haynes alloys B, C, X, and 25. No values of emissivity were obtained for tungsten or Haynes alloy B because of the nature of the oxides produced. The refractory oxide coatings tested were flame-sprayed alumina and zirconia. The results of the investigation indicate that strongly adherent, oxidized surfaces of a high stable emissivity can be produced on type 347 stainless steel for which the total hemispherical emissivity varied from 0.87 to 0.91 for temperatures from 600 F to 2,000 F. For this same temperature range, the Haynes alloys tested showed values of total hemispherical emissivity from 0.90 to 0.96 for alloy C, from 0.85 to 0.88 for alloy X, and from 0.85 to 0.89 for alloy 25. Haynes alloy B and tungsten formed nonadherent oxides at elevated temperatures and, therefore, stable emissivities were not obtained. The results obtained for the flame-sprayed ceramics (alumina and zirconia) showed considerably higher values of total emissivity than those measured for coatings applied by other methods. Emissivity values ranging from 0.69 to 0.44 for aluminum oxide and from 0.62 to 0.44 for zirconium oxide were measured for temperatures from 800 F to 2,000 F.

  13. Use of ns and fs pulse excitation in laser-induced breakdown spectroscopy to improve its analytical performances: A case study on quaternary bronze alloys

    Energy Technology Data Exchange (ETDEWEB)

    Almaviva, Salvatore [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Fantoni, Roberta, E-mail: roberta.fantoni@enea.it [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Caneve, Luisa; Colao, Francesco [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Fornarini, Lucilla [ENEA,UTTAMB, SP Anguillarese 301, Roma (Italy); Santagata, Antonio [CNR-IMIP, UOS Potenza, Zona Industriale, 85050 Tito Scalo (PZ) (Italy); Teghil, Roberto [Università degli Studi della Basilicata, Dipartimento di Scienze, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy)

    2014-09-01

    Analytical performances of Laser Induced Breakdown Spectroscopy (LIBS) resulted not fully satisfactory in some cases such as historical bronzes, therefore, efforts should be focussed on improving ablation efficiency and on better understanding the plasma parameter evolution. To this aim a set of double pulse experiments have been carried out in almost collinear geometry at about 530 nm laser excitation. The first emitting source was either a ns or a fs laser the second a ns one. Data were collected as a function of the interpulse delay, in order to determine the ablation efficiency increase, to study the kinetics of plasma parameters (temperature, electron density) and the decay of atomic and ionic intensities with respect to the optical background. In parallel a previously developed model for laser ablation, ionization and following plasma decay, was implemented, adding a second laser pulse, to analyse the double pulse excitation in the considered geometry, and the time evolution of the same variables was investigated. Model results are able to reproduce the observed experimental trends and support the possibility of improving analytical performances by using the double pulse technique with inter-pulse delays in the entire investigated range. - Highlights: • The Double Pulse LIBS technique is applied to a quaternary metal alloy sample. • Two different Double Pulse LIBS configurations are investigated. • Signal enhancement was experimentally verified in the Double Pulse technique. • Comparison of the experimental results with the proposed theoretical model • Dependence of the LIBS signal by some experimental parameters.

  14. N-doped graphene layers encapsulated NiFe alloy nanoparticles derived from MOFs with superior electrochemical performance for oxygen evolution reaction

    Science.gov (United States)

    Feng, Yi; Yu, Xin-Yao; Paik, Ungyu

    2016-01-01

    Water splitting, an efficient approach for hydrogen production, is often hindered by unfavorable kinetics of oxygen evolution reaction (OER). In order to reduce the overpotential, noble metal oxides-based electrocatalysts like RuO2 and IrO2 are usually utilized. However, due to their scarcity, the development of cost-effective non-precious OER electrocatalysts with high efficiency and good stability is urgently required. Herein, we report a facile one-step annealing of metal-organic frameworks (MOFs) strategy to synthesize N-doped graphene layers encapsulated NiFe alloy nanoparticles (NiFe@C). Through tuning the nanoparticle size and calcination temperature, NiFe@C with an average size of around 16 nm obtained at 700 °C exhibits superior OER performance with an overpotential of only 281 mV at 10 mA cm−2 and high durability. The facile synthesis method and excellent electrochemical performance show great potential of NiFe@C in replacing the precious metal-based electrocatalysts in the OER. PMID:27658968

  15. Effect of nanostructured composite powders on the structure and strength properties of the high-temperature inconel 718 alloy

    Science.gov (United States)

    Cherepanov, A. N.; Ovcharenko, V. E.

    2015-12-01

    The experimental results of the effect of powder nanomodifiers of refractory compounds on the strength properties, the macro- and microstructure of the high-temperature Inconel 718 alloy have been presented. It has been shown that the introduction of powder modifiers into the melt leads to a decrease in the average grain size by a factor of 1.5-2 in the alloy. The long-term tensile strength of the alloy at 650°C increases 1.5-2 times, and the number of cycles at 482°C before fracture grows by more than three times. The effect of nanoparticles on the grain structure and strength properties of the alloy is due to an increase in the number of generated crystallization centers and the formation of nanoparticle clusters of refractory compounds at boundaries and junctions in the formed grain structure, which hinder the development of recrystallization processes in the alloy.

  16. Development of a Mo-Si-B coating for Nb-based Alloys and the Effects of Zr Additions to Mo-Si-B Coatings for Enhanced Oxidation Protection in Ultra-High Temperature Applications

    Science.gov (United States)

    Lu-Steffes, Otto John

    Higher efficiencies and reduced emissions performance of fossil fuel energy systems are achieved with increasing operation temperatures. This increase in operating temperature requires the use of materials with higher melting points such as refractory metal alloys. However, refractory metals suffer from catastrophic oxidation in this type of environment. Thus, oxidation protection for refractory metal alloys is a crucial step in developing next generation ultra-high temperature materials. To meet this challenge, an oxidation resistant coating for Nb based alloys has been designed as well as the incorporation of zirconium into the Mo-Si-B coating to provide further corrosion protection and a reduction in temperature for the underlying multi-layered structure. Niobium samples coated with a Mo-Si-B coating demonstrate enhanced oxidation protection compared to samples only coated with Si-B. Thermogravimetric analysis testing at 1300°C for 24 hours for both the Mo-Si-B coated Nb and Nb-based alloys show enhanced oxidation protection with mass changes of 0.44 mg/cm2 and 0.55 mg/cm2, respectively, compared to the uncoated alloy that had a mass change of 87.6 mg/cm2. To demonstrate the design concept for a coating with thermal barrier behavior, Zr is added to the Mo-Si-B coating through the pack cementation technique. The resulting coating shows that the Zr reacts with the aluminosilica top layer to form Zr silicides and ZrO2. Upon oxidation, the coating forms a mixed top layer composed of borosilica, ZrO2 and ZrSiO 4. Oxidation testing of the Zr modified Mo-Si-B coating exhibits low mass change indicating that the coating provides oxidation protection and that the Zr additions do not interfere with the oxidation protection of the Mo-Si-B coating. Finite element modeling using object oriented finite element analysis of the coating structures yielded an evaluation of the mechanical and thermal properties of the coatings, providing insight into the thermal performance and

  17. Enhanced catalytic performance for methane combustion of 3DOM CoFe2O4 by co-loading MnOx and Pd-Pt alloy nanoparticles

    Science.gov (United States)

    Li, Xiangyu; Liu, Yuxi; Deng, Jiguang; Xie, Shaohua; Zhao, Xingtian; Zhang, Yang; Zhang, Kunfeng; Arandiyan, Hamidreza; Guo, Guangsheng; Dai, Hongxing

    2017-05-01

    Three-dimensionally ordered macroporous (3DOM) CoFe2O4, zMnOx/3DOM CoFe2O4 (z = 4.99-12.30 wt%), and yPd-Pt/6.70 wt% MnOx/3DOM CoFe2O4 (y = 0.44-1.81 wt%; Pd/Pt molar ratio = 2.1-2.2) have been prepared using the polymethyl methacrylate microspheres-templating, incipient wetness impregnation, and bubble-assisted polyvinyl alcohol-protected reduction strategies, respectively. All of the samples were characterized by means of various techniques. Catalytic performance of the samples was measured for methane combustion. It is shown that the as-prepared samples exhibited a high-quality 3DOM structure (103 ± 20 nm in pore size) and a surface area of 19-28 m2/g, and the noble metal or alloy nanoparticles (NPs) with a size of 2.2-3.0 nm were uniformly dispersed on the macropore wall surface of 3DOM CoFe2O4. The loading of MnOx on CoFe2O4 gave rise to a slight increase in activity, however, the dispersion of Pd-Pt NPs on 6.70MnOx/3DOM CoFe2O4 significantly enhanced the catalytic performance, with the 1.81Pd2.1Pt/6.70MnOx/3DOM CoFe2O4 sample showing the highest activity (T10% = 255 °C, T50% = 301 °C, and T90% = 372 °C at a space velocity of 20,000 mL/(g h)). We believe that the excellent catalytic activity of 1.81Pd2.1Pt/6.70MnOx/3DOM CoFe2O4 was related to its well-dispersed Pd-Pt alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between MnOx or Pd-Pt NPs and 3DOM CoFe2O4.

  18. Creep Performance of HP40 Alloy for Ethylene Cracking Tube%乙烯裂解炉管HP40合金的蠕变性能

    Institute of Scientific and Technical Information of China (English)

    安俊超; 荆洪阳; 徐连勇; 胡庆广

    2011-01-01

    The changes of microstructure were studied and the creep constitutive equations were obtained through the investigation on the creep performance of HP40 alloy at 900 ℃ on different stress levels. SEM and EDX were used to analyze the changes of microstructures and phase chemical compositions. The results show that, along with the increase in the stress level, the creep rate of HP40 alloy increases correspondingly. After long-term creep test, the original skeleton-like eutectic carbide(r+M7C3+a little M23C6) turns into strip and block carbide (M23C6) gradually. Meanwhile, a certain amount of secondary carbide precipitation is also observed. The changes of skeleton-like eutectic carbide cause the decline of creep strength. Moreover, the creep cavity results in the decline of creep performance and accelerates the creep deformation process.%在900℃不同应力条件下,对HP40合金高温下的蠕变性能进行研究,观察试验前后显微组织的转变,并得到其蠕变本构方程.同时借助SEM+ EDX对组织转变及相成分变化进行深入分析.HP40合金在高温下,随着应力的增加蠕变速率增大.其原始组织骨架状的共晶碳化物(r+ M7C3+少量M23C6),经过长时蠕变试验后,逐渐变成条状和块状的M23C6,且有一定量的二次碳化物析出.HP40合金中骨架状共晶碳化物的消失会造成蠕变强度的下降.同时由于蠕变孔洞的出现,导致蠕变性能的下降,加速其蠕变变形的过程.

  19. Identification of platelet refractoriness in oncohematologic patients

    Directory of Open Access Journals (Sweden)

    Aline Aparecida Ferreira

    2011-01-01

    Full Text Available OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA. RESULTS: Of the 16 patients evaluated (median age: 53 years, nine (56% were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43% of the transfusion events, being more frequent in transfusions of random platelet concentrates (54%. Platelet refractoriness was confirmed in three patients (19%, who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50% by the PIFT and in three (19% by the PRA-HLA. Among alloimmunized patients, nine (64% had a history of transfusion, and three as a result of pregnancy (43%. Of the former, two were refractory (29%. No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management.

  20. Multifunctional coating MAI D5 intended for the protection of refractory materials

    Science.gov (United States)

    Zhestkov, B. E.; Terent'eva, V. S.

    2010-01-01

    A thin-layer heterophase MAI D5 coating intended for the protection of carbon-containing composite materials (C-C-, C-SiC-, SiC-SiC-composite material) and refractory metal-based alloys against high-temperature gas corrosion and erosion is tested. The coating is formed from a specially developed Si-Ti-Mo-B-Y microcomposition powder material. A new approach to creating self-healing heterophase coatings is used. At operating temperatures, the structure and phase composition of the MAI D5 coating provides rapid self-healing of random defects on the coating surface and in the base material owing to the presence of a silicon-containing eutectic, which favors rapid recovery of a protective amorphous silica layer consumed during operation. Under operating conditions, the coating undergoes self-organization to form a multilayer system with a number of functional oxide micro-, submicro-, and nanolayers. Samples with the MAI D5 coating are subjected to combined tests on bench plants located at MAI and TsAGI under conditions emulating the re-entry of a hypersonic aircraft, when its surface temperature reaches 2400 K. Certification tests are performed in wind tunnels located at TsAGI during a simultaneous action of a hypersonic dissociated-air flow and mechanical loads. The protection of heat-loaded structural elements in space vehicles made of ultrahigh-temperature materials against high-temperature gas corrosion and erosion by the MAI D5 coating in hypersonic dissociated-air flows is shown to be efficient.

  1. Irradiation performance of uranium-molybdenum alloy dispersion fuels; Desempenho sob irradiacao de elementos combustiveis do tipo U-Mo

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Cirila Tacconi de

    2005-07-01

    The U-Mo-Al dispersion fuels of Material Test Reactors (MTR) are analyzed in terms of their irradiation performance. The irradiation performance aspects are associated to the neutronic and thermal hydraulics aspects to propose a new core configuration to the IEA-R1 reactor of IPEN-CNEN/SP using U-Mo-Al fuels. Core configurations using U-10Mo-Al fuels with uranium densities variable from 3 to 8 gU/cm{sup 3} were analyzed with the computational programs Citation and MTRCR-IEA R1. Core configurations for fuels with uranium densities variable from 3 to 5 gU/cm{sup 3} showed to be adequate to use in IEA-R1 reactor e should present a stable in reactor performance even at high burn-up. (author)

  2. Refractory Behaviors of Magnetite-Kaolin Bricks

    Science.gov (United States)

    Adeosun, S. O.; Akpan, E. I.; Gbenebor, O. P.; Taiwo, O. O.; Eke, I. J.

    2016-11-01

    In this work, the suitability of using kaolin-magnetite-plastic clay to produce refractory bricks has been experimentally explored. Thirty bricks of different compositions were produced and fired at 1200°C. The density, shrinkage moisture content, loss on ignition, porosity and permeability of the bricks were examined. Results show that the bricks remained stable during firing and thus possess good insulating characteristics. The highest (2.23 g/cm3) and lowest (2.00 g/cm3) bulk densities obtained in this study are higher than the highest bulk density reported for Al dross-filled refractories (1.23 g/cm3). The bricks also possessed very low effective moisture content (10-23%) and very high compression modulus (16-100 MPa) desirable in insulating refractory bricks with high resistance to abrasion.

  3. Dramatic response to infliximab in refractory neurosarcoidosis

    Directory of Open Access Journals (Sweden)

    Chintamaneni Sreekanth

    2010-01-01

    Full Text Available Sarcoidosis is a systemic disease characterized by noncaseating granulomas in the involved organs. Neurologic manifestations involving the central and/or peripheral nervous system occur in about 5% of patients. Neurosarcoidosis is often refractory to conventional treatment and therefore more effective treatment options are needed. While the etiology of the disease is still unknown, there is now a better understanding of its pathogenesis on a molecular level. It is clear that tumor necrosis factor-α (TNFα plays a pivotal role in the development of the granulomas and it is believed to be a key cytokine involved in the pathogenesis of the disease. Taking advantage of this better understanding of disease pathogenesis, anti-TNFα agents are being increasingly used to treat refractory sarcoidosis. We report a patient with refractory neurosarcoidosis who showed dramatic improvement in the clinical and radiological manifestations following treatment with infliximab; he suffered a relapse upon discontinuation of the medication.

  4. Topical cidofovir for refractory verrucae in children.

    Science.gov (United States)

    Gupta, Monique; Bayliss, Susan J; Berk, David R

    2013-01-01

    Warts are common and are a challenge to treat in some children, especially immunocompromised children and those who fail or cannot tolerate salicylic acid preparations and cryotherapy. Cidofovir, a nucleotide analogue with antiviral activity, has demonstrated promising results when compounded into a topical form to treat refractory warts. We present a retrospective institutional review of 12 children with refractory verrucae treated with 1% to 3% topical cidofovir compounded in an unscented moisturizing cream, applied every other day to daily. In our institutional series, only three patients (25%) demonstrated complete clearance of their verrucae. An additional four patients (33%) demonstrated partial clearance. Our experience using topical cidofovir has been less successful than previous institutional reviews, possibly because we used a lower concentration and less-frequent dosing. More studies are needed to better characterize the efficacy, safety, and dosing of topical cidofovir for the treatment of refractory warts.

  5. Effects of the shape of the foil corners on the irradiation performance of U10Mo alloy based monolithic mini-plates

    Energy Technology Data Exchange (ETDEWEB)

    Ozaltun, Hakan [Idaho National Laboratory; Medvedev, Pavel G [Idaho National Laboratory

    2015-06-01

    Monolithic plate-type fuel is a fuel form being developed for high performance research and test reactors to minimize the use of enriched material. These fuel elements are comprised of a high density, low enrichment, U-Mo alloy based fuel foil, sandwiched between Zirconium liners and encapsulated in Aluminum cladding. The use of a high density fuel in a foil form presents a number of fabrication and operational concerns, such as: foil centering, flatness of the foil, fuel thickness variation, geometrical tilting, foil corner shape etc. To benchmark this new design, effects of various geometrical and operational variables on irradiation performance have been evaluated. As a part of these series of sensitivity studies, the shape of the foil corners were studied. To understand the effects of the corner shapes of the foil on thermo-mechanical performance of the plates, a behavioral model was developed for a selected plate from RERTR-12 experiments (Plate L1P785). Both fabrication and irradiation processes were simulated. Once the thermo-mechanical behavior the plate is understood for the nominal case, the simulations were repeated for two additional corner shapes to observe the changes in temperature, displacement and stress-strain fields. The results from the fabrication simulations indicated that the foil corners do not alter the post-fabrication stress-strain magnitudes. Furthermore, the irradiation simulations revealed that post-fabrication stresses of the foil would be relieved very quickly in operation. While, foils with chamfered and filleted corners yielded stresses with comparable magnitudes, they are slightly lower in magnitudes, and provided a more favorable mechanical response compared with the foil with sharp corners.

  6. EFFECT OF ALLOY ELEMENTS ON ELECTROCHEMICAL PERFORMANCE OF ALUMINUM SACRIFICIAL ANODE%合金元素对铝基牺牲阳极性能的影响

    Institute of Scientific and Technical Information of China (English)

    李威力; 闫永贵; 陈光; 马力

    2012-01-01

    通过合金化方法,在Al-Zn-In三元牺牲阳极中依次添加Mg、Ti、Ga、Mn、Sn等元素,炼制不同成分的铝合金牺牲阳极。采用电化学性能测试、极化曲线测量及扫描电子显微镜分析等手段分析了合金元素对铝合金牺牲阳极性能的影响。结果表明,随着添加元素种类的增加,牺牲阳极电化学性能提高。在Al-Zn-In三元阳极中加入Mg和Ti,阳极溶解形貌更加均匀;加入Ga与Sn后,阳极的开路电位与工作电位负移;加入Mn后阳极的电流效率提高。%Elements such as Mg,Ti,Ga,Mn and Sn were added to the Al-Zn-In based ternary anode in order using alloying method and the aluminum sacrificial anodes with different incorporated elements were cast.The electrochemical performance test,polarization plots and scanning electron microscope technique were carried out to analyze the influence of several familiar elements to the performance of the aluminum anode.The experiment results indicated that with the increase of the adding element the anode electrochemical performance was improved.When the elements of Mg and Ti were added to Al-Zn-In ternary anode the dissolution morphology was more uniform.When Ga and Sn were added,the anode open-circuit potential and closed-circuit potential were more negative.When Mn was added,the current efficiency was promoted.

  7. Magnetic Characteristics of Two Metglas Alloys

    Science.gov (United States)

    Blatnik, Marie; SNS nEDM Collaboration

    2016-09-01

    Magnetic shielding is gaining greater significance as precision experiments become more sensitive, such as for the Spallation Neutron Source nEDM [neutron electric dipole moment] measurement. Targeting a sensitivity of 10-28 e-cm, the SNS nEDM collaboration minimizes magnetic shield gradients and magnetic noise with a superconducting lead shield and several shield layers that include using a Metglas layer as a primary component. Metglas is a thin ribbon of proprietary engineered alloy that comes in many varieties. One alloy with high (as cast) permeability is Metglas alloy 2705M, which is primarily composed of Cobalt. However, this alloy will activate under neutron radiation and is therefore unsuitable. However, another high-performance Metglas alloy, 2826 MB, contains only trace amounts of Cobalt. A study of the shielding characteristics of the two alloys was performed, paying close attention to field oscillation frequency and magnitude.

  8. An Investigation on the Tribological Performances of the SiO2/MoS2 Hybrid Nanofluids for Magnesium Alloy-Steel Contacts.

    Science.gov (United States)

    Xie, Hongmei; Jiang, Bin; Liu, Bo; Wang, Qinghang; Xu, Junyao; Pan, Fusheng

    2016-12-01

    Hybrid nano-materials offer potential scope for an increasing numerous novel applications when engineered to deliver availably functional properties. In the present study, the SiO2/MoS2 hybrid nanoparticles with different mass ratios were employed as lubricant additives in the base oil, and their tribological properties were evaluated using a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. The results demonstrate that the SiO2/MoS2 hybrid nanoparticles exhibit superior lubrication performances than individual nano-SiO2 or nano-MoS2 even in high load and diverse velocity cases. The optimal SiO2/MoS2 mixing ratio and the concentration of SiO2/MoS2 hybrid nanoparticles in the base oil are 0.25:0.75 and 1.00-1.25 wt%, respectively. The excellent lubrication properties of the SiO2/MoS2 hybrid nanoparticles are attributed to the physical synergistic lubricating actions of nano-SiO2 and nano-MoS2 during the rubbing process.

  9. AgI alloying in SnTe boosts the thermoelectric performance via simultaneous valence band convergence and carrier concentration optimization

    Science.gov (United States)

    Banik, Ananya; Biswas, Kanishka

    2016-10-01

    SnTe, a Pb-free analogue of PbTe, was earlier assumed to be a poor thermoelectric material due to excess p-type carrier concentration and large energy separation between light and heavy hole valence bands. Here, we report the enhancement of the thermoelectric performance of p-type SnTe by Ag and I co-doping. AgI (1-6 mol%) alloying in SnTe modulates its electronic structure by increasing the band gap of SnTe, which results in decrease in the energy separation between its light and heavy hole valence bands, thereby giving rise to valence band convergence. Additionally, iodine doping in the Te sublattice of SnTe decreases the excess p-type carrier concentration. Due to significant decrease in hole concentration and reduction of the energy separation between light and heavy hole valence bands, significant enhancement in Seebeck coefficient was achieved at the temperature range of 600-900 K for Sn1-xAgxTe1-xIx samples. A maximum thermoelectric figure of merit, zT, of ~1.05 was achieved at 860 K in high quality crystalline ingot of p-type Sn0.95Ag0.05Te0.95I0.05.

  10. An Investigation on the Tribological Performances of the SiO2/MoS2 Hybrid Nanofluids for Magnesium Alloy-Steel Contacts

    Science.gov (United States)

    Xie, Hongmei; Jiang, Bin; Liu, Bo; Wang, Qinghang; Xu, Junyao; Pan, Fusheng

    2016-07-01

    Hybrid nano-materials offer potential scope for an increasing numerous novel applications when engineered to deliver availably functional properties. In the present study, the SiO2/MoS2 hybrid nanoparticles with different mass ratios were employed as lubricant additives in the base oil, and their tribological properties were evaluated using a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. The results demonstrate that the SiO2/MoS2 hybrid nanoparticles exhibit superior lubrication performances than individual nano-SiO2 or nano-MoS2 even in high load and diverse velocity cases. The optimal SiO2/MoS2 mixing ratio and the concentration of SiO2/MoS2 hybrid nanoparticles in the base oil are 0.25:0.75 and 1.00-1.25 wt%, respectively. The excellent lubrication properties of the SiO2/MoS2 hybrid nanoparticles are attributed to the physical synergistic lubricating actions of nano-SiO2 and nano-MoS2 during the rubbing process.

  11. 贮氢合金/石墨烯复合材料的电化学性能%Electrochemical performance of hydrogen absorbing alloy/graphene composite

    Institute of Scientific and Technical Information of China (English)

    夏同驰; 李晓峰; 董会超; 李超

    2012-01-01

    Graphite oxide was prepared by modified Hummers' method and then the graphene accumulation was prepared by a chemical reducing method. The graphene accumulation and hydrogen absorbing alloy were groud together to obtain a composite. The results of cyclic voltammetry, linear polarization and galvanostatic charge-discharge tests showed that compared to hydrogen absorbing alloy,the charge-discharge polarization of the composite electrode was decreased;its high-power and cyclic performance were improved.The discharge capacity of the electrode was 225 mAh/g at 3.0 C and 200 mAh/g at 5.0 C, which was increased by 64% and 220% respectively.The discharge voltage plateau of the electrodes was increased by 70 mV at 3.0 C and 120 mV at 5.0 C,respectively.%用改进的Hummers 法制备了石墨氧化物,用化学还原法制得石墨烯聚集物;用研磨法制备了贮氢合金/石墨烯复合材料.循环伏安、线性极化法及模拟电池充放电实验结果表明:与未复合的贮氢合金相比,贮氢合金/石墨烯复合材料降低了电极的极化,改善了大电流放电性能及循环性能.在实验条件下,3.0 C放电比容量达225 mAh/g,提高了64%,平台电压提高了70 mV,5.0 C放电比容量达200 mAh/g,提高了220%,平台电压提高了120 mV.

  12. Performance of 40-millimeter-bore ball bearings with lead- and lead-alloy-plated retainers in liquid hydrogen at 1.2 million DN

    Science.gov (United States)

    Brewe, D. E.; Wisander, D. W.; Scribbe, H. W.

    1972-01-01

    Forty-millimeter-bore ball bearings with lead- and lead-alloy-coated retainers were operated in liquid hydrogen at 30,000 rpm under a thrust load of 1780 N (400 lb.) Four different substrate materials were used for the retainer. Longer bearing run times were achieved with a lead-tin-copper alloy coating plated onto a leaded-bronze material (22.5 hr) and an aluminum-bronze alloy (19.3 hr). One bearing with a pure lead coating achieved the desired objective of 10 hr. This bearing had an aluminum - bronze substrate retainer and ran successfully for 12.4 hr. Additions of antimony to the lead provided an alloy coating with better wear resistance than pure lead; however, this coating was abrasive to the outer-race lands.

  13. Obtaining of platinum-titanium alloys by sol-gel and their performance for the detachment reactions and oxygen reduction; Obtencion de aleaciones de platino-titanio por sol-gel y su desempeno para las reacciones de desprendimiento y reduccion de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Regueira R, B. I.

    2011-07-01

    In the present work, platinum-titanium (Pt-Ti) alloys were prepared, characterized and evaluated in acid media as bifunctional electrocatalysts for the oxygen evolution reaction (Oer) and oxygen reduction reactions (Orr) in acid media. The alloys were synthesized by sol-gel method, heating the gel at temperatures of 400 and 600 C. The alloys characterization was realized by X-ray diffraction, scanning electron microscopy and EDS. Both alloys were formed by agglomerates of nanometer particles. The particle sizes were lower for the alloy obtained at 400 C (120 nm to 257 nm) compared to the alloy prepared at 600 C (555 nm to 833 nm). Cyclic and linear voltammetry techniques were used for the electrochemical evaluation of the alloy obtained at both temperatures for the Oer and Orr, in a 0.5 M sulfuric acid solution. The materials have response for both electrochemical reactions, therefore the best performance was for the Pt-Ti alloy, obtained at 400 C and it was stable for the oxygen evolution reaction. The alloy obtained at 400 C presents satisfactory electrocatalytic characteristics to be used as bifunctional material in a unified regenerative fuel cell. (Author)

  14. The microstructures and electrochemical performances of La0.6Gd0.2Mg0.2Ni3.0Co0.5-xAlx (x=0-0.5) hydrogen storage alloys as negative electrodes for nickel/metal hydride secondary batteries

    Science.gov (United States)

    Li, Rongfeng; Xu, Peizhen; Zhao, Yamin; Wan, Jing; Liu, Xiaofang; Yu, Ronghai

    2014-12-01

    La0.6Gd0.2Mg0.2Ni3.0Co0.5-xAlx (x = 0-0.5) hydrogen storage alloys were prepared by induction melting followed by annealing treatment at 1173 K for 8 h. The effects of substitution Al for Co on the microstructures and electrochemical performances were studied systematically. The structure analyses show that all alloys consist of multiphase structures such as (La, Mg)2Ni7 phase, (La, Mg) Ni3 phase and LaNi5 phase. The abundance of (La, Mg)2Ni7 phase decreases while the abundance of LaNi5 phase and (La, Mg)Ni3 phase increases directly as the Al content increasing. The electrochemical tests show that the maximum discharge capacity of alloy electrodes are almost unchanged when x ≤ 0.2 while the cyclic stability of the alloy electrode are improved significantly after proper amount of Al substitution for Co. The alloy electrode with x = 0.1 exhibits the better balance between discharge capacity and cycling life than any others. Moreover, at the discharge current density of 900 mA g-1, the high rate dischargeability (HRD) of the alloy electrodes decreases with increasing Al substitution and the relative analyses reveal that the charge transfer on alloy surface is more important than the hydrogen diffusion in alloy bulk for the kinetic properties of the alloy electrodes.

  15. Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on A1,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.

  16. Glatiramer Acetate-associated Refractory Immune Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Iftach Sagy

    2016-04-01

    Full Text Available We present a case of glatiramer acetate-associated refractory immune thrombocytopenic purpura (ITP in a female patient with multiple sclerosis. A search of MEDLINE/PubMed did not find any connection between glatiramer acetate and thrombocytopenia, specifically ITP. The autoimmune reaction was resistant to conservative ITP treatment, and was eventually managed only by splenectomy. To the best of our knowledge, this is the first report of glatiramer acetate-associated ITP. Physicians should be aware of this condition, and consider performing routine blood counts at the beginning of glatiramer acetate treatment.

  17. Office Procedures in Refractory Chronic Rhinosinusitis.

    Science.gov (United States)

    Thamboo, Andrew; Patel, Zara M

    2017-02-01

    Office procedures in chronic rhinosinusitis (CRS) can be considered before and after medical management, as well as before and after surgical management. This article focuses specifically on refractory CRS, meaning those patients who have failed medical and surgical management already. The options available in the management of refractory CRS depend on the personnel, equipment, and instrumentation available in the office setting; surgeon experience; and patient suitability and tolerability. This article provides readers with possible procedural options that can be done in their clinics with indications, patient selection, potential complications, and postoperative considerations.

  18. Effects of Boron Bearing Additives on Oxidation and Corrosion Resistance of Doloma—based carbon bonded Refractories

    Institute of Scientific and Technical Information of China (English)

    YEFangbao; ZHONGXiangchong; 等

    1998-01-01

    Oxidation of the added graphite and the bonding carbon is an imortant degradation mode of doloma-carbon refractories in service,In this work,the behavior and effects of various boron bearing materials(CaB6,ZrB2,Bc and colemanite)as an-tioxidants have been investigated and compared to the effect of Al-Mg alloy,For CaO-MgO-C mate-rials,the effect of boron bearingadditives is better than Al-Mg alloy,The borate melt formed at high temperature would retard or prevent carbon oxidation,thus contributing to improved oxidation resistance,Preliminary investigations on the effect of boron bearing additives and Al-Mg alloy on corrosion resistance of doloma-carbon materials have indicated that simultaneous addition of the two types of additives would lead to pronounced improvement of slag corrosion resistance.

  19. High-temperature deformation of L12-FCC two-phase Ir-15Nb-Ni refractory superalloys

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The creep behaviors of the Ni-added Ir 85Nb15 alloys were investigated at 1 650~1 800 ℃ by compressi on tests in vacuum. X-ray diffractometry, transmission electron microscopy and scanning electron microscopy were conducted to characterize the microstructure and lattice misfit change by the addition of Ni in the Ir85Nb15 alloy. The results reveal that the Ni addition has a significant effect on the creep resistance of the Ir85Nb15 two-phase refractory superal loys. Basing on the results, the relationship among the Ni addition, lattice mis fit, microstructure development, and the creep behavior in the Ni-added Ir8 5Nb15 alloys is discussed.

  20. Electrodeposition of Tantalum and Tantalum-Chromium Alloys

    Science.gov (United States)

    1980-05-01

    authors wish to acknowledge Mrs. Theresa Brassard and Mr. Joe Barranco for preparing micrographs of the specimens and microhardness measure- ments, and...Ahmad, P. Greco, G. D’Andrea, J. Barranco , "Potential Erosion Resistant Refractory Metal (And/Or) Alloy Coatings for Gun Tubes," Proceedings 1978...U.S. Patent 344058 (1969), Canadian Patent 688546 (1963). 17 REFERENCES 1. I. Ahmad, P. Greco, G. D’Andrea, and J. Barranco , "Potential Erosion

  1. The Exomet Project: EU/ESA Research on High-Performance Light-Metal Alloys and Nanocomposites

    Science.gov (United States)

    Sillekens, W. H.

    The performance of structural materials is commonly associated with such design parameters as strength and stiffness relative to their density; a recognized means to further enhance the weight-saving potential of low-density materials is thus to improve on their mechanical attributes. The European Community research project ExoMet that started in mid-2012 targets such high-performance aluminum- and magnesium-based materials by exploring novel grain-refining and nanoparticle additions in conjunction with melt treatment by means of external fields (electromagnetic, ultrasonic, mechanical). These external fields are to provide for an effective and efficient dispersion of the additions in the melt and their uniform distribution in the as-cast material. The consortium of 27 companies, universities and research organizations from eleven countries integrates various scientific and technological disciplines as well as application areas — including automotive and (aero)-space.

  2. Refractory disease in antineutrophil cytoplasmic antibodies associated vasculitis

    NARCIS (Netherlands)

    Rutgers, Abraham; Kallenberg, Cornelis

    2012-01-01

    Purpose of review Induction treatment of antineutrophil cytoplasmic antibodies (ANCA) associated vasculitis (AAV) is not always successful and nonresponding patients are considered refractory. Recent findings Refractory disease should be subdefined to the treatment that was received. Cyclophosphamid

  3. Surgical treatment for medically refractory myasthenic blepharoptosis

    Directory of Open Access Journals (Sweden)

    Shimizu Y

    2014-09-01

    Full Text Available Yusuke Shimizu,1 Shigeaki Suzuki,2 Tomohisa Nagasao,1 Hisao Ogata,1 Masaki Yazawa,1 Norihiro Suzuki,2 Kazuo Kishi1 1Department of Plastic and Reconstructive Surgery, 2Department of Neurology, Keio University School of Medicine, Tokyo, JapanPurpose: Currently, only a few reports have recommended surgery as a suitable treatment for blepharoptosis associated with myasthenia gravis. The present study aims to introduce our surgical criteria, surgical options, outcomes, and precautions for medically refractory myasthenic blepharoptosis. Patients and methods: Eight patients who failed to respond to at least 2 years of medical treatment and who underwent blepharoptosis surgery, from January 2008 to December 2011, were enrolled in this study. Medical records, photographs, and questionnaire results regarding postoperative status were evaluated. Of the eleven procedures performed, four involved frontal suspension, four involved external levator advancement, one involved nonincisional transconjunctival levator advancement, and two involved subbrow blepharoplasty with orbicularis oculi muscle tucking. The margin reflex distance improved postoperatively in seven patients. Results: Seven patients had very minimal scarring, and one had minimal scarring. Five patients showed no eyelid asymmetry, one had subtle asymmetry, and two had obvious asymmetry. Seven patients were very satisfied, and one patient was satisfied with the overall result. Postoperative complications included mild lid lag with incomplete eyelid closure, prolonged scar redness, and worsened heterophoria. No patient experienced postoperative exposure keratitis or recurrent blepharoptosis during the study period. Conclusion: Our results indicate that blepharoptosis surgery is effective for patients with myasthenia gravis, especially those with residual blepharoptosis despite multiple sessions of medical treatments. We recommend that neurologists and surgeons collaborate more systematically and

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

    Science.gov (United States)

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

    2009-01-01

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

  5. Recent advances in silica-alumina refractory: A review

    Directory of Open Access Journals (Sweden)

    Chaouki Sadik

    2014-06-01

    Full Text Available In this article, the elaboration and the characterization of silica-alumina refractory have been reviewed. Refractory oxides encompass a broad range of unary, binary, and ternary ceramic compounds that can be used in structural, insulating, and other applications. This paper provides a historical perspective on the elaboration and the use of silica-alumina refractory, reviews applications for refractory oxides, describes typical processing routes, overviews fundamental structure–property relations, and summarizes the properties of these materials.

  6. In Situ Observation of MgO Inclusions in Liquid Iron-Aluminum Alloys

    Science.gov (United States)

    Mu, Haoyuan; Zhang, Tongsheng; Yang, Liang; Xavier, Rodrigo R.; Fruehan, Richard J.; Webler, Bryan A.

    2016-08-01

    This study showed that MgO inclusions can be stable in liquid iron with elevated Al and it illustrated an important role of vaporization in the evolution of inclusions. Previous studies have shown that dissolved Al reduces MgO from slags and refractories, leading to spinel (MgAl2O4) inclusions. The elevated Al content of newer steels raises the possibility that MgO inclusions can be stable. In this work, MgO inclusions were produced and observed in an Fe-Al alloy. The inclusions in the liquid alloy at 1873 K (1600 °C) were observed in situ with a Confocal Laser Scanning Microscope (CLSM). Two types of experiments were performed: one where only a metal sample was melted and the other where the sample was in contact with a liquid, MgO-saturated slag. When no slag was present, the MgO inclusions shrank and disappeared at 1873 K (1600 °C). No inclusions were observed in situ during cooling or in post-CLSM analysis. When the MgO-saturated slag was present, the inclusion sizes were essentially constant and MgO was observed on the surface of post-CLSM samples. Analysis of the results showed that MgO can be stable in 1873 K (1600 °C), but that its presence depends on the rate of removal of Mg due to vaporization and the supply of Mg due to slag/metal or refractory/metal reactions.

  7. RESEARCH ON BENDING FATIGUE PERFORMANCE OF TWO KINDS OF ORGANIZATION TC11 TITANIUM ALLOY THIN STEEL PLATE%两种组织钛合金薄板弯曲疲劳性能的研究

    Institute of Scientific and Technical Information of China (English)

    杜勤; 张渠; 信明宇

    2011-01-01

    以具有(α+β)等轴组织和α/β粗片层组织的TC11钛合金为研究对象,研究了TC11合金薄板样品在恒总应变幅控制下的弯曲疲劳性能及其损伤行为,通过对疲劳开裂路径和断裂的观察与表征,探讨了疲劳损伤与组织结构间的关系.研究发现,恒总应变幅控制下的等轴组织TC11钛合金薄板的弯曲疲劳性能明显高于粗片层组织合金;等轴组织合金的疲劳裂纹沿α相中的滑移带萌生并扩展,片层组织样品疲劳裂纹沿着α相或与片层垂直的方向扩展.%A (α+β) equiaxed organizations and α/β coarse lamellar TC1 1 titanium alloy were selected for researching the bending fatigue and the damage behaviorthe of the TC11 alloy sheet sample at a constant total strain amplitude - control. Relationship between fatigue damage and the structure and organization was studied. It was found that under constant total strain amplitude control bending fatigue performance of equiaxed organization TC11 titanium alloy sheet was significantly higher than that of the coarse lamellar alloy. Fatigue crack of equiaxed alloys organization initiated and expanded along the α phase and the fatigue crack of lamellar samples expanded along the lamellarα phase or vertical direction.

  8. The Application Status and Perspective of Alloys for High Performance and Advanced Naval Vessels%高性能先进舰船用合金材料的应用现状及展望

    Institute of Scientific and Technical Information of China (English)

    王文杰

    2013-01-01

    船体结构、冷却器、管路和螺旋桨是战舰、潜艇的重要组成部分.综述了合金材料在国内外高性能知名舰船关键部位中的使用情况,指出美国依托高纯净冶金和控冷控轧技术的HSLA微合金高强钢代表了当前舰艇壳体和甲板用钢的最高水平,多数国家的舰船结构用钢仍然以HY-80和HY-100钢为主.此外,俄罗斯的舰船用钛和德国的高强低磁钢的应用水平居国际领先,而美国和俄罗斯在铝合金舰船结构的应用技术上较其他国家更为先进.当前用量最大的舰船冷凝管用合金是铁白铜,而钛不仅更加适于建造舰艇冷凝器,还是制造管路和螺旋桨的优秀材料.轻质、高强和低成本是当今各类舰船选材的重要依据.%The hull structure,cooler, piping and propeller are the important parts of a naval vessel. The applica tion status of alloys for high performance and advanced naval vessels are introduced. It is showed that HSLA microal-loyed high strength steel developed by USA through the method of high purity metallurgy and TMCP technology re presents the highest level of steel designed for ship hull and deck. Most countries still use HY-80 and HY-100 high yield steel to build their ship. Applied technologies of naval vessel, such as titanium alloy and high strengh low mag netic steel of Russia and Germany,respectively, have reached international advanced standards,while the United States and Russia are advanced in the application of ship structure of the aluminum alloy. The copper-nickels containing iron are most used in condense pipe of vessels. Compared with other alloys, titanium alloy is the best alloy used for not only ship condensator, but also piping and propeller. Today, light weight, high strengh and low cost are important basis when selecting alloys for vessel design.

  9. Adhesive performance of silver-palladium-copper-gold alloy and component metals bonded with organic sulfur-based priming agents and a tri-n-butylborane initiated luting material.

    Science.gov (United States)

    Yamashita, Miyuki; Koizumi, Hiroyasu; Ishii, Takaya; Nakayama, Daisuke; Oba, Yusuke; Matsumura, Hideo

    2013-01-01

    The purpose of the current study was to evaluate the effect of thione-based metal priming agents on the adhesive behavior of a Ag-Pd-Cu-Au alloy and component metals bonded with an acrylic resin. Disk specimens (10 mm in diameter by 3 mm thick) were prepared from a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell M.C.12), high-purity silver, palladium, copper and gold. Four single-liquid priming agents containing organic sulfur compound (Alloy Primer, Metaltite, M.L. Primer and V-Primer) and three acidic priming agents (All Bond II Primer B, Estenia Opaque Primer and Super-Bond Liquid) were assessed. The metal specimens were flat-ground with abrasive papers, primed with one of the agents and bonded with a tri-n-butylborane initiated resin. The shear bond strengths were determined both before and after repeated thermocycling (5°C and 55°C, 1 min each, 20,000 cycles). The results were statistically analyzed with a non-parametric procedure (p = 0.05 level). The post-thermocycling bond strengths in MPa (median; n = 11) associated with the Alloy Primer, Metaltite, M.L. Primer and V-Primer materials were, respectively, 20.8, 22.8, 17.8 and 18.4 for the Ag-Pd-Cu-Au alloy; 19.6, 21.9, 14.4 and 20.1 for silver; 5.4, 4.5, 12.8 and 5.3 for palladium; 17.1, 19.2, 0.7 and 6.6 for copper; and 18.5, 17.7, 22.8 and 15.4 for gold. It can be concluded that the use of the four priming agents, which are based on organic sulfur compounds, effectively enhanced bonding to the Ag-Pd-Cu-Au alloy and the component metals, although the bonding performance varied among the priming agents and metal elements. The priming agents appeared to have more of an effect on the alloy, silver and gold than on the palladium and copper.

  10. Tungsten and other refractory metals for VLSI applications II

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, E.K.

    1987-01-01

    This book presents papers on tungsten and other refractory metals for VLSI applications. Topics include the following: Selectivity loss and nucleation on insulators, fundamental reaction and growth studies, chemical vapor deposition of tungsten, chemical vapor deposition of molybdenum, reactive ion etching of refractory metal films; and properties of refractory metals deposited by sputtering.

  11. An Overview on China's Refractories-Market and New Demands

    Institute of Scientific and Technical Information of China (English)

    LIU Jiehua; ZHOU Ningsheng

    2004-01-01

    Based on the authors' information sources and personal viewpoints, this paper provides updated information on China s refractories situation in terms of output, consumption in main refractory using sectors, exportation and importation of refractory products and raw materials,structural change, future prosperity and new demands .From authors understanding, some analyses have also been given.

  12. Export and Import Situation of Refractories in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    China has been the biggest country in production and exporting of refractories. The article describes the problems in the export and import and suggestions on development of refractories. In the future, China will expand its cooperation with world refractories community in science, technology, economy and trade to play a more important role in the international and domestic markets.

  13. Management of refractory ischemic priapism: current perspectives.

    Science.gov (United States)

    Capece, Marco; Gillo, Arianna; Cocci, Andrea; Garaffa, Giulio; Timpano, Massimiliano; Falcone, Marco

    2017-01-01

    The aim of the present manuscript is to review the current literature on priapism, focusing on the state-of-the-art knowledge of both the diagnosis and the treatment of the refractory ischemic priapism (IP). Pubmed and EMBASE search engines were used to search for words "priapism", "refractory priapism", "penile prosthesis", "diagnosis priapism", "priapism treatment", "penile fibrosis", "priapism therapy". All the studies were carefully examined by the authors and then included in the review. First-line treatment involves ejaculation, physical exercise and cold shower followed by corporal blood aspiration and injection of α-adrenoceptor agonists. Subsequently, a distal or proximal shunt may be considered. If none of the treatment is effective or the priapism episode lasts >48 hours penile prosthesis implantation could be the only option to solve the priapism and treat the ongoing erectile dysfunction. The management of IP is to achieve detumescence of persistent penile erection and to preserve erectile function after resolution of the priapic episode. On the other hand, penile fibrosis and following shortening should be prevented. Early penile prosthesis implantation in patients with refractory IP is able to solve both the priapic episode and prevent the otherwise certain penile shortening. Penile prosthesis implantation is the actual gold standard of care in cases of refractory IP.

  14. Synthetic Raw Materials for Refractories in China

    Institute of Scientific and Technical Information of China (English)

    SHIGan; YUEWeidong

    2001-01-01

    The development and status of synthetic raw materials for refractories in China are reviewed,including magne-site-based materials,alumina ,ullite,calcium alumi-nate cement ,ultrafine powder,spinel,silicon carbide and cordierite.The research work on calcium zirconate and sialon materials are also introduced.

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

    Institute of Scientific and Technical Information of China (English)

    王家淳; 于荣海; 刘庆

    2004-01-01

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

  16. Thermodynamic and Experimental Investigations of High-Temperature Refractory Corrosion by Molten Slags

    Science.gov (United States)

    Wagner, Christoph; Wenzl, Christine; Gregurek, Dean; Kreuzer, Daniel; Luidold, Stefan; Schnideritsch, Holger

    2017-02-01

    Corrosion mechanisms between MgO refractory substrates and FeNi slags were investigated. The FeNi slags taken into consideration represent a simple synthetically mixed slag with specific oxides and a real slag from a ferroalloy producer. The MgO refractory substrates with the specimens of FeNi slag were heated in a hot-stage microscope at 10 K/min from room temperature to three different temperatures 1573 K, 1723 K, and 1923 K (1300 °C, 1450 °C, and 1650 °C). The experiments were carried out under a controlled gas atmosphere that simulates the relevant process conditions. The corrosion mechanisms of each system were followed by scanning electron microscope analyses. The results obtained showed that slag corrosion dominates, with a pronounced partial dissolution of refractory fines forming Mg-silicates of type forsterite. It was also observed that iron oxide present in the slag diffused into the coarse refractory grains forming magnesiowustite. Finally, the results obtained were compared with those predicted by FACTSAGE software to understand the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.

  17. Thermodynamic and Experimental Investigations of High-Temperature Refractory Corrosion by Molten Slags

    Science.gov (United States)

    Wagner, Christoph; Wenzl, Christine; Gregurek, Dean; Kreuzer, Daniel; Luidold, Stefan; Schnideritsch, Holger

    2016-12-01

    Corrosion mechanisms between MgO refractory substrates and FeNi slags were investigated. The FeNi slags taken into consideration represent a simple synthetically mixed slag with specific oxides and a real slag from a ferroalloy producer. The MgO refractory substrates with the specimens of FeNi slag were heated in a hot-stage microscope at 10 K/min from room temperature to three different temperatures 1573 K, 1723 K, and 1923 K (1300 °C, 1450 °C, and 1650 °C). The experiments were carried out under a controlled gas atmosphere that simulates the relevant process conditions. The corrosion mechanisms of each system were followed by scanning electron microscope analyses. The results obtained showed that slag corrosion dominates, with a pronounced partial dissolution of refractory fines forming Mg-silicates of type forsterite. It was also observed that iron oxide present in the slag diffused into the coarse refractory grains forming magnesiowustite. Finally, the results obtained were compared with those predicted by FACTSAGE software to understand the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.

  18. Monitoring of Refractory Wall recession using high temperature impact echo instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    University of Dayton

    2004-04-30

    Regression of refractory linings of furnaces occurs due to a variety of mechanisms. The specific mechanism selected for investigation during this program is the regression of refractories which are in direct contact with a liquid corrodant. Examples include the melting of glass, the production of pig iron and steel, and the melting of aluminum. The rates of regression to a wall thickness which requires reline or extensive reconstruction vary widely, from less than a year to over ten years depending on the specific service environment. This program investigated the feasibility of measuring refractory wall thickness with an impact-echo method while at operating temperature (wall temperatures exceeding 500 C). The impact-echo method uses the impact of a small sphere with the surface of the test object to send a stress wave into the object. In a plate-like structure, the stress wave reflects back to the front surface, reverberating in the structure and causing a periodic surface displacement whose frequency is inversely proportional to the thickness of the test object. Impact-echo testing was chosen because it requires access to only one side of the test object and could be performed during the operation of a refractory structure. Commercially-available impact-echo instrumentation is available for room temperature use for a variety of tests on concrete. The enabling technology for this work was to use a high-temperature piezoelectric material, aluminum nitride, as the receiving sensor for the stress waves, allowing its use on refractories during furnace operation.

  19. Melting processes and performance improvement of kilogram-grade V-based BCC hydrogen storage alloy%钒基贮氢合金的公斤级熔炼工艺与性能改善

    Institute of Scientific and Technical Information of China (English)

    胡凡; 陈云贵; 吴朝玲; 周晶晶

    2011-01-01

    In this paper, the effect of melting processes (vacuum induction and non-consumable vacuum arc melting) on the microstructure and hydrogen storage performance of kilogram-grade V-60% (TiCrFeMn) hydrogen storage alloys were investigated. The results show that the performance of alloy melted by medium frequency induction deteriorates because its oxygen content is too high, which results from the reaction of the liquid alloy and the crucible during melting process. The alloy made by non-consumable vacuum arc melting has a much better performance,where the initial hydrogen absorption and desorption capacity is 3.69 % and 2.25wt% respectively, and the hydrogen desorption plateau pressure is O. 45MPa.%研究了V-60%(TiCrFeMn)贮氢合金的公斤级熔炼工艺和热处理工艺,采用真空中频感应和非自耗真空电弧熔炼两种不同的熔炼方法制备公斤级钒基贮氢合金,采用高温退火方法改善合金的性能.结果表明,采用真空中频感应熔炼的合金由于熔炼过程中合金液与坩埚反应,致使合金含氧量过高,合金性能恶化,而采用非自耗真空电弧熔炼的合金表现出优良的吸放氢性能,初始吸氢量为3.69%(质量分数),放氢量达到了2.25%(质量分数),平台压为0.45MPa.

  20. Improvement in Fatigue Performance of Aluminium Alloy Welded Joints by Laser Shock Peening in a Dynamic Strain Aging Temperature Regime

    Directory of Open Access Journals (Sweden)

    Chun Su

    2016-09-01

    Full Text Available As a new treatment process after welding, the process parameters of laser shock peening (LSP in dynamic strain aging (DSA temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the sin2ϕ method and Abaqus software. The fatigue life of the welded joints was estimated by performing tensile fatigue tests. The microstructural evolution in surface and fatigue fractures of the welded joints was presented by means of surface integrity and fracture surface testing. In the DSA temperature regime of AA6061-T6 welded joints, the residual compressive stress was distributed more stably than that of LSP at room temperature. The thermal corrosion resistance and fatigue properties of the welded joints were also improved. The experimental results and numerical analysis were in mutual agreement.