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Sample records for a-si alloy production

  1. Large-area triple-junction a-Si alloy production scaleup. Annual subcontract report, 17 March 1993--18 March 1994

    SciTech Connect

    Oswald, R.; Morris, J.

    1994-11-01

    The objective of this subcontract over its three-year duration is to advance Solarex`s photovoltaic manufacturing technologies, reduce its a-Si:H module production costs, increase module performance and expand the Solarex commercial production capacity. Solarex shall meet these objectives by improving the deposition and quality of the transparent front contact, by optimizing the laser patterning process, scaling-up the semiconductor deposition process, improving the back contact deposition, scaling-up and improving the encapsulation and testing of its a-Si:H modules. In the Phase 2 portion of this subcontract, Solarex focused on improving deposition of the front contact, investigating alternate feed stocks for the front contact, maximizing throughput and area utilization for all laser scribes, optimizing a-Si:H deposition equipment to achieve uniform deposition over large-areas, optimizing the triple-junction module fabrication process, evaluating the materials to deposit the rear contact, and optimizing the combination of isolation scribe and encapsulant to pass the wet high potential test. Progress is reported on the following: Front contact development; Laser scribe process development; Amorphous silicon based semiconductor deposition; Rear contact deposition process; Frit/bus/wire/frame; Materials handling; and Environmental test, yield and performance analysis.

  2. Large-area, triple-junction a-Si alloy production scale-up. Semiannual subcontract report, 17 March 1993--18 September 1993

    SciTech Connect

    Oswald, R.; O`Dowd, J.; Ashenfelter, W.

    1994-03-01

    This report describes work to improve the efficiency of large-area, multi-junction amorphous silicon (a-Si) alloy modules. Equipment capable of producing modules up to 0.74 m{sup 2} in area is on line and process development has begun. Preliminary cost analysis/reduction has begun to ensure that these development efforts will result in a commercialization of the large-area technology. The approach was to transfer the high-efficiency multi-junction technology from R&D into the manufacturing environment by using three different substrate sizes. Initial attempts to transfer the multijunction silicon process were made using a 0.1-m{sup 2} substrate (approximately 1 ft{sup 2}). These efforts resulted in a module with a measured aperture area efficiency of 10.32%. Simultaneous with the transfer of the silicon technology, the most complicated aspect of the technology transfer, Solarex began process development techniques on large-area modules by using the 0.37-m{sup 2} substrates. These efforts resulted in modules with a total area efficiency of 7%. Finally, initial runs on substrates 0.74 m{sup 2} were made to debug the large-area equipment in preparation of transferring the knowledge gained in the processing of the smaller substrates.

  3. Structural and electronic studies of a-SiGe:H alloys

    SciTech Connect

    Paul, W. )

    1993-04-01

    This report describes work to produce alloys of a-Si[sub 1-x]Ge[sub x]:H of improved photoelectronic quality by plasma-enhanced chemical vapor deposition (PECVD). The goal was to discover optimum preparation conditions for the end-component, a-Ge:H, to establish whether modification of the usual practice of starting from a-Si:H preparation conditions was advisable. Such modification, found to be necessary, gave films of a-Ge:H with efficiency-mobility-lifetime products ([eta][mu][tau]) 10[sup 2] to 10[sup 3] higher than were earlier available, in homogeneous environmentally stable material. Both a-Ge:H and a-Si[sub 1-x]Ge[sub x]:H of large x were studied in detail. Alloy material was shown to have [eta][mu][tau] 10[sup 2] larger than found earlier. However, just as the [eta][mu][tau] of a-Si:H decreases when Ge is added, so also the [eta][mu][tau] of these alloys with Si addition. By contrast, the ambipolar diffusion lengths, L[sub o] which are governed by the hole mobility, vary by only a factor of two over the whole alloy series. Using the experimental finding of a small valence band offset between a-Si:H and a-Ge:H compositional fluctuations on a 10-mm scale are suggested to explain the behavior of [eta][mu][tau] and L[sub o] The implications for eventual improvement of the alloys are profound, but require direct experimental tests of the postulated compositional fluctuations.

  4. Development of high stable-efficiency, triple-junction a-Si alloy solar cells. Annual subcontract report, July 18, 1994--July 17, 1995

    SciTech Connect

    Deng, X.

    1996-02-01

    This report describes work performed by Energy Conversion Devices, Inc. (ECD) under a 3-year, cost-shared amorphous silicon (a-Si) research program to develop advanced technologies and to demonstrate stable 14%-efficient, triple-junction a-Si alloy solar cells. The technologies developed under the program will then be incorporated into ECD`s continuous roll-to-roll deposition process to further enhance ECD`s photovoltaic manufacturing technology. In ECD`s solar cell design, triple-junction a-Si alloy solar cells are deposited onto stainless-steel substrates coated with Ag/ZnO back-reflector layers. This type of cell design enabled ECD to use a continuous roll- to-roll deposition process to manufacture a-Si PV materials in high volume at low cost. Using this cell design, ECD previously achieved 13.7% initial solar cell efficiency using the following features: (1) a triple-junction, two-band-gap, spectrum-splitting solar cell design; (2) a microcrystalline silicon p-layer; (3) a band-gap-profiled a- SiGe alloy as the bottom cell i-layer; (4) a high-performance AgZnO back-reflector; and (5) a high-performance tunnel junction between component cells. ECD also applied the technology into its 2-MW/yr a- Si production line and achieved the manufacturing of 4-ft{sup 2} PV modules with 8% stable efficiency. During this program, ECD is also further advancing its existing PV technology toward the goal of 14% stable solar cells by performing the following four tasks: (1) improving the stability of the intrinsic a-Si alloy materials; (2) improving the quality of low-band-gap a-SiGe alloy; (3) improving p{sup +} window layers, and (4) developing high stable-efficiency triple-junction a-Si alloy solar cells.

  5. Comprehensive research on the stability and electronic properties of a-Si:H and a-SiGe:H alloys and devices. Final subcontract report, 10 March 1991--30 August 1994

    SciTech Connect

    Dalal, V.

    1995-04-01

    This report describes work on the growth of a-Si:H and a-(Si,Ge):H materials and devices using well-controlled growth techniques. The a-Si:H materials were grown at higher temperatures (300{degrees}-375{degrees}C) using electron-cyclotron-resonance (ECR) plasma techniques with a remote H beam. These films have excellent electronic quality and show significant improvements in stability compared with glow-discharge-produced a-Si:H materials. Several problems were encountered during the fabrication of devices in these materials, and we were able to overcome them by a systematic work on buffer layers in these cells. We also studied alternative designs for improving the stability of a-Si:H cells and produced graded-gap a-Si:H cells using glow-discharge that are more stable than comparable standard, ungraded glow discharge devices. Finally, systematic work was done to produce good-quality a-(Si,Ge):H films, using triode radio frequency (RF) glow-discharge with ion bombardment during growth. Diagnostic devices were made using these films, and the properties of the material, such as Urbach energies and hole mobility-lifetime products, were measured in these devices. We found a systematic increase in the Urbach energies, and a corresponding decrease in the hole and electron {mu}{tau} products, as the Ge content of the alloys increases.

  6. Light induced effects in a-Si:H films alloyed with sulfur

    SciTech Connect

    Yoon, J.H.; Taylor, P.C.; Yan, B.; Lee, C.H.

    1997-07-01

    Light-induced effects are studied in hydrogenated amorphous silicon-sulfur alloys (a-SiS{sub x}:H) and compared to those that exist in a-Si:H. The A-SiS{sub x}:H films were grown by decomposition of pre-mixtures of SiH{sub 4} and H{sub 2}S. The light-induced effects were monitored using electrical (dark conductivity and photoconductivity, including the constant photocurrent method [CPM]) and optical (photoluminescence) measurements and electron spin resonance. It is found that sulfur alloying results in a significant reduction in the degradation in the dark- and photo-conductivity. For an a-SiS{sub x}:H film grown with a gas mixture of H{sub 2}S/SiH{sub 4} = 0.02, there is an increase of over an order of magnitude in the dark conductivity and a small decrease in the photoconductivity after 50 hours of light soaking. The subgap deep defect density as measured by CPM increases with illumination time, following a stretched exponential to saturation. The saturated defect density is an order of magnitude higher than that observed in the annealed state.

  7. Development of high, stable-efficiency triple-junction a-Si alloy solar cells. Final technical report

    SciTech Connect

    Deng, X.; Jones, S.J.; Liu, T.; Izu, M.

    1998-04-01

    This report summarizes Energy Conversion Devices, Inc.`s (ECD) research under this program. ECD researchers explored the deposition of a-Si at high rates using very-high-frequency plasma MHz, and compared these VHF i-layers with radio-frequency (RF) plasma-deposited i-layers. ECD conducted comprehensive research to develop a {mu}c-Si p{sup +} layer using VHF deposition process with the objectives of establishing a wider process window for the deposition of high-quality p{sup +} materials and further enhancing their performance of a-Si solar cells by improving its p-layers. ECD optimized the deposition of the intrinsic a-Si layer and the boron-doped {mu}c-Si p{sup +} layer to improve the V{sub oc}. Researchers deposited wide-bandgap a-Si films using high hydrogen dilution; investigated the deposition of the ZnO layer (for use in back-reflector) using a sputter deposition process involving metal Zn targets; and obtained a baseline fabrication for single-junction a-Si n-i-p devices with 10.6% initial efficiency and a baseline fabrication for triple-junction a-Si devices with 11.2% initial efficiency. ECD researchers also optimized the deposition parameters for a-SiGe with high Ge content; designed a novel structure for the p-n tunnel junction (recombination layer) in a multiple-junction solar cell; and demonstrated, in n-i-p solar cells, the improved stability of a-Si:H:F materials when deposited using a new fluorine precursor. Researchers investigated the use of c-Si(n{sup +})/a-Si alloy/Pd Schottky barrier device as a tool for the effective evaluation of photovoltaic performance on a-Si alloy materials. Through alterations in the deposition conditions and system hardware, researchers improved their understanding for the deposition of uniform and high-quality a-Si and a-SiGe films over large areas. ECD researchers also performed extensive research to optimize the deposition process of the newly constructed 5-MW back-reflector deposition machine.

  8. Progress towards high performance low cost [ital a]-Si:H alloy multijunction modules

    SciTech Connect

    Catalano, A.; Bennett, M.; Newton, J.; Yang, L.; Li, Y.; Fieselmann, B.; Wiedeman, S.; D'Aiello, R.V. )

    1992-12-01

    Amorphous silicon alloy based triple junction solar cells and modules with initial efficiencies of approximately 11% have been developed. These devices are expected to exhibit less than a 20% loss before stabilizing. An improved transparent front contact and silicon carbide alloys promise to raise conversion efficiencies to 13%--14%.

  9. Chemical reactivity of nickel and nickel-based alloys with a SiAlON ceramic

    SciTech Connect

    Vleugels, J.; Van Der Biest, O.

    1995-11-01

    At the high cutting speeds typical for machining with ceramics and the concomitant high temperatures generated at the cutting edge and the rake face of the tool, chemical interaction between tool and workpiece material becomes the predominant mode of tool wear. To obtain more information concerning this chemical interaction mechanism, the chemical interaction of a {beta}{prime}-O{prime} SiAlON ceramic with pure nickel, Inconel 600, and Nimonic 105 is studied. The chemical reactivity was assessed by studying ceramic-alloy interaction couples after exposure at elevated temperatures (1,100--1,200 C) for times long enough to be able to characterize the interaction layer. At 1,200 C, the {beta}{prime}-O{prime} SiAlON ceramic dissociates in contact with pure nickel. Silicon from the dissociation of the ceramic dissolves and diffuses into the nickel, whereas Al and O form Al{sub 2}O{sub 3} particles. At the interface, a nitrogen pressure is built up. Inconel 600 is very reactive with the SiAlON ceramic, with the formation of molten silicides at 1,200 C. Cr{sub 3}Ni{sub 2}Si, Al{sub 2}O{sub 3}, and Ni{sub 31}Si{sub 12} are the major reaction products. The reactivity of Nimonic 105 is less than that of pure nickel because of the formation of a continuous protective TiN layer at the ceramic-metal interface.

  10. Research on the stability, electronic properties, and structure of a-Si:H and its alloys. Final subcontract report, 1 June 1991--31 May 1994

    SciTech Connect

    Jackson, W.B.; Johnson, N.; Nickel, N.; Schumm, G.; Street, R.A.; Thompson, R.; Tsai, C.C.; Van de Walle, C.; Walker, J.

    1995-07-01

    The authors research has focused on defect metastability and a-Si:C:H alloys. A new aspect of the metastability is the growing interest in the defect recovery process. They have continued to explore the role of hydrogen in the metastability and other properties of a-Si:H. This has led them to perform first principles calculations of Si-H bonding configurations. Another new feature of the metastability work is the study of the effects in hydrogenated poly-silicon. They have grown and studied the properties of a-Si:C:H alloys, particularly to observe the effects of hydrogen dilution. Finally they have also studied the recent defect relaxation phenomenon, and concluded that the effects arise from contact effects and are not an intrinsic effect in a-Si:H. Section A presents some recent models of metastability. Section B discusses the metastability and equilibration effects in hydrogenated polysilicon, studied because of it`s close similarity to a-Si:H. Section C describes results on a-Si:C:H alloys. Section D contains first principle LDA calculations of Si-H bonds and relates these results to the a-Si:H diffusion and metastability properties. In section E the authors report capacitance measurements aimed at exploring the recent results by Cohen et al who find an anomalous relaxation process from the trap filling kinetics of a DLTS experiment.

  11. Tritium Production from Palladium Alloys

    SciTech Connect

    Claytor, T.N.; Schwab, M.J.; Thoma, D.J.; Teter, D.F.; Tuggle, D.G.

    1998-04-19

    A number of palladium alloys have been loaded with deuterium or hydrogen under low energy bombardment in a system that allows the continuous measurement of tritium. Long run times (up to 200 h) result in an integration of the tritium and this, coupled with the high intrinsic sensitivity of the system ({approximately}0.1 nCi/l), enables the significance of the tritium measurement to be many sigma (>10). We will show the difference in tritium generation rates between batches of palladium alloys (Rh, Co, Cu, Cr, Ni, Be, B, Li, Hf, Hg and Fe) of various concentrations to illustrate that tritium generation rate is dependent on alloy type as well as within a specific alloy, dependent on concentration.

  12. Low-antimony—lead alloy strip production

    NASA Astrophysics Data System (ADS)

    Kolisnyk, P. S.; Vincze, A. M.

    Cominco is developing a new casting process for the continuous production of low-antimony—lead alloy strip that is expanded to make positive plates for hybrid-design, maintenance-free batteries. The stages of development from initial trials to pilot production plant are reviewed. The advantages of the process and the product are also discussed.

  13. In vitro evaluation of diamond-like carbon coatings with a Si/SiC x interlayer on surgical NiTi alloy

    NASA Astrophysics Data System (ADS)

    Liu, C. L.; Chu, Paul K.; Yang, D. Z.

    2007-04-01

    Diamond-like carbon (DLC) coatings were produced with a Si/SiCx interlayer by a hybrid plasma immersion ion implantation and deposition process to improve the adhesion between the carbon layer and surgical NiTi alloy substrate. The structure, mechanical properties, corrosion resistance and biocompatibility of the coatings were evaluated in vitro by Raman spectroscopy, pin-on-disk tests, potentiodynamic polarization tests and simulated fluid immersion tests. The DLC coatings with a Si/SiCx interlayer of a suitable thickness have better adhesion, lower friction coefficients and enhanced corrosion resistance. In the simulated body fluid tests, the coatings exhibit effective corrosion protection and good biocompatibility as indicated by PC12 cell cultures. DLC films fabricated on a Si/SiCx interlayer have high potential as protective coatings for biomedical NiTi materials.

  14. FIB-assisted a-SiGe:H/a-SiC:H alloy analysis for ultra-low biased multispectral pixn sensors with enhanced color separation features and low reflective ZnO:Al back-contacts

    NASA Astrophysics Data System (ADS)

    Bablich, Andreas; Watty, Krystian; Merfort, Christian; Böhm, Markus

    2012-06-01

    Common security CCD and CMOS imaging systems are not able to distinguish colorimetrically between dangerous chemical substances, for example whitish powders [1]. Hydrogenated amorphous silicon (a-Si:H) with profiled bandgaps can be found in solar cells to optimize the collection of incoming photons [2]. We developed multicolor photodiodes based on a-Si:H with different spectral response characteristics for a reliable, fast, cheap and non-destructive identification of potentially dangerous substances. Optical and I-V measurements were performed to explore the effect of combining linearly graded a-SiC:H-/a-SiGe:H layers with low reflective aluminum doped zinc oxide (ZnO:Al) cathodes. We determined absorption coefficients and mobility-lifetime products (μτ) of graded and non-graded absorbers to calculate the penetration depth of photons at different energies into the device structure. This set of parameters enables an optimization of the intrinsic layers so that charge accumulations are generated precisely at defined device depths. Significant color separation improvements could be achieved by using ZnO:Al cathodes instead of commonly used ZnO:Al/Chromium (Cr) reflectors. As a result, we obtained multicolor diodes with highly precise adjustment of the spectral sensitivity ranging from 420 nm to 580 nm, reduced interference fringes and a very low reverse bias voltage of -2.5 V maximum. Three terminal device architectures with similar absorbers exhibit a shift from 440 nm to 630 nm by applying reverse voltages of, for instance, -11.5 V at 580 nm [3]. Present research efforts concentrate on further improvements of the absorption region to reduce the bias without affecting the optical sensor performance, using extensive bandgap engineering techniques.

  15. Formation of Au-Pt alloy nanoparticles on a Si substrate by simple dip-coating at room temperature.

    PubMed

    Zhao, Liyan; Heinig, Nina; Leung, K T

    2013-01-22

    Spherical Au-Pt alloy nanoparticles of 10 nm average size have been prepared on a H-terminated Si(100) substrate by an extremely simple method of dip-coating. X-ray photoelectron spectroscopy and glancing-incidence X-ray diffraction confirm the formation of Au-Pt alloy. The Au(3+) ions are first reduced on the Si substrate upon dipping, and the freshly formed Au nuclei then work as a "catalyst" by promoting the reduction of PtCl(6)(2-) ions on the Au nuclei. The subsequent interdiffusion of Au and Pt atoms leads to the observed alloy formation. The present method provides an environment-friendly, low-cost route to preparing anode electrodes in fuel cells. PMID:23234580

  16. Powder and particulate production of metallic alloys

    NASA Technical Reports Server (NTRS)

    Grant, N. J.

    1982-01-01

    Developments of particulate metallurgy of alloyed materials where the final products is a fully dense body are discussed. Particulates are defined as powders, flakes, foils, silvers, ribbons and strip. Because rapid solidification is an important factor in particulate metallurgy, all of the particulates must have at least one dimension which is very fine, sometimes as fine as 10 to 50 microns, but move typically up to several hundred microns, provided that the dimension permits a minimum solidification rate of at least 100 K/s.

  17. Non-Heat Treatable Alloy Sheet Products

    SciTech Connect

    Hayden, H.W.; Barthold, G.W.; Das, S.K.

    1999-08-01

    ALCAR is an innovative approach for conducting multi-company, pre-competitive research and development programs. ALCAR has been formed to crate a partnership of aluminum producers, the American Society of Mechanical Engineers Center for Research and Technology Development (ASME/CRTD), the United States Department of Energy (USDOE), three USDOE National Laboratories, and a Technical Advisory Committee for conducting cooperative, pre-competitive research on the development of flower-cost, non-heat treated (NHT) aluminum alloys for automotive sheet applications with strength, formability and surface appearance similar to current heat treated (HT) aluminum alloys under consideration. The effort has been supported by the USDOE, Office of Transportation Technology (OTT) through a three-year program with 50/50 cost share at a total program cost of $3 million. The program has led to the development of new and modified 5000 series aluminum ally compositions. Pilot production-size ingots have bee n melted, cast, hot rolled and cold rolled. Stamping trials on samples of rolled product for demonstrating production of typical automotive components have been successful.

  18. Dependence of thermal residual stress on temperature in a SiC particle-reinforced 6061Al alloy

    NASA Astrophysics Data System (ADS)

    Li, H.; Wang, D. Z.; Li, J. B.; Wang, Z. G.; Chen, C. R.

    1998-07-01

    The thermal stresses (TS) in the matrix of a SiC p /6061Al composite during thermal cycling were measured by X-ray diffraction. Also, the TS during thermal cycling and residual stress distribution (RSD) at room temperature in the two phases of composite were calculated by finite element modeling (FEM). The measured and calculated results indicated that the closed stress-temperature loop was formed during thermal cycling. The stress state in the matrix changed from tension to compression during heating and from compression to tension during cooling. Plastic deformation took place in the matrix of the composite during thermal cycling. The general change trend of TS with temperature during thermal cycling was in agreement between the experiment and calculation.

  19. REGENERATION OF FISSION-PRODUCT-CONTAINING MAGNESIUM-THORIUM ALLOYS

    DOEpatents

    Chiotti, P.

    1964-02-01

    A process of regenerating a magnesium-thorium alloy contaminated with fission products, protactinium, and uranium is presented. A molten mixture of KCl--LiCl-MgCl/sub 2/ is added to the molten alloy whereby the alkali, alkaline parth, and rare earth fission products (including yttrium) and some of the thorium and uranium are chlorinated and

  20. Production and processing of Cu-Cr-Nb alloys

    NASA Technical Reports Server (NTRS)

    Ellis, David L.; Michal, Gary M.; Orth, Norman W.

    1990-01-01

    A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon to sheet by hot pressing and hot rolling.

  1. Measurement protocol dependent magnetocaloric properties in a Si-doped Mn-rich Mn-Ni-Sn-Si off-stoichiometric Heusler alloy

    NASA Astrophysics Data System (ADS)

    Ghosh, Arup; Sen, Pintu; Mandal, Kalyan

    2016-05-01

    This work reports the magnetocaloric properties in a Si-doped, Mn-rich Mn46Ni39.5Sn10Si4.5 alloy in the aspects of different measurement protocols across its martensitic and reverse transition. A good agreeable value of the magnetic entropy changes (ΔSM ˜ 20 J/kg K due to a ΔH = 50 kOe) along with large refrigerant capacity (RC ˜ 110 J/kg) has been obtained from the high field M-T measurements, which can be a very handy tool for magnetocaloric study. We have analyzed the field dependent magnetization data during heating and cooling near the structural transition for different field changes and fitted them universally using a Lorentz function. The isothermal measurement by ramping the temperature discontinuously during cooling is found to be one of the most convenient and energy efficient ways to minimize the field induced losses, which helps to achieve a very high RC in similar materials exhibiting first order phase transition. A significant amount of zero field cooled exchange bias field (˜720 Oe at 5 K) and magnetoresistance (˜-25% due to a ΔH = 80 kOe) has also been achieved from this sample.

  2. Self-consistent analysis of mobility-lifetime products and subgap absorption on different PECVD a-Si:H films

    SciTech Connect

    Jiao, L.; Semoushikina, S.; Lee, Y.; Wronski, C.R.

    1997-07-01

    The photoconductivity and subband gap absorption measurements over a wide range of generation rate(G) have been carried out on diluted and undiluted a-Si:H. It is found that in these high quality films there are significant differences in the functional dependence of mobility-lifetime ({micro}{tau}) products on G. In addition to the different values of subgap absorption ({alpha}) there are also distinct differences in the dependence of {alpha} on photon energy (E) as well as G. It is difficult to self consistently analyze the results on the undiluted film with the previously used three gaussian distribution, particularly at high generation rates. Self consistent analysis is obtained when the (+/0) transitions of negative charged defects and the (0/{minus}) transitions of positive charged defects are introduced respectively closer to the valence and conduction bands. This new gap state distribution is a better representation for the defect pool model and potential fluctuation model.

  3. Production feature of soft magnetic amorphous alloys

    NASA Astrophysics Data System (ADS)

    Tyagunov, A. G.; Baryshev, E. E.; Shmakova, K. Yu

    2016-06-01

    Methods for making nanocrystalline alloys have been discussed. Temperature dependences of the surface tension (σ), electric resistivity (ρ), magnetic susceptibility (χ) and kinematic viscosity (ν) have been obtained. Comparison of the properties of amorphous ribbons obtained by the pilot and serial technologies has been conducted. Science-based technology of multi-component alloy smelting makes it possible to prepare equilibrium smelt, the structure of which has a significant effect on the properties of the amorphous ribbon before spinning and kinetics of its crystallization has been offered.

  4. Comprehensive research on stability and performance of a-Si:H and alloys. Phase I team annual technical report, 31, May 1994--30, May 1995

    SciTech Connect

    Dalal, V

    1996-08-01

    This report covers the research done during the first phase of the subcontract. During this period, we have concentrated on two areas: improving the voltage and stability of a-Si:H devices made using ECR deposition, and improving the properties of a-(Si,Ge):H films also using ECR deposition.

  5. Efficiency and throughput advances in continuous roll-to-roll a-Si alloy PV manufacturing technology: Annual technical progress report: 22 June 1998--21 June 1999

    SciTech Connect

    Izu, M.

    1999-11-09

    This document reports on work performed by Energy Conversion Devices, Inc. (ECD) during Phase 1 of this subcontract. During this period, ECD researchers: (1) Completed design and construction of new, improved substrate heater; (2) Tested and verified improved performance of the new substrate heater in the pilot machine; (3) Verified improved performance of the new substrate heater in the production machine; (4) Designed and bench-tested a new infrared temperature sensor; (5) Installed a prototype new infrared temperature sensor in the production machine for evaluation; (6) Designed a new rolling thermocouple temperature sensor; (7) Designed and bench-tested a reflectometer for the backreflector deposition machine; (8) Designed and bench-tested in-line non-contacting cell diagnostic sensor and PV capacitive diagnostic system; (9) Installed the in-line cell diagnostic sensor in the 5-MW a-Si deposition machine for evaluation; (10) Demonstrated a new low-cost zinc metal process in the pilot back reflector machine; and (11) Fully tested a new cathode design for improved uniformity.

  6. The Pv product required for the frictional ignition of alloys

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Benz, Frank J.; Homa, John

    1989-01-01

    NASA-White Sands has developed a frictional heating tester capable of evaluating the ignition properties of alloys in oxygen under friction conditions which involve rubbing. Sixteen alloys have been thus evaluated, yielding determinations of the product of the contact pressure and surface speed required for ignition in oxygen at 6.9 MPa; those which contained large Ni fractions manifested the greatest resistance to rubbing-induced ignition. The effect of the coefficient of friction is noted to be a major influence on ignition, and the results obtained indicate the value of frictional heating tests for environments involving frictional heating.

  7. Identification of the Chemical Bonding Prompting Adhesion of a-C:H Thin Films on Ferrous Alloy Intermediated by a SiCx:H Buffer Layer.

    PubMed

    Cemin, F; Bim, L T; Leidens, L M; Morales, M; Baumvol, I J R; Alvarez, F; Figueroa, C A

    2015-07-29

    Amorphous carbon (a-C) and several related materials (DLCs) may have ultralow friction coefficients that can be used for saving-energy applications. However, poor chemical bonding of a-C/DLC films on metallic alloys is expected, due to the stability of carbon-carbon bonds. Silicon-based intermediate layers are employed to enhance the adherence of a-C:H films on ferrous alloys, although the role of such buffer layers is not yet fully understood in chemical terms. The chemical bonding of a-C:H thin films on ferrous alloy intermediated by a nanometric SiCx:H buffer layer was analyzed by X-ray photoelectron spectroscopy (XPS). The chemical profile was inspected by glow discharge optical emission spectroscopy (GDOES), and the chemical structure was evaluated by Raman and Fourier transform infrared spectroscopy techniques. The nature of adhesion is discussed by analyzing the chemical bonding at the interfaces of the a-C:H/SiCx:H/ferrous alloy sandwich structure. The adhesion phenomenon is ascribed to specifically chemical bonding character at the buffer layer. Whereas carbon-carbon (C-C) and carbon-silicon (C-Si) bonds are formed at the outermost interface, the innermost interface is constituted mainly by silicon-iron (Si-Fe) bonds. The oxygen presence degrades the adhesion up to totally delaminate the a-C:H thin films. The SiCx:H deposition temperature determines the type of chemical bonding and the amount of oxygen contained in the buffer layer. PMID:26135943

  8. The effects of a SiO2 coating on the corrosion parameters cpTi and Ti-6Al-7Nb alloy

    PubMed Central

    Basiaga, Marcin; Walke, Witold; Paszenda, Zbigniew; Karasiński, Paweł; Szewczenko, Janusz

    2014-01-01

    The aim of this paper was to evaluate the usefulness of the sol-gel method application, to modificate the surface of the Ti6Al7Nb alloy and the cpTi titanium (Grade 4) with SiO2 oxide, applied on the vascular implants to improve their hemocompatibility. Mechanical treatment was followed by film deposition on surface of the titanium samples. An appropriate selection of the process parameters was verified in the studies of corrosion, using potentiodynamic and impedance method. A test was conducted in the solution simulating blood vessels environment, in simulated body fluid at t = 37.0 ± 1 °C and pH = 7.0 ± 0.2. Results showed varied electrochemical properties of the SiO2 film, depending on its deposition parameters. Correlations between corrosion resistance and layer adhesion to the substrate were observed, depending on annealing temperature. PMID:25482412

  9. Investigation of the radiation resistance of triple-junction a-Si:H alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1993-01-01

    The effect of 1.00 MeV proton irradiation on hydrogenated amorphous silicon alloy triple-junction solar cells is reported for the first time. The cells were designed for radiation resistance studies and included 0.35 cm(sup 2) active areas on 1.0 by 2.0 cm(sup 2) glass superstrates. Three cells were irradiated through the bottom contact at each of six fluences between 5.10E12 and 1.46E15 cm(sup -2). The effect of the irradiations was determined with light current-voltage measurements. Proton irradiation degraded the cell power densities from 8.0 to 98 percent for the fluences investigated. Annealing irradiated cells at 200 C for two hours restored the power densities to better than 90 percent. The cells exhibited radiation resistances which are superior to cells reported in the literature for fluences less than 1E14 cm(sup -2).

  10. Process for continuous production of metallic uranium and uranium alloys

    DOEpatents

    Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

    1995-01-01

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  11. Process for continuous production of metallic uranium and uranium alloys

    DOEpatents

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  12. Dimensional control of quasisingle crystals of aluminum alloy in production

    SciTech Connect

    Radchenko, A.I.; Karuskevich, M.V.; Naim, V.R.

    1995-01-01

    The article deals with a method of controlling the dimensions of quasisingle crystal grains of an aluminum alloy used instead of single crystal specimens in static fatigue tests with the object of substantiating a discrete probabilistic model of the fatigue of metals and alloys. We obtained a mathematical model of dimensional control of quasisingle crystals of the aluminum alloy.

  13. Atomic scale modelling of hexagonal structured metallic fission product alloys

    PubMed Central

    Middleburgh, S. C.; King, D. M.; Lumpkin, G. R.

    2015-01-01

    Noble metal particles in the Mo-Pd-Rh-Ru-Tc system have been simulated on the atomic scale using density functional theory techniques for the first time. The composition and behaviour of the epsilon phases are consistent with high-entropy alloys (or multi-principal component alloys)—making the epsilon phase the only hexagonally close packed high-entropy alloy currently described. Configurational entropy effects were considered to predict the stability of the alloys with increasing temperatures. The variation of Mo content was modelled to understand the change in alloy structure and behaviour with fuel burnup (Mo molar content decreases in these alloys as burnup increases). The predicted structures compare extremely well with experimentally ascertained values. Vacancy formation energies and the behaviour of extrinsic defects (including iodine and xenon) in the epsilon phase were also investigated to further understand the impact that the metallic precipitates have on fuel performance. PMID:26064629

  14. Spiked Alloy Production for Accelerated Aging of Plutonium

    SciTech Connect

    Wilk, P A; McNeese, J A; Dodson, K E; Williams, W L; Krikorian, O H; Blau, M S; Schmitz, J E; Bajao, F G; Mew, D A; Matz, T E; Torres, R A; Holck, D M; Moody, K J; Kenneally, J M

    2009-07-10

    The accelerated aging effects on weapons grade plutonium alloys are being studied using {sup 238}Pu-enriched plutonium metal to increase the rate of formation of defect structures. Pyrochemical processing methods have been used to produce two {sup 238}Pu-spiked plutonium alloys with nominal compositions of 7.5 wt% {sup 238}Pu. Processes used in the preparation of the alloys include direct oxide reduction of PuO{sub 2} with calcium and electrorefining. Rolled disks were prepared from the spiked alloys for sampling. Test specimens were cut out of the disks for physical property measurements.

  15. Process for making a martensitic steel alloy fuel cladding product

    DOEpatents

    Johnson, Gerald D.; Lobsinger, Ralph J.; Hamilton, Margaret L.; Gelles, David S.

    1990-01-01

    This is a very narrowly defined martensitic steel alloy fuel cladding material for liquid metal cooled reactors, and a process for making such a martensitic steel alloy material. The alloy contains about 10.6 wt. % chromium, about 1.5 wt. % molybdenum, about 0.85 wt. % manganese, about 0.2 wt. % niobium, about 0.37 wt. % silicon, about 0.2 wt. % carbon, about 0.2 wt. % vanadium, 0.05 maximum wt. % nickel, about 0.015 wt. % nitrogen, about 0.015 wt. % sulfur, about 0.05 wt. % copper, about 0.007 wt. % boron, about 0.007 wt. % phosphorous, and with the remainder being essentially iron. The process utilizes preparing such an alloy and homogenizing said alloy at about 1000.degree. C. for 16 hours; annealing said homogenized alloy at 1150.degree. C. for 15 minutes; and tempering said annealed alloy at 700.degree. C. for 2 hours. The material exhibits good high temperature strength (especially long stress rupture life) at elevated temperature (500.degree.-760.degree. C.).

  16. Ni-Si Alloys for the S-I Reactor-Hydrogen Production Process Interface

    SciTech Connect

    Joseph W. Newkirk; Richard K. Brow

    2010-01-21

    The overall goal of this project was to develop Ni-Si alloys for use in vessels to contain hot, pressurized sulfuric acid. The application was to be in the decomposition loop of the thermochemical cycle for production of hydrogen.

  17. Sintered rare earth-iron Laves phase magnetostrictive alloy product and preparation thereof

    DOEpatents

    Malekzadeh, Manoochehr; Pickus, Milton R.

    1979-01-01

    A sintered rare earth-iron Laves phase magnetostrictive alloy product characterized by a grain oriented morphology. The grain oriented morphology is obtained by magnetically aligning powder particles of the magnetostrictive alloy prior to sintering. Specifically disclosed are grain oriented sintered compacts of Tb.sub.x Dy.sub.1-x Fe.sub.2 and their method of preparation. The present sintered products have enhanced magnetostrictive properties.

  18. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D

    SciTech Connect

    Johnson, W.R.; Smith, J.P.; Stambaugh, R.D.

    1996-04-01

    V-4Cr-4-Ti alloy has been recently selected for use in the manufacture of a portion of the DIII-D Radiative Divertor modification, as part of an overall DIII-D vanadium alloy deployment effort developed by General Atomics (GA) in conjunction with the Argonne and Oak Ridge National Laboratories (ANL or ORNL). The goal of this work is to produce a production-scale heat of the alloy and fabricate it into product forms for the manufacture of a portion of the Radiative Divertor (RD) for the DIII-D tokamak, to develop the fabrications technology for manufacture of the vanadium alloy radiative Divertor components, and to determine the effects of typical tokamak environments in the behavior of the vanadium alloy. The production of a {approx}1300-kg heat of V-4Cr-4Ti alloy is currently in progress at Teledyne Wah Chang of Albany, oregon (TWCA) to provide sufficient material for applicable product forms. Two unalloyed vanadium ingots for the alloy have already been produced by electron beam melting of raw processes vanadium. Chemical compositions of one ingot and a portion of the second were acceptable, and Charpy V-Notch (CVN) impact test performed on processed ingot samples indicated ductile behavior. Material from these ingots are currently being blended with chromium and titanium additions, and will be vacuum-arc remelted into a V-4Cr-4Ti alloy ingot and converted into product forms suitable for components of the DIII-D RD structure. Several joining methods selected for specific applications in fabrication of the RD components are being investigated, and preliminary trials have been successful in the joining of V-alloy to itself by both resistance and inertial welding processes and to Inconel 625 by inertial welding.

  19. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D

    SciTech Connect

    Johnson, W.R.; Smith, J.P.; Trester, P.W.

    1997-04-01

    V-4Cr-4Ti alloy has been selected for use in the manufacture of a portion of the DIII-D Radiative Divertor upgrade. The production of a 1200-kg ingot of V-4Cr-4Ti alloy, and processing into final sheet and rod product forms suitable for components of the DIII-D Radiative Divertor structure, has been completed at Wah Chang (formerly Teledyne Wah Chang) of Albany, Oregon (WCA). Joining of V-4Cr-4Ti alloy has been identified as the most critical fabrication issue for its use in the RD Program, and research into several joining methods for fabrication of the RD components, including resistance seam, friction, and electron beam welding, is continuing. Preliminary trials have been successful in the joining of V-alloy to itself by electron beam, resistance, and friction welding processes, and to Inconel 625 by friction welding. An effort to investigate the explosive bonding of V-4Cr-4Ti alloy to Inconel 625 has also been initiated, and results have been encouraging. In addition, preliminary tests have been completed to evaluate the susceptibility of V-4Cr-4Ti alloy to stress corrosion cracking in DIII-D cooling water, and the effects of exposure to DIII-D bakeout conditions on the tensile and fracture behavior of V-4Cr-4Ti alloy.

  20. [Using Raman spectrum analysis to research corrosive productions occurring in alloy of ancient bronze wares].

    PubMed

    Jia, La-jiang; Jin, Pu-jun

    2015-01-01

    The present paper analyzes the interior rust that occurred in bronze alloy sample from 24 pieces of Early Qin bronze wares. Firstly, samples were processed by grinding, polishing and ultrasonic cleaning-to make a mirror surface. Then, a confocal micro-Raman spectrometer was employed to carry out spectroscopic study on the inclusions in samples. The conclusion indicated that corrosive phases are PbCO3 , PbO and Cu2O, which are common rusting production on bronze alloy. The light-colored circular or massive irregular areas in metallographic structure of samples are proved as Cu2O, showing that bronze wares are not only easy to be covered with red Cu2O rusting layer, but also their alloy is easy to be eroded by atomic oxygen. In other words, the rust Cu2O takes place in both the interior and exterior parts of the bronze alloy. In addition, Raman spectrum analysis shows that the dark grey materials are lead corrosive products--PbCO3 and PbO, showing the corroding process of lead element as Pb -->PbO-->PbCO3. In the texture of cast state of bronze alloy, lead is usually distributed as independent particles between the different alloy phases. The lead particles in bronze alloy would have oxidation reaction and generate PbO when buried in the soil, and then have chemical reaction with CO3(2-) dissolved in the underground water to generate PbCO3, which is a rather stable lead corrosive production. A conclusion can be drawn that the external corrosive factors (water, dissolved oxygen and carbonate, etc) can enter the bronze ware interior through the passageway between different phases and make the alloy to corrode gradually. PMID:25993834

  1. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D

    SciTech Connect

    Johnson, W.R.; Smith, J.P.

    1997-08-01

    V-4Cr-4Ti alloy has been selected for use in the manufacture of a portion of the DIII-D Radiative Divertor upgrade. The production of a 1200-kg ingot of V-4Cr-4Ti alloy, and processing into final sheet and rod product forms suitable for components of the DIII-D Radiative Divertor Program (RDP), has been completed by Wah Chang (formerly Teledyne Wah Chang) of Albany, Oregon (WCA). CVN impact tests on sheet material indicate that the material has properties comparable to other previously-processed V-4Cr-4Ti and V-5Cr-5Ti alloys. Joining of V-4Cr-4Ti alloy has been identified as the most critical fabrication issue for its use in the RDP, and research into several joining methods for fabrication of the RDP components, including resistance seam, friction, and electron beam welding, and explosive bonding is being pursued. Preliminary trials have been successful in the joining of V-alloy to itself by resistance, friction, and electron beam welding processes, and to Inconel 625 by friction welding. In addition, an effort to investigate the explosive bonding of V-4Cr-4Ti alloy to Inconel 625, in both tube-to-bar and sheet-to-sheet configurations, has been initiated, and results have been encouraging.

  2. Development of alloy 718 tubular product for nuclear reactor internals

    SciTech Connect

    1981-01-01

    The Upper Internals Structure (UIS) of the Clinch River Breeder Reactor Plant (CRBRP) provides mixing and flow direction of the core outlet flow. Alloy 718 tubes are the major components used in the UIS to provide this flow direction. The UIS is located directly above the reactor core and is exposed to a severe environment. This environment consists of high temperature sodium, alternating temperatures induced by mixing high temperature core assembly outlet flow with cooler core assembly outlet flow and rapid changes in temperature of the core outlet flow. The paper presents the UIS configuration, functions and environmental conditions that led to the selection of Alloy 718 as the material used to protect the basic UIS structure and to provide flow direction. The paper describes the tube fabrication process, the development of a finish sanding procedure and the results of high temperature thermal cycle testing.

  3. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    NASA Astrophysics Data System (ADS)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-07-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  4. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    NASA Astrophysics Data System (ADS)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-05-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  5. Cerium-based, intermetallic-strengthened aluminum casting alloy: High-volume co-product development

    DOE PAGESBeta

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-05-23

    Here, several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanicalmore » properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.« less

  6. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    SciTech Connect

    Guha, S.; Yang, J.

    2005-10-01

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  7. Large-scale production and quality assurance of hydrogen storage (battery) alloys

    SciTech Connect

    Friedrich, B. )

    1994-02-01

    The new generation of high-capacity metal hydride rechargeable batteries is a cadmium-free energy alternative to current types of accumulators. While the first steps were made for consumer wireless applications, the newest developments aim toward traction systems (zero-emission cars). This article introduces the materials selection, quality control, and production principles of alloy systems suitable for storing hydrogen either electrochemically or by gas absorption. Examples of Zr-Ni, Ti-Mn[sub 2], and rare earth-Ni[sub 5] are demonstrated from the metallurgical standpoint. These alloys (currently produced in large scale--tons/day) are now used in industry after approximately 20 years of development.

  8. Large-scale production and quality assurance of hydrogen storage (battery) alloys

    NASA Astrophysics Data System (ADS)

    Friedrich, B.

    1994-02-01

    The new generation of high-capacity metal hydride rechargeable batteries is a cadmium-free energy alternative to current types of accumulators. While the first steps were made for consumer wireless applications, the newest developments aim toward traction systems (zero-emission cars). This article introduces the materials selection, quality control, and production principles of alloy systems suitable for storing hydrogen either electrochemically or by gas absorption. Examples of Zr-Ni, Ti-Mn2, and rare earth-Ni5 are demonstrated from the metallurgical standpoint. These alloys (currently produced in large scale— tons/day) are now used in industry after approximately 20 years of development.

  9. Thermal Exposure Effects on Properties of Al-Li Alloy Plate Products

    NASA Technical Reports Server (NTRS)

    Shah, Sandeep; Wells, Douglas; Wagner, John; Babel, Henry

    2002-01-01

    Aluminum-Lithium (AL-Li) alloys offer significant performance benefits for aerospace structural applications due to their higher specific properties compared with conventional aluminum alloys. For example, the application of an Al-Li alloy to the space shuttle external cryogenic fuel tank contributed to the weight savings that enabled successful deployment of International Space Station components. The composition and heat treatment of this alloy were optimized specifically for strength-toughness considerations for an expendable cryogenic tank. Time dependent properties related to reliability, such as thermal stability, fatigue, and corrosion, will be of significant interest when materials are evaluated for a reusable cryotank structure. As most aerospace structural hardware is weight sensitive, a reusable cryotank will be designed to the limits of the materials mechanical properties. Therefore, this effort was designed to establish the effects of thermal exposure on the mechanical properties and microstructure of one relatively production mature alloy and two developmental alloys C458 and L277. Tensile and fracture toughness behavior was evaluated after exposure to temperatures as high as 3oooF for up to IO00 hrs. Microstructural changes were also evaluated to correlate with the observed data trends. The ambient temperature parent metal data showed an increase in strength and reduction in elongation after exposure at lower temperatures. Strength reached a peak with intermediate temperature exposure followed by a decrease at highest exposure temperature. Characterizing the effect of thermal exposure on the properties of Al-Li alloys is important to defining a service limiting temperature, exposure time, and end-of-life properties.

  10. Production of Magnesium and Aluminum-Magnesium Alloys from Recycled Secondary Aluminum Scrap Melts

    NASA Astrophysics Data System (ADS)

    Gesing, Adam J.; Das, Subodh K.; Loutfy, Raouf O.

    2016-02-01

    An experimental proof of concept was demonstrated for a patent-pending and trademark-pending RE12™ process for extracting a desired amount of Mg from recycled scrap secondary Al melts. Mg was extracted by electrorefining, producing a Mg product suitable as a Mg alloying hardener additive to primary-grade Al alloys. This efficient electrorefining process operates at high current efficiency, high Mg recovery and low energy consumption. The Mg electrorefining product can meet all the impurity specifications with subsequent melt treatment for removing alkali contaminants. All technical results obtained in the RE12™ project indicate that the electrorefining process for extraction of Mg from Al melt is technically feasible. A techno-economic analysis indicates high potential profitability for applications in Al foundry alloys as well as beverage—can and automotive—sheet alloys. The combination of technical feasibility and potential market profitability completes a successful proof of concept. This economical, environmentally-friendly and chlorine-free RE12™ process could be disruptive and transformational for the Mg production industry by enabling the recycling of 30,000 tonnes of primary-quality Mg annually.

  11. Examination of Corrosion Products and the Alloy Surface After Crevice Corrosion of a Ni-Cr-Mo- Alloy

    SciTech Connect

    X. Shan; J.H. Payer

    2006-06-09

    The objective of this study is to investigate the composition of corrosion products and the metal surface within a crevice after localized corrosion. The analysis provides insight into the propagation, stifling and arrest processes for crevice corrosion and is part of a program to analyze the evolution of localized corrosion damage over long periods of time, i.e. 10,000 years and longer. The approach is to force the initiation of crevice corrosion by applying anodic polarization to a multiple crevice assembly (MCA). Results are reported here for alloy C-22, a Ni-Cr-Mo alloy, exposed to a high temperature, concentrated chloride solution. Controlled crevice corrosion tests were performed on C-22 under highly aggressive, accelerated condition, i.e. 4M NaCl, 100 C and anodic polarization to -0.15V-SCE. The crevice contacts were by either a polymer tape (PTFE) compressed by a ceramic former or by a polymer (PTFE) crevice former. Figure 1 shows the polarization current during a crevice corrosion test. After an incubation period, several initiation-stifle-arrest events were indicated. The low current at the end of the test indicated that the metal surface had repassivated.

  12. The consequences of helium production on microstructural development in isotopically tailored ferritic alloys

    SciTech Connect

    Gelles, D.S.

    1996-10-01

    A series of alloys have been made adding various isotopes of nickel in order to vary the production of helium during irradiation by a two step nuclear reaction in a mixed spectrum reactor. The alloys use a base composition of Fe-12Cr with an addition of 1.5% nickel, either in the form of {sup 60}Ni which produces no helium, {sup 59}Ni which produces helium at a rate of about 10 appm He/dpa, or natural nickel ({sup Nat}Ni) which provides an intermediate level of helium due to delayed development of {sup 59}Ni. Specimens were irradiated in the HFIR at Oak Ridge, TN to {approx}7 dpa at 300 and 400{degrees}C. Microstructural examinations indicated that nickel additions promote precipitation in all alloys, but the effect appears to be much stronger at 400{degrees}C than at 300{degrees}C. There is sufficient dose by 7 dpa (and with 2 appm He) to initiate void swelling in ferritic/martensitic alloys. Little difference was found between response from {sup 59}Ni and {sup Nat}Ni. Also, helium bubble development for high helium generation conditions appeared to be very different at 300 and 400{degrees}C. At 300{degrees}C, it appeared that high densities of bubbles formed whereas at 400{degrees}C, bubbles could not be identified, possibly because of the complexity of the microstructure, but more likely because helium accumulated at precipitate interfaces.

  13. Production Process of Biocompatible Magnesium Alloy Tubes Using Extrusion and Dieless Drawing Processes

    NASA Astrophysics Data System (ADS)

    Kustra, Piotr; Milenin, Andrij; Płonka, Bartłomiej; Furushima, Tsuyoshi

    2016-06-01

    Development of technological production process of biocompatible magnesium tubes for medical applications is the subject of the present paper. The technology consists of two stages—extrusion and dieless drawing process, respectively. Mg alloys for medical applications such as MgCa0.8 are characterized by low technological plasticity during deformation that is why optimization of production parameters is necessary to obtain good quality product. Thus, authors developed yield stress and ductility model for the investigated Mg alloy and then used the numerical simulations to evaluate proper manufacturing conditions. Grid Extrusion3d software developed by authors was used to determine optimum process parameters for extrusion—billet temperature 400 °C and extrusion velocity 1 mm/s. Based on those parameters the tube with external diameter 5 mm without defects was manufactured. Then, commercial Abaqus software was used for modeling dieless drawing. It was shown that the reduction in the area of 60% can be realized for MgCa0.8 magnesium alloy. Tubes with the final diameter of 3 mm were selected as a case study, to present capabilities of proposed processes.

  14. Production Process of Biocompatible Magnesium Alloy Tubes Using Extrusion and Dieless Drawing Processes

    NASA Astrophysics Data System (ADS)

    Kustra, Piotr; Milenin, Andrij; Płonka, Bartłomiej; Furushima, Tsuyoshi

    2016-05-01

    Development of technological production process of biocompatible magnesium tubes for medical applications is the subject of the present paper. The technology consists of two stages—extrusion and dieless drawing process, respectively. Mg alloys for medical applications such as MgCa0.8 are characterized by low technological plasticity during deformation that is why optimization of production parameters is necessary to obtain good quality product. Thus, authors developed yield stress and ductility model for the investigated Mg alloy and then used the numerical simulations to evaluate proper manufacturing conditions. Grid Extrusion3d software developed by authors was used to determine optimum process parameters for extrusion—billet temperature 400 °C and extrusion velocity 1 mm/s. Based on those parameters the tube with external diameter 5 mm without defects was manufactured. Then, commercial Abaqus software was used for modeling dieless drawing. It was shown that the reduction in the area of 60% can be realized for MgCa0.8 magnesium alloy. Tubes with the final diameter of 3 mm were selected as a case study, to present capabilities of proposed processes.

  15. TEM characterization of corrosion products formed on a SS-15ZR alloy.

    SciTech Connect

    Luo, J. S.; Abraham, D. P.

    2000-01-04

    The corrosion products formed on a stainless steel-15Zr (SS-15Zr) alloy have been characterized by transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). Examination of alloy particles that were immersed in 90 C deionized water for two years revealed that different corrosion products were formed on the stainless steel and intermetallic phases. Two corrosion products were identified on an austenite particle: trevorite (NiFe{sub 2}O{sub 4}) in the layer close to the metal and maghemite (Fe{sub 2}O{sub 3}) in the outer layer. The corrosion layer formed on the intermetallic was uniform, adherent, and amorphous. The EDS analysis indicated that the layer was enriched in zirconium when compared with the intermetallic composition. High-resolution TEM images of the intermetallic-corrosion layer interface show an interlocking metal-oxide interface which may explain the relatively strong adherence of the corrosion layer to the intermetallic surface. These results will be used to evaluate corrosion mechanisms and predict long-term corrosion behavior of the alloy waste form.

  16. The huastec region: a second locus for the production of bronze alloys in ancient mesoamerica.

    PubMed

    Hosler, D; Stresser-Pean, G

    1992-08-28

    Chemical analyses of 51 metal artifacts, one ingot, and two pieces of intermediate processed material from two Late Post Classic archeological sites in the Huastec area of Eastern Mesoamerica point to a second production locus for copper-arsenic-tin alloys, copper-arsenic-tin artifacts, and probably copper-tin and copper-arsenic bronze artifacts. Earlier evidence had indicated that these bronze alloys were produced exclusively in West Mexico. West Mexico was the region where metallurgy first developed in Mesoamerica, although major elements of that technology had been introduced from the metallurgies of Central and South America. The bronze working component of Huastec metallurgy was transmitted from the metalworking regions of West Mexico, most likely through market systems that distributed Aztec goods. PMID:17742754

  17. Triple-junction amorphous silicon alloy PV manufacturing plant of 5 MW annual capacity

    SciTech Connect

    Guha, S.; Yang, J.; Banerjee, A.

    1997-12-31

    A spectral-splitting, triple-junction a-Si alloy solar cell processor has been designed, built and optimized. A roll-to-roll process has been used to deposit two layers of back reflector, a triple-cell structure with nine layers of a-Si and a-SiGe alloys and a single layer of antireflection coating consecutively on a half-a-mile roll of stainless steel. The coated web is next slabbed and processed to make a variety of products. The design of the machine and processes used incorporate several key features developed for improving cell efficiency. In order to reduce manufacturing cost, higher deposition rates and thinner cells than are used in R and D have been used. The back reflector also consists of Al/ZnO rather than Ag/ZnO. Large-scale production has begun, and products are being shipped for a wide range of applications.

  18. In-situ monitoring of surface hydrogen on the a-SiGe:H films

    SciTech Connect

    Toyoshima, Y.; Ganguly, G.; Ikeda, T.; Saitoh, K.; Kondo, M.; Matsuda, A.

    1997-07-01

    The bonded hydrogen on the growing surface of hydrogenated amorphous silicon germanium (a-SiGe:H) alloy films has been investigated by use of infrared reflection absorption spectroscopy (IR-RAS). When the alloy films are Si-rich, the surface hydrogen bonded to Si atoms is found to behave in a similar way to those on the hydrogenated amorphous silicon (a-Si:H) films. This means that the thermal desorption stability of surface Si hydride species is not significantly affected by the coexistence of a small amount (typically 20 at.%) of Ge. On the contrary, the desorption behavior of surface hydrogen depends on the alloy composition when the a-SiGe:H films are Ge-rich. A surface reaction scheme is provided in an attempt to explain this series of behavior in surface hydrogen on the a-SiGe:H films.

  19. Degradation of bioabsorbable Mg-based alloys: Assessment of the effects of insoluble corrosion products and joint effects of alloying components on mammalian cells.

    PubMed

    Grillo, Claudia A; Alvarez, Florencia; Fernández Lorenzo de Mele, Mónica A

    2016-01-01

    This work is focused on the processes occurring at the bioabsorbable metallic biomaterial/cell interfaces that may lead to toxicity. A critical analysis of the results obtained when degradable metal disks (pure Mg and rare earth-containing alloys (ZEK100 alloys)) are in direct contact with cell culture and those obtained with indirect methods such as the use of metal salts and extracts was made. Viability was assessed by Acridine Orange dye, neutral red and clonogenic assays. The effects of concentration of corrosion products and possible joint effects of the binary and ternary combinations of La, Zn and Mg ions, as constituents of ZEK alloys, were evaluated on a mammalian cell culture. In all cases more detrimental effects were found for pure Mg than for the alloys. Experiments with disks showed that gradual alterations in pH and in the amount of corrosion products were better tolerated by cells and resulted in higher viability than abrupt changes. In addition, viability was dependent on the distance from the source of ions. Experiments with extracts showed that the effect of insoluble degradation products was highly detrimental. Indirect tests with Zn ions revealed that harmful effects may be found at concentrations ≥ 150 μM and at ≥ 100 μM in mixtures with Mg. These mixtures lead to more deleterious effects than single ions. Results highlight the need to develop a battery of tests to evaluate the biocompatibility of bioabsorbable biomaterials. PMID:26478323

  20. Continuous roll-to-roll serpentine deposition for high throughput a-Si PV manufacturing

    SciTech Connect

    Izu, M.; Ovshinsky, H.C.; Deng, X.; Krisko, A.J.; Narasimhan, K.L.; Crucet, R.; Laarman, T.; Myatt, A.; Ovshinsky, S.R.

    1994-12-31

    In order to further improve the economies of scale which are inherent in ECD`s continuous roll-to-roll amorphous silicon alloy solar cell manufacturing process, the authors have developed a concept for a serpentine web plasma CVD deposition process to maximize throughput while keeping the size of the deposition chambers small. When this technique is incorporated into a continuous roll-to-roll PV manufacturing process, it will maximize the throughput for a high volume production plant, reduce the machine cost, improve gas utilization, reduce power consumption, and improve the solar cell stability. To demonstrate the serpentine web deposition concept, the authors have constructed a single loop serpentine deposition chamber to deposit a-Si for n-i-p structure solar cells. During the initial process of optimization, they have produced single-junction a-Si solar cells with 8.6% efficiency, and triple-junction a-Si solar cells with a 9.5% initial efficiency, where the top cell intrinsic layer was deposited in the serpentine deposition chamber.

  1. A solid state approach to the production of kilogram quantities of Si- 20 at.% Ge thermoelectric alloys

    SciTech Connect

    Cook, B.A.; Harringa, J.A.; Beaudry, B.J.

    1992-08-01

    A critical engineering question in the development of improved materials for thermal-to-electrical power generation is whether the research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 1 at. % B in the form SiB{sub 4} by X-ray diffraction, scanning laser mass spectrometry, Hall effect, and high temperature electrical resistivity and Seebeck coefficient studies is described. The properties of these alloys are shown to be comparable with those measured on similar samples prepared in small quantities by a vibratory mill approach.

  2. A solid state approach to the production of kilogram quantities of Si- 20 at. % Ge thermoelectric alloys

    SciTech Connect

    Cook, B.A.; Harringa, J.A.; Beaudry, B.J.

    1992-01-01

    A critical engineering question in the development of improved materials for thermal-to-electrical power generation is whether the research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 1 at. % B in the form SiB{sub 4} by X-ray diffraction, scanning laser mass spectrometry, Hall effect, and high temperature electrical resistivity and Seebeck coefficient studies is described. The properties of these alloys are shown to be comparable with those measured on similar samples prepared in small quantities by a vibratory mill approach.

  3. A solid state approach to the production of kilogram quantities of Si80Ge20 thermoelectric alloys

    NASA Astrophysics Data System (ADS)

    Cook, Bruce A.; Harringa, Joel H.; Beaudry, Bernard J.

    1993-01-01

    An important consideration in the development of improved materials for thermal-to-electrical power generation is whether a research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 0.8 at. % B in the form SiB4 by X-ray diffraction, scanning laser mass spectroscopy, Hall effect, and high temperature electrical resistivity and Seebeck coefficient measurements are described. The transport properties of these alloys are shown to be comparable to those measured on similar samples prepared in small quantities by a research-grade vibratory mill.

  4. A solid state approach to the production of kilogram quantities of Si80Ge20 thermoelectric alloys

    NASA Astrophysics Data System (ADS)

    Cook, B. A.; Harringa, J. L.; Beaudry, B. J.

    1992-10-01

    An important consideration in the development of improved materials for thermal-to-electrical power generation is whether a research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. percent Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 0.8 at. percent B in the form SiB4 by X-ray diffraction, scanning laser mass spectroscopy, Hall effect, and high temperature electrical resistivity and Seebeck coefficient measurements are described. The transport properties of these alloys are shown to be comparable to those measured on similar samples prepared in small quantities by a research-grade vibratory mill.

  5. Stoichiometrically controlled production of bimetallic Gold-Silver alloy colloids using micro-alga cultures.

    PubMed

    Dahoumane, Si Amar; Wijesekera, Kushlani; Filipe, Carlos D M; Brennan, John D

    2014-02-15

    This paper reports the production of well-defined, highly stable Ag-Au alloy nanoparticles (NPs) using living cells of Chlamydomonas reinhardtii, with the composition of the bimetallic alloys being solely determined by the stoichiometric ratio in which the metal salts were added to the cultures. The NPs exhibited a single, well-defined surface plasmon resonance (SPR) band confirming that they were made of a homogeneous population of bimetallic alloys. Particle creation by the cells occurred in three stages: (1) internalization of the noble metals by the cells and their reduction resulting in the formation of the NPs; (2) entrapment of the NPs in the extracellular matrix (ECM) surrounding the cells, where they are colloidally stabilized; and (3) release of the NPs from the ECM to the culture medium. We also investigated the effect of the addition of the metals salts on cell viability and the impact on characteristics of the NPs formed. When silver was added to the cultures, cell viability was decreased and this resulted in a ~30nm red shift on the SPR band due to changes in the surrounding environment into which the NPs were released. The same observations (in SPR and cell viability) was made when gold was added to a final concentration of 2 × 10(-4)M, but not when the concentration was equal to 10(-4)M, where cell viability was high and the red shift was negligible. PMID:24370403

  6. Production of Fe from Fe2O3 using a dry Mechanical Alloying Process

    SciTech Connect

    Waanders, F.B.; Mulaba-Bafubiandi, A.F.

    2005-04-26

    Mechanical alloying has been, and is still being employed extensively to synthesize a variety of alloy phases. The primary interest is to produce materials for scientific research and technological applications for magnetic recording media and permanent magnetic field devices. In the present investigation however the aim was not to produce a special alloy phases but to prove the viability of the production of iron from naturally occurring hematite, using mechanical alloying. Discard fines from the biggest hematite producer, Kumba Resources, Sishen, South Africa, were obtained and mixed with aluminum powder in the ratio of 25 at.% Al, balance hematite. About 50 g of the hematite-Al mixture, to be mechanically milled, was dry milled in a planetary ball milling equipment. The milling times varied between 30 min. and 30 hours and samples for Moessbauer spectroscopy, SEM analyses and Malvern sizing were obtained for each milling interval. Milling of the fine hematite with the much coarser Al resulted in a mixture with a particle size distribution of d0.5 = 54{mu}m to be extracted from the mill after 30 min. The Moessbauer spectra yielded 93% Fe2O3 and a 7% intermetallic Fe-Al component for this milling period. A final particle size of d0.5 = 20{mu}m for the milled product was obtained after milling for up to 30 h. However, within an hour all the hematite was completely converted to iron ({approx_equal} 86%) and two intermetallic Fe-Al compounds of combined intensity {approx_equal} 14%. The intensity ratio of the two intermetallic Fe-Al alloys that were observed as two doublets, changed after 3 h milling time and the averaged Moessbauer parameters for the two doublets are reported as: D1 = ({delta} = 0.50 {+-} 0.03 mm.s-1 and {delta} = 0.24 {+-} 0.03 mm.s-1) and D2 = ({delta} = 2.07 {+-} 0.03 mm.s-1 and {delta} = 0.98 {+-} 0.03 mm.s-1) respectively.

  7. Corrosion product layers on magnesium alloys AZ31 and AZ61: Surface chemistry and protective ability

    NASA Astrophysics Data System (ADS)

    Feliu, S.; Llorente, I.

    2015-08-01

    This paper studies the chemical composition of the corrosion product layers formed on magnesium alloys AZ31 and AZ61 following immersion in 0.6 M NaCl, with a view to better understanding their protective action. Relative differences in the chemical nature of the layers were quantified by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) and low-angle X-ray diffraction (XRD). Corrosion behavior was investigated by Electrochemical Impedance Spectroscopy (EIS) and hydrogen evolution measurement. An inhibitive effect from the corrosion product layers was observed from EIS, principally in the case of AZ31, as confirmed by hydrogen evolution tests. A link was found between carbonate enrichment observed by XPS in the surface of the corrosion product layer, concomitant with the increase in the protective properties observed by EIS.

  8. Structure and optical properties of aSiAl and aSiAlHx magnetron sputtered thin films

    NASA Astrophysics Data System (ADS)

    Thøgersen, Annett; Stange, Marit; Jensen, Ingvild J. T.; Røyset, Arne; Ulyashin, Alexander; Diplas, Spyros

    2016-03-01

    Thin films of homogeneous mixture of amorphous silicon and aluminum were produced with magnetron sputtering using 2-phase Al-Si targets. The films exhibited variable compositions, with and without the presence of hydrogen, aSi1-xAlx and aSi1-xAlxHy. The structure and optical properties of the films were investigated using transmission electron microscopy, X-ray photoelectron spectroscopy, UV-VisNIR spectrometry, ellipsometry, and atomistic modeling. We studied the effect of alloying aSi with Al (within the range 0-25 at. %) on the optical band gap, refractive index, transmission, and absorption. Alloying aSi with Al resulted in a non-transparent film with a low band gap (<1 eV). Hydrogenation of the films increased the band gap to values >1 eV. Variations of the Al and hydrogen content allowed for tuning of the optoelectronic properties. The films are stable up to a temperature of 300 °C. At this temperature, we observed Al induced crystallization of the amorphous silicon and the presence of large Al particles in a crystalline Si matrix.

  9. Nanostructure of a-Si:H and related alloys by small-angle scattering of neutrons and X-rays: Annual technical progress report: May 22, 1998 -- May 21, 1999

    SciTech Connect

    Williamson, D. L.

    1999-12-21

    This report describes work being performed to provide details of the microstructure in high-quality hydrogenated amorphous silicon and related alloys on the nanometer scale. The materials under study are being prepared by state-of-the-art deposition methods, as well as by new and emerging deposition techniques. The purpose is to establish the role of nanostructural features in controlling opto-electronic and photovoltaic properties. The approach centers around the use of the uncommon technique of small-angle scattering of both X-rays (SAXS) and neutrons (SANS). SAXS has already been established as highly sensitive to microvoids and columnar-like microstructure. A major goal of this research is to establish the sensitivity of SANS to the hydrogen nanostructure. Conventional X-ray diffraction techniques are being used to examine medium-range order and microcrystallinity, particularly near the boundary between amorphous and microcrystalline material.

  10. Molecular dynamics simulations of high energy cascade in ordered alloys: Defect production and subcascade division

    NASA Astrophysics Data System (ADS)

    Crocombette, Jean-Paul; Van Brutzel, Laurent; Simeone, David; Luneville, Laurence

    2016-06-01

    Displacement cascades have been calculated in two ordered alloys (Ni3Al and UO2) in the molecular dynamics framework using the CMDC (Cell Molecular Dynamics for Cascade) code (J.-P. Crocombette and T. Jourdan, Nucl. Instrum. Meth. B 352, 9 (2015)) for energies ranking between 0.1 and 580 keV. The defect production has been compared to the prediction of the NRT (Norgett, Robinson and Torrens) standard. One observes a decrease with energy of the number of defects compared to the NRT prediction at intermediate energies but, unlike what is commonly observed in elemental solids, the number of produced defects does not always turn to a linear variation with ballistic energy at high energies. The fragmentation of the cascade into subcascades has been studied through the analysis of surviving defect pockets. It appears that the common knowledge equivalence of linearity of defect production and subcascades division does not hold in general for alloys. We calculate the average number of subcascades and average number of defects per subcascades as a function of ballistic energy. We find an unexpected variety of behaviors for these two average quantities above the threshold for subcascade formation.

  11. Molecular dynamics simulations of high energy cascade in ordered alloys: Defect production and subcascade division

    NASA Astrophysics Data System (ADS)

    Crocombette, Jean-Paul; Van Brutzel, Laurent; Simeone, David; Luneville, Laurence

    2016-06-01

    Displacement cascades have been calculated in two ordered alloys (Ni3Al and UO2) in the molecular dynamics framework using the CMDC (Cell Molecular Dynamics for Cascade) code (J.-P. Crocombette and T. Jourdan, Nucl. Instrum. Meth. B 352, 9 (2015)) for energies ranking between 0.1 and 580 keV. The defect production has been compared to the prediction of the NRT (Norgett, Robinson and Torrens) standard. One observes a decrease with energy of the number of defects compared to the NRT prediction at intermediate energies but, unlike what is commonly observed in elemental solids, the number of produced defects does not always turn to a linear variation with ballistic energy at high energies. The fragmentation of the cascade into subcascades has been studied through the analysis of surviving defect pockets. It appears that the common knowledge equivalence of linearity of defect production and subcascades division does not hold in general for alloys. We calculate the average number of subcascades and average number of defects per subcascades as a function of ballistic energy. We find an unexpected variety of behaviors for these two average quantities above the threshold for subcascade formation.

  12. Production of pristine, sulfur-coated and silicon-alloyed germanium nanoparticles via laser pyrolysis

    NASA Astrophysics Data System (ADS)

    Kim, Seongbeom; Park, Song Yi; Jeong, Jaeki; Kim, Gi-Hwan; Rohani, Parham; Kim, Dong Suk; Swihart, Mark T.; Kim, Jin Young

    2015-07-01

    Here we demonstrate production of three types of germanium containing nanoparticles (NPs) by laser pyrolysis of GeH4 and characterize their sizes, structures and composition. Pristine Ge NPs were fabricated with 50 standard cubic centimeter per minute (sccm) of GeH4 and 25 sccm of SF6 as a photosensitizer gas, while sulfur-coated Ge NPs were produced with 25 sccm of GeH4 and 50 sccm of SF6. The laser pyrolysis of SiH4/GeH4 mixtures produced Si1-xGex alloy NPs. Effects of key process parameters including laser intensity and gas flow rates on NP properties have been investigated. The ability of the laser pyrolysis technique to flexibly produce a variety of germanium-containing NPs, as illustrated in this study shows promise for commercial-scale production of new nanomaterials as high purity dry powders.

  13. Production of pristine, sulfur-coated and silicon-alloyed germanium nanoparticles via laser pyrolysis.

    PubMed

    Kim, Seongbeom; Yi Park, Song; Jeong, Jaeki; Kim, Gi-Hwan; Rohani, Parham; Suk Kim, Dong; Swihart, Mark T; Young Kim, Jin

    2015-07-31

    Here we demonstrate production of three types of germanium containing nanoparticles (NPs) by laser pyrolysis of GeH4 and characterize their sizes, structures and composition. Pristine Ge NPs were fabricated with 50 standard cubic centimeter per minute (sccm) of GeH4 and 25 sccm of SF6 as a photosensitizer gas, while sulfur-coated Ge NPs were produced with 25 sccm of GeH4 and 50 sccm of SF6. The laser pyrolysis of SiH4/GeH4 mixtures produced Si1-xGex alloy NPs. Effects of key process parameters including laser intensity and gas flow rates on NP properties have been investigated. The ability of the laser pyrolysis technique to flexibly produce a variety of germanium-containing NPs, as illustrated in this study shows promise for commercial-scale production of new nanomaterials as high purity dry powders. PMID:26152899

  14. Fundamental studies on electrochemical production of dendrite-free aluminum and titanium-aluminum alloys

    NASA Astrophysics Data System (ADS)

    Pradhan, Debabrata

    A novel dendrite-free electrorefining of aluminum scrap was investigated by using AlCl3-1-Ethyl-3-methyl-imidazolium chloride (EMIC) ionic liquid electrolyte. Electrodeposition of aluminum were conducted on copper/aluminum cathodes at voltage of 1.5 V, temperatures (50-110°C), stirring rate (0-120 rpm), molar ratio (MR) of AlCl3:EMIC (1.25-2.0) and electrode surface modification (modified/unmodified). The study was focused to investigate the effect of process variables on deposit morphology, cathode current density and their role in production of dendrite-free aluminum. The deposits were characterized using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Modified electrodes and stirring rate (60 rpm) eliminate dendritic deposition by reducing cathode overpotential below critical overpotential (etacrt≈ -0.54 V) for dendrite formation. Pure aluminum (>99%) was deposited with current efficiency of 84-99%. Chronoamperometry study was conducted using AlCl3-EMIC and AlCl3-1-Butyl-3-methyl-imidazolium chloride (BMIC) (MR = 1.65:1) at 90°C to understand the mechanism of aluminum electrodeposition and find out diffusion parameter of electroactive species Al2C 7-. It was concluded that electrodeposition of aluminum is a diffusion controlled instantaneous nucleation process and diffusion coefficient of Al2C7- was found to be 5.2-6.9 x 10-11 m2/s and 2.2 x 10-11 m2/s for AlCl3-EMIC and AlCl3-BMIC, respectively. A novel production route of Ti-Al alloys was investigated using AlCl 3-BMIC-TiCl4 (MR = 2:1:0.019) and AlCl3-BMIC (MR = 2:1) electrolytes at constant voltages of 1.5-3.0 V and temperatures (70-125°C). Ti sheet was used as anode and cathode. Characterization of electrodeposited Ti-Al alloys was carried out using SEM, EDS, XRD and inductively coupled plasma-optical emission spectrometer (ICP-OES). Effect of voltage and temperature on cathode current density, current efficiency, composition and morphology of Ti

  15. MECHANICAL ALLOYING AND THERMAL TREATMENT FOR PRODUCTION OF ZIRCONIUM IRON HYDROGEN ISOTOPE GETTERS

    SciTech Connect

    Fox, K.

    2008-02-20

    The objective of this task was to demonstrate that metal hydrides could be produced by mechanical alloying in the quantities needed to support production-scale hydrogen isotope separations. Three starting compositions (ratios of elemental Zr and Fe powders) were selected and attritor milled under argon for times of 8 to 60 hours. In general, milling times of at least 24 hours were required to form the desired Zr{sub 2}Fe and Zr{sub 3}Fe phases, although a considerable amount of unalloyed Zr and Fe remained. Milling in liquid nitrogen does not appear to provide any advantages over milling in hexane, particularly due to the formation of ZrN after longer milling times. Carbides of Zr formed during some of the milling experiments in hexane. Elemental Zr was present in the as-milled material but not detected after annealing for milling times of 48 and 60 hours. It may be that after intimate mixing of the powders in the attritor mill the annealing temperature was sufficient to allow for the formation of a Zr-Fe alloy. Further investigation of this conversion is necessary, and could provide an opportunity for reducing the amount of unreacted metal powder after milling.

  16. Shape and Composition Effects on Photocatalytic Hydrogen Production for Pt-Pd Alloy Cocatalysts.

    PubMed

    Luo, Muhua; Lu, Pan; Yao, Weifeng; Huang, Cunping; Xu, Qunjie; Wu, Qiang; Kuwahara, Yasutaka; Yamashita, Hiromi

    2016-08-17

    The shape and composition effects of platinum-palladium (Pt-Pd) alloy nanoparticle cocatalysts on visible-light photocatalytic hydrogen evolution from an aqueous ammonium sulphite solution have been reported and discussed. The activity of Pt-Pd nanoparticles loaded Pt-Pd/CdS photocatalysts are affected based on both the Pt-Pd alloy nanoparticles' shape and their compositions. In this research, two shapes of Pt-Pd nanoparticles have been studied. One is Pt-Pd nanocubes enclosed by {100} crystal planes and the other is nano-octahedra covered with {111} crystal facets. Results show that the photocatalytic turnover frequency (TOF), defined as moles of hydrogen produced per surface mole of Pt-Pd metal atom per second, for Pt-Pd nanocubes/CdS (Pt-Pd NCs/CdS) photocatalyst can be 3.4 times more effective than Pt-Pd nano-octahedra/CdS (Pt-Pd NOTa/CdS) nanocomposite photocatalyst. Along with the shape effect, the atomic ratio of Pt to Pd can also impact the efficiency of Pt-Pd/CdS photocatalysts. When the Pt to Pd atomic ratio changes from 1:0 to about 2:1, the rate of hydrogen production increases from 900 μmol/h for Pt NCs/CdS catalyst to 1837 μmol/h for Pt-Pd (2:1) NCs/CdS photocatalyst-a 104% rate increase. This result suggests that the 33 mol % of more expensive Pt can be replaced with less costly Pd, resulting in a more than 100% hydrogen production rate increase. The finding of this research will lead to the research and development of highly effective catalysts for photocatalytic hydrogen production using solar photonic energy. PMID:27439590

  17. Development of Low Cost Gas Atomization of Precursor Powders for Simplified ODS Alloy Production

    SciTech Connect

    Anderson, Iver

    2014-08-05

    A novel gas atomization reaction synthesis (GARS) method was developed in this project to enable production (at our partner’s facility) a precursor Ni-Cr-Y-Ti powder with a surface oxide and an internal rare earth (RE) containing intermetallic compound (IMC) phase. Consolidation and heat-treatment experiments were performed at Ames Lab to promote the exchange of oxygen from the surface oxide to the RE intermetallic to form nano-metric oxide dispersoids. Alloy selection was aided by an internal oxidation and serial grinding experiments at Ames Lab and found that Hf-containing alloys may form more stable dispersoids than Ti-containing alloy, i.e., the Hf-containing system exhibited five different oxide phases and two different intermetallics compared to the two oxide phases and one intermetallic in the Ti-containing alloys. Since the simpler Ti-containing system was less complex to characterize, and make observations on the effects of processing parameters, the Ti-containing system was selected by Ames Lab for experimental atomization trials at our partner. An internal oxidation model was developed at Ames Lab and used to predict the heat treatment times necessary for dispersoid formation as a function of powder size and temperature. A new high-pressure gas atomization (HPGA) nozzle was developed at Ames Lab with the aim of promoting fine powder production at scales similar to that of the high gas-flow and melt-flow of industrial atomizers. The atomization nozzle was characterized using schlieren imaging and aspiration pressure testing at Ames Lab to determine the optimum melt delivery tip geometry and atomization pressure to promote enhanced secondary atomization mechanisms. Six atomization trials were performed at our partner to investigate the effects of: gas atomization pressure and reactive gas concentration on the particle size distribution (PSD) and the oxygen content of the resulting powder. Also, the effect on the rapidly solidified microstructure (as a

  18. Advancements in Ti Alloy Powder Production by Close-Coupled Gas Atomization

    SciTech Connect

    Heidloff, Andy; Rieken, Joel; Anderson, Iver; Byrd, David

    2011-04-01

    As the technology for titanium metal injection molding (Ti-MIM) becomes more readily available, efficient Ti alloy fine powder production methods are required. An update on a novel close-coupled gas atomization system has been given. Unique features of the melting apparatus are shown to have measurable effects on the efficiency and ability to fully melt within the induction skull melting system (ISM). The means to initiate the melt flow were also found to be dependent on melt apparatus. Starting oxygen contents of atomization feedstock are suggested based on oxygen pick up during the atomization and MIM processes and compared to a new ASTM specification. Forming of titanium by metal injection molding (Ti-MIM) has been extensively studied with regards to binders, particle shape, and size distribution and suitable de-binding methods have been discovered. As a result, the visibility of Ti-MIM has steadily increased as reviews of technology, acceptability, and availability have been released. In addition, new ASTM specification ASTM F2885-11 for Ti-MIM for biomedical implants was released in early 2011. As the general acceptance of Ti-MIM as a viable fabrication route increases, demand for economical production of high quality Ti alloy powder for the preparation of Ti-MIM feedstock correspondingly increases. The production of spherical powders from the liquid state has required extensive pre-processing into different shapes thereby increasing costs. This has prompted examination of Ti-MIM with non-spherical particle shape. These particles are produced by the hydride/de-hydride process and are equi-axed but fragmented and angular which is less than ideal. Current prices for MIM quality titanium powder range from $40-$220/kg. While it is ideal for the MIM process to utilize spherical powders within the size range of 0.5-20 {mu}m, titanium's high affinity for oxygen to date has prohibited the use of this powder size range. In order to meet oxygen requirements the top size

  19. Fission Product Release from Molten U/Al Alloy Fuel: A Vapor Transpiration Model

    SciTech Connect

    Whitkop, P.G.

    2001-06-26

    This report describes the application of a vapor transportation model to fission product release data obtained for uranium/aluminum alloy fuel during early Oak Ridge fuel melt experiments. The Oak Ridge data validates the vapor transpiration model and suggests that iodine and cesium are released from the molten fuel surface in elemental form while tellurium and ruthenium are released as oxides. Cesium iodide is postulated to form in the vapor phase outside of the fuel matrix. Kinetic data indicates that cesium iodide can form from Cs atoms and diatomic iodine in the vapor phase. Temperatures lower than those capable of melting fuel are necessary in order to maintain a sufficient I2 concentration. At temperatures near the fuel melting point, cesium can react with iodine atoms to form CsI only on solid surfaces such as aerosols.

  20. Production, fabrication, and performance of alloy 625 clad steel for aggressive corrosive environments

    SciTech Connect

    Stevens, C.E.; Ross, R.W. Jr.

    1986-06-01

    INCONEL/sup */ alloy 625 is a nickel-chromium-molybdenum-columbium alloy used in aggressive corrosive applications where high strength, fabricability, and outstanding corrosion resistance are required. Because of these properties, the alloy is used by the power and chemical industries in a variety of components in coal-fired, nuclear, and chemical process plants. However, widespread use of INCONEL alloy 625 is limited due to its cost. There is a need, notably in utility flue gas desulfurization systems (scrubbers) for an economical, highly corrosive-resistant material. To satisfy this need, INCONEL alloy 625 thin-gauge clad steel plate was developed by Lukens Steel Company. The corrosion resistance of INCONEL alloy 625 in several aggressive corrosive environments will be reviewed. Additionally, this paper will describe methods used to manufacture, fabricate, and weld INCONEL alloy 625 clad plate. Field test evaluation programs conducted at six power plant scrubber systems will also be reported.

  1. Large-scale production of Si{sub 0.8}Ge{sub 0.2} thermoelectric alloys by mechanical alloying

    SciTech Connect

    Cook, B.A.; Harringa, J.L.; Loughin, S.; Centurioni, D.X.

    1993-10-01

    Advanced processing techniques were combined with refinements in composition to produce homogeneous, production-scale quantities of n- and p-type Si{sub 0.8}Ge{sub 0.2} alloys with improved thermoelectric properties. Two p-type compacts of Si{sub 0.8}Ge{sub 0.2} doped with 0.8 atom% boron and one n-type compact doped with 0.8 m/o GaP and a P/Ga ratio of 2.38 were prepared by mechanical alloying. Resulting powders were consolidated into 7.62 cm diameter compacts by vacuum hot pressing. Transport and thermoelectric properties were measured. As-pressed samples were found to have low carrier mobility. Metallographic analysis revealed a sub-micron grain size which would suggest a high density of grain boundary potential barriers. A heat treatment was applied and the measurements were repeated. The post-treatment p-type samples showed a 33% grain growth and an integrated average figure of merit of 0.6{times}10{sup {minus}3} K{sup {minus}1} over the 573--1273 K range. This paper presents the details of fabrication method and compares the thermoelectric properties with the properties of similar alloys manufactured by traditional vacuum casting and hot pressing.

  2. Energetics of gaseous and volatile fission products in molten U-10Zr alloy: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Tian, Jie; Jiang, Tao; Yang, Yanqiu; Hu, Sheng; Peng, Shuming; Yan, Liuming

    2015-11-01

    Gaseous and volatile fission products have a number of adverse effects on the safety and efficiency of the U-10Zr alloy fuel. The theoretical calculations were applied to investigate the energetics related to the formation, nucleation, and degassing of gaseous and volatile fission products (Kr, Xe and I) in molten U-10Zr alloy. The molecular dynamics (MD) simulations were applied to generate equilibrium configurations. The density functional theory (DFT) calculations were used to build atomistic models including molten U-10Zr alloy as well as its fission products substituted systems. The vacancy formation in liquid U-10Zr alloy were studied using DFT calculations, with average Gibbs free formation energies at 8.266 and 6.333 eV for U- and Zr-vacancies, respectively. And the interaction energies were -1.911 eV, -2.390 eV, and -1.826 eV for the I-I, Xe-Xe, and Kr-Kr interaction in lattice when two of the adjacent uranium atoms were substituted by gaseous atoms. So it could be concluded that the interaction between I, Kr, and Xe in lattice is powerful than the interaction between these two atoms and the other lattice atoms in U-10Zr.

  3. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D - Annual report input for 1996

    SciTech Connect

    Johnson, W.R.; Smith, J.P.; Stambaugh, R.D.

    1996-10-01

    V-4Cr-4Ti alloy has been selected for use in the manufacture of a portion of the DIII-D Radiative Divertor (RD) upgrade. The production of a 1200-kg ingot of V-4Cr-4Ti alloy has been completed at Teledyne Wah Chang of Albany, Oregon (TWCA) to provide {approximately}800-kg of applicable product forms, and two billets have been extruded from the ingot. Chemical compositions of the ingot and both extruded billets were acceptable. Material from these billets will be converted into product forms suitable for components of the DIII-D Radiative Divertor structure. Joining of V-4Cr-4Ti alloy has been identified as the most critical fabrication issue for its use in the RD Program, and research into several joining methods for fabrication of the RD components, including resistance seam, friction, and electron beam welding, is continuing. Preliminary trials have been successful in the joining of V-alloy to itself by electron beam, resistance, and friction welding processes and to Inconel 625 by friction welding.

  4. Production and blast-furnace smelting of boron-alloyed iron-ore pellets

    SciTech Connect

    A.A. Akberdin; A.S. Kim

    2008-08-15

    Industrial test data are presented regarding the production (at Sokolovsk-Sarbaisk mining and enrichment enterprise) and blast-furnace smelting (at Magnitogorsk metallurgical works) of boron-alloyed iron-ore pellets (500000 t). It is shown that, thanks to the presence of boron, the compressive strength of the roasted pellets is increased by 18.5%, while the strength in reduction is doubled; the limestone consumption is reduced by 11%, the bentonite consumption is halved, and the dust content of the gases in the last section of the roasting machines is reduced by 20%. In blast-furnace smelting, the yield of low-sulfur (<0.02%) hot metal is increased from 65-70 to 85.1% and the furnace productivity from 2.17-2.20 to 2.27 t/(m{sup 3} day); coke consumption is reduced by 3-8 kg/t of hot metal. The plasticity and stamping properties of 08IO auto-industry steel are improved by microadditions of boron.

  5. Continuous production of granular or powder Ti, Zr and Hf or their alloy products

    DOEpatents

    White, Jack C.; Oden, Laurance L.

    1993-01-01

    A continuous process for producing a granular metal selected from the group consisting of Ti, Zr or Hf under conditions that provide orderly growth of the metal free of halide inclusions comprising: a) dissolving a reducing metal selected from the group consisting of Na, Mg, Li or K in their respective halide salts to produce a reducing molten salt stream; b) preparing a second molten salt stream containing the halide salt of Ti, Zr or Hf; c) mixing and reacting the two molten streams of steps a) and b) in a continuous stirred tank reactor; d) wherein steps a) through c) are conducted at a temperature range of from about 800.degree. C. to about 1100.degree. C. so that a weight percent of equilibrium solubility of the reducing metal in its respective halide salt varies from about 1.6 weight percent at about 900.degree. C. to about 14.4 weight percent at about 1062.degree. C.; and wherein a range of concentration of the halide salt of Ti, Zn or Hf in molten halides of Na, Mg, Li or K is from about 1 to about 5 times the concentration of Na, Mg, Li or K; e) placing the reacted molten stream from step c) in a solid-liquid separator to recover an impure granular metal product by decantation, centrifugation, or filtration; and f) removing residual halide salt impurity by vacuum evaporator or inert gas sweep at temperatures from about 850.degree. C. to 1000.degree. C. or cooling the impure granular metal product to ambient temperature and water leaching off the residual metal halide salt.

  6. Effect of Different Production Methods on the Mechanical and Microstructural Properties of Hypereutectic Al-Si Alloys

    NASA Astrophysics Data System (ADS)

    Fatih Kilicaslan, M.; Uzun, Orhan; Yilmaz, Fikret; Çağlar, Seyit

    2014-10-01

    In this study, the effects of different production methods like melt spinning, high-energy ball milling, and combined melt spinning and high-energy ball milling on the mechanical and microstructural properties of hypereutectic Al-20Si-5Fe alloys were investigated. While microstructural and spectroscopic analyses were performed using scanning electron microscopy and X-ray diffractometry, mechanical properties were measured using a depth-sensing indentation instrument with a Berkovich tip. Microstructural and spectroscopic analyses demonstrate that high-energy ball milling process applied on the melt-spun Al-20-Si-5Fe alloy for 10 minutes brings about a reduction in the size of silicon particles and intermetallic compounds. However, further increase in milling time does not yield any significant reduction in size. High-energy ball milling for 10 minutes on the starting powders is not enough to form any intermetallic phase. According to the depth-sensing indentation experiments, high-energy milling of melt-spun Al-20Si-5Fe alloys shows an incremental behavior in terms of hardness values. For the Al-20Si-5Fe alloys investigated in this study, the production technique remarkably influences their elastic-plastic response to the indentation process in terms of both magnitude and shape of P- h curves.

  7. Commercialization of multijunction a-Si modules

    NASA Astrophysics Data System (ADS)

    Carlson, D. E.; Arya, R. R.; Chen, L.-F.; Oswald, R.; Newton, J.; Rajan, K.; Romero, R.; Willing, F.; Yang, L.

    1997-02-01

    Solarex has just completed building a plant in James City County, Virginia that has the capacity to produce 10 MW per year of multijunction amorphous silicon PV modules. The plant will start commercial production of 8.6 ft2 tandem modules in early 1997. The tandem device structure consists of two stacked p-i-n junctions, a front junction containing amorphous silicon and a back junction containing an amorphous silicon germanium alloy. All amorphous silicon alloys are deposited using plasma-enhanced chemical vapor deposition, and the large-area monolithic modules are interconnected using computerized laser scribing coupled with a machine vision system. The principle products will be monolithic modules (26″×48″) with nominal stabilized power ratings of 56, 50 and 43 peak watts. All modules will be fabricated using a glass-EVA-glass encapsulation to ensure long-term reliability. These products are expected to be widely used in both remote and grid-tied applications.

  8. Commercialization of multijunction a-Si modules

    SciTech Connect

    Carlson, D.E.; Arya, R.R.; Chen, L.; Oswald, R.; Newton, J.; Rajan, K.; Romero, R.; Willing, F.; Yang, L.

    1997-02-01

    Solarex has just completed building a plant in James City County, Virginia that has the capacity to produce 10 MW per year of multijunction amorphous silicon PV modules. The plant will start commercial production of 8.6ft{sup 2} tandem modules in early 1997. The tandem device structure consists of two stacked p-i-n junctions, a front junction containing amorphous silicon and a back junction containing an amorphous silicon germanium alloy. All amorphous silicon alloys are deposited using plasma-enhanced chemical vapor deposition, and the large-area monolithic modules are interconnected using computerized laser scribing coupled with a machine vision system. The principle products will be monolithic modules (26{double_prime}{times}48{double_prime}) with nominal stabilized power ratings of 56, 50 and 43 peak watts. All modules will be fabricated using a glass-EVA-glass encapsulation to ensure long-term reliability. These products are expected to be widely used in both remote and grid-tied applications. {copyright} {ital 1997 American Institute of Physics.}

  9. Overcoming residual stresses and machining distortion in the production of aluminum alloy satellite boxes.

    SciTech Connect

    Younger, Mandy S.; Eckelmeyer, Kenneth Hall

    2007-11-01

    Distortion frequently occurs during machining of age hardening aluminum alloys due to residual stresses introduced during the quenching step in the heat treatment process. This report quantifies, compares, and discusses the effectiveness of several methods for minimizing residual stresses and machining distortion in aluminum alloys 7075 and 6061.

  10. Parameters controlling the milling process applied to the production of AI-Cu-Mg-Si alloys (2214) by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Yan, X. X.; Bois, N.; Cizeron, G.

    1994-10-01

    In this study are analysed the respective influence of various parameters (processing time t_p, speed of rotation ω of the attritor axis and ratio R : the ball to powder masses) on the mechanical alloying process applied to mixed powders in order to obtain Al-Cu-Mg-Si alloys (2214 type). It was deduced that the most effective parameter is ω. Furthermore the optimum processing conditions were determined as well as the main characteristics of the powder resulting from the milling process using microscopy and X-ray diffraction. The sintering ability of samples pressed from " MA " powders was also studied thanks to dilatometric tests and compared with that of initial powder mixtures. A relationship between the size reduction of Al particles and the milling parameters is established. Dans cette étude ont été analysées les influences respectives de divers paramètres (temps de broyage t_p vitesse de rotation de l'axe de l'attriteur ω et rapport R : masse des billes/masse des poudres) sur le processus de mécanosynthèse appliqué à des poudres mélangées en vue d'obtenir des alliages Al-Cu-Mg-Si (type 2214). Il en a été déduit que le paramètre essentiel était ω. En outre, par microscopie et par diffraction X, les conditions optimales de broyage ont été déterminées, ainsi que les caractéristiques essentielles de la poudre résultant du processus d'attrition. L'aptitude au frittage des comprimés réalisés à partir de poudres traitées par voie mécanique a également été étudiée par dilatométrie et comparée à celle de la poudre initiale. Une relation permettant de relier la diminution de la taille des particules d'aluminium aux paramètres d'attrition a été établie.

  11. Examination of an alternative method for the pyrometallurgical production of copper-chromium alloys

    NASA Astrophysics Data System (ADS)

    Brenk, J.; Hassan-Pour, S.; Spiess, P.; Friedrich, B.

    2016-07-01

    In this paper an alternative to the usual route for the production of copper-chromium alloys by Hot Isostatic Pressing (HIP) followed by Vacuum Arc Remelting (VAR) is investigated. Therefore the HIP is replaced by an aluminothermic reduction. As oxidizing agents for this aluminothermic reduction (ATR) chromium oxide (Cr2O3) and copper oxide (CuO) are used. These oxidants are mixed in a stoichiometric relation with aluminium (Al) to get the following aluminothermic reactions going: As ATRs always are exothermic reductions, it is important to control the heat output of the reaction. A common simplification for the heat calculation in the field of ATR is the “Shemshushny Factor” (Sh-Factor). This factor determines the rate of energy input per reactant mass: To avoid a secondary melt phase after ATR, inline casting is used to directly obtain vacuum arc remeltable electrodes out of the liquid melt of the ATR. The second part of this work deals with the remelting of these electrodes via VAR. The first VAR trials aim at finding process parameters for remelting a copper-chromium ingot. As demixing is to avoid, it is necessary to control process parameters within a small range to obtain a shallow melt pool.

  12. [Evaluation of the chest roentgenograms of 90 workers employed in the production of silicon-alloys (author's transl)].

    PubMed

    Taddei, L; Cristofolini, A; Bradamante, D

    1979-10-01

    The chest X-rays (double exposed; focus 0.6 X 0.6 mm2; grid 10:1 ratio; FFD 2.0 m) of 90 workers employed in the production of silicon-alloys were classified according to ILO U/C 1971: 14 have been considered "border line" and 14 showed definite pathologic findings. Among the last, 10 concerned subjects who had never previously been exposed to ther dusts. PMID:554189

  13. Cost-Effective Method for Producing Self Supported Palladium Alloy Membranes for Use in Efficient Production of Coal Derived Hydrogen

    SciTech Connect

    K. Coulter

    2008-03-31

    Southwest Research Institute{reg_sign} (SwRI{reg_sign}) has utilized its expertise in large-area vacuum deposition methods to conduct research into the fabrication of dense, freestanding Pd-alloy membranes that are 3-5 microns thick and over 100 in{sup 2} in area. The membranes were deposited onto flexible and rigid supports that were subsequently removed and separated using novel techniques developed over the course of the project. Using these methods, the production of novel alloy compositions centered around the Pd-Cu system were developed with the objective of producing a thermally stable, nano-crystalline grain structure with the highest flux recorded as 242 SCFH/ft{sup 2} for a 2 {micro}m thick Pd{sub 53}Cu{sub 47} at 400 C and 20 psig feed pressure which when extrapolated is over twice the 2010 Department of Energy pure H{sub 2} flux target. Several membranes were made with the same permeability, but with different thicknesses and these membranes were highly selective. Researchers at the Colorado School of Mines supported the effort with extensive testing of experimental membranes as well as design and modeling of novel alloy composite structures. IdaTech provided commercial bench testing and analysis of SwRI-manufactured membranes. The completed deliverables for the project include test data on the performance of experimental membranes fabricated by vacuum deposition and several Pd-alloy membranes that were supplied to IdaTech for testing.

  14. Synthesis of Ge nanocrystals embedded in a Si host matrix

    NASA Astrophysics Data System (ADS)

    Ngiam, Shih-Tung; Jensen, Klavs F.; Kolenbrander, K. D.

    1994-12-01

    The synthesis of a composite material consisting of Ge nanoclusters (greater than or equal to 2 nm in diameter) embedded in a Si host matrix is reported. The Ge nanoparticles are produced by pulsed laser ablation and are codeposited in a Si film simultaneously grown by chemical beam epitaxy using disilane. Scanning transmission electron microscopy, combined with energy-dispersive x-ray measurements, show that discrete Ge particles (greater than or equal to 2 nm diameter) are deposited within a polycrystalline Si host matrix. High-resolution transmission electron microscopy reveals that the paricles are crystalline with a lattice spacing corresponding to that of Ge. The enhancement of Si deposition rates from silanes in the presence of Ge, previously demonstrated in chemical vapor deposition of Si(1 - x)Ge(x) alloys, is shown to facilitate the growth of a Si layer around the Ge nanocrystals. The overall composition of the Ge cluster/Si host composite material is determined by Rutherford backscattering measurements.

  15. Silicon purification using a Cu-Si alloy source

    NASA Technical Reports Server (NTRS)

    Powell, R. C.; Tejedor, P.; Olson, J. M.

    1986-01-01

    Production of 99.9999% pure silicon from 98% pure metallurgical grade (MG) silicon by a vapor transport filtration process (VTP) is described. The VTF process is a cold wall version of an HCl chemical vapor transport technique using a Si:Cu3Si alloy as the silicon source. The concentration, origin, and behavior of the various impurities involved in the process were determined by chemically analyzing alloys of different purity, the slag formed during the alloying process, and the purified silicon. Atomic absorption, emission spectrometry, inductively coupled plasma, spark source mass spectrometry, and secondary ion mass spectroscopy were used for these analyses. The influence of the Cl/H ratio and the deposition temperature on the transport rate was also investigated.

  16. Production of Gas-Solid Structures in Aluminum and Nickel Alloys by Gasar Processing

    SciTech Connect

    Apprill, J.M.; Baldwin, M.D.; Maguire, M.C.; Miszkiel, M.E.; Shapovalov, V.I.

    1999-01-06

    Experimental data on directional and bulk solidification of hydrogen-charged samples of aluminum alloy A356 and nickel alloy Inconel 718 are discussed. The solidification structure of the porous zone is shown to be dependent on many process variables. Of these variables, hydrogen content in the melt prior to solidification, and furnace atmospheric pressure during solidification play the decisive role. Also important are the furnace atmosphere composition, the solidification velocity, and the temperature distribution of the liquid metal inside the mold.

  17. Purification of uranium alloys by differential solubility of oxides and production of purified fuel precursors

    DOEpatents

    McLean, II, William; Miller, Philip E.

    1997-01-01

    A method for purifying metallic alloys of uranium for use as nuclear reactor fuels in which the metal alloy is first converted to an oxide and then dissolved in nitric acid. Initial removal of metal oxide impurities not soluble in nitric acid is accomplished by filtration or other physical means. Further purification can be accomplished by carbonate leaching of uranyl ions from the partially purified solution or using traditional methods such as solvent extraction.

  18. Purification of uranium alloys by differential solubility of oxides and production of purified fuel precursors

    DOEpatents

    McLean, W. II; Miller, P.E.

    1997-12-16

    A method is described for purifying metallic alloys of uranium for use as nuclear reactor fuels in which the metal alloy is first converted to an oxide and then dissolved in nitric acid. Initial removal of metal oxide impurities not soluble in nitric acid is accomplished by filtration or other physical means. Further purification can be accomplished by carbonate leaching of uranyl ions from the partially purified solution or using traditional methods such as solvent extraction. 3 figs.

  19. Solid-state chemistry-enabled scalable production of octahedral Pt-Ni alloy electrocatalyst for oxygen reduction reaction.

    PubMed

    Zhang, Changlin; Hwang, Sang Youp; Trout, Alexis; Peng, Zhenmeng

    2014-06-01

    Although octahedral Pt-Ni alloy nanoparticles possess an excelling property in oxygen reduction reaction (ORR) and are of great potential as an electrocatalyst for polymer electrolyte membrane fuel cells (PEMFCs), mass production of the materials at low cost remains a big challenge. By combining the advantages of both solid-state chemistry and wet synthetic chemistry, we developed one scalable, surfactant-free, and cost-effective method for producing octahedral Pt-Ni alloy nanoparticles on carbon support. The octahedral Pt-Ni samples were prepared with different compositions and studied for the ORR property. They exhibit a much improved reaction activity compared to the commercial catalyst. The experiments demonstrate an innovative strategy for preparing shaped metal nanoparticles and make significant progress in the ORR catalyst research. PMID:24827592

  20. Risks of beryllium disease related to work processes at a metal, alloy, and oxide production plant.

    PubMed Central

    Kreiss, K; Mroz, M M; Zhen, B; Wiedemann, H; Barna, B

    1997-01-01

    OBJECTIVES: To describe relative hazards in sectors of the beryllium industry, risk factors of beryllium disease and sensitisation related to work process were sought in a beryllium manufacturing plant producing pure metal, oxide, alloys, and ceramics. METHODS: All 646 active employees were interviewed; beryllium sensitisation was ascertained with the beryllium lymphocyte proliferation blood test on 627 employees; clinical evaluation and bronchoscopy were offered to people with abnormal test results; and industrial hygiene measurements related to work processes taken in 1984-93 were reviewed. RESULTS: 59 employees (9.4%) had abnormal blood tests, 47 of whom underwent bronchoscopy. 24 new cases of beryllium disease were identified, resulting in a beryllium disease prevalence of 4.6%, including five known cases (29/632). Employees who had worked in ceramics had the highest prevalence of beryllium disease (9.0%). Employees in the pebble plant (producing beryllium metal) who had been employed after 1983 also had increased risk, with a prevalence of beryllium disease of 6.4%, compared with 1.3% of other workers hired in the same period, and a prevalence of abnormal blood tests of 19.2%. Logistic regression modelling confirmed these two risk factors for beryllium disease related to work processes and the dependence on time of the risk at the pebble plant. The pebble plant was not associated with the highest gravimetric industrial hygiene measurements available since 1984. CONCLUSION: Further characterisation of exposures in beryllium metal production may be important to understanding how beryllium exposures confer high contemporary risk of beryllium disease. PMID:9326165

  1. A solid state approach to the production of kilogram quantities of Si[sub 80]Ge[sub 20] thermoelectric alloys

    SciTech Connect

    Cook, B.A.; Harringa, J.L.; Beaudry, B.J.

    1992-01-01

    An important consideration in the development of improved materials for thermal-to-electrical power generation is whether a research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 0.8 at. % B in the form SiB[sub 4] by X-ray diffraction, scanning laser mass spectroscopy, Hall effect, and high temperature electrical resistivity and Seebeck coefficient measurements are described. The transport properties of these alloys are shown to be comparable to those measured on similar samples prepared in small quantities by a research-grade vibratory mill.

  2. A solid state approach to the production of kilogram quantities of Si[sub 80]Ge[sub 20] thermoelectric alloys

    SciTech Connect

    Cook, B.A.; Harringa, J.H.; Beaudry, B.J. )

    1993-01-15

    An important consideration in the development of improved materials for thermal-to-electrical power generation is whether a research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 0.8 at. % B in the form SiB[sub 4] by X-ray diffraction, scanning laser mass spectroscopy, Hall effect, and high temperature electrical resistivity and Seebeck coefficient measurements are described. The transport properties of these alloys are shown to be comparable to those measured on similar samples prepared in small quantities by a research-grade vibratory mill.

  3. A solid state approach to the production of kilogram quantities of Si{sub 80}Ge{sub 20} thermoelectric alloys

    SciTech Connect

    Cook, B.A.; Harringa, J.L.; Beaudry, B.J.

    1992-12-01

    An important consideration in the development of improved materials for thermal-to-electrical power generation is whether a research-scale process or methodology is amenable to production of kilogram quantities. Research efforts on the solid state technique of mechanical alloying have shown that both n- and p-type Si-20 at. % Ge alloys can be produced which have improved thermoelectric properties compared to state-of-the-art MOD-RTG materials. Studies on the production of large quantities of mechanically alloyed powder alloys using a planetary mill indicate that properties similar to those observed in alloys prepared in smaller quantities by a vibratory mill can be obtained. The characterization of several p-type alloys doped with 0.8 at. % B in the form SiB{sub 4} by X-ray diffraction, scanning laser mass spectroscopy, Hall effect, and high temperature electrical resistivity and Seebeck coefficient measurements are described. The transport properties of these alloys are shown to be comparable to those measured on similar samples prepared in small quantities by a research-grade vibratory mill.

  4. Accelerated Helium and Hydrogen Production in Fe-54 Doped Alloys - Measurements and Calculations for the FIST Experiment

    SciTech Connect

    Greenwood, Lawrence R.; Oliver, Brian M.; Ohnuki, S.; Shiba, K.; Kohno, Y.; Kohyama, A.; Robertson, J. P.; Meadows, J. W.; Gelles, David S.

    2000-09-01

    Helium and hydrogen measurements for F-82H alloys enriched up to 96% in 54Fe demonstrate accelerated gas production due to differences in the isotopic cross sections. The samples were irradiated in the JP-17 and JP-22 experiments in HFIR. Results are compared to calculations using isotopic helium production cross sections from ENDF/B-VI or the computer code, GNASH, for the radioactive isotope 55Fe. Helium measurements demonstrated an accelerated helium (appm)/dpa ratio of 2.3 after a 1.25-year irradiation, an increase of a factor of 4.3 over natural iron, due to higher helium production cross sections for 54Fe and 55Fe. Alloys doped with 55Fe could achieve helium/dpa ratios up to about 20, well above the fusion reactor ratio of 10. Calculations predict that hydrogen production is accelerated by about a factor of 13 over natural iron. However, measurements show that most of this hydrogen is not retained in the samples.

  5. Near-Net-Shape Production of Hollow Titanium Alloy Components via Electrochemical Reduction of Metal Oxide Precursors in Molten Salts

    NASA Astrophysics Data System (ADS)

    Hu, Di; Xiao, Wei; Chen, George Z.

    2013-04-01

    Metal oxide precursors (ca. 90 wt pct Ti, 6 wt pct Al, and 4 wt pct V) were prepared with a hollow structure in various shapes such as a sphere, miniature golf club head, and cup using a one-step solid slip-casting process. The precursors were then electro-deoxidized in molten calcium chloride [3.2 V, 1173 K (900 °C)] against a graphite anode. After 24 hours of electrolysis, the near-net-shape Ti-6Al-4V product maintained its original shape with controlled shrinkage. Oxygen contents in the Ti-6Al-4V components were typically below 2000 ppm. The maximum compressive stress and modulus of electrolytic products obtained in this work were approximately 243 MPa and 14 GPa, respectively, matching with the requirement for medical implants. Further research directions are discussed for mechanical improvement of the products via densification during or after electrolysis. This simple, fast, and energy-efficient near-net-shape manufacturing method could allow titanium alloy components with desired geometries to be prepared directly from a mixture of metal oxides, promising an innovative technology for the low-cost production of titanium alloy components.

  6. Characterization of corrosion products of AB{sub 5}-type hydrogen storage alloys for nickel-metal hydride batteries

    SciTech Connect

    Maurel, F.; Knosp, B.; Backhaus-Ricoult, M.

    2000-01-01

    To better understand the decrease in storage capacity of AB{sub 5}-type alloys in rechargeable Ni/MH batteries undergoing repeated charge/discharge cycles, the corrosion of a MnNi{sub 3.55}Co{sub 0.75}Mn{sub 0.4}Al{sub 0.3} alloy in aqueous KOH electrolyte was studied. The crystal structure, chemical composition, and distribution of corrosion products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Hollow and filed needles of a mixed rare earth hydroxide Mn(OH){sub 3} were found to cover a continuous nanocrystalline corrosion scale composed of metal (Ni, Co) solid solution, oxide (Ni,Co)O solid solution and rare earth hydroxide, and a Mn-depleted alloy subscale. Corrosion kinetics were measured for three different temperatures. Growth kinetics of the continuous corrosion scale and of the Mm(OH){sub 3} needles obeyed linear and parabolic rate laws, respectively. Models for the corrosion mechanism were developed on the basis of diffusional transport of Mn and OH through the hydroxide needles and subsequent diffusion along grain boundaries through the nanocrystalline scale.

  7. Synergic Catalysis of PdCu Alloy Nanoparticles within a Macroreticular Basic Resin for Hydrogen Production from Formic Acid.

    PubMed

    Mori, Kohsuke; Tanaka, Hiromasa; Dojo, Masahiro; Yoshizawa, Kazunari; Yamashita, Hiromi

    2015-08-17

    Highly dispersed PdCu alloy nanoparticles have been successfully prepared within a macroreticular basic resin bearing N(CH3 )2 functional groups. This previously unappreciated combination of alloy is first proven to be responsible for the efficient production of high-purity H2 from formic acid (HCOOH) dehydrogenation for chemical hydrogen storage. By the addition of Cu, the electronically promoted Pd sites show significantly higher catalytic activity as well as a better tolerance towards CO poisoning as compared to their monometallic Pd counterparts. Experimental and DFT calculation studies revealed not only the synergic alloying effect but also cooperative action by the N(CH3 )2 groups within the resin play crucial roles in achieving exceptional catalytic performances. In addition to the advantages such as, facile preparation method, free of additives, recyclable without leaching of active component, and suppression of unfavorable CO formation less than 3 ppm, the present catalytic system is cost-effective because of the superior catalytic activity compared with that of well-established precious PdAg or PdAu catalysts. The present catalytic system is particularly desirable for an ideal hydrogen vector in terms of potential industrial application for fuel cells. PMID:26178687

  8. Binary synaptic connections based on memory switching in a-Si:H for artificial neural networks

    NASA Technical Reports Server (NTRS)

    Thakoor, A. P.; Lamb, J. L.; Moopenn, A.; Khanna, S. K.

    1987-01-01

    A scheme for nonvolatile associative electronic memory storage with high information storage density is proposed which is based on neural network models and which uses a matrix of two-terminal passive interconnections (synapses). It is noted that the massive parallelism in the architecture would require the ON state of a synaptic connection to be unusually weak (highly resistive). Memory switching using a-Si:H along with ballast resistors patterned from amorphous Ge-metal alloys is investigated for a binary programmable read only memory matrix. The fabrication of a 1600 synapse test array of uniform connection strengths and a-Si:H switching elements is discussed.

  9. Photovoltaic semiconductor materials based on alloys of tin sulfide, and methods of production

    DOEpatents

    Lany, Stephan

    2016-06-07

    Photovoltaic thin-film materials comprising crystalline tin sulfide alloys of the general formula Sn.sub.1-x(R).sub.xS, where R is selected from magnesium, calcium and strontium, as well as methods of producing the same, are disclosed.

  10. Turbine Blade Alloy

    NASA Technical Reports Server (NTRS)

    MacKay, Rebecca

    2001-01-01

    The High Speed Research Airfoil Alloy Program developed a fourth-generation alloy with up to an +85 F increase in creep rupture capability over current production airfoil alloys. Since improved strength is typically obtained when the limits of microstructural stability are exceeded slightly, it is not surprising that this alloy has a tendency to exhibit microstructural instabilities after high temperature exposures. This presentation will discuss recent results obtained on coated fourth-generation alloys for subsonic turbine blade applications under the NASA Ultra-Efficient Engine Technology (UEET) Program. Progress made in reducing microstructural instabilities in these alloys will be presented. In addition, plans will be presented for advanced alloy development and for computational modeling, which will aid future alloy development efforts.

  11. Finemet nanocrystalline soft magnetic alloy: Investigation of glass forming ability, crystallization mechanism, production techniques, magnetic softness and the effect of replacing the main constituents by other elements

    NASA Astrophysics Data System (ADS)

    Gheiratmand, T.; Hosseini, H. R. Madaah

    2016-06-01

    Finemet soft magnetic alloy has been in the focus of interest in the last years due to its high saturation magnetization, high permeability and low core loss. The great quantity of papers has been devoted to the study of its structural and magnetic properties, confirms this claim. This paper reviews the different researches performed on Finemet up to now. The criteria that should be satisfied in order to have the high glass forming ability in an alloy and also the techniques applied for production of Finemet ribbons, powders and bulk samples have been explained. In addition, the mechanism of devitrification, nanocrystallization and magnetic softness in this applicable magnetic alloy has been discussed in detail. Finally, the effect of different elements substituted with the main constituents in Finemet has been summarized through the studies on the characterization and magnetic properties of different Finemet-type alloys.

  12. Production of chromium base alloys by ball milling in hydrogen iodide

    NASA Technical Reports Server (NTRS)

    Arias, A.

    1975-01-01

    The effects of processing variables on the tensile properties and ductile-to-brittle transition temperature (DBTT) of Cr + 4 vol% ThO2 alloys and of pure Cr produced by ball milling in hydrogen iodide were investigated. Hot rolled Cr + ThO2 was stronger than either hot pressed Cr + ThO2 or pure Cr at temperatures up to 1540 C. Hot pressed Cr + ThO2 had a DBTT of 500 C as compared with -8 to 24 C for the hot rolled Cr + ThO2 and with 140 C for pure Cr. It is postulated that the dispersoid in the hot rolled alloys lowers the DBTT by inhibiting recovery and recrystallization of the strained structure.

  13. Sintering of the reaction products of combustion of alloys in nitrogen

    SciTech Connect

    Maksimov, Y.M.; Raskolenko, L.G.; Zepakova, O.K.; Ziatdinov, M.K.

    1986-05-01

    An investigation of the mechanism of compacting of Fe-V alloy with a sigma-phase structure, a low porosity composite material consisting of alpha-iron and a filler of delta-vanadium nitride, is made after the synthesis surge. Alloys containing 50 wt.% Fe were prepared by sintering in a vacuum furnace of powders of type VEL-1 vandium and special purity carbonyl iron. The mechanism of compacting was studied on specimens in hardened water. Metallographic investigations were made on MIM-7 and PMT-3 instruments and the phase analysis on a DRON-2 instrument. Rapid compacting in combustion of sigma-FeV in nitrogen is determined by combining of the solid-liquid drops formed in the combustion front and consisting of molten iron and vanadium nitrides.

  14. Induction heat treatment and technique of bioceramic coatings production on medical titanium alloys

    NASA Astrophysics Data System (ADS)

    Fomin, Aleksandr A.; Rodionov, Igor V.; Fomina, Marina A.; Poshivalova, Elena Y.; Krasnikov, Aleksandr V.; Petrova, Natalia N.; Zakharevich, Andrey M.; Skaptsov, Alexander A.; Gribov, Andrey N.; Atkin, Vsevolod S.

    2015-03-01

    Prospective composite bioceramic titania coatings were obtained on intraosseous implants fabricated from medical titanium alloy VT16 (Ti-2.5Al-5Mo-5V). Consistency changes of morphological characteristics, physico-mechanical properties and biocompatibility of experimental titanium implant coatings obtained by oxidation during induction heat treatment are defined. Technological recommendations for obtaining bioceramic coatings with extremely high strength on titanium items surface are given.

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

    PubMed

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

    2016-11-01

    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. PMID:27289269

  16. Identifying electronic properties relevant to improving stability in a-Si:H-based cells and overall performance in a-Si,Ge:H-based cells. Annual subcontract report, 18 April 1995--17 April 1996

    SciTech Connect

    Cohen, J.D.

    1997-03-01

    The work done during this second phase of the University of Oregon`s NREL subcontract focused on degradation studies in both pure a-Si:H and a-Si,Ge:H alloys, as well as a detailed study of the interface between these two materials in a-Si:H/a-Si, Ge:H heterostructures. All samples discussed in this report were produced by the glow-discharge method and were obtained either in collaboration with United Solar Systems Corporation or with researchers at Lawrence Berkeley laboratory. First, the results from the a-Si, Ge:H degradation studies support the conclusion that considerable quantities of charged defects exist in nominally intrinsic material. Researchers found that on light-soaking, all the observed defect sub-bands increased; however, their ratios varied significantly. Second, researchers performed voltage pulse stimulated capacitance transient measurements on a-Si:H/a-Si, Ge:H heterostructure samples and found a clear signature of trapped hole emission extending over long times. Finally, researchers began comparison studies of the electronic properties of a-Si:H grown by glow discharge either with 100% silane, or with silane diluted in H{sub 2} or He gas. The results on these samples indicate that the films grown under high hydrogen dilution exhibit roughly a factor of 3 lower deep defect densities than those grown using pure silane.

  17. Regularities of crystallographic texture formation in cladding tubes from Zr-based alloys during their production

    NASA Astrophysics Data System (ADS)

    Isaenkova, M.; Perlovich, Yu; Fesenko, V.

    2016-04-01

    This paper summarizes researches of the authors, which are directed on the development of the methodological basis of X-ray studies in the materials science of zirconium and on the systematization of new experimental results obtained using developed methods. The paper describes regularities of the formation of the crystallographic texture and the substructure inhomogeneity of cladding tubes from zirconium alloys at various stages of their manufacturing, i.e. during hot and cold deformation, recrystallization, phase transformations and interactions of the above processes.

  18. Direct production of nanostructured copper-nickel (Cu-Ni) alloy particles

    SciTech Connect

    Apaydin, Ramazan Oguzhan; Ebin, Burcak; Gurmen, Sebahattin

    2013-12-16

    Copper-Nickel (CuNi) nanostructured alloy particles were produced by Ultrasonic Spray Pyrolysis and Hydrogen Reduction Method (USP-HR) from high purity copper and nickel nitrate aqueous solutions. The effect of the precursor solution in the range of 0.1 and 0.5 mol/L on the morphology and crystallite size of CuNi nanoparticles were investigated under 2 h running time, 700 °C operating temperature and 0.5 L/min H{sub 2} flow rate. Particle size, morphology, composition and crystallite structure were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). Particle characterization studies show that nanostructured alloy particles have cubic crystal structure and they are in submicron size range with spherical morphology. The crystallite sizes of the particles calculated with Scherrer formula are 40 and 34 nm and average particles sizes observed from the SEM images are 300 and 510 nm for each experiment respectively.

  19. Study and Simulation of the Heterojunction Thin Film Solar Cell a-Si(n)/a-Si(i)/c-Si(p)/a-Si(i)/a-Si(p)

    NASA Astrophysics Data System (ADS)

    Toufik, Zarede; Hamza, Lidjici; Mohamed, Fathi; Achour, Mahrane

    2016-05-01

    In this article, we present a study based on numerical simulation of the electrical characteristics of a thin-film heterojunction solar cell (a-Si(n)/a-Si(i)/c-Si(p)/a-Si(i)/a-Si(p)), using the automat for simulation of hetero-structures (AFORS-Het) software. This cell is composed of four main layers of silicon (Si): (i) 5 nm amorphous silicon doped n, (ii) 100 μm crystalline silicon (substrate) doped p, (iii) 5 nm amorphous silicon doped p, and (iv) 3 nm amorphous silicon intrinsic. This cell has a front and rear metal contact of aluminum and zinc oxide (ZnO) front layer transparent conductive oxide of 80 nm thickness. The simulations were performed at conditions of "One Sun" irradiation with air mass 1.5 (AM1.5), and under absolute temperature T = 300 K. The simulation results have shown a high electrical conversion efficiency of about 30.29% and high values of open circuit voltage V oc = 779 mV. This study has also shown that the studied cell has good quality light absorption on a very broad spectrum.

  20. Transformation process for production of ultrahigh carbon steels and new alloys

    DOEpatents

    Strum, Michael J.; Goldberg, Alfred; Sherby, Oleg D.; Landingham, Richard L.

    1995-01-01

    Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50.degree. C. above the A.sub.1 transformation temperature, soaking the steel above the A.sub.1 temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature.

  1. Transformation process for production of ultrahigh carbon steels and new alloys

    DOEpatents

    Strum, M.J.; Goldberg, A.; Sherby, O.D.; Landingham, R.L.

    1995-08-29

    Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50 C above the A{sub 1} transformation temperature, soaking the steel above the A{sub 1} temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature. 9 figs.

  2. Catalyst Alloys Processing

    NASA Astrophysics Data System (ADS)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  3. Tungsten and tungsten alloy powder metallurgy: Powder production and applications excluding lamps. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    1995-02-01

    The bibliography contains citations of selected patents concerning the preparation of metallic and ceramic powders of tungsten and tungsten alloys, including applications of these materials. The hydrogen reduction of tungsten compounds together with alloying element compounds produce forms with characteristics of high density, hardness, wear resistance, high melting points, and abrasiveness. Topics include production of cathodes, heaters, filament wires, electrical contacts, acoustic absorbers, high-density sheets and coatings, hard penetrators, and tungsten carbide and metallized ceramics. Tungsten halogen lamps are examined in a separate bibliography. (Contains a minimum of 115 citations and includes a subject term index and title list.)

  4. Tungsten and tungsten alloy powder metallurgy: Powder production and applications excluding lamps. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    1997-01-01

    The bibliography contains citations of selected patents concerning the preparation of metallic and ceramic powders of tungsten and tungsten alloys, including applications of these materials. The hydrogen reduction of tungsten compounds together with alloying element compounds produce forms with characteristics of high density, hardness, wear resistance, high melting points, and abrasiveness. Topics include production of cathodes, heaters, filament wires, electrical contacts, acoustic absorbers, high-density sheets and coatings, hard penetrators, and tungsten carbide and metallized ceramics. Tungsten halogen lamps are examined in a separate bibliography.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  5. Tungsten and tungsten alloy powder metallurgy: Powder production and applications excluding lamps. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations of selected patents concerning the preparation of metallic and ceramic powders of tungsten and tungsten alloys, including applications of these materials. The hydrogen reduction of tungsten compounds together with alloying element compounds produce forms with characteristics of high density, hardness, wear resistance, high melting points, and abrasiveness. Topics include production of cathodes, heaters, filament wires, electrical contacts, acoustic absorbers, high-density sheets and coatings, hard penetrators, and tungsten carbide and metallized ceramics. Tungsten halogen lamps are examined in a separate bibliography.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  6. Tungsten and tungsten alloy powder metallurgy: Powder production and applications excluding lamps. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1993-05-01

    The bibliography contains citations of selected patents concerning the preparation of metallic and ceramic powders of tungsten and tungsten alloys, including applications of these materials. The hydrogen reduction of tungsten compounds together with alloying element compounds produce forms with characteristics of high density, hardness, wear resistance, high melting points, and abrasiveness. Topics include production of cathodes, heaters, filament wires, electrical contacts, acoustic absorbers, high-density sheets and coatings, hard penetrators, and tungsten carbide and metallized ceramics. Tungsten halogen lamps are examined in a separate bibliography. (Contains a minimum of 97 citations and includes a subject term index and title list.)

  7. Low activation ferritic alloys

    DOEpatents

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

    1985-02-07

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  8. Low activation ferritic alloys

    DOEpatents

    Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  9. Integral bypass diodes in an amorphous silicon alloy photovoltaic module

    NASA Technical Reports Server (NTRS)

    Hanak, J. J.; Flaisher, H.

    1991-01-01

    Thin-film, tandem-junction, amorphous silicon (a-Si) photovoltaic modules were constructed in which a part of the a-Si alloy cell material is used to form bypass protection diodes. This integral design circumvents the need for incorporating external, conventional diodes, thus simplifying the manufacturing process and reducing module weight.

  10. Weldability of High Alloys

    SciTech Connect

    Maroef, I

    2003-01-22

    The purpose of this study was to investigate the effect of silicon and iron on the weldability of HAYNES HR-160{reg_sign} alloy. HR-I60 alloy is a solid solution strengthened Ni-Co-Cr-Si alloy. The alloy is designed to resist corrosion in sulfidizing and other aggressive high temperature environments. Silicon is added ({approx}2.75%) to promote the formation of a protective oxide scale in environments with low oxygen activity. HR-160 alloy has found applications in waste incinerators, calciners, pulp and paper recovery boilers, coal gasification systems, and fluidized bed combustion systems. HR-160 alloy has been successfully used in a wide range of welded applications. However, the alloy can be susceptible to solidification cracking under conditions of severe restraint. A previous study by DuPont, et al. [1] showed that silicon promoted solidification cracking in the commercial alloy. In earlier work conducted at Haynes, and also from published work by DuPont et al., it was recognized that silicon segregates to the terminal liquid, creating low melting point liquid films on solidification grain boundaries. Solidification cracking has been encountered when using the alloy as a weld overlay on steel, and when joining HR-160 plate in a thickness greater than19 millimeters (0.75 inches) with matching filler metal. The effect of silicon on the weldability of HR-160 alloy has been well documented, but the effect of iron is not well understood. Prior experience at Haynes has indicated that iron may be detrimental to the solidification cracking resistance of the alloy. Iron does not segregate to the terminal solidification product in nickel-base alloys, as does silicon [2], but iron may have an indirect or interactive influence on weldability. A set of alloys covering a range of silicon and iron contents was prepared and characterized to better understand the welding metallurgy of HR-160 alloy.

  11. New Amorphous Silicon Alloy Systems

    NASA Astrophysics Data System (ADS)

    Kapur, Mridula N.

    1990-01-01

    The properties of hydrogenated amorphous silicon (a-Si:H) have been modified by alloying with Al, Ga and S respectively. The Al and Ga alloys are in effect quaternary alloys as they were fabricated in a carbon-rich discharge. The alloys were prepared by the plasma assisted chemical vapor deposition (PACVD) method. This method has several advantages, the major one being the relatively low defect densities of the resulting materials. The PACVD system used to grow the alloy films was designed and constructed in the laboratory. It was first tested with known (a-Si:H and a-Si:As:H) materials. Thus, it was established that device quality alloy films could be grown with the home-made PACVD setup. The chemical composition of the alloys was characterized by secondary ion mass spectrometry (SIMS), and electron probe microanalysis (EPMA). The homogeneous nature of hydrogen distribution in the alloys was established by SIMS depth profile analysis. A quantitative analysis of the bulk elemental content was carried out by EPMA. The analysis indicated that the alloying element was incorporated in the films more efficiently at low input gas concentrations than at the higher concentrations. A topological model was proposed to explain the observed behavior. The optical energy gap of the alloys could be varied in the 0.90 to 1.92 eV range. The Al and Ga alloys were low band gap materials, whereas alloying with S had the effect of widening the energy gap. It was observed that although the Si-Al and Si-Ga alloys contained significant amounts of C and H, the magnitude of the energy gap was determined by the metallic component. The various trends in optical properties could be related to the binding characteristics of the respective alloy systems. A quantitative explanation of the results was provided by White's tight binding model. The dark conductivity-temperature dependence of the alloys was examined. A linear dependence was observed for the Al and Ga systems. Electronic conduction in

  12. Properties Evaluation and Studying Production Mechanism of Nanocrystalline NiAl Intermetallic Compound by Mechanical Alloying

    NASA Astrophysics Data System (ADS)

    Khajesarvi, Ali; Akbari, Golamhossein

    2016-04-01

    Ni50Al50 intermetallic compound was synthesized by mechanical alloying (MA) of elemental mixtures of Ni and Al powders in a planetary ball mill. After 16 hours of milling and obtaining crystallites with a critical size, the initial NiAl compound was formed along with the combustive reaction after opening the vial lid. In the time interval of 16 to 128 hours, the reaction from combustive state reached the explosive state. Finally, after 128 hours of milling, the initial powders were wholly transformed into NiAl before completion of the milling time. Structural changes of powder particles during MA were studied by X-ray diffractometry and scanning electron microscopy. The crystallite size measurements revealed that the grain size of the NiAl phase decreased from 155 to 26 nm with increasing MA time from 8 to 128 hours. Microhardness for nanocrystalline Ni50Al50 intermetallic compound produced after 128 hours of milling was measured as about 350 Hv.

  13. Fe-Zn Alloy Coating on Galvannealed (GA) Steel Sheet to Improve Product Qualities

    NASA Astrophysics Data System (ADS)

    Pradhan, Debabrata; Guin, Akshya Kumar; Raju, Pankaj; Manna, Manindra; Dutta, Monojit; Venugopalan, T.

    2014-09-01

    Galvannealed steel sheets (GA) have become the mainstream steel sheet for automobile applications because of their superior corrosion resistance, paintability, and weldability. To impart specific properties, different coatings on GA steel sheet were reported to improve properties further. In this context, we have developed an electroplating process (flash coating) for bright and adherent Fe-Zn alloy coating on GA steel sheet to enhance performances such as weldability, frictional behavior, phosphatability, and defect coverage. A comparative study with bare GA steel sheet was carried out for better elastration. The electroplating time was reduced below 10 s for practical applicability in an industrial coating line by modulating the bath composition. Electroplating was performed at current density of 200-500 A/m2 which yielded with higher cathode current efficiency of 85-95%. The performance results show that Fe-10 wt.% Zn-coated GA steel sheet (coating time 7 s) has better spot weldability, lower dynamic coefficient of friction (0.06-0.07 in lubrication), and better corrosion resistance compared to bare GA steel sheet. Uniform phosphate coating with globular crystal size of 2-5 µm was obtained on Fe-Zn flash-coated GA steel sheet. Hopeite was the main phosphate compound (77.9 wt.%) identified along with spencerite (13.6 wt.%) and phosphophyllite (8.5 wt.%).

  14. Production of aluminum-silicon alloy and ferrosilicon and commercial purity aluminum by the direct reduction process. Third interim technical report, Phase C for the period 1980 July 1-1980 September 30

    SciTech Connect

    Bruno, M.J.

    1980-10-01

    Pilot reactor VSR-3 operation in the third quarter was directed to tapping molten alloy product. Modifications to the hearth region included a tapping furnace to maintain taphole temperature, a graphite ring filter to separate carbides from matal and an alumina liner to eliminate carbiding from reaction of alloy with the graphite hearth walls. Tapping was not successful, however, due to high alloy viscosity from a large concentration of carbides. Three runs were made on the pilot crystallizer to determine the effects of alloy composition, cooling rate, tamping rate, remelt temperature and rate on eutectic Al-Si yield.

  15. Production of aluminum-silicon alloy and ferrosilicon and commercial purity aluminum by the direct reduction process. First interim technical report, Phase D, January 1-March 31, 1981

    SciTech Connect

    Bruno, M.J.

    1981-04-01

    Operation of the bench AF-reactor on burden with all reducing carbon exterior to the ore pellet resulted in low metal alloy product yields and prematurely terminated runs, indicating the need for intimate contact between alumina and carbon to produce oxycarbide liquid prior to reaction with solid silicon carbide. Carbon solubility tests made on 60Al-40Si alloys at 2200/sup 0/C in graphite crucibles indicated continued reaction to form SiC for one hour. Efficiency of reduction to SiC ranged from 68 to 100%. The A-C two-electrode submerged arc reactor pilot, SAR-II, was successfully operated on both alumina-clay-coke and alumina-silicon carbide-coke (from the VSR prereduction) burdens. Metal alloy was produced and tapped in each of four runs. The pilot crystallizer was operated to evalute the two-stage (stop and go) crystallization technique on obtaining high yields of Al in Al-Si eutectic, with a limit of 1.0% Fe and 0.1% Ti in the alloy product. 18 figures, 19 tables. (DLC)

  16. Nano-Scale Fission Product Phases in an Irradiated U-7Mo Alloy Nuclear Fuel

    SciTech Connect

    Dennis Keiser, Jr.; Brandon Miller; James Madden; Jan-Fong Jue; Jian Gan

    2014-09-01

    Irradiated nuclear fuel is a very difficult material to characterize. Due to the large radiation fields associated with these materials, they are hard to handle and typically have to be contained in large hot cells. Even the equipment used for performing characterization is housed in hot cells or shielded glove boxes. The result is not only a limitation in the techniques that can be employed for characterization, but also a limitation in the size of features that can be resolved The most standard characterization techniques include light optical metallography (WM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). These techniques are applied to samples that are typically prepared using grinding and polishing approaches that will always generate some mechanical damage on the sample surface. As a result, when performing SEM analysis, for example, the analysis is limited by the quality of the sample surface that can be prepared. However, a new approach for characterizing irradiated nuclear fuel has recently been developed at the Idaho National Laboratory (INL) in Idaho Falls, Idaho. It allows for a dramatic improvement in the quality of characterization that can be performed when using an instrument like an SEM. This new approach uses a dual-beam scanning microscope, where one of the beams isa focused ion beam (FIB), which can be used to generate specimens of irradiated fuel (-10µm x 10µm) for microstructural characterization, and the other beam is the electron beam of an SEM. One significant benefit of this approach is that the specimen surface being characterized has received much less damage (and smearing) than is caused by the more traditional approaches, which enables the imaging of nanometer­ sized microstructural features in the SEM. The process details are for an irradiated low-enriched uranium (LEU) U-Mo alloy fuel Another type of irradiated fuel that has been characterized using this technique is a mixed oxide fuel.

  17. Comparative life-cycle energy payback analysis of multi-junction a-SiGe and nanocrystalline/a-Si modules

    SciTech Connect

    Fthenakis, V.; Kim, H.

    2010-07-15

    Despite the publicity of nanotechnologies in high tech industries including the photovoltaic sector, their life-cycle energy use and related environmental impacts are understood only to a limited degree as their production is mostly immature. We investigated the life-cycle energy implications of amorphous silicon (a-Si) PV designs using a nanocrystalline silicon (nc-Si) bottom layer in the context of a comparative, prospective life-cycle analysis framework. Three R and D options using nc-Si bottom layer were evaluated and compared to the current triple-junction a-Si design, i.e., a-Si/a-SiGe/a-SiGe. The life-cycle energy demand to deposit nc-Si was estimated from parametric analyses of film thickness, deposition rate, precursor gas usage, and power for generating gas plasma. We found that extended deposition time and increased gas usages associated to the relatively high thickness of nc-Si lead to a larger primary energy demand for the nc-Si bottom layer designs, than the current triple-junction a-Si. Assuming an 8% conversion efficiency, the energy payback time of those R and D designs will be 0.7-0.9 years, close to that of currently commercial triple-junction a-Si design, 0.8 years. Future scenario analyses show that if nc-Si film is deposited at a higher rate (i.e., 2-3 nm/s), and at the same time the conversion efficiency reaches 10%, the energy-payback time could drop by 30%.

  18. Reducing metal alloy powder costs for use in powder bed fusion additive manufacturing: Improving the economics for production

    NASA Astrophysics Data System (ADS)

    Medina, Fransisco

    Titanium and its associated alloys have been used in industry for over 50 years and have become more popular in the recent decades. Titanium has been most successful in areas where the high strength to weight ratio provides an advantage over aluminum and steels. Other advantages of titanium include biocompatibility and corrosion resistance. Electron Beam Melting (EBM) is an additive manufacturing (AM) technology that has been successfully applied in the manufacturing of titanium components for the aerospace and medical industry with equivalent or better mechanical properties as parts fabricated via more traditional casting and machining methods. As the demand for titanium powder continues to increase, the price also increases. Titanium spheroidized powder from different vendors has a price range from 260/kg-450/kg, other spheroidized alloys such as Niobium can cost as high as $1,200/kg. Alternative titanium powders produced from methods such as the Titanium Hydride-Dehydride (HDH) process and the Armstrong Commercially Pure Titanium (CPTi) process can be fabricated at a fraction of the cost of powders fabricated via gas atomization. The alternative powders can be spheroidized and blended. Current sectors in additive manufacturing such as the medical industry are concerned that there will not be enough spherical powder for production and are seeking other powder options. It is believed the EBM technology can use a blend of spherical and angular powder to build fully dense parts with equal mechanical properties to those produced using traditional powders. Some of the challenges with angular and irregular powders are overcoming the poor flow characteristics and the attainment of the same or better packing densities as spherical powders. The goal of this research is to demonstrate the feasibility of utilizing alternative and lower cost powders in the EBM process. As a result, reducing the cost of the raw material to reduce the overall cost of the product produced with

  19. Electrospun a-Si using Liquid Silane/Polymer Inks

    SciTech Connect

    Doug Schulz

    2010-12-09

    Amorphous silicon nanowires (a-SiNWs) were prepared by electrospinning cyclohexasilane (Si{sub 6}H{sub 12}) admixed with polymethylmethacrylate (PMMA) in toluene. Raman spectroscopy characterization of these wires (d {approx} 50-2000 nm) shows 350 C treatment yields a-SiNWs. Porous a-SiNWs are obtained using a volatile polymer.

  20. Electrospun a-Si using Liquid Silane/Polymer Inks

    SciTech Connect

    D.L. Schulz; J.M. Hoey; J. Smith; J. Lovaasen; C. Braun; X. Dai; K. Anderson; A. Elangovan; X. Wu; S. Payne; K. Pokhodnya; I. Akhatov; L. Pederson; P. Boudjouk

    2010-12-01

    Amorphous silicon nanowires (a-SiNWs) were prepared by electrospinning cyclohexasilane (Si{sub 6}H{sub 12}) admixed with polymethylmethacrylate (PMMA) in toluene. Raman spectroscopy characterization of these wires (d {approx} 50-2000 nm) shows 350 C treatment yields a-SiNWs. Porous a-SiNWs are obtained using a volatile polymer.

  1. Utilization of amorphous silicon carbide (a-Si:C:H) as a resistive layer in gas microstrip detectors

    SciTech Connect

    Hong, W.S.; Cho, H.S.; Perez-Mendez, V.; Gong, W.G.

    1995-04-01

    Thin semiconducting films of hydrogenated amorphous silicon (a-Si:H) and its carbon alloy (a-Si:C:H) were applied to gas microstrip detectors in order to control gain instabilities due to charges on the substrate. Thin ({approximately}100nm) layers of a-Si:H or p-doped a-Si:C:H were placed either over or under the electrodes using the plasma enhanced chemical vapor deposition (PECVD) technique to provide the substrate with a suitable surface conductivity. By changing the carbon content and boron doping density, the sheet resistance of the a-Si:C:H coating could be successfully controlled in the range of 10{sup 12} {approximately} 10{sup 17} {Omega}/{four_gradient}, and the light sensitivity, which causes the resistivity to vary with ambient light conditions, was minimized. An avalanche gain of 5000 and energy resolution of 20% FWHM were achieved and the gain remained constant over a week of operation. A-Si:C:H film is an attractive alternative to ion-implanted or semiconducting glass due to the wide range of resistivities possible and the feasibility of making deposits over a large area at low cost.

  2. Utilization of amorphous silicon carbide (a-Si:C:H) as a resistive layer in gas microstrip detectors

    NASA Astrophysics Data System (ADS)

    Hong, W. S.; Cho, H. S.; Perez-Mendez, V.; Gong, W. G.

    1995-04-01

    Thin semiconducting films of hydrogenated amorphous silicon (a-Si:H) and its carbon alloy (a-Si:C:H) were applied to gas microstrip detectors in order to control gain instabilities due to charges on the substrate. Thin (approximately 100nm) layers of a-Si:H or p-doped a-Si:C:H were placed either over or under the electrodes using the plasma enhanced chemical vapor deposition (PECVD) technique to provide the substrate with a suitable surface conductivity. By changing the carbon content and boron doping density, the sheet resistance of the a-Si:C:H coating could be successfully controlled in the range of 10(exp 12) to approximately 10(exp 17) Omega/(four gradient), and the light sensitivity, which causes the resistivity to vary with ambient light conditions, was minimized. An avalanche gain of 5000 and energy resolution of 20% FWHM were achieved and the gain remained constant over a week of operation. A-Si:C:H film is an attractive alternative to ion-implanted or semiconducting glass due to the wide range of resistivities possible and the feasibility of making deposits over a large area at low cost.

  3. Alloy Selection System

    SciTech Connect

    2001-02-01

    Software will Predict Corrosion Rates to Improve Productivity in the Chemical Industry. Many aspects of equipment design and operation are influenced by the choice of the alloys used to fabricate process equipment.

  4. High efficiency thin film CdTe and a-Si based solar cells

    SciTech Connect

    Compaan, A. D.; Deng, X.; Bohn, R. G.

    2000-01-04

    This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and {approximately}9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence features and studied their correlation with cell performance including their dependence on temperature and E-fields; studied band-tail absorption in CdS{sub x}Te{sub 1{minus}x} films at 10 K and 300 K; collaborated with the National CdTe PV Team on (1) studies of high-resistivity tin oxide (HRT) layers from ITN Energy Systems, (2) fabrication of cells on the HRT layers with 0, 300, and 800-nm CdS, and (3) preparation of ZnTe:N-based contacts on First Solar materials for stress testing; and collaborated with Brooklyn College for ellipsometry studies of CdS{sub x}Te{sub 1{minus}x} alloy films, and with the University of Buffalo/Brookhaven NSLS for synchrotron X-ray fluorescence studies of interdiffusion in CdS/CdTe bilayers. The a-Si group established a baseline for fabricating a-Si-based solar cells with single, tandem, and triple-junction structures; fabricated a-Si/a-SiGe/a-SiGe triple-junction solar cells with an initial efficiency of 9.7% during the second quarter, and 10.6% during the fourth quarter (after 1166 hours of light-soaking under 1-sun light intensity at 50 C, the 10.6% solar cells stabilized at about 9%); fabricated wide-bandgap a-Si top cells, the highest Voc achieved for the single-junction top cell was 1.02 V, and top cells with high FF (up to 74%) were fabricated routinely; fabricated high-quality narrow-bandgap a-SiGe solar cells with 8.3% efficiency; found that bandgap-graded buffer layers improve the performance (Voc and FF) of the narrow-bandgap a-SiGe bottom cells; and found that a small amount of oxygen partial pressure ({approximately}2 {times} 10

  5. Continuous roll-to-roll a-Si photovoltaic manufacturing technology. Annual subcontractor report, 1 April 1992--31 March 1993

    SciTech Connect

    Izu, M.

    1993-12-01

    This report describes work done under a 3-year program to advance ECD`s roll-to-roll, triple-junction photovoltaic manufacturing technologies, to reduce the module production costs, to increase the stabilized module performance, and to expand commercial capacity utilizing ECD technology. The specific 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1.00 per peak watt. Accomplishments during Phase 1 included: (1) ECD successfully incorporated a high-performance Ag/metal-oxide back-reflector system into its continuous roll-to-roll commercial production operation. (2) High-quality a-Si-Ge narrow-band-gap solar cells were incorporated into the manufacturing. (3) ECD demonstrated the continuous roll-to-roll production of high-efficiency, triple-junction, two-band-gap solar cells consistently and uniformly throughout a 762-m (2500-ft) run with high yield. (4) ECD achieved 11.1% initial sub-cell efficiency of triple-junction, two-band-gap a-Si alloy solar cells in the production line. (5) The world`s first 0.37-m{sup 2} (4-ft{sup 2}) PV modules were produced utilizing triple-junction spectrum-splitting solar cells manufactured in the production line. (6) As a result of process optimization to reduce the layer thickness and to improve the gas utilization, ECD achieved a 77% material cost reduction for germane and 58% reduction for disilane. Additionally, ECD developed a new low-cost module that saves approximately 30% in assembly material costs.

  6. Production of hydroxyapatite layers on the plasma electrolytically oxidized surface of titanium alloys.

    PubMed

    Lugovskoy, Alex; Lugovskoy, Svetlana

    2014-10-01

    Hydroxyapatite (HA) is a bioactive material that is widely used for improving the osseointegration of titanium dental implants. Titanium can be coated with HA by various methods, such as chemical vapor deposition (CVD), thermal spray, or plasma spray. HA coatings can also be grown on titanium surfaces by hydrothermal, chemical, and electrochemical methods. Plasma electrolytic oxidation (PEO), or microarc oxidation (MAO), is an electrochemical method that enables the production of a thick porous oxide layer on the surface of a titanium implant. If the electrolyte in which PEO is performed contains calcium and phosphate ions, the oxide layer produced may contain hydroxyapatite. The HA content can then be increased by subsequent hydrothermal treatment. The HA thus produced on titanium surfaces has attractive properties, such as a high porosity, a controllable thickness, and a considerable density, which favor its use in dental and bone surgery. This review summarizes the state of the art and possible further development of PEO for the production of HA on Ti implants. PMID:25175246

  7. Grinding as an approach to the production of high-strength, dispersion-strengthened nickel-base alloys

    NASA Technical Reports Server (NTRS)

    Orth, N. W.; Quatinetz, M.; Weeton, J. W.

    1970-01-01

    Mechanical process produces dispersion-strengthened metal alloys. Power surface contamination during milling is removed by a cleaning method that involves heating thin shapes or partially-compacted milled powder blends in hydrogen to carefully controlled temperature schedules.

  8. Method for the production of strongly adhesive films on titanium and titanium alloys with a metallization process

    NASA Technical Reports Server (NTRS)

    Hahn, H. J.

    1986-01-01

    A process for the spray-application of a strongly adhesive, thick antifriction layer on titanium and titanium alloys is proposed. The titanium/titanium alloy component to be coated is first subjected to cleaning in a pickling bath with reducing additives and sand-blasting, then coated with an intermediate layer of nickel, after which the final layer is applied. The formation of TiNi at the interface ensures strong bonding of the antifriction layer.

  9. Alloy materials

    DOEpatents

    Hans Thieme, Cornelis Leo; Thompson, Elliott D.; Fritzemeier, Leslie G.; Cameron, Robert D.; Siegal, Edward J.

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  10. Preparation of a-Si:H films and devices in the Interdigital-Vertical-Electrode Deposition Apparatus

    SciTech Connect

    Sakai, H.; Ichimura, T.; Kamiyama, M.; Maruyama, K.; Uchida, Y.; Yoshida, T.

    1984-05-01

    A new a-Si:H film deposition apparatus named ''Interdigital-Vertical-Electrode Deposition Apparatus'' has been developed to achieve a high production throughput of a-Si:H devices. In the IVE apparatus, since vertically positioned several rf electrodes and grounded electrodes are arranged interdigitally, the number of discharging section for the deposition can be increased. The a-Si:H films prepared in the IVE apparatus have been evaluated in terms of the film thickness uniformity and electrical and optical properties. It has been confirmed that the IVE apparatus is suitable for fabricating a-Si:H devices with large cell area. The conversion efficiency obtained in glass substrate a-Si:H solar cells was 9.2% and 8.0% for cells with an area of 1 cm/sup 2/ and 100 cm/sup 2/, respectively.

  11. Correlation of the energy product with evolution of the nanostructure in Y,Dy,Nd-(Fe,Co)-B magnetic alloy

    SciTech Connect

    Wu, Y.Q; Tang, W.; Kramer, M.J.; Dennis, K.W.; Oster, N.; McCallum, R.W.; Anderson, I.E.

    2009-07-24

    The devitrification behavior of nanocrystalline MRE{sub 2}(Fe,Co){sub 14}B+ZrC (MRE = Nd+Y+Dy) was studied using differential scanning calorimetry (DSC), synchrotron high temperature x-ray diffraction, and analytical transmission electron microscopy (TEM) techniques. Alloy ribbons were melt spun at 25 m/s to obtain an amorphous structure. Optimum hard magnetic properties (B{sub r} = 7.2 kG, H{sub c} = 12.7 kOe and (BH){sub max} = 10.8 MG Oe) were obtained in ribbons annealed at 750 C for 15 min. A reduced annealing temperature of 638 C and holding time from 0 to 11 min were chosen based on DSC analysis. Large changes in both microstructure and hard magnetic properties were found in a narrow window of annealing time, 4.5-6 min, resulting in a dramatic increase in energy product, remanence and coercivity: 0.96 MG Oe, 5.2 kG, 2.7 kOe to 5.7 MG Oe, 7.2 kG, 8.5 kOe for (BH){sub max}, B{sub r} and H{sub c}, respectively. Energy dispersive x-ray spectroscopy and energy filtered TEM analyses indicate that Zr- and C-rich particles ({approx} 5 nm) and thin grain boundary layers (1-2 nm thick) are formed surrounding 2-14-1 hard phase grains when the annealing time is over 6 min. Further annealing resulted in a more distinct hard phase surrounded by a nonmagnetic grain boundary phase {approx} 1 nm in thickness. The thin grain boundary layer phase starts to disappear with annealing time over 11 min. The partitioning behavior of various elements at different annealing conditions appears to be associated with significant changes in magnetic properties, leading to an improved optimum microstructure.

  12. Low-temperature-processed a-SiOx:H/a-Si:H tandem cells for full spectrum solar cells

    NASA Astrophysics Data System (ADS)

    Kang, Dong-Won; Sichanugrist, Porponth; Miyajima, Shinsuke; Konagai, Makoto

    2015-08-01

    We developed wide-bandgap amorphous silicon (a-Si:H) and amorphous silicon oxide (a-SiOx:H) absorbers by extremely decreasing deposition temperature to as low as 100 °C. By adjusting hydrogen and carbon dioxide gas flow rates, device-quality absorbers and thus suitable single junction cells were obtained. An a-SiOx:H single-junction cell (i = 100 nm) fabricated employing the absorber we developed showed an open circuit voltage (Voc) of 1.007 V and a fill factor of 0.741, which are better than those of a-Si:H cells. This a-SiOx:H cell was introduced in a-SiOx:H/a-Si:H tandem cells as the top cell, which contributed to the achievement of a markedly high Voc of 1.910 V. This tandem cell with an efficiency of 9.25% showed better Voc and current matching property than the a-Si:H/a-Si:H (8.74%) tandem structure. The low-temperature-gradient a-SiOx:H/a-Si:H tandem cells can be a promising configuration for spectrum splitting applications.

  13. Defect formation mechanism during PECVD of a-Si:H

    SciTech Connect

    Maeda, Keiji; Umezu, Ikurou

    1997-07-01

    Defect formation mechanism in a-Si:H during PECVD at substrate temperature below 250 C is considered to be breaking of weak bonds in the Urbach tail. To break weak bonds, an extra energy is necessary. This energy is supplied by the reaction energy of SiH{sub 3} precursor at the growing surface incorporating SiH{sub 2} into the network. The defect density is experimentally shown to be proportional to a product of the energy supply frequency, i.e., SiH{sub 2} density, and the weak bond density which is obtained by the Urbach energy. By analysis using the configurational coordinate diagram the energy level of the broken weak bond is determined to be 0.2 eV above the valence band mobility edge. There is similarity of the defect formation mechanism during deposition to that of the Staebler-Wronski effect.

  14. Hydrogen populations in PECVD a-Si:H,D

    SciTech Connect

    Cull, T.S.; Kernan, M.J.; Chan, P.H.; Fedders, P.A.; Leopold, D.J.; Norberg, R.E.; Wickboldt, P.; Paul, W.

    1997-07-01

    Proton NMR and deuteron NMR (DMR) have been used to measure hydrogen populations in a series of PECVD a-Si:H,D films. The sharp DMR doublet from Si-D is fitted and subtracted out. The residual spectra then show specific signatures for molecular D{sub 2} and HD. The fitting procedures yield quantitative measures of Si-bonded and molecular species. A particular comparison is made between a pair of films prepared as the powered and unpowered electrodes in the same plasma deposition. Both silicon-bonded and molecular populations are significantly different in the two films and correlate with photoresponse products {eta}{mu}{tau} and with IR as well as other materials characterizations.

  15. Chemical composition of individual aerosol particles in workplace air during production of manganese alloys.

    PubMed

    Gunst, S; Weinbruch, S; Wentzel, M; Ortner, H M; Skogstad, A; Hetland, S; Thomassen, Y

    2000-02-01

    Aerosol particle samples were collected at ELKEM ASA ferromanganese (FeMn) and silicomanganese (SiMn) smelters at Porsgrunn, Norway, during different production steps: raw material mixing, welding of protective steel casings, tapping of FeMn and slag, crane operation moving the ladles with molten metal, operation of the Metal Oxygen Refinement (MOR) reactor and casting of SiMn. Aerosol fractions were assessed for the analysis of the bulk elemental composition as well as for individual particle analysis. The bulk elemental composition was determined by inductively coupled plasma atomic emission spectrometry. For individual particle analysis, an electron microprobe was used in combination with wavelength-dispersive techniques. Most particles show a complex composition and cannot be attributed to a single phase. Therefore, the particles were divided into six groups according to their chemical composition: Group I, particles containing mainly metallic Fe and/or Mn; Group II, slag particles containing mainly Fe and/or Mn oxides; Group III, slag particles consisting predominantly of oxidized flux components such as Si, Al, Mg, Ca, Na and K; Group IV, particles consisting mainly of carbon; Group V, mixtures of particles from Groups II, III and IV; Group VI, mixtures of particles from Groups II and III. In raw material mixing, particles originating from the Mn ores were mostly found. In the welding of steel casings, most particles were assigned to Group II, Mn and Fe oxides. During the tapping of slag and metal, mostly slag particles from Group III were found (oxides of the flux components). During movement of the ladles, most particles came from Group II. At the MOR reactor, most of the particles belonged to the slag phase consisting of the flux components (Group III). The particles collected during the casting of SiMn were mainly attributed to the slag phase (Groups III and V). Due to the compositional complexity of the particles, toxicological investigations on the

  16. The effect of prolonged irradiation on defect production and ordering in Fe-Cr and Fe-Ni alloys.

    PubMed

    Vörtler, K; Juslin, N; Bonny, G; Malerba, L; Nordlund, K

    2011-09-01

    The understanding of the primary radiation damage in Fe-based alloys is of interest for the use of advanced steels in future fusion and fission reactors. In this work Fe-Cr alloys (with 5, 6.25, 10 and 15% Cr content) and Fe-Ni alloys (with 10, 40, 50 and 75% Ni content) were used as model materials for studying the features of steels from a radiation damage perspective. The effect of prolonged irradiation (neglecting diffusion), i.e. the overlapping of single 5 keV displacement cascade events, was studied by molecular dynamics simulation. Up to 200 single cascades were simulated, randomly induced in sequence in one simulation cell, to study the difference between fcc and bcc lattices, as well as initially ordered and random crystals. With increasing numbers of cascades we observed a saturation of Frenkel pairs in the bcc alloys. In fcc Fe-Ni, in contrast, we saw a continuous accumulation of defects: the growth of stacking-fault tetrahedra and a larger number of self-interstitial atom clusters were seen in contrast to bcc alloys. For all simulations the defect clusters and the short range order parameter were analysed in detail depending on the number of cascades in the crystal. We also report the modification of the repulsive part of the Fe-Ni interaction potential, which was needed to study the non-equilibrium processes. PMID:21846941

  17. Production and Precipitation Hardening of Beta-Type Ti-35Nb-10Cu Alloy Foam for Implant Applications

    NASA Astrophysics Data System (ADS)

    Mutlu, Ilven; Yeniyol, Sinem; Oktay, Enver

    2016-04-01

    In this study, beta-type Ti-35Nb-10Cu alloy foams were produced by powder metallurgy method for dental implant applications. 35% Nb was added to stabilize the beta-Ti phase with low Young's modulus. Cu addition enhanced sinterability and gave precipitation hardening capacity to the alloy. Sintered specimens were precipitation hardened in order to enhance the mechanical properties. Electrochemical corrosion behavior of the specimens was examined by electrochemical impedance spectroscopy in artificial saliva. Electrochemical impedance spectroscopy results indicated that the oxide film on the surface of foam is a bi-layer structure consisting of outer porous layer and inner barrier layer. Impedance values of barrier layer were higher than porous layer. Corrosion resistance of specimens decreased at high fluoride concentrations and at low pH of artificial saliva. Corrosion resistance of alloys was slightly decreased with aging. Mechanical properties, microstructure, and surface roughness of the specimens were also examined.

  18. Stimulatory effects of the degradation products from Mg-Ca-Sr alloy on the osteogenesis through regulating ERK signaling pathway

    PubMed Central

    Li, Mei; He, Peng; Wu, Yuanhao; Zhang, Yu; Xia, Hong; Zheng, Yufeng; Han, Yong

    2016-01-01

    The influence of Mg-1Ca-xwt.% Sr (x = 0.2, 0.5, 1.0, 2.0) alloys on the osteogenic differentiation and mineralization of pre-osteoblast MC3T3-E1 were studied through typical differentiation markers, such as intracellular alkaline phosphatase (ALP) activity, extracellular collagen secretion and calcium nodule formation. It was shown that Mg-1Ca alloys with different content of Sr promoted cell viability and enhanced the differentiation and mineralization levels of osteoblasts, and Mg-1Ca-2.0Sr alloy had the most remarkable and significant effect among all. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the mRNA expression level of osteogenesis-related genes and intracellular signaling pathways involved in osteogenesis, respectively. RT-PCR results showed that Mg-1Ca-2.0Sr alloy significantly up-regulated the expressions of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), Integrin subunits, as well as alkaline phosphatase (ALP), Bone sialoprotein (BSP), Collagen I (COL I), Osteocalcin (OCN) and Osteopontin (OPN). Western Blotting results suggested that Mg-1Ca-2.0Sr alloy rapidly induced extracellular signal-regulated kinase (ERK) activation but showed no obvious effects on c-Jun N terminal kinase (JNK) and p38 kinase of MAPK. Taken together, our results demonstrated that Mg-1Ca-2.0Sr alloy had excellent biocompatibility and osteogenesis via the ERK pathway and is expected to be promising as orthopedic implants and bone repair materials. PMID:27580744

  19. Stimulatory effects of the degradation products from Mg-Ca-Sr alloy on the osteogenesis through regulating ERK signaling pathway.

    PubMed

    Li, Mei; He, Peng; Wu, Yuanhao; Zhang, Yu; Xia, Hong; Zheng, Yufeng; Han, Yong

    2016-01-01

    The influence of Mg-1Ca-xwt.% Sr (x = 0.2, 0.5, 1.0, 2.0) alloys on the osteogenic differentiation and mineralization of pre-osteoblast MC3T3-E1 were studied through typical differentiation markers, such as intracellular alkaline phosphatase (ALP) activity, extracellular collagen secretion and calcium nodule formation. It was shown that Mg-1Ca alloys with different content of Sr promoted cell viability and enhanced the differentiation and mineralization levels of osteoblasts, and Mg-1Ca-2.0Sr alloy had the most remarkable and significant effect among all. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the mRNA expression level of osteogenesis-related genes and intracellular signaling pathways involved in osteogenesis, respectively. RT-PCR results showed that Mg-1Ca-2.0Sr alloy significantly up-regulated the expressions of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), Integrin subunits, as well as alkaline phosphatase (ALP), Bone sialoprotein (BSP), Collagen I (COL I), Osteocalcin (OCN) and Osteopontin (OPN). Western Blotting results suggested that Mg-1Ca-2.0Sr alloy rapidly induced extracellular signal-regulated kinase (ERK) activation but showed no obvious effects on c-Jun N terminal kinase (JNK) and p38 kinase of MAPK. Taken together, our results demonstrated that Mg-1Ca-2.0Sr alloy had excellent biocompatibility and osteogenesis via the ERK pathway and is expected to be promising as orthopedic implants and bone repair materials. PMID:27580744

  20. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant

    PubMed Central

    Park, Robert M.; Baldwin, Mary; Bouchard, Maryse F.; Mergler, Donna

    2015-01-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t = 6.95, 7.44, respectively; p < 10 −5). Partitioning exposure concentrations based on process origin into two categories: (1) “large” respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) “small” respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t = −0.16, p = 0.87) and Mn-SRP (t = 6.45, p < 10 −5), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t = 7.87 vs. 7.44, R2 = 0.2333 vs. 0.2157). In a model containing both duration (t = 0.79, p = 0.43) and (square root) fume (t = 2.47, p = 0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood

  1. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant.

    PubMed

    Park, Robert M; Baldwin, Mary; Bouchard, Maryse F; Mergler, Donna

    2014-12-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t=6.95, 7.44, respectively; p<10(-5)). Partitioning exposure concentrations based on process origin into two categories: (1) "large" respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) "small" respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t=-0.16, p=0.87) and Mn-SRP (t=6.45, p<10(-5)), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t=7.87 vs. 7.44, R(2)=0.2333 vs. 0.2157). In a model containing both duration (t=0.79, p=0.43) and (square root) fume (t=2.47, p=0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood and other body tissues and be

  2. Molybdenum carbide supported nickel-molybdenum alloys for synthesis gas production via partial oxidation of surrogate biodiesel

    NASA Astrophysics Data System (ADS)

    Shah, Shreya; Marin-Flores, Oscar G.; Norton, M. Grant; Ha, Su

    2015-10-01

    In this study, NiMo alloys supported on Mo2C are synthesized by wet impregnation for partial oxidation of methyl oleate, a surrogate biodiesel, to produce syngas. When compared to single phase Mo2C, the H2 yield increases from 70% up to >95% at the carbon conversion of ∼100% for NiMo alloy nanoparticles that are dispersed over the Mo2C surface. Supported NiMo alloy samples are prepared at two different calcination temperatures in order to determine its effect on particle dispersion, crystalline phase and catalytic properties. The reforming test data indicate that catalyst prepared at lower calcination temperature shows better nanoparticle dispersion over the Mo2C surface, which leads to higher initial performance when compared to catalysts synthesized at higher calcination temperature. Activity tests using the supported NiMo alloy on Mo2C that are calcined at the lower temperature of 400 °C shows 100% carbon conversion with 90% H2 yield without deactivation due to coking over 24 h time-on-stream.

  3. Optimization of the procedure for determining integral texture parameters of products from zirconium-based alloys using the orientation distribution function

    NASA Astrophysics Data System (ADS)

    Perlovich, Yu A.; Isaenkova, M. G.; Krymskaya, O. A.; Fesenko, V. A.; Babich, Y. A.

    2016-04-01

    Integral texture Kearns parameters, or f-parameters, are the one of the characteristics that is controlled during the tube production of Zr-based alloys now. These parameters define the anisotropy of physical and mechanical properties of the products. f-parameters are the sum of effective fractions of basal normals aligned in a selected sample direction. However, so far there is no standardized procedure for their calculation. The widespread availability of X-ray diffractometers, the high statistical significance of the results and the software development for texture analysis causes the optimality of the f-parameters determination by complete pole figures (0001) calculated through orientation distribution function (ODF). Accuracy analysis of the ODF extraction by several incomplete pole figures using LaboTex software was carried out in this paper. The comparison of the calculated data was performed with experimental complete pole figures (0001) obtained by «sewing» method. Various texture types, different number and combinations of incomplete pole figures were considered. For this purpose, 6 incomplete pole figures - - were registered for each of three mutually perpendicular surfaces of the CANDU-tube sample. By comparison of experimental and calculated by ODF complete pole figures as well as f-parameters, procedures of their determination were optimized for products from Zr-based alloys.

  4. Molecular beam epitaxy of GaNAs alloys with high As content for potential photoanode applications in hydrogen production

    SciTech Connect

    Novikov, S. V.; Staddon, C. R.; Foxon, C. T.; Yu, K. M.; Broesler, R.; Hawkridge, M.; Liliental-Weber, Z.; Walukiewicz, W.; Denlinger, J.; Demchenko, I.

    2009-10-06

    The authors have succeeded in growing GaN1?xAsx alloys over a large composition range (0 < x < 0.8) by plasma-assisted molecular beam epitaxy. The enhanced incorporation of As was achieved by growing the films with high As{sub 2} flux at low (as low as 100 C) growth temperatures, which is much below the normal GaN growth temperature range. Using x-ray and transmission electron microscopy, they found that the GaNAs alloys with high As content x > 0.17 are amorphous. Optical absorption measurements together with x-ray absorption and emission spectroscopy results reveal a continuous gradual decrease in band gap from -3.4 to < 1 eV with increasing As content. The energy gap reaches its minimum of -0.8 eV at x - 0.8. The composition dependence of the band gap of the crystalline GaN{sub 1?x}As{sub x} alloys follows the prediction of the band anticrossing model (BAC). However, our measured band gap of amorphous GaN{sub 1?x}As{sub x} with 0.3 < x < 0.8 are larger than that predicted by BAC. The results seem to indicate that for this composition range the amorphous GaN{sub 1?x}As{sub x} alloys have short-range ordering that resembles random crystalline GaN{sub 1?x}As{sub x} alloys. They have demonstrated the possibility of the growth of amorphous GaN{sub 1?x}As{sub x} layers with variable As content on glass substrates

  5. COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

    SciTech Connect

    B. Lanning; J. Arps

    2004-04-01

    Extending upon development efforts last quarter to produce ''free-standing'', copper and palladium alloy films, the goal this quarter has been to produce pinhole-free, Pd-Cu alloy films up to 5 x 5 inches in area (1-3 microns thick) using both magnetron sputtering and e-beam evaporation on PVA (Solublon) and polystyrene backing materials. A set of experiments were conducted to assess processing methods/solutions chemistry for removing the polymer backing material from the Pd-Cu film. For all of the alloy films produced to this point, we were unable to produce pinhole-free films on plastic although we were able to produce free-standing Pd-Cu films at less than 0.5 microns thick with minimal intrinsic stress. Subsequently, to evaluate gas permeation and leakage across the films, two films were sandwiched together on top of a porous Monel support disc (25 mm in diameter) and then tested in a leak test apparatus. Using two Cu films (10 micron thickness total) in the sandwich configuration, leak rates were about 20% of the background leak rate.

  6. COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

    SciTech Connect

    B. Lanning; J. Arps

    2004-01-01

    Competed fabrication of an initial series of copper and palladium-copper alloy membranes in the range of 1-8 microns in thickness up to 6 inch x 8 inch in area. Films were produced using both e-beam evaporation (with and without ion assist) and magnetron sputtering from a 60%Pd/40%Cu alloy target. Pure copper and palladium-copper alloy films, with essential no intrinsic stress, were produced on both polystyrene and polyvinyl alcohol substrates. Various processing parameters and techniques were investigated in order to minimize defects and maximize uniformity in single layer films. Even though films to date are visually defect free, we are able to observe sub-micron size defects using a backlighting technique; we are currently investigating a number of methods to create a gas impermeable membrane. At present, the metal films are effectively removed from the polymer backing material by merely immersing the film in an appropriate solvent; chloroform for the polystyrene and water for the PVA. In the future we plan to investigate alternative methods for removing the polymer backing that are more suited to large scale, low-cost manufacturing.

  7. Characterization of the visible photoluminescence from porous a-Si:H and porous a-Si:C:H thin films

    SciTech Connect

    Estes, M.J.; Hirsch, L.R.; Wichart, S.; Moddel, G.

    1996-12-31

    The authors report on the influence of doping, temperature, porosity, and bandgap on the visible photoluminescence properties of anodically-etched porous a-Si:H and a-Si:C:H thin films. Only boron-doped, p-type a-Si:H or a-Si:C:H samples exhibited any visible photoluminescence. The authors see evidence of discrete defect or impurity levels in temperature-dependent luminescence measurements. Unlike in porous crystalline silicon, they see no correlation of luminescence energy with porosity. The authors do, though, observe a correlation of luminescence energy with bandgap of the starting a-Si:C:H films. They discuss the implication of these observations on the nature of the luminescence mechanism.

  8. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  9. BRAZING ALLOYS

    DOEpatents

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

    1963-02-26

    A brazing alloy which, in the molten state, is characterized by excellent wettability and flowability, said alloy being capable of forming a corrosion resistant brazed joint wherein at least one component of said joint is graphite and the other component is a corrosion resistant refractory metal, said alloy consisting essentially of 20 to 50 per cent by weight of gold, 20 to 50 per cent by weight of nickel, and 15 to 45 per cent by weight of molybdenum. (AEC)

  10. VANADIUM ALLOYS

    DOEpatents

    Smith, K.F.; Van Thyne, R.J.

    1959-05-12

    This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

  11. Monotonic and cyclic deformation behavior of a SiCw/6061 Al composite at elevated temperature

    SciTech Connect

    Wang, L.; Sun, Z.M.; Kobayashi, T.

    1996-10-15

    With the advent of new processing techniques, the technological interest and research activity in the development of metal-matrix composites have increased rapidly. Particularly, discontinuously reinforced composites, such as whisker and particle reinforced aluminum-based metal-matrix composites, exhibit attractive advantages, such as high specific modulus, high specific strength, good fatigue resistance and easy fabrication. They have emerged as a new class of structural materials for ambient and elevated temperature applications in aerospace and automobile industries. Therefore, great attention has been paid on their mechanical properties. However, a limited number of investigations on the cyclic deformation behavior have been reported, and little research has been done in this aspect at elevated temperature. The present study is based on a previous study at room temperature to investigate the monotonic and cyclic deformation behavior of a SiC whisker reinforced 6061 Al alloy composite and its unreinforced counterpart at elevated temperature.

  12. COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

    SciTech Connect

    J. Arps; K. Coulter

    2006-09-30

    In the past quarter, we have conducted additional characterization and permeation tests on different Pd alloy membranes including PdCuTa ternary alloy materials. We attempted to address some discrepancies between SwRI{reg_sign} and CSM relating to PdCu stoichiometry by preparing a range of PdCu membranes with compositions from {approx}58-65 at% Pd (bal. Cu). While some difficulties in cutting and sealing these thin membranes at CSM continue, some progress has been made in identifying improved membrane support materials. We have also completed an initial cost analysis for large-scale vacuum deposition and fabrication of thin Pd ally membranes and project that the process can meet DOE cost targets. Minimal progress was made in the past quarter relating to the testing of prototype membrane modules at Idatech. In the past quarter Idatech was acquired by a UK investment firm, which we believe may have impacted the ability of key technical personnel to devote sufficient time to support this effort. We are hopeful their work can be completed by the end of the calendar year.

  13. Material properties and device evaluations of ECR-deposited a-Si:H and a-SiC:H films

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Pool, F. S.; Essick, J. M.

    1991-01-01

    Device-quality a-Si:H and a-SiC:H films have been deposited using electron cyclotron resonance (ECR) microwave plasmas of SiH4, CH4, and H2 mixtures. Typical material properties of ECR-deposited, photosensitive a-Si:H films are: (1) high photosensitivity up to 2 x 106 with a photoconductivity of 10 exp -5 to 10 exp -4/(Ohm-cm), (2) a Tauc gap of 1.75 to 1.85 eV, (3) an Urbach slope of 50-60 meV determined by the constant photocurrent method, and (4) an integrated defect density of 1-2 x 10 exp 16/cu cm determined by junction capacitance measurements. Highly conductive, p-type a-SiC:H films have been produced by ECR plasmas with a conductivity of 0.2/(Ohm-cm).

  14. Micro Raman spectroscopy used for the study of corrosion products on copper alloys: study of the chemical composition of artificial patinas used for restoration purposes.

    PubMed

    Hayez, Valerie; Costa, Virginia; Guillaume, Joseph; Terryn, Herman; Hubin, Annick

    2005-04-01

    Studying the atmospheric corrosion of copper alloy artifacts is important to acquire a better knowledge about the condition of the object and its possible conservation and restoration. The nature of the formed product, e.g. sulfate, carbonate or chloride, depends on factors such as the amount of polluting elements or humidity but may also depend on the nature of the underlying aesthetic patina, applied by the artist. The composition of the patination solution and the method of patination will both influence the nature of this aesthetic patina, i.e. its chemical composition and morphology. However, although a lot of patination recipes exist, little is known about these patinas as far as composition, structure and ageing is concerned. Therefore, a combination of several surface analytical techniques is required for the complete characterization of patina layers. In this paper, Raman spectroscopy is used to study the characteristics of several patinas obtained on copper following different traditional recipes. PMID:15776167

  15. ZIRCONIUM ALLOY

    DOEpatents

    Wilhelm, H.A.; Ames, D.P.

    1959-02-01

    A binary zirconiuin--antimony alloy is presented which is corrosion resistant and hard containing from 0.07% to 1.6% by weight of Sb. The alloys have good corrosion resistance and are useful in building equipment for the chemical industry.

  16. URANIUM ALLOYS

    DOEpatents

    Seybolt, A.U.

    1958-04-15

    Uranium alloys containing from 0.1 to 10% by weight, but preferably at least 5%, of either zirconium, niobium, or molybdenum exhibit highly desirable nuclear and structural properties which may be improved by heating the alloy to about 900 d C for an extended period of time and then rapidly quenching it.

  17. Testing and prediction of erosion-corrosion for corrosion resistant alloys used in the oil and gas production industry

    NASA Astrophysics Data System (ADS)

    Rincon, Hernan E.

    The corrosion behavior of CRAs has been thoroughly investigated and documented in the public literature by many researchers; however, little work has been done to investigate erosion-corrosion of such alloys. When sand particles are entrained in the flow, the degradation mechanism is different from that observed for sand-free corrosive environment. There is a need in the oil and gas industry to define safe service limits for utilization of such materials. The effects of flow conditions, sand rate, pH and temperature on the erosion-corrosion of CRAs were widely studied. An extensive experimental work was conducted using scratch tests and flow loop tests using several experimental techniques. At high erosivity conditions, a synergistic effect between erosion and corrosion was observed. Under the high sand rate conditions tested, erosivity is severe enough to damage the passive layer protecting the CRA thereby enhancing the corrosion rate. In most cases there is likely a competition between the rates of protective film removal due to mechanical erosion and protective film healing. Synergism occurs for each of the three alloys examined (13Cr and Super13Cr and 22Cr); however, the degree of synergism is quite different for the three alloys and may not be significant for 22Cr for field conditions where erosivities are typically much lower that those occurring in the small bore loop used in this research. Predictions of the corrosion component of erosion-corrosion based on scratch test data compared reasonably well to test results from flow loops for the three CRAs at high erosivity conditions. Second order behavior appears to be an appropriate and useful model for representing the repassivation process of CRAs. A framework for a procedure to predict penetration rates for erosion-corrosion conditions was developed based on the second order model behavior observed for the re-healing process of the passive film of CRAs and on computational fluid dynamics (CFD) simulations

  18. Deposition of a-SiC:H, a-SiO{sub 2} and tetrahedral-C with programmable in-situ etching. Final performance report, March 1, 1988--November 30, 1991

    SciTech Connect

    Collis, W.J.

    1995-06-01

    This research program was originally defined to investigate the deposition of semiconductor and dielectric thin films using a low pressure remote plasma chemical vapor deposition system incorporating a process for etching the films. This etching was to be performed in a periodic fashion during the deposition process to remove defect regions in the film being deposited. The goal was to remove voids and other defects which are characteristic of low temperature deposition processes. While the original research proposal suggested that the studies include the amorphous alloys (Si/C):H and (Si/Ge):H, subsequent funding reductions limited the work to the deposition of an amorphous silicon alloy material (a-Si:H). Intrinsic and doped forms of these materials have applications in the fabrication of single and multi-junction thin film solar cells.

  19. Charge collection in a-Si:H/a-Si{sub 1-x}C{sub x} multilayers photodetectors

    SciTech Connect

    Jing, T.; Drewray, J.; Hong, W.S.; Lee, H.; Kaplan, S.N.; Mireshghi, A.; Perez-Mendez, V.; Delgado, J.C.; Bertomeu, J.

    1994-04-01

    Amorphous semiconductors have been used as thin film transistor(TFT), solar cell, phototransistors. In this paper we study the charge collected properties of a-Si:H/a-Si{sub 1-x}C:H{sub x} multilayer pin photodiode. In a-Si:H pin photodiode, the photogenerated carriers can be totally collected under strong electric field under reverse bias. However, our measurements show that in the a-Si:H/a-Si{sub l-x}C:H{sub x} multilayer pin photodiode photogenerated electrons and holes drift toward the electrodes under a certain bias, the total collected charge shows no saturation with bias and exhibits a continuous increase with reverse bias. We classify that the device works at two regions. In Region 1, the device behaves like a photodiode. This charge collection efficiency drop from theoretical value may indicate charge capture or confinement at the interfaces and trapping at the a-Si:H potential wells. These charges trapped or confined can be released at the interface and quantum well at higher electric field. In Region 2, above a critical bias voltage, the device works as a breakdown diode with a series photosensitive resistor which contributes higher collection efficiency, namely optical gain greater than unity.

  20. Effect of transcrystalline fusing during flash heat of alloyed steels and its application prospects in welding production

    SciTech Connect

    Kalinushkin, E.P.; Taran, J.N.; Cerednichenko, G.M.; Gutchenko, A.P.

    1996-12-31

    The fusing and crystallization of many industrial alloy (peritectic-type steels) steels are usually treated as complex process presupposing the successive implementation of the following transformations: L {Leftrightarrow} {delta}, crystallization (fusing) of {delta}-ferrite; (L + {delta} {Leftrightarrow} {gamma}), the peritectic reaction of forming austenite ({delta}-ferrite); L {Leftrightarrow} ({gamma} + k), the eutectic reaction. However, though the general form of this scheme does not evoke any doubts, the mechanism of some crystallization (fusing) processes on actual kinetic conditions of steel cooling (heating) was studied insufficiently. To the greatest extent this relates to welding processes, because structure formation in the weld at the final stages of solidification inherits all the features of the preceding phase transformations. Moreover, high heating and cooling rates during welding provide special effects. Some of them which may have practical application are reported in this paper.

  1. Production and characterization of high porosity porous Fe-Cr-C alloys by the space holder leaching technique

    NASA Astrophysics Data System (ADS)

    Tian, Da-rong; Pang, Yu-hua; Yu, Liang; Sun, Li

    2016-07-01

    Spherical carbamide particles were employed to produce porous Fe-Cr-C alloy with high porosity and large aperture via the space-holder leaching technique. A series of porous samples were prepared by regulating the processing parameters, which included the carbamide content and the compaction pressure. The pore characteristics and compression properties of the produced samples were investigated. The samples were characterized by scanning electron microscopy, image analysis, and compression tests. The results showed that the macro-porosity and the mean pore size were in the ranges 40.4%-82.4% and 0.6-1.5 mm, respectively. The compressive strength varied between 25.38 MPa and 127.9 MPa, and was observed to decrease with increasing total porosity.

  2. COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

    SciTech Connect

    J. Arps

    2006-01-01

    In the past quarter, significant progress has been made in optimize the deposition and release characteristics of ultrathin (less than 4 micron) membranes from rigid silicon substrates. Specifically, we have conducted a series of statistically designed experiments to examine the effects of plasma cleaning and compliant layer deposition conditions on the stress, release and pinhole density of membranes deposited on 4 inch and 6 inch round substrates. With this information we have progressed to the deposition and release of ultra-thin membranes from 12-inch diameter (113 sq. in.) rigid substrates, achieving a key milestone for large-area membrane fabrication. Idatech received and is beginning preparations to test the Pd alloy membranes fabricated at SwRI the previous quarter. They are currently evaluating alternate gasketing methods and support materials that will allow for effective sealing and mounting of such thin membranes. David Edlund has also recently left Idatech and Bill Pledger (Chief Engineer) has replaced him as the primary technical point of contact. At Idetech's request a small number of additional 16 sq. in, samples were provided in a 2 in. by 8 in. geometry for use in a new module design currently under development. Recent work at the Colorado School of Mines has focused on developing preconditioning methods for thin Pd alloy membranes (6 microns or less) and continuing tests of thin membranes produced at SwRI. Of particular note, a 300-hour short-term durability study was completed over a range of temperatures from 300-450 C on a foil that showed perfect hydrogen selectivity throughout the entire test. With a 20 psi driving force, pure hydrogen flow rates ranged from 500 to 700 cc/min. Calculated at DOE specified conditions, the H{sub 2} flux of this membrane exceeded the 2010 Fossil target value of 200 SCFH/ft{sup 2}.

  3. Tungsten and tungsten-alloy powder metallurgy: Powder production and applications-excluding lamps. November 1971-July 1989 (Citations from the US Patent data base). Report for November 1971-July 1989

    SciTech Connect

    Not Available

    1989-10-01

    This bibliography contains citations of selected patents concerning the preparation of metallic and ceramic powders of tungsten and tungsten alloys including various applications of these materials. The hydrogen reduction of tungsten compounds together with alloying-element compounds produce forms with characteristics of high density, hardness, wear resistance, high melting points, and abrasiveness. Topics include production of various cathodes, heaters, filament wires, electrical contacts, acoustic absorbers, high-density sheets and coatings, hard penetrators, and tungsten carbide and metallized ceramics. Tungsten halogen lamps are examined in a separate bibliography. (Contains 60 citations fully indexed and including a title list.)

  4. Aluminum alloy

    NASA Technical Reports Server (NTRS)

    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.

  5. PLUTONIUM ALLOYS

    DOEpatents

    Chynoweth, W.

    1959-06-16

    The preparation of low-melting-point plutonium alloys is described. In a MgO crucible Pu is placed on top of the lighter alloying metal (Fe, Co, or Ni) and the temperature raised to 1000 or 1200 deg C. Upon cooling, the alloy slug is broke out of the crucible. With 14 at. % Ni the m.p. is 465 deg C; with 9.5 at. % Fe the m.p. is 410 deg C; and with 12.0 at. % Co the m.p. is 405 deg C. (T.R.H.) l6262 l6263 ((((((((Abstract unscannable))))))))

  6. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  7. BRAZING ALLOYS

    DOEpatents

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

    1962-02-20

    A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)

  8. Tin induced a-Si crystallization in thin films of Si-Sn alloys

    SciTech Connect

    Neimash, V. E-mail: oleks.goushcha@nuportsoft.com; Poroshin, V.; Goushcha, A. O. E-mail: oleks.goushcha@nuportsoft.com; Shepeliavyi, P.; Yukhymchuk, V.; Melnyk, V.; Kuzmich, A.; Makara, V.

    2013-12-07

    Effects of tin doping on crystallization of amorphous silicon were studied using Raman scattering, Auger spectroscopy, scanning electron microscopy, and X-ray fluorescence techniques. Formation of silicon nanocrystals (2–4 nm in size) in the amorphous matrix of Si{sub 1−x}Sn{sub x}, obtained by physical vapor deposition of the components in vacuum, was observed at temperatures around 300 °C. The aggregate volume of nanocrystals in the deposited film of Si{sub 1−x}Sn{sub x} exceeded 60% of the total film volume and correlated well with the tin content. Formation of structures with ∼80% partial volume of the nanocrystalline phase was also demonstrated. Tin-induced crystallization of amorphous silicon occurred only around the clusters of metallic tin, which suggested the crystallization mechanism involving an interfacial molten Si:Sn layer.

  9. Structural and photoelectronic properties of a-SiGe:H thin films with varied Ge prepared by PECVD

    NASA Astrophysics Data System (ADS)

    Xu, Rui; Li, Wei; He, Jian; Qi, Kang-Cheng; Jiang, Ya-Dong

    2011-12-01

    Hydrogenated amorphous silicon-germanium (a-SiGe:H) alloy thin films were fabricated by conventional radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) with a gas mixture of silane (SiH4) and germane (GeH4). The structural, optical and electrical properties of the films with different gas volume fraction of germane were investigated by Raman and Fourier transform infrared (FTIR) spectroscopy, ultraviolet and visible (UV-vis) spectroscopy and I-V curves, respectively. The amorphous network and structural disorder in the a-SiGe:H thin films were evaluated by Raman spectroscopy. Meanwhile, the Si-H and Ge-H configurations of the films were investigated by FTIR spectroscopy. From UV-vis spectroscopy and I-V curves, the optical and electrical properties of the testing films could be deduced with varied germanium. It can be concluded that the structural and photoelectronic properties of a-SiGe:H thin films can be influenced apparently by varing of GeH4/(SiH4+ GeH4) ratio in PECVD process.

  10. Environmental fatigue in aluminum-lithium alloys

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.

    1992-01-01

    Aluminum-lithium alloys exhibit similar environmental fatigue crack growth characteristics compared to conventional 2000 series alloys and are more resistant to environmental fatigue compared to 7000 series alloys. The superior fatigue crack growth behavior of Al-Li alloys 2090, 2091, 8090, and 8091 is due to crack closure caused by tortuous crack path morphology and crack surface corrosion products. At high R and reduced closure, chemical environment effects are pronounced resulting in accelerated near threshold da/dN. The beneficial effects of crack closure are minimized for small cracks resulting in rapid growth rates. Limited data suggest that the 'chemically small crack' effect, observed in other alloy system, is not pronounced in Al-Li alloys. Modeling of environmental fatigue in Al-Li-Cu alloys related accelerated fatigue crack growth in moist air and salt water to hydrogen embrittlement.

  11. Study and Simulation of the Heterojunction Thin Film Solar Cell a-Si( n)/a-Si( i)/c-Si( p)/a-Si( i)/a-Si( p)

    NASA Astrophysics Data System (ADS)

    Toufik, Zarede; Hamza, Lidjici; Mohamed, Fathi; Achour, Mahrane

    2016-08-01

    In this article, we present a study based on numerical simulation of the electrical characteristics of a thin-film heterojunction solar cell (a-Si( n)/a-Si( i)/c-Si( p)/a-Si( i)/a-Si( p)), using the automat for simulation of hetero-structures (AFORS-Het) software. This cell is composed of four main layers of silicon (Si): (i) 5 nm amorphous silicon doped n, (ii) 100 μm crystalline silicon (substrate) doped p, (iii) 5 nm amorphous silicon doped p, and (iv) 3 nm amorphous silicon intrinsic. This cell has a front and rear metal contact of aluminum and zinc oxide (ZnO) front layer transparent conductive oxide of 80 nm thickness. The simulations were performed at conditions of "One Sun" irradiation with air mass 1.5 (AM1.5), and under absolute temperature T = 300 K. The simulation results have shown a high electrical conversion efficiency of about 30.29% and high values of open circuit voltage V oc = 779 mV. This study has also shown that the studied cell has good quality light absorption on a very broad spectrum.

  12. Corrosion of a-Si cells and modules

    NASA Technical Reports Server (NTRS)

    Mon, G. R.; Wen, L.; Ross, R. G., Jr.

    1987-01-01

    The authors report on corrosion/erosion phonemena observed in exposing a-Si cells, modules, and specially designed test structures to natural and accelerated test environments. Relevant cell and module I-V curve data used for monitoring degradation are presented. The causes of the observed degradation, methods of mitigation, and consequences for fielded modules are discussed.

  13. Osteoblasts exhibit a more differentiated phenotype and increased bone morphogenetic protein production on titanium alloy substrates than on poly-ether-ether-ketone

    PubMed Central

    Olivares-Navarrete, Rene; Gittens, Rolando A.; Schneider, Jennifer M.; Hyzy, Sharon L.; Haithcock, David A.; Ullrich, Peter F.; Schwartz, Zvi; Boyan, Barbara D.

    2013-01-01

    Background Context Multiple biomaterials are clinically available to spine surgeons for performing interbody fusion. Poly-ether-ether-ketone (PEEK) is used frequently for lumbar spine interbody fusion, but alternative materials are also used, including titanium (Ti) alloys. Previously, we showed that osteoblasts exhibit a more differentiated phenotype when grown on machined or grit-blasted titanium aluminum vanadium (Ti6Al4V) alloys with micron-scale roughened surfaces than when grown on smoother Ti6Al4V surfaces or on tissue culture polystyrene (TCPS). We hypothesized that osteoblasts cultured on rough Ti alloy substrates would present a more mature osteoblast phenotype than cells cultured on PEEK, suggesting that textured Ti6Al4V implants may provide a more osteogenic surface for interbody fusion devices. Purpose The aim of the present study was to compare osteoblast response to smooth Ti6Al4V (sTiAlV) and roughened Ti6Al4V (rTiAlV) with their response to PEEK with respect to differentiation and production of factors associated with osteogenesis. Study Design This in vitro study compared the phenotype of human MG63 osteoblast-like cells cultured on PEEK, sTiAlV, or rTiAlV surfaces and their production of bone morphogenetic proteins (BMPs). Methods Surface properties of PEEK, sTiAlV, and rTiAlV discs were determined. Human MG63 cells were grown on TCPS and the discs. Confluent cultures were harvested, and cell number, alkaline phosphatase–specific activity, and osteocalcin were measured as indicators of osteoblast maturation. Expression of messenger RNA (mRNA) for BMP2 and BMP4 was measured by real-time polymerase chain reaction. Levels of BMP2, BMP4, and BMP7 proteins were also measured in the conditioned media of the cell cultures. Results Although roughness measurements for sTiAlV (Sa=0.09±0.01), PEEK (Sa=0.43±0.07), and rTiAlV (Sa= 1.81±0.51) varied, substrates had similar contact angles, indicating comparable wettability. Cell morphology differed

  14. Elevated temperature aluminum alloys

    NASA Technical Reports Server (NTRS)

    Meschter, Peter (Inventor); Lederich, Richard J. (Inventor); O'Neal, James E. (Inventor)

    1989-01-01

    Three aluminum-lithium alloys are provided for high performance aircraft structures and engines. All three alloys contain 3 wt % copper, 2 wt % lithium, 1 wt % magnesium, and 0.2 wt % zirconium. Alloy 1 has no further alloying elements. Alloy 2 has the addition of 1 wt % iron and 1 wt % nickel. Alloy 3 has the addition of 1.6 wt % chromium to the shared alloy composition of the three alloys. The balance of the three alloys, except for incidentql impurities, is aluminum. These alloys have low densities and improved strengths at temperatures up to 260.degree. C. for long periods of time.

  15. Influence of base pressure and atmospheric contaminants on a-Si:H solar cell properties

    SciTech Connect

    Woerdenweber, J.; Schmitz, R.; Mueck, A.; Zastrow, U.; Niessen, L.; Gordijn, A.; Carius, R.; Beyer, W.; Rau, U.; Merdzhanova, T.; Stiebig, H.

    2008-11-01

    The influence of atmospheric contaminants oxygen and nitrogen on the performance of thin-film hydrogenated amorphous silicon (a-Si:H) solar cells grown by plasma-enhanced chemical vapor deposition at 13.56 MHz was systematically investigated. The question is addressed as to what degree of high base pressures (up to 10{sup -4} Torr) are compatible with the preparation of good quality amorphous silicon based solar cells. The data show that for the intrinsic a-Si:H absorber layer exists critical oxygen and nitrogen contamination levels (about 2x10{sup 19} atoms/cm{sup 3} and 4x10{sup 18} atoms/cm{sup 3}, respectively). These levels define the minimum impurity concentration that causes a deterioration in solar cell performance. This critical concentration is found to depend little on the applied deposition regime. By enhancing, for example, the flow of process gases, a higher base pressure (and leak rate) can be tolerated before reaching the critical contamination level. The electrical properties of the corresponding films show that increasing oxygen and nitrogen contamination results in an increase in dark conductivity and photoconductivity, while activation energy and photosensitivity are decreased. These effects are attributed to nitrogen and oxygen induced donor states, which cause a shift of the Fermi level toward the conduction band and presumably deteriorate the built-in electric field in the solar cells. Higher doping efficiencies are observed for nitrogen compared to oxygen. Alloying effects (formation of SiO{sub x}) are observed for oxygen contaminations above 10{sup 20} atoms/cm{sup 3}, leading to an increase in the band gap.

  16. Influence of base pressure and atmospheric contaminants on a-Si:H solar cell properties

    NASA Astrophysics Data System (ADS)

    Woerdenweber, J.; Merdzhanova, T.; Schmitz, R.; Mück, A.; Zastrow, U.; Niessen, L.; Gordijn, A.; Carius, R.; Beyer, W.; Stiebig, H.; Rau, U.

    2008-11-01

    The influence of atmospheric contaminants oxygen and nitrogen on the performance of thin-film hydrogenated amorphous silicon (a-Si:H) solar cells grown by plasma-enhanced chemical vapor deposition at 13.56 MHz was systematically investigated. The question is addressed as to what degree of high base pressures (up to 10-4 Torr) are compatible with the preparation of good quality amorphous silicon based solar cells. The data show that for the intrinsic a-Si:H absorber layer exists critical oxygen and nitrogen contamination levels (about 2×1019 atoms/cm3 and 4×1018 atoms/cm3, respectively). These levels define the minimum impurity concentration that causes a deterioration in solar cell performance. This critical concentration is found to depend little on the applied deposition regime. By enhancing, for example, the flow of process gases, a higher base pressure (and leak rate) can be tolerated before reaching the critical contamination level. The electrical properties of the corresponding films show that increasing oxygen and nitrogen contamination results in an increase in dark conductivity and photoconductivity, while activation energy and photosensitivity are decreased. These effects are attributed to nitrogen and oxygen induced donor states, which cause a shift of the Fermi level toward the conduction band and presumably deteriorate the built-in electric field in the solar cells. Higher doping efficiencies are observed for nitrogen compared to oxygen. Alloying effects (formation of SiOx) are observed for oxygen contaminations above 1020 atoms/cm3, leading to an increase in the band gap.

  17. Structure and electronic parameters of a-Si:H deposited by DC-MASD

    SciTech Connect

    Golikova, O.A.; Kuznetsov, A.N.; Kudoyarova, V.K.; Kazanin, M.M.; Adriaenssens, G.J.; Herremans, H.

    1997-07-01

    A systematic study of structure and electronic parameters of a-Si:H deposited by dc-magnetron assisted SiH{sub 4} decomposition (MASD) depending on substrate temperature, gas pressure, gas flow and grid mounting has been carried out. Correlation between the film microstructure, dangling bond density and electron mobility-life time product were established. The photoconductivity changes under light soaking were shown to be minimal when the films contained hydrogen in the (SiH{sub 2}){sub n} chains.

  18. Mechanically alloyed Ni-base alloys for heat-resistant applications

    SciTech Connect

    Wilson, R.K.; Fischer, J.J.

    1995-12-31

    INCONEL alloys MA 754 and MA 758 are nickel-base oxide dispersion-strengthened (ODS) alloys made by mechanical alloying (MA). Commercial use of Ma Ni-base alloys to date has been predominantly in aerospace applications of alloy MA 754 as turbine engine vanes. Both alloys are suitable for industrial heat treating components and other heat resistant alloy applications. Field trials and commercial experience in such applications of MA alloys are being gained while high temperature property characterization and new product form development continue. Hot isostatic pressing (HIP) is the standard consolidation method for billets from which large bar and plate are produced for industrial applications of MA. This paper describes production of standard mill shapes from HIP billets, and it presents information on current and potential uses of MA alloys in applications such as: skid rails for use in high temperature walking beam furnaces, heat treating furnace components, components for handling molten glass, and furnace tubes. The paper includes comparison of the properties obtained in alloy MA 754 (20% Cr) and alloy MA 758 (30% Cr).

  19. Imparting passivity to vapor deposited magnesium alloys

    NASA Astrophysics Data System (ADS)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

  20. Imparting passivity to vapor deposited magnesium alloys

    NASA Astrophysics Data System (ADS)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

  1. Structural Properties of Mismatched Alloys

    NASA Astrophysics Data System (ADS)

    Mousseau, Normand

    The problem of understanding the local structure of disordered alloys has been around for a long time. In this thesis, I look more specifically at the effect of size-mismatch disorder in binary alloys under many forms: metallic and semiconductor alloys, bulk and surfaces, two and three dimensional systems. I have studied the limitations of a central-force model (CFM) and an embedded-atom potential (EAM) in describing the local structure of binary metallic alloys composed of Ag, Au, Cu, Ni, Pd, or Pt. Although an analytical model developed using the CFM explains qualitatively well the experimental and numerical results, in many cases, it is important to add electronic density effects through a more sophisticated potential like EAM in order to agree quantitatively with experiment. I have also looked at amorphous and crystalline silicon-germanium alloys. It turns out that the effect of size-mismatch is the same on a crystalline and an amorphous lattice. In the latter case, it can be seen as a perturbation of the much larger disorder due to the amorphisation process. However, the analytical predictions differ, for both the crystalline and amorphous alloys, from the experimental results. If one is to believe the data, there is only one possible explanation for this inconsistency: large amounts of hydrogen are present in the samples used for the measurements. Since the data analysis of EXAFS results is not always straightforward, I have proposed some experiments that could shed light on this problem. One of these experiments would be to look at the (111) surface of a Si-Ge alloy with a scanning tunneling microscope. I also present in this thesis the theoretical predictions for the height distribution at the surface as well as some more general structural information about the relaxation in the network as one goes away from the surface. Finally, I have studied the effect of size -mismatch in a purely two dimensional lattice, looking for mismatch-driven phase transitions

  2. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Diffusion of Fission Product Surrogates

    SciTech Connect

    Henager, Charles H.; Jiang, Weilin

    2014-11-01

    MAX phases, such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been suggested in the literature as a possible fuel cladding material. Prior to the application, it is necessary to investigate diffusivities of fission products in the ternary compound at elevated temperatures. This study attempts to obtain relevant data and make an initial assessment for Ti3SiC2. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti3SiC2, SiC, and a dual-phase nanocomposite of Ti3SiC2/SiC synthesized at PNNL. Thermal annealing and in-situ Rutherford backscattering spectrometry (RBS) were employed to study the diffusivity of the various implanted species in the materials. In-situ RBS study of Ti3SiC2 implanted with Au ions at various temperatures was also performed. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti3SiC2 occurs during ion implantation at 873 K. Cs in Ti3SiC2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Further studies of the related materials are recommended.

  3. Heat treatment study of aluminum casting alloy M45

    NASA Technical Reports Server (NTRS)

    Lovoy, C. V.

    1967-01-01

    Study determines the heat treatment cycle of aluminum casting alloy M-45 which will increase the strength levels of the alloy while maintaining optimum stress corrosion resistance. Evidence indicates that present production castings are overaged too severely to take full advantage of the strength of the alloy.

  4. Powder metallurgy of vanadium and its alloys (review)

    SciTech Connect

    Radomysel'skii, I.D.; Solntsev, V.P.; Evtushenko, O.V.

    1987-10-01

    This article reviews the current powder metallurgy technology of vanadium and its alloys. Data are given on sintering, compacting, electrowinning and other current production techniques, as well as on the corrosion behavior and mechanical and physical properties of alloys produced by these different methods. The use of vanadium alloys as reactor and jet engine materials is also briefly discussed.

  5. Oxide dispersion hardened mechanically alloyed materials for high temperatures

    NASA Technical Reports Server (NTRS)

    Benjamin, J. S.; Strassburg, F. W.

    1982-01-01

    The procedure of mechanical alloying makes it possible to obtain, with the aid of powder-metallurgy techniques, alloys that consist of a metallic matrix in which very fine oxide particles are dispersed. Mechanically alloyed compound powders can be used for making either forged or hot-rolled semifinished products. For these products, dispersion strengthening and precipitation hardening has been combined. At high temperatures, the strength characteristics of the alloy are determined by both dispersion hardening and by precipitation hardening processes. The effect produced by each process is independent of that due to the other. Attention is given to the principle of mechanical alloying developed by Benjamin (1970, 1976), the strength characteristics of mechanically alloyed materials, the corrosion resistance of mechanically alloyed material at high temperatures, and the preparation and characteristics of the alloy MA 6000 E.

  6. Correlation of the energy product with evolution of the nanostructure in the Y,Dy,Nd-(Fe, Co)-B magnetic alloy

    NASA Astrophysics Data System (ADS)

    Wu, Y. Q.; Tang, W.; Kramer, M. J.; Dennis, K. W.; Oster, N.; McCallum, R. W.; Anderson, I. E.

    2009-04-01

    The devitrification behavior of nanocrystalline MRE2(Fe,Co)14B+ZrC (MRE=Nd+Y+Dy) was studied using differential scanning calorimetry (DSC), synchrotron high temperature x-ray diffraction, and analytical transmission electron microscopy (TEM) techniques. Alloy ribbons were melt spun at 25 m/s to obtain an amorphous structure. Optimum hard magnetic properties (Br=7.2 kG, Hc=12.7 kOe and (BH)max=10.8 MG Oe) were obtained in ribbons annealed at 750 °C for 15 min. A reduced annealing temperature of 638 °C and holding time from 0 to 11 min were chosen based on DSC analysis. Large changes in both microstructure and hard magnetic properties were found in a narrow window of annealing time, 4.5-6 min, resulting in a dramatic increase in energy product, remanence and coercivity: 0.96 MG Oe, 5.2 kG, 2.7 kOe to 5.7 MG Oe, 7.2 kG, 8.5 kOe for (BH)max, Br and Hc, respectively. Energy dispersive x-ray spectroscopy and energy filtered TEM analyses indicate that Zr- and C-rich particles (˜5 nm) and thin grain boundary layers (1-2 nm thick) are formed surrounding 2-14-1 hard phase grains when the annealing time is over 6 min. Further annealing resulted in a more distinct hard phase surrounded by a nonmagnetic grain boundary phase ˜1 nm in thickness. The thin grain boundary layer phase starts to disappear with annealing time over 11 min. The partitioning behavior of various elements at different annealing conditions appears to be associated with significant changes in magnetic properties, leading to an improved optimum microstructure.

  7. Thermal effects on the Ga+ ion beam induced structural modification of a-SiC:H

    NASA Astrophysics Data System (ADS)

    Tsvetkova, T.; Wright, C. D.; Craciun, M. F.; Bischoff, L.; Angelov, O.; Dimova-Malinovska, D.

    2012-12-01

    The effects of implantation temperature and post-implantation thermal annealing on the Ga+ ion beam induced optical contrast formation in hydrogenated silicon-carbon alloy (a-SiC:H) films and underlying structural modifications have been studied. The optical contrast formed (between implanted and unimplanted regions of the film material) has been made use of in the form of optical pattern formation by computer-operated Ga+-focused ion beam. Possible applications of this effect in the area of submicron lithography and high-density optical data storage have been suggested with regard to the most widely spread focused micro-beam systems based on Ga+ liquid metal ion sources. The implanted samples were structurally analysed using vibrational spectroscopies, like Raman and infra-red (IR) spectroscopy, to define optimum implantation conditions. The precise role of implantation temperature effects, i.e. the target temperature during Ga+ ion irradiation, on the structural modification obtainable has been therefore a key part of this study. Appropriate post-implantation annealing treatments were also studied, since these are expected to offer further benefits in reducing the required ion dose and enhancing the optical contrast, thus increasing the cost-effectiveness of the method.

  8. [Prosthetic dental alloys. 1].

    PubMed

    Quintero Engelmbright, M A

    1990-11-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements. PMID:2132464

  9. [Prosthetic dental alloys (2)].

    PubMed

    Quintero Englembright, M A

    1990-12-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements. PMID:2132470

  10. Evolution of a Native Oxide Layer at the a-Si:H/c-Si Interface and Its Influence on a Silicon Heterojunction Solar Cell.

    PubMed

    Liu, Wenzhu; Meng, Fanying; Zhang, Xiaoyu; Liu, Zhengxin

    2015-12-01

    The interface microstructure of a silicon heterojunction (SHJ) solar cell was investigated. We found an ultrathin native oxide layer (NOL) with a thickness of several angstroms was formed on the crystalline silicon (c-Si) surface in a very short time (∼30 s) after being etched by HF solution. Although the NOL had a loose structure with defects that are detrimental for surface passivation, it acted as a barrier to restrain the epitaxial growth of hydrogenated amorphous silicon (a-Si:H) during the plasma-enhanced chemical vapor deposition (PECVD). The microstructure change of the NOL during the PECVD deposition of a-Si:H layers with different conditions and under different H2 plasma treatments were systemically investigated in detail. When a brief H2 plasma was applied to treat the a-Si:H layer after the PECVD deposition, interstitial oxygen and small-size SiO2 precipitates were transformed to hydrogenated amorphous silicon suboxide alloy (a-SiO(x):H, x ∼ 1.5). In the meantime, the interface defect density was reduced by about 50%, and the parameters of the SHJ solar cell were improved due to the post H2 plasma treatment. PMID:26565116

  11. Respiratory manganese particle size, time-course and neurobehavioral outcomes in workers at a manganese alloy production plant

    PubMed Central

    Park, Robert M.; Bouchard, Maryse F.; Baldwin, Mary; Bowler, Rosemarie; Mergler, Donna

    2015-01-01

    The progression of manganism with chronic exposure to airborne manganese (Mn) is not well understood. Here, we further investigate the findings on exposure and neurobehavioral outcomes of workers from a silico- and ferromanganese production plant and non-exposed workers from the same community in 1990 and 2004, using a variety of exposure metrics that distinguish particle size and origin within the range of respirable airborne exposures. Mn exposure matrices for large respirable particulate (Mn-LRP, dust) and small respirable particulate (Mn-SRP, fume), based on process origins, were used together with detailed work histories since 1973 (plant opening), to construct exposure metrics including burdens and cumulative burdens with various clearance half-lives. For three out of eight 1990 neurobehavioral tests analyzed with linear regression models, duration of Mn exposure was the best predictor: Luria-Nebraska Neuropsychological Battery – Motor Scale, Trail-Making B and Finger Tapping. The Luria-Nebraska Motor Scale had the strongest association (t ~ 5.0, p < 10−6). For outcomes on three other tests, the duration and Mn-SRP metrics were comparable: Trail Making Test A, Cancellation H and Stroop Color-Word Test (color/word subtest). Delayed Word Recall was best predicted by Mn-SRP (based on square root or truncated air-concentrations). The Word score on the Stroop Color-Word Test was the only outcome for which Mn-LRP was the leading predictor (t = −2.92, p = 0.003), while performance on the WAIS-R Digit Span Test was not significantly predicted by any metric. For outcomes evaluated in both 1990 and 2004, a mixed-effect linear regression model was used to examine estimates of within-individual trends. Duration and Mn-SRP were associated with performance on the Luria-Nebraska Motor Scale, as well as with other outcomes that appeared to have both reversible and progressive features, including Trail Making A and B, Cancellation H and Delayed Word Recall. With the

  12. Alloy softening in binary molybdenum alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    An investigation was conducted to determine the effects of alloy additions of Hf, Ta, W, Re, Os, Ir, and Pt on the hardness of Mo. Special emphasis was placed on alloy softening in these binary Mo alloys. Results showed that alloy softening was produced by those elements having an excess of s+d electrons compared to Mo, while those elements having an equal number or fewer s+d electrons than Mo failed to produce alloy softening. Alloy softening and hardening can be correlated with the difference in number of s+d electrons of the solute element and Mo.

  13. Single-Step Production of Nanostructured Copper-Nickel (CuNi) and Copper-Nickel-Indium (CuNiIn) Alloy Particles

    NASA Astrophysics Data System (ADS)

    Apaydın, Ramazan Oğuzhan; Ebin, Burçak; Gürmen, Sebahattin

    2016-04-01

    Nanostructured copper-nickel (CuNi) and copper-nickel-indium (CuNiIn) alloy particles were produced from aqueous solutions of copper, nickel nitrates and indium sulfate by hydrogen reduction-assisted ultrasonic spray pyrolysis. The effects of reduction temperatures, at 973 K, 1073 K, and 1173 K (700 °C, 800 °C, and 900 °C), on the morphology and crystalline structure of the alloy particles were investigated under the conditions of 0.1 M total precursor concentration and 0.5 L/min H2 volumetric flow rate. X-ray diffraction studies were performed to investigate the crystalline structure. Particle size and morphology were investigated by scanning electron microscope and energy-dispersive spectroscopy was applied to determine the chemical composition of the particles. Spherical nanocrystalline binary CuNi alloy particles were prepared in the particle size range from 74 to 455 nm, while ternary CuNiIn alloy particles were obtained in the particle size range from 80 to 570 nm at different precursor solution concentrations and reduction temperatures. Theoretical and experimental chemical compositions of all the particles are nearly the same. Results reveal that the precursor solution and reduction temperature strongly influence the particle size of the produced alloy particles.

  14. Final Assessment of Preindustrial Solid-State Route for High-Performance Mg-System Alloys Production: Concluding the EU Green Metallurgy Project

    NASA Astrophysics Data System (ADS)

    D'Errico, Fabrizio; Plaza, Gerardo Garces; Giger, Franz; Kim, Shae K.

    2013-10-01

    The Green Metallurgy Project, a LIFE+ project co-financed by the European Union Commission, has now been completed. The purpose of the Green Metallurgy Project was to establish and assess a preindustrial process capable of using nanostructured-based high-performance Mg-Zn(Y) magnesium alloys and fully recycled eco-magnesium alloys. In this work, the Consortium presents the final outcome and verification of the completed prototype construction. To compare upstream cradle-to-grave footprints when ternary nanostructured Mg-Y-Zn alloys or recycled eco-magnesium chips are produced during the process cycle using the same equipment, a life cycle analysis was completed following the ISO 14040 methodology. During tests to fine tune the prototype machinery and compare the quality of semifinished bars produced using the scaled up system, the Buhler team produced interesting and significant results. Their tests showed the ternary Mg-Y-Zn magnesium alloys to have a highest specific strength over 6000 series wrought aluminum alloys usually employed in automotive components.

  15. Single-Step Production of Nanostructured Copper-Nickel (CuNi) and Copper-Nickel-Indium (CuNiIn) Alloy Particles

    NASA Astrophysics Data System (ADS)

    Apaydın, Ramazan Oğuzhan; Ebin, Burçak; Gürmen, Sebahattin

    2016-07-01

    Nanostructured copper-nickel (CuNi) and copper-nickel-indium (CuNiIn) alloy particles were produced from aqueous solutions of copper, nickel nitrates and indium sulfate by hydrogen reduction-assisted ultrasonic spray pyrolysis. The effects of reduction temperatures, at 973 K, 1073 K, and 1173 K (700 °C, 800 °C, and 900 °C), on the morphology and crystalline structure of the alloy particles were investigated under the conditions of 0.1 M total precursor concentration and 0.5 L/min H2 volumetric flow rate. X-ray diffraction studies were performed to investigate the crystalline structure. Particle size and morphology were investigated by scanning electron microscope and energy-dispersive spectroscopy was applied to determine the chemical composition of the particles. Spherical nanocrystalline binary CuNi alloy particles were prepared in the particle size range from 74 to 455 nm, while ternary CuNiIn alloy particles were obtained in the particle size range from 80 to 570 nm at different precursor solution concentrations and reduction temperatures. Theoretical and experimental chemical compositions of all the particles are nearly the same. Results reveal that the precursor solution and reduction temperature strongly influence the particle size of the produced alloy particles.

  16. Coagulated silica - a-SiO2 admixture in cement paste

    NASA Astrophysics Data System (ADS)

    Pokorný, Jaroslav; Pavlíková, Milena; Záleská, Martina; Rovnaníková, Pavla; Pavlík, Zbyšek

    2016-07-01

    Amorphous silica (a-SiO2) in fine-grained form possesses a high pozzolanic activity which makes it a valuable component of blended binders in concrete production. The origin of a-SiO2 applied in cement-based composites is very diverse. SiO2 in amorphous form is present in various amounts in quite a few supplementary cementing materials (SCMs) being used as partial replacement of Portland cement. In this work, the applicability of a commercially produced coagulated silica powder as a partial replacement of Portland cement in cement paste mix design is investigated. Portland cement CEM I 42.5R produced according to the EU standard EN 197-1 is used as a reference binder. Coagulated silica is applied in dosages of 5 and 10 % by mass of cement. The water/binder ratio is kept constant in all the studied pastes. For the applied silica, specific surface area, density, loss on ignition, pozzolanic activity, chemical composition, and SiO2 amorphous phase content are determined. For the developed pastes on the basis of cement-silica blended binder, basic physical properties as bulk density, matrix density, and total open porosity are accessed. Pore size distribution is determined using MIP analysis. Initial and final setting times of fresh mixtures are measured by automatic Vicat apparatus. Effect of silica admixture on mechanical resistivity is evaluated using compressive strength, bending strength, and dynamic Young's modulus measurement. The obtained data gives evidence of a decreased workability of paste mixtures with silica, whereas the setting process is accelerated. On the other hand, reaction activity of silica with Portland cement minerals results in a slight decrease of porosity and improvement of mechanical resistivity of cement pastes containing a-SiO2.

  17. A Study of Tungsten-Technetium Alloys

    NASA Technical Reports Server (NTRS)

    Maltz, J. W.

    1965-01-01

    Technetium is a sister element to rhenium and has many properties that are similar to rhenium. It is predicted that technetium will have about the same effects on tungsten as rhenium in regard to increase in workability, lowered ductile to brittle transition temperature, and improved ductility. The objectives of the current work are to recover technetium from fission product wastes at Hanford Atomic Products Operation and reduce to purified metal; prepare W-Tc alloys containing up to 50 atomic% Tc; fabricate the alloy ingots to sheet stock, assessing the effect of technetium on workability; and perform metallurgical and mechanical properties evaluation of the fabricated alloys. Previous reports have described the separation and purification of 800 g of technetium metal powder, melting of technetium and W-Tc alloys, and some initial observation of the alloy material.

  18. Amorphous silicon-tellurium alloys

    NASA Astrophysics Data System (ADS)

    Shufflebotham, P. K.; Card, H. C.; Kao, K. C.; Thanailakis, A.

    1986-09-01

    Amorphous silicon-tellurium alloy thin films were fabricated by coevaporation over the composition range of 0-82 at. % Te. The electronic and optical properties of these films were systematically investigated over this same range of composition. The optical gap of these films was found to decrease monotonically with increasing Te content. Conduction near room temperature was due to extended state conduction, while variable range hopping dominated below 250 K. The incorporation of Te in concentrations of less than 1 at. % was found to produce an increase in the density of localized states at the Fermi level and a decrease in the activation energy. This was attributed to the Te being incorporated as a substitutional, fourfold coordinated, double donor in a-Si. At approximately 60 at. % Te, a decrease in the density of localized states at the Fermi level, and an increase in the activation energy and photoresponse was indicated. This was attributed to the possible formation of a less defective a-Si:Te compound.

  19. NASA-427: A New Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

  20. Ultralight amorphous silicon alloy photovoltaic modules for space applications

    NASA Technical Reports Server (NTRS)

    Hanak, J. J.; Chen, Englade; Fulton, C.; Myatt, A.; Woodyard, J. R.

    1987-01-01

    Ultralight and ultrathin, flexible, rollup monolithic PV modules have been developed consisting of multijunction, amorphous silicon alloys for either terrestrial or aerospace applications. The rate of progress in increasing conversion efficiency of stable multijunction and multigap PV cells indicates that arrays of these modules can be available for NASA's high power systems in the 1990's. Because of the extremely light module weight and the highly automated process of manufacture, the monolithic a-Si alloy arrays are expected to be strongly competitive with other systems for use in NASA's space station or in other large aerospace applications.

  1. ZnO/Ag sputtering deposition on a-Si solar cells

    SciTech Connect

    Hayashi, Katsuhiko; Kondo, Masataka; Ishikawa, Atsuo; Yamagishi, Hideo

    1994-12-31

    In order to produce large area amorphous silicon solar cell modules and to simplify the module production process, a continuous ZnO/Ag sputtering deposition process has been applied. The authors found that by means of a continuous ZnO/Ag sputtering deposition method an adhesive a-Si/electrode contact can be realized. They compared short circuit currents of Al,ZnO/Al and ZnO/Ag back side contact cells and confirmed short circuit current increase by application of ZnO/Ag back side contact. They found that the series resistance is severely dependent on the conditions during the first stage of ZnO deposition. They confirmed the reliability of ZnO/Ag structure as the back side contact through high temperature high humidity test. After 310 hours accelerated light induced degradation test which corresponds to one year light exposure the 100cm2 integrated a-Si tandem solar cell kept the efficiency higher than 8.5%.

  2. New magnetic alloys.

    PubMed

    Chin, G Y

    1980-05-23

    Three notable new developments in magnetic alloys are highlighted. These include rare earth-cobalt permanent magnets with maximum energy products up to 240 kilojoules per cubic meter; chromium-cobalt-iron permanent magnets that have magnetic properties similar to those of the Alnicos, but contain only about half as much cobalt and are sufficiently ductile to be cold-formable; and high-induction grain-oriented silicon steels that exhibit 20 percent less core loss as transformer core materials than conventional oriented grades. PMID:17772813

  3. Production of aluminum-silicon alloy and ferrosilicon and commercial purity aluminum by the direct reduction process. Second annual technical report for the period 1978 September 1-1979 December 31

    SciTech Connect

    Bruno, M.J.

    1980-10-01

    A new computer program was developed for simultaneously solving heat and mass balance at steady state for a flowing one-dimensional chemical reactor. Bench scale reactor results confirmed that minimum final stage reaction temperature is 1950 to 2000/sup 0/C, depending on the Fe/sub 2/O/sub 3/ concentration in the burden. Additions of Fe/sub 2/O/sub 3/ to the charge produced significant increase in metallic yield. A new bench reactor was designed, built, and operated to facilitate semi-continuous operation, using O/sub 2/ injection to burn coke supporting the burden, resulting in burden movement. Validity of the equipment and test procedures was demonstrated by successfully operating the reactor as an iron blast furnace at 1500/sup 0/C. Bench scale fractional crystallizer runs were continued to determine the impurity effects of Fe up to 6.9% and Ti up to 1.25% on alloy product purity and yield. High initial impurity concentrations resulted in less pure Al-Si product and product yield below 50% due to Al and Si losses as Fe-Si-Al and Ti-Si-Al intermetallics. Long term testing was continued in the large bench scale membrane cell to evaluate woven cloth membrane and other construction materials, operating procedures, and effects of operating parameters on cell performance. Included in the latter were starting alloy composition, current density, anode-cathode spacing, and electrolyte composition.

  4. Titanium Alloys and Processing for High Speed Aircraft

    NASA Technical Reports Server (NTRS)

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.

    1996-01-01

    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  5. Systems study of transport aircraft incorporating advanced aluminum alloys

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.

    1982-01-01

    A study was performed to quantify the potential benefits of utilizing advanced aluminum alloys in commercial transport aircraft and to define the effort necessary to develop fully the alloys to a viable commercial production capability. The comprehensive investigation (1) established realistic advanced aluminum alloy property goals to maximize aircraft systems effectiveness (2) identified performance and economic benefits of incorporating the advanced alloy in future advanced technology commercial aircraft designs (3) provided a recommended plan for development and integration of the alloys into commercial aircraft production (4) provided an indication of the timing and investigation required by the metal producing industry to support the projected market and (5) evaluate application of advanced aluminum alloys to other aerospace and transit systems as a secondary objective. The results of the investigation provided a roadmap and identified key issues requiring attention in an advanced aluminum alloy and applications technology development program.

  6. Low-band-gap, amorphous-silicon-based alloys by photochemical vapor deposition: Final report, 1 October 1985--30 November 1986

    SciTech Connect

    Baron, B.N.; Hegedus, S.S.; Jackson, S.C.

    1988-02-01

    Thin films of hydrogenated amorphous silicon-germanium alloys were deposited by mercury-sensitized photochemical vapor deposition using a novel photo-CVD reactor. Thin films of a-Si/sub 1-x/Ge/sub x/:H with 0 less than or equal to x less than or equal to 1 and 1.0 less than E/sub g/ less than 1.8 eV were deposited from mixtures of silane and disilane with germane and inert gas diluents at substrate temperatures from 160/degree/ to 200/degree/C. Alloy films were characterized by measurements of photo- and dark conductivity, electron mobility-lifetime product, sub-band-gap absorption, and density of states. Dilution with hydrogen increased the photoconductivity to 10/sup /minus/5/ Scm and mobility-lifetime product to 6 /times/ 10/sup /minus/8/ cm/sup 2/V for alloys having a band gap of 1.4 eV.

  7. Graphene Nanoribbons Anchored to a SiC Substrate

    NASA Astrophysics Data System (ADS)

    Woods, Lilia; Le, Nam

    Due to their exceptional fundamental characteristics graphene nanoribbons play a major role in the development of future nano-technological applications. The high chemical reactivity of the graphene nanoribbon edges can be utilized to create modified materials. Using first principles simulations we explore this possibility to construct patterned systems composed of anchored ribbons of zigzag edges covalently bonded to a SiC substrate. The hybrid edge states are found to possess interesting electronic and magnetic properties, which alter the overall behavior of the entire system as compared to the behavior of the individual components. It is found that the van der Waals interactions are important for the overall stability and structure of the anchored ribbons. Also, spin-polarization effects play a profound role in the electronic structure and associated density of states. The hybrid graphene/SiC zigzag edges are analyzed in terms of their transport characteristics as well.

  8. MBE growth of GaP on a Si substrate

    SciTech Connect

    Sobolev, M. S. Lazarenko, A. A.; Nikitina, E. V.; Pirogov, E. V.; Gudovskikh, A. S.; Egorov, A. Yu.

    2015-04-15

    It is shown that single-crystal GaP buffer layers can be formed on a Si substrate by molecular-beam epitaxy, with the “migration-enhanced epitaxy” procedure applied in the stage in which the nucleating layer is formed. When a GaP layer is produced on a p-type silicon substrate, a p-n junction is created in a natural way between the p-Si substrate and the surface n-Si layer produced by the diffusion of phosphorus into the substrate during the course of the epitaxial growth of GaP. This p-n junction can be used as the first junction of a silicon-based multijunction photovoltaic converter.

  9. Hydrogenated Amorphous Silicon (a-Si:H) Colloids

    SciTech Connect

    Harris, Justin T.; Hueso, Jose L.; Korgel, Brian A.

    2010-12-14

    Colloidal particles of hydrogenated amorphous silicon (a-Si:H) were synthesized by decomposition of trisilane (Si{sub 3}H{sub 8}) in supercritical n-hexane (sc-hexane) at temperatures ranging from 380 to 550 °C. The reaction temperature, pressure and Si{sub 3}H{sub 8} concentration have a significant influence on the average particle size, Si bond order and hydrogen content. The particle diameter could be varied from 170 nm to 1.7 μm, with hydrogen loadings between 10% and 58%. Raman spectroscopy of the particles revealed significant differences in Si bond order that correlated with hydrogen content, with the lowest reaction temperatures yielding particles with the least structural order and most associated hydrogen. Particles synthesized at temperatures higher than 420 °C had sufficient bond order to allow crystallization under the Raman laser probe.

  10. Metal alloy identifier

    DOEpatents

    Riley, William D.; Brown, Jr., Robert D.

    1987-01-01

    To identify the composition of a metal alloy, sparks generated from the alloy are optically observed and spectrographically analyzed. The spectrographic data, in the form of a full-spectrum plot of intensity versus wavelength, provide the "signature" of the metal alloy. This signature can be compared with similar plots for alloys of known composition to establish the unknown composition by a positive match with a known alloy. An alternative method is to form intensity ratios for pairs of predetermined wavelengths within the observed spectrum and to then compare the values of such ratios with similar values for known alloy compositions, thereby to positively identify the unknown alloy composition.

  11. The potential of hydrogenated amorphous silicon-chalcogen alloys for photovoltaic applications: The role of persistent photoconductivity

    SciTech Connect

    Wang, S.L.; Viner, J.M.; Taylor, P.C.; Itoh, T.; Nitta, S.

    1997-02-01

    The potential improvement in stability of hydrogenated silicon-sulfur alloys (a-SiS{sub x}:H) with respect to ordinary hydrogenated amorphous silicon (a-Si:H) has been attributed to the introduction of an additional metastability known as persistent photoconductivity (PPC). In order to examine the PPC process in more detail we examine a series of alloys with large sulfur concentrations (x{gt}0.01). Although these alloys are not useful in photovoltaic devices, the high sulfur concentrations accentuate the PPC effect and allow one to study this effect with little competition from the ordinary Staebler-Wronski effect that dominates the metastable processes that occur in a -Si:H. {copyright} {ital 1997 American Institute of Physics.}

  12. Stress corrosion in high-strength aluminum alloys

    NASA Technical Reports Server (NTRS)

    Dorward, R. C.; Hasse, K. R.

    1980-01-01

    Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

  13. Silicon Solar Cells with Front Hetero-Contact and Aluminum Alloy Back Junction: Preprint

    SciTech Connect

    Yuan, H.-C.; Page, M. R.; Iwaniczko, E.; Xu, Y.; Roybal, L.; Wang, Q.; Branz, H. M.; Meier, D. L.

    2008-05-01

    We prototype an alternative n-type monocrystalline silicon (c-Si) solar cell structure that utilizes an n/i-type hydrogenated amorphous silicon (a-Si:H) front hetero-contact and a back p-n junction formed by alloying aluminum (Al) with the n-type Si wafer.

  14. Scanning tunneling microscopy studies of the surfaces of a-Si:H and a-SiGe:H films

    SciTech Connect

    Gallagher, A.; Ostrom, R.; Tannenbaum, D. )

    1991-06-01

    The report contains a detailed description of the experimental complexities encountered in developing scanning tunneling microscope (STM) probing of atomic structure on the surface of freshly-grown hydrogenated-amorphous semiconductors. It also contains a speculative microscopic film-growth model that explains differences between the disorder in CVD grown a-Ge:H versus a-Si:H films. This model is derived from prior results obtained in the chemical analysis of GeH{sub 4} plasmas, combined with surface reaction and thermodynamic considerations. The neutral radical fragments of silane, disilane and germane dissociation in discharges, which dominate the vapor and film-growth reactions, have been deduced from detailed analysis of prior data and are reported. 4 refs., 7 figs.

  15. Hydrogenated amorphous silicon-germanium alloys

    SciTech Connect

    Luft, W.

    1988-02-01

    This report describes the effects of the germanium fraction in hydrogenated amorphous silicon-germanium alloys on various parameters, especially those that are indicators of film quality, and the impact of deposition methods, feedgas mixtures, and other deposition parameters on a SiGe:H and a-SiGe:H:F film characteristics and quality. Literature data show the relationship between germanium content, hydrogen content, deposition method (various glow discharges and CVD), feedgas lmixture, and other parameters and properties, such as optical band gap, dark and photoconductivities, photosensitivity, activation energy, Urbach parameter, and spin density. Some of these are convenient quality indicators; another is the absence of microstructure. Examining RF glow discharge with both a diode and triode geometry, DC proximity glow discharge, microwave glow discharge, and photo-CVD, using gas mixtures such as hydrogen-diluted and undiluted mixtures of silane/germane, disilane/germane, silane/germaniumtetrafluoride, and others, it was observed that hydrogen dilution (or inert gas dilution) is essential in achieving high photosensitivity in silicon-germanium alloys (in contradistinction to amorphous hydrogenated silicon). Hydrogen dilution results in a higher photosensitivity than do undiluted gas mixtures. 81 refs., 42 figs., 7 tabs.

  16. Production of porous oxide coatings with ultrafine crystalline structure on medical implants fabricated from alloy 12Cr18Ni9Ti

    NASA Astrophysics Data System (ADS)

    Rodionov, Igor V.; Fomina, Marina A.; Fomin, Aleksandr A.; Poshivalova, Elena Yu.; Zakharevich, Andrey M.

    2015-06-01

    Using scanning electron microscopy the crystalline structure of porous oxide coatings produced by air-thermal oxidation of orthopedic implants of alloy 12Cr18Ni9Ti at the temperatures of 350 and 400 °C and duration of 1.5 hours was studied. In vivo tests revealed that the resulting coatings promote successful engraftment of thermally modified implants in the body with highly efficient interaction between morphologically heterogeneous coatings and surrounding bone tissue.

  17. Alloyed steel wastes utilization

    SciTech Connect

    Sokol, I.V.

    1995-12-31

    Alloyed steel chips and swarf formed during metal processing are looked upon as additional raw materials in metallurgical production. This paper presents some new methods for steel waste chips and swarf cleaning. One of them is swarf and steel chips cleaning in tetrachloroethylene with ultrasonic assistance and solvent regeneration. Thermal cleaning of waste chips and swarf provides off gas products utilization. The catalyst influence of the metal surface on the thermal decomposition of liquid hydrocarbons during the cleaning process has been studied. It has been determined that the efficiency of this metal waste cleaning technique depends on the storage time of the swarf. The waste chips and swarf cleaning procedures have been proven to be economically advantageous and environmentally appropriate.

  18. Lead-calcium alloy development: quality improvement

    NASA Astrophysics Data System (ADS)

    Caillerie, J.-L.; Albert, L.

    In the 1980s, most of the European lead producers and battery manufacturers had an interest in the lead-calcium alloys developed in the North American market. Fifteen years later, the alloy is used in most of the automotive and industrial batteries produced in Europe. During this development period, the composition of lead-calcium alloy has been improved. Physical metallurgy and electrochemistry research carried out by the lead industry has established the composition of the lead-calcium for negative grids. Metaleurop, as a lead producer, initiated in 1975 the production of lead-calcium alloys for sealed lead/acid batteries and was quickly convinced of the necessity to improve the performance of the alloy by further fundamental research (in 1980) and supporting customers' efforts. The parameters involved in the production battery plates are well specified. The composition of the alloy is dependent on the equipment used to cast the alloy. Improving the hardness by increasing the calcium content over 0.10 wt.% may not be the solution when melting and cooling conditions should als be adapted. The addition of aluminium to prevent calcium oxidation is efficient, its level being linked to the remelting and casting conditions.

  19. Results of a Si/Cdte Compton Telescope

    SciTech Connect

    Oonuki, Kousuke; Tanaka, Takaaki; Watanabe, Shin; Takeda, Shin'ichiro; Nakazawa, Kazuhiro; Mitani, Takefumi; Takahashi, Tadayuki; Tajima, Hiroyasu; Fukazawa, Yasushi; Nomachi, Masaharu; /Sagamihara, Inst. Space Astron. Sci. /Tokyo U. /SLAC /Hiroshima U. /Osaka U.

    2005-09-23

    We have been developing a semiconductor Compton telescope to explore the universe in the energy band from several tens of keV to a few MeV. We use a Si strip and CdTe pixel detector for the Compton telescope to cover an energy range from 60 keV. For energies above several hundred keV, the higher efficiency of CdTe semiconductor in comparison with Si is expected to play an important role as an absorber and a scatterer. In order to demonstrate the spectral and imaging capability of a CdTe-based Compton Telescope, we have developed a Compton telescope consisting of a stack of CdTe pixel detectors as a small scale prototype. With this prototype, we succeeded in reconstructing images and spectra by solving the Compton equation from 122 keV to 662 keV. The energy resolution (FWHM) of reconstructed spectra is 7.3 keV at 511 keV and 3.1 keV at 122 keV, respectively. The angular resolution obtained at 511 keV is measured to be 12.2{sup o}(FWHM).

  20. Signal and noise analysis of a-Si:H radiation detector-amplifier system

    SciTech Connect

    Cho, Gyuseong

    1992-03-01

    Hydrogenated amorphous silicon (a-Si:H) has potential advantages in making radiation detectors for many applications because of its deposition capability on a large-area substrate and its high radiation resistance. Position-sensitive radiation detectors can be made out of a 1d strip or a 2-d pixel array of a Si:H pin diodes. In addition, signal processing electronics can be made by thin-film transistors on the same substrate. The calculated radiation signal, based on a simple charge collection model agreed well with results from various wave length light sources and 1 MeV beta particles on sample diodes. The total noise of the detection system was analyzed into (a) shot noise and (b) 1/f noise from a detector diode, and (c) thermal noise and (d) 1/f noise from the frontend TFT of a charge-sensitive preamplifier. the effective noise charge calculated by convoluting these noise power spectra with the transfer function of a CR-RC shaping amplifier showed a good agreement with the direct measurements of noise charge. The derived equations of signal and noise charge can be used to design an a-Si:H pixel detector amplifier system optimally. Signals from a pixel can be readout using switching TFTs, or diodes. Prototype tests of a double-diode readout scheme showed that the storage time and the readout time are limited by the resistances of the reverse-biased pixel diode and the forward biased switching diodes respectively. A prototype charge-sensitive amplifier was made using poly-Si TFTs to test the feasibility of making pixel-level amplifiers which would be required in small-signal detection. The measured overall gain-bandwidth product was {approximately}400 MHz and the noise charge {approximately}1000 electrons at a 1 {mu}sec shaping time. When the amplifier is connected to a pixel detector of capacitance 0.2 pF, it would give a charge-to-voltage gain of {approximately}0.02 mV/electron with a pulse rise time less than 100 nsec and a dynamic range of 48 dB.

  1. Hydrogen-plasma-induced Rapid, Low-Temperature Crystallization of μm-thick a-Si:H Films

    PubMed Central

    Zhou, H. P.; Xu, M.; Xu, S.; Liu, L. L.; Liu, C. X.; Kwek, L. C.; Xu, L. X.

    2016-01-01

    Being a low-cost, mass-production-compatible route to attain crystalline silicon, post-deposition crystallization of amorphous silicon has received intensive research interest. Here we report a low-temperature (300 °C), rapid (crystallization rate of ~17 nm/min) means of a-Si:H crystallization based on high-density hydrogen plasma. A model integrating the three processes of hydrogen insertion, etching, and diffusion, which jointly determined the hydrogenation depth of the excess hydrogen into the treated micrometer thick a-Si:H, is proposed to elucidate the hydrogenation depth evolution and the crystallization mechanism. The effective temperature deduced from the hydrogen diffusion coefficient is far beyond the substrate temperature of 300 °C, which implies additional driving forces for crystallization, i.e., the chemical annealing/plasma heating and the high plasma sheath electric field. The features of LFICP (low-frequency inductively coupled plasma) and LFICP-grown a-Si:H are also briefly discussed to reveal the underlying mechanism of rapid crystallization at low temperatures. PMID:27600866

  2. Hydrogen-plasma-induced Rapid, Low-Temperature Crystallization of μm-thick a-Si:H Films.

    PubMed

    Zhou, H P; Xu, M; Xu, S; Liu, L L; Liu, C X; Kwek, L C; Xu, L X

    2016-01-01

    Being a low-cost, mass-production-compatible route to attain crystalline silicon, post-deposition crystallization of amorphous silicon has received intensive research interest. Here we report a low-temperature (300 °C), rapid (crystallization rate of ~17 nm/min) means of a-Si:H crystallization based on high-density hydrogen plasma. A model integrating the three processes of hydrogen insertion, etching, and diffusion, which jointly determined the hydrogenation depth of the excess hydrogen into the treated micrometer thick a-Si:H, is proposed to elucidate the hydrogenation depth evolution and the crystallization mechanism. The effective temperature deduced from the hydrogen diffusion coefficient is far beyond the substrate temperature of 300 °C, which implies additional driving forces for crystallization, i.e., the chemical annealing/plasma heating and the high plasma sheath electric field. The features of LFICP (low-frequency inductively coupled plasma) and LFICP-grown a-Si:H are also briefly discussed to reveal the underlying mechanism of rapid crystallization at low temperatures. PMID:27600866

  3. Comparison of Three Primary Surface Recuperator Alloys

    SciTech Connect

    Matthews, Wendy; More, Karren Leslie; Walker, Larry R

    2010-01-01

    Extensive work performed by Capstone Turbine Corporation, Oak Ridge National Laboratory, and various others has shown that the traditional primary surface recuperator alloy, type 347 stainless steel, is unsuitable for applications above 650 C ({approx}1200 F). Numerous studies have shown that the presence of water vapor greatly accelerates the oxidation rate of type 347 stainless steel at temperatures above 650 C ({approx}1200 F). Water vapor is present as a product of combustion in the microturbine exhaust, making it necessary to find replacement alloys for type 347 stainless steel that will meet the long life requirements of microturbine primary surface recuperators. It has been well established over the past few years that alloys with higher chromium and nickel contents than type 347 stainless steel have much greater oxidation resistance in the microturbine environment. One such alloy that has replaced type 347 stainless steel in primary surface recuperators is Haynes Alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.), a solid-solution-strengthened alloy with nominally 33 wt % Fe, 37 wt % Ni and 25 wt % Cr. Unfortunately, while HR-120 is significantly more oxidation resistant in the microturbine environment, it is also a much more expensive alloy. In the interest of cost reduction, other candidate primary surface recuperator alloys are being investigated as possible alternatives to type 347 stainless steel. An initial rainbow recuperator test has been performed at Capstone to compare the oxidation resistance of type 347 stainless steel, HR-120, and the Allegheny Ludlum austenitic alloy AL 20-25+Nb (AL 20-25+Nb is a trademark of ATI Properties, Inc. and is licensed to Allegheny Ludlum Corporation). Evaluation of surface oxide scale formation and associated alloy depletion and other compositional changes has been carried out at Oak Ridge National Laboratory. The results of this initial rainbow test will be presented and discussed in this

  4. Antibacterial biodegradable Mg-Ag alloys.

    PubMed

    Tie, D; Feyerabend, F; Müller, W D; Schade, R; Liefeith, K; Kainer, K U; Willumeit, R

    2013-01-01

    The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4) and aging (T6) heat treatment. The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH)₂ and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7), revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231) and Staphylococcus epidermidis (DSMZ 3269), and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials. PMID:23771512

  5. Hydrogen storage systems from waste Mg alloys

    NASA Astrophysics Data System (ADS)

    Pistidda, C.; Bergemann, N.; Wurr, J.; Rzeszutek, A.; Møller, K. T.; Hansen, B. R. S.; Garroni, S.; Horstmann, C.; Milanese, C.; Girella, A.; Metz, O.; Taube, K.; Jensen, T. R.; Thomas, D.; Liermann, H. P.; Klassen, T.; Dornheim, M.

    2014-12-01

    The production cost of materials for hydrogen storage is one of the major issues to be addressed in order to consider them suitable for large scale applications. In the last decades several authors reported on the hydrogen sorption properties of Mg and Mg-based systems. In this work magnesium industrial wastes of AZ91 alloy and Mg-10 wt.% Gd alloy are used for the production of hydrogen storage materials. The hydrogen sorption properties of the alloys were investigated by means of volumetric technique, in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and calorimetric methods. The measured reversible hydrogen storage capacity for the alloys AZ91 and Mg-10 wt.% Gd are 4.2 and 5.8 wt.%, respectively. For the Mg-10 wt.% Gd alloy, the hydrogenated product was also successfully used as starting reactant for the synthesis of Mg(NH2)2 and as MgH2 substitute in the Reactive Hydride Composite (RHC) 2LiBH4 + MgH2. The results of this work demonstrate the concrete possibility to use Mg alloy wastes for hydrogen storage purposes.

  6. SUPERCONDUCTING VANADIUM BASE ALLOY

    DOEpatents

    Cleary, H.J.

    1958-10-21

    A new vanadium-base alloy which possesses remarkable superconducting properties is presented. The alloy consists of approximately one atomic percent of palladium, the balance being vanadium. The alloy is stated to be useful in a cryotron in digital computer circuits.

  7. Separation in Binary Alloys

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.

    1986-01-01

    Studies of monotectic alloys and alloy analogs reviewed. Report surveys research on liquid/liquid and solid/liquid separation in binary monotectic alloys. Emphasizes separation processes in low gravity, such as in outer space or in free fall in drop towers. Advances in methods of controlling separation in experiments highlighted.

  8. DELTA PHASE PLUTONIUM ALLOYS

    DOEpatents

    Cramer, E.M.; Ellinger, F.H.; Land. C.C.

    1960-03-22

    Delta-phase plutonium alloys were developed suitable for use as reactor fuels. The alloys consist of from 1 to 4 at.% zinc and the balance plutonium. The alloys have good neutronic, corrosion, and fabrication characteristics snd possess good dimensional characteristics throughout an operating temperature range from 300 to 490 deg C.

  9. PLUTONIUM-THORIUM ALLOYS

    DOEpatents

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  10. Structural studies of secondary crystallization products of the Fe23B6-type in a nanocrystalline FeCoB-based alloy

    NASA Astrophysics Data System (ADS)

    Long, Jianguo; Ohodnicki, P. R.; Laughlin, D. E.; McHenry, M. E.; Ohkubo, T.; Hono, K.

    2007-05-01

    A stable Fe23B6-type phase formed in a nanocomposite soft magnetic alloy Fe40Co40Nb4B13Ge2Cu1 after thermal treatment was investigated. The primary crystallization temperature and second crystallization temperature for this alloy were determined to be 405 and 740°C, respectively. After annealing the sample at 820°C for 1h, a Fe23B6-type phase (FeCoNb)23B6 was observed. The structural information was investigated by x-ray diffraction, transmission electron microscopy, and three-dimensional atom probe. The Fe23B6-type phase contains about 33±5at.% Fe, 38±5at.% Co, 7±1at.% Nb, and 20±3at.% B. The Nb atoms tend to occupy the 8c sites and Co /Fe atoms occupy the 4a, 32f, and 48h sites of the Fm3m space group for this structure.