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Sample records for powder composites ldrd

  1. LDRD FY2004 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Kotta, P. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kline, K. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2005-02-28

    The Laboratory Directed Research and Development (LDRD) Program is our primary means for pursuing innovative, long-term, high-risk, and potentially high-payoff research that supports the missions of the Laboratory, the Department of Energy, and the National Nuclear Security Administration in national security, homeland security, energy security, environmental management, bioscience and healthcare technology, and breakthroughs in fundamental science and technology. The LDRD Program was authorized by Congress in 1991 and is administered by the Laboratory Science and Technology Office. The accomplishments described in this Annual Report demonstrate how the LDRD portfolio is strongly aligned with these missions and contributes to the Laboratory’s success in meeting its goals. The LDRD budget of $69.8 million for FY2004 sponsored 220 projects. These projects were selected through an extensive peer-review process to ensure the highest scientific and technical quality and mission relevance. Each year, the number of meritorious proposals far exceeds the funding available, making the selection a challenging one indeed. Our ongoing investments in LDRD have reaped long-term rewards for the Laboratory and the Nation. Many Laboratory programs trace their roots to research thrusts that began several years ago under LDRD sponsorship. In addition, many LDRD projects contribute to more than one mission area, leveraging the Laboratory’s multidisciplinary team approach to science and technology. Safeguarding the Nation from terrorist activity and the proliferation of weapons of mass destruction will be an enduring mission of this Laboratory, for which LDRD will continue to play a vital role. The LDRD Program is a success story. Our projects continue to win national recognition for excellence through prestigious awards, papers published in peer-reviewed journals, and patents granted. With its reputation for sponsoring innovative projects, the LDRD Program is also a major vehicle

  2. LDRD Annual Report FY2006

    International Nuclear Information System (INIS)

    Sketchley, J A; Kotta, P; De Yoreo, J; Jackson, K; van Bibber, K

    2007-01-01

    The Laboratory Directed Research and Development (LDRD) Program, authorized by Congress in 1991 and administered by the Laboratory Science and Technology Office, is our primary means for pursuing innovative, long-term, high-risk, and potentially high-payoff research that supports the missions of the Laboratory, the Department of Energy, and National Nuclear Security Administration in national security, energy security, environmental management, bioscience and technology to improve human health, and breakthroughs in fundamental science and technology. The accomplishments described in this Annual Report demonstrate the strong alignment of the LDRD portfolio with these missions and contribute to the Laboratory's success in meeting its goals. The LDRD budget of $92 million for FY2006 sponsored 188 projects. These projects were selected through an extensive peer-review process to ensure the highest scientific quality and mission relevance. Each year, the number of deserving proposals far exceeds the funding available, making the selection a tough one indeed. Our ongoing investments in LDRD have reaped long-term rewards for the Laboratory and the nation. Many Laboratory programs trace their roots to research thrusts that began several years ago under LDRD sponsorship. In addition, many LDRD projects contribute to more than one mission area, leveraging the Laboratory's multidisciplinary team approach to science and technology. Safeguarding the nation from terrorist activity and the proliferation of weapons of mass destruction will be an enduring mission of this Laboratory, for which LDRD will continue to play a vital role. The LDRD Program is a success story. Our projects continue to win national recognition for excellence through prestigious awards, papers published in peer-reviewed journals, and patents granted. With its reputation for sponsoring innovative projects, the LDRD Program is also a major vehicle for attracting and retaining the best and the brightest

  3. 2007 LDRD ANNUAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    French, T

    2008-12-16

    I am pleased to present the fiscal year 2007 Laboratory Directed Research and Development (LDRD) annual report. This represents the first year that SRNL has been eligible for LDRD participation and our results to date demonstrate we are off to an excellent start. SRNL became a National Laboratory in 2004, and was designated the 'Corporate Laboratory' for the DOE Office of Environmental Management (EM) in 2006. As you will see, we have made great progress since these designations. The LDRD program is one of the tools SRNL is using to enable achievement of our strategic goals for the DOE. The LDRD program allows the laboratory to blend a strong basic science component into our applied technical portfolio. This blending of science with applied technology provides opportunities for our scientists to strengthen our capabilities and delivery. The LDRD program is vital to help SRNL attract and retain leading scientists and engineers who will help build SRNL's future and achieve DOE mission objectives. This program has stimulated our research staff creativity, while realizing benefits from their participation. This investment will yield long term dividends to the DOE in its Environmental Management, Energy, and National Security missions.

  4. SRNL LDRD ANNUAL REPORT 2008

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    French, T

    2008-12-29

    The Laboratory Director is pleased to have the opportunity to present the 2008 Laboratory Directed Research and Development (LDRD) annual report. This is my first opportunity to do so, and only the second such report that has been issued. As will be obvious, SRNL has built upon the excellent start that was made with the LDRD program last year, and researchers have broken new ground in some important areas. In reviewing the output of this program this year, it is clear that the researchers implemented their ideas with creativity, skill and enthusiasm. It is gratifying to see this level of participation, because the LDRD program remains a key part of meeting SRNL's and DOE's strategic goals, and helps lay a solid scientific foundation for SRNL as the premier applied science laboratory. I also believe that the LDRD program's results this year have demonstrated SRNL's value as the EM Corporate Laboratory, having advanced knowledge in a spectrum of areas, including reduction of the technical risks of cleanup, separations science, packaging and transportation of nuclear materials, and many others. The research in support of Energy Security and National and Homeland Security has been no less notable. SRNL' s researchers have shown again that the nascent LDRD program is a sound investment for DOE that will pay off handsomely for the nation as time goes on.

  5. FY2014 LBNL LDRD Annual Report

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    Ho, Darren [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-01

    Laboratory (Berkeley Lab or LBNL) is a multi-program national research facility operated by the University of California for the Department of Energy (DOE). As an integral element of DOE’s National Laboratory System, Berkeley Lab supports DOE’s missions in fundamental science, energy resources, and environmental quality. Berkeley Lab programs advance four distinct goals for DOE and the nation. The LDRD program supports Berkeley Lab’s mission in many ways. First, because LDRD funds can be allocated within a relatively short time frame, Berkeley Lab researchers can support the mission of the Department of Energy (DOE) and serve the needs of the nation by quickly responding to forefront scientific problems. Second, LDRD enables Berkeley Lab to attract and retain highly qualified scientists and to support their efforts to carry out worldleading research. In addition, the LDRD program also supports new projects that involve graduate students and postdoctoral fellows, thus contributing to the education mission of Berkeley Lab.

  6. Biodegradation of thermoplastic starch/eggshell powder composites.

    Science.gov (United States)

    Bootklad, Munlika; Kaewtatip, Kaewta

    2013-09-12

    Thermoplastic starch (TPS) was prepared using compression molding and chicken eggshell was used as a filler. The effect of the eggshell powder (EP) on the properties of TPS was compared with the effect of commercial calcium carbonate (CC). The organic compound on the surface of the eggshell powder acted as a coupling agent that resulted in a strong adhesion between the eggshell powder and the TPS matrix, as confirmed by SEM micrographs. The biodegradation was determined by the soil burial test. The TPS/EP composites were more rapidly degraded than the TPS/CC composites. In addition, the eggshell powder improved the water resistance and thermal stability of the TPS. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Properties of magnetic nickel/porous-silicon composite powders

    Directory of Open Access Journals (Sweden)

    Toshihiro Nakamura

    2012-09-01

    Full Text Available The magnetic and photoluminescence (PL properties of nickel/porous-silicon (Ni/PSi composite powders are investigated. Ni/PSi composite powders are prepared by stain etching of Si powder in a HF/HNO3 solution followed by electroless plating of Ni nanoparticles on the stain-etched PSi powder in a NiCl2 solution. The Ni/PSi powders exhibit hydrophillicity, superparamagnetism caused by the deposited Ni nanoparticles, and orange-red PL owing to the nanostructured PSi surface. The degree of magnetization decreases with increasing Ni plating time, indicating its dependence on the size of the Ni nanoparticles. The Ni/PSi composite powders also show a stronger magnetization as compared to that of the Ni-particle-plated Si powder. The stronger magnetization results from the larger surface area of PSi. The PL intensity, peak wavelength, and lifetime of Ni/PSi are strongly dependent on the NiCl2 concentration. This dependence is due to the different thickness of the oxide overlayer on the PSi surface formed during the Ni plating process. The existence of the oxide overlayer also results in a small change in the PL intensity against excitation time.

  8. Electrospun composites of PHBV/pearl powder for bone repairing

    Directory of Open Access Journals (Sweden)

    Jingjing Bai

    2015-08-01

    Full Text Available Electrospun fiber has highly structural similarity with natural bone extracelluar matrix (ECM. Many researches about fabricating organic–inorganic composite materials have been carried out in order to mimic the natural composition of bone and enhance the biocompatibility of materials. In this work, pearl powder was added to the poly (3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV and the composite nanofiber scaffold was prepared by electrospinning. Mineralization ability of the composite scaffolds can be evaluated by analyzing hydroxyapatite (HA formation on the surface of nanofiber scaffolds. The obtained composite nanofiber scaffolds showed an enhanced mineralization capacity due to incorporation of pearl powder. The HA formed amount of the composite scaffolds was raised as the increase of pearl powder in composite scaffolds. Therefore, the prepared PHBV/pearl composite nanofiber scaffolds would be a promising candidate as an osteoconductive composite material for bone repairing.

  9. 1999 LDRD Laboratory Directed Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    Rita Spencer; Kyle Wheeler

    2000-06-01

    This is the FY 1999 Progress Report for the Laboratory Directed Research and Development (LDRD) Program at Los Alamos National Laboratory. It gives an overview of the LDRD Program, summarizes work done on individual research projects, relates the projects to major Laboratory program sponsors, and provides an index to the principal investigators. Project summaries are grouped by their LDRD component: Competency Development, Program Development, and Individual Projects. Within each component, they are further grouped into nine technical categories: (1) materials science, (2) chemistry, (3) mathematics and computational science, (4) atomic, molecular, optical, and plasma physics, fluids, and particle beams, (5) engineering science, (6) instrumentation and diagnostics, (7) geoscience, space science, and astrophysics, (8) nuclear and particle physics, and (9) bioscience.

  10. LDRD Highlights at the National Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Alayat, R. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-10

    To meet the nation’s critical challenges, the Department of Energy (DOE) national laboratories have always pushed the boundaries of science, technology, and engineering. The Atomic Energy Act of 1954 provided the basis for these laboratories to engage in the cutting edge of science and technology and respond to technological surprises, while retaining the best scientific and technological minds. To help re-energize this commitment, in 1991 the U.S. Congress authorized the national laboratories to devote a relatively small percentage of their budget to creative and innovative work that serves to maintain their vitality in disciplines relevant to DOE missions. Since then, this effort has been formally called the Laboratory Directed Research and Development (LDRD) Program. LDRD has been an essential mechanism to enable the laboratories to address DOE’s current and future missions with leading-edge research proposed independently by laboratory technical staff, evaluated through expert peer-review committees, and funded by the individual laboratories consistent with the authorizing legislation and the DOE LDRD Order 413.2C.

  11. Metal-Matrix Hardmetal/Cermet Reinforced Composite Powders for Thermal Spray

    Directory of Open Access Journals (Sweden)

    Dmitri GOLJANDIN

    2012-03-01

    Full Text Available Recycling of materials is becoming increasingly important as industry response to public demands, that resources must be preserved and environment protected. To produce materials competitive in cost with primary product, secondary producers have to pursue new technologies and other innovations. For these purposes different recycling technologies for composite materials (oxidation, milling, remelting etc are widely used. The current paper studies hardmetal/cermet powders produced by mechanical milling technology. The following composite materials were studied: Cr3C2-Ni cermets and WC-Co hardmetal. Different disintegrator milling systems for production of powders with determined size and shape were used. Chemical composition of produced powders was analysed.  To estimate the properties of recycled hardmetal/cermet powders, sieving analysis, laser granulometry and angularity study were conducted. To describe the angularity of milled powders, spike parameter–quadric fit (SPQ was used and experiments for determination of SPQ sensitivity and precision to characterize particles angularity were performed. Images used for calculating SPQ were taken by SEM processed with Omnimet Image Analyser 22. The graphs of grindability and angularity were composed. Composite powders based on Fe- and Ni-self-fluxing alloys for thermal spray (plasma and HVOF were produced. Technological properties of powders and properties of thermal sprayed coatings from studied powders were investigated. The properties of spray powders reinforced with recycled hardmetal and cermet particles as alternatives for cost-sensitive applications were demonstrated.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1348

  12. Aluminum powder size and microstructure effects on properties of boron nitride reinforced aluminum matrix composites fabricated by semi-solid powder metallurgy

    International Nuclear Information System (INIS)

    Chen, Cunguang; Guo, Leichen; Luo, Ji; Hao, Junjie; Guo, Zhimeng; Volinsky, Alex A.

    2015-01-01

    Al matrix composite reinforced by hexagonal boron nitride (h-BN) with nearly full densification was successfully fabricated by the semi-solid powder metallurgy technique. The h-BN/Al composites were synthesized with elemental pure Al powder size of d_5_0=35, 12 and 2 μm. The powder morphology and the structural characteristics of the composites were analyzed using X-ray diffraction, scanning and transmission electron microscopy. The density, Brinell hardness and compressive behavior of the samples were characterized. Density measurement of the Al composites revealed that the composite densification can be effectively promoted by plenty of embedded liquid phase under pressure. Composites prepared using Al powder with varying granularity showed different grain characteristics, and in situ recrystallization occurred inside the original grains with 35 μm Al powder. A sharp interface consisting of Al/Al_2O_3/h-BN was present in the composites. Both the compressive strength and the fracture strain of the investigated composites increased with the decrease of the Al powder size, along with the Brinell hardness. The composite with 2 μm Al powder exhibited the highest relative density (99.3%), Brinell harness (HB 128), compressive strength (763 MPa) and fracture strain (0.299).

  13. Characterization of composite materials based on cement-ceramic powder blended binder

    Science.gov (United States)

    Kulovaná, Tereza; Pavlík, Zbyšek

    2016-06-01

    Characterization of newly developed composite mortars with incorporated ceramic powder coming from precise brick cutting as partial Portland cement replacement up to 40 mass% is presented in the paper. Fine ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker production which generally results in lower production costs of blended binder and lower CO2 emission. In this paper, the ceramic powder is used in cement based mortar composition in amount of 8, 16, 24, 32, and 40 mass% of cement. Chemical composition of ceramic powder is analyzed by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramics is accessed on laser diffraction principle. For 28 days cured mortar samples, basic physical and mechanical properties are experimentally determined. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites and to reduce negative environmental impact of their production.

  14. FY 2014 LDRD Annual Report Project Summaries

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    Tomchak, Dena [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-02-01

    The FY 2014 Laboratory Directed Research and Development (LDRD) Annual Report is a compendium of the diverse research performed to develop and ensure the INL's technical capabilities can support future DOE missions and national research priorities. LDRD is essential to INL - it provides a means for the laboratory to pursue novel scientific and engineering research in areas that are deemed too basic or risky for programmatic investments. This research enahnces technical capabilities at the laboratory, providing scientific and engineering staff with opportunities for skill building and partnership development.

  15. Polymer-Cement Composites Containing Waste Perlite Powder

    Directory of Open Access Journals (Sweden)

    Paweł Łukowski

    2016-10-01

    Full Text Available Polymer-cement composites (PCCs are materials in which the polymer and mineral binder create an interpenetrating network and co-operate, significantly improving the performance of the material. On the other hand, the need for the utilization of waste materials is a demand of sustainable construction. Various mineral powders, such as fly ash or blast-furnace slag, are successfully used for the production of cement and concrete. This paper deals with the use of perlite powder, which is a burdensome waste from the process of thermal expansion of the raw perlite, as a component of PCCs. The results of the testing of the mechanical properties of the composite and some microscopic observations are presented, indicating that there is a possibility to rationally and efficiently utilize waste perlite powder as a component of the PCC. This would lead to creating a new type of building material that successfully meets the requirements of sustainable construction.

  16. LDRD 2012 Annual Report: Laboratory Directed Research and Development Program Activities

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    Bookless, William [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2012-12-31

    Each year, Brookhaven National Laboratory (BNL) is required to provide a program description and overview of its Laboratory Directed Research and Development Program (LDRD) to the Department of Energy in accordance with DOE Order 413.2B dated April 19, 2006. This report provides a detailed look at the scientific and technical activities for each of the LDRD projects funded by BNL in FY2012, as required. In FY2012, the BNL LDRD Program funded 52 projects, 14 of which were new starts, at a total cost of $10,061,292.

  17. LDRD 2014 Annual Report: Laboratory Directed Research and Development Program Activities

    Energy Technology Data Exchange (ETDEWEB)

    Hatton, Diane [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-03-01

    Each year, Brookhaven National Laboratory (BNL) is required to provide a program description and overview of its Laboratory Directed Research and Development Program (LDRD) to the Department of Energy (DOE) in accordance with DOE Order 413.2B dated April 19, 2006. This report provides a detailed look at the scientific and technical activities for each of the LDRD projects funded by BNL in FY 2014, as required. In FY 2014, the BNL LDRD Program funded 40 projects, 8 of which were new starts, at a total cost of $9.6M.

  18. LDRD 2015 Annual Report: Laboratory Directed Research and Development Program Activities

    Energy Technology Data Exchange (ETDEWEB)

    Hatton, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-12-31

    Each year, Brookhaven National Laboratory (BNL) is required to provide a program description and overview of its Laboratory Directed Research and Development Program (LDRD) to the Department of Energy (DOE) in accordance with DOE Order 413.2B dated April 19, 2006. This report provides a detailed look at the scientific and technical activities for each of the LDRD projects funded by BNL in FY 2015, as required. In FY 2015, the BNL LDRD Program funded 43 projects, 12 of which were new starts, at a total cost of $9.5M.

  19. Fabrication of metal matrix composite by semi-solid powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yufeng [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

  20. LDRD 2016 Annual Report: Laboratory Directed Research and Development Program Activities

    Energy Technology Data Exchange (ETDEWEB)

    Hatton, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-03-31

    Each year, Brookhaven National Laboratory (BNL) is required to provide a program description and overview of its Laboratory Directed Research and Development Program (LDRD) to the Department of Energy (DOE) in accordance with DOE Order 413.2C dated October 22, 2015. This report provides a detailed look at the scientific and technical activities for each of the LDRD projects funded by BNL in FY 2016, as required. In FY 2016, the BNL LDRD Program funded 48 projects, 21 of which were new starts, at a total cost of $11.5M. The investments that BNL makes in its LDRD program support the Laboratory’s strategic goals. BNL has identified four Critical Outcomes that define the Laboratory’s scientific future and that will enable it to realize its overall vision. Two operational Critical Outcomes address essential operational support for that future: renewal of the BNL campus; and safe, efficient laboratory operations.

  1. Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Huiyang, E-mail: hl209@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Zhang, Deliang, E-mail: zhangdeliang@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Gabbitas, Brian, E-mail: briang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Yang, Fei, E-mail: fyang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Matthews, Steven, E-mail: S.Matthews@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Auckland (New Zealand)

    2014-09-01

    Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study.

  2. Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

    International Nuclear Information System (INIS)

    Lu, Huiyang; Zhang, Deliang; Gabbitas, Brian; Yang, Fei; Matthews, Steven

    2014-01-01

    Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study

  3. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  4. Idaho National Laboratory Annual Report FY 2013 LDRD Project Summaries

    Energy Technology Data Exchange (ETDEWEB)

    Dena Tomchak

    2014-03-01

    The FY 2013 LDRD Annual Report is a compendium of the diverse research performed to develop and ensure the INL’s technical capabilities support the current and future DOE missions and national research priorities. LDRD is essential to INL—it provides a means for the Laboratory to maintain scientific and technical vitality while funding highly innovative, high-risk science and technology research and development (R&D) projects. The program enhances technical capabilities at the Laboratory, providing scientific and engineering staff with opportunities to explore proof-of-principle ideas, advanced studies of innovative concepts, and preliminary technical analyses. Established by Congress in 1991, the LDRD Program proves its benefit each year through new programs, intellectual property, patents, copyrights, national and international awards, and publications.

  5. Chemical and toxicological assessment of arsenic sorption onto Fe-sericite composite powder and beads.

    Science.gov (United States)

    Kim, Jiwon; Lee, Cheongho; Lee, Seung Mok; Lalhmunsiama; Jung, Jinho

    2018-01-01

    Batch sorption and leaching of arsenic (1-30mgL -1 ) on Fe-sericite composite powder and beads were investigated in this study. Fe-sericite composite powder was made from natural sericite modified with iron, and alginate was used to transform the powder into beads. The maximum sorption capacities of the Fe-sericite composite powder (15.04 and 13.21mgg -1 for As(III) and As(V), respectively) were higher than those of the corresponding beads (9.02 and 7.11mgg -1 for As(III) and As(V), respectively) owing to the higher specific surface area of the powder. In addition, the leaching amounts of As(III) from Fe-sericite composite beads (≤ 15.03%) were higher than those of the corresponding powder (≤ 5.71%). However, acute toxicity of As(III)-sorbed Fe-sericite composite beads toward Daphnia magna was not significantly different from that of the corresponding powder (p > 0.05). Considering higher uptake of the powder particles by the daphnids, Fe-sericite composite beads seem to be a more appropriate and safer sorbent for arsenic removal in practical application. Based on Fe content, Fe-sericite composite beads had similar or higher maximum sorption capacities (71.19 and 56.11mgg -1 Fe for As(III) and As(V), respectively) than those of previously reported sorbents. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Nonvolatile RRAM cells from polymeric composites embedding recycled SiC powders.

    Science.gov (United States)

    De Girolamo Del Mauro, Anna; Nenna, Giuseppe; Miscioscia, Riccardo; Freda, Cesare; Portofino, Sabrina; Galvagno, Sergio; Minarini, Carla

    2014-10-21

    Silicon carbide powders have been synthesized from tires utilizing a patented recycling process. Dynamic light scattering, Raman spectroscopy, SEM microscopy, and X-ray diffraction have been carried out to gather knowledge about powders and the final composite structure. The obtained powder has been proven to induce resistive switching in a PMMA polymer-based composite device. Memory effect has been detected in two-terminal devices having coplanar contacts and quantified by read-write-erase measurements in terms of level separation and persistence.

  7. Ultrasonic Characterisation of Epoxy Resin/Polyethylene Terephthalate (PET Char Powder Composites

    Directory of Open Access Journals (Sweden)

    Imran ORAL

    2016-11-01

    Full Text Available This study is carried out in order to determine the elastic properties of the Epoxy Resin (ER / Polyethylene terephthalate (PET Char Powder Composites by ultrasonic wave velocity measurement method. Plastic waste was recycled as raw material for the preparation of epoxy composite materials. The supplied chars were mixed with epoxy resin matrix at weight percentages of 10 %, 20 % and 30 % for preparing ER/PET Char Powder (PCP composites. The effect of PET char powder on the elastic properties of ER/PCP composites were investigated by ultrasonic pulse-echo method. According to the obtained results, the composition ratio of 80:20 is the most appropriate composition ratio, which gave the highest elastic constants values for ER/PCP composites. On the other hand, the best electrical conductivity value was obtained for 70:30 composition ratio. It was observed that ultrasonic shear wave velocity correlated more perfectly than any other parameters with hardness.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12190

  8. Synthesis and densification of Cu-coated Ni-based amorphous composite powders

    International Nuclear Information System (INIS)

    Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

    2007-01-01

    Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

  9. γ-ray radiation effect on properties of straw powder/PBS composite

    International Nuclear Information System (INIS)

    Yang Mingcheng; Luo Yongquan; Liu Wentao; Zhu Jun; Guo Dongquan; Li Zhaopeng; Gen Feng; Qu Lingbo

    2013-01-01

    Background: In recent years, with decreasing global fossil resources and increasing 'white pollution', renewable and biodegradable materials attract more and more attentions. Poly (butylene succinate) (PBS) has good mechanical property, biodegradability and processing performance, which is the focus of hot topics in the study of biodegradable plastic materials, however, being soft and of high cost, it is still limited in application range. Purpose: In order to improve the mechanical and thermal properties, a series of wheat straw powder/PBS composites were prepared by melt extrusion, and then the 60 Co-y ray was directly utilized to irradiate the straw powder/PBS composite. Methods: The influence of TAIC (triallyl isocyanurate) radiation absorbed dose and radiation sensitizer on the mechanical property and thermal performance of straw powder/PBS composite was investigated, and the impact fracture surface morphology of the composite was observed by SEM (scanning electron microscope). Results: The tensile strength and flexural strength were enhanced with increasing radiation dosage, and then tend to be stable, the heat distortion temperature also increased but not significantly with increasing radiation dosage. The results show that when TAIC content is 2%, with straw powder/PBS composite irradiated by 30-kGy dose, the tensile strength and flexural strength are increased by 26% and 39.8%, respectively. Conclusion: The radiation modification of composite material has no effect on thermal stability, but do improve the tensile strength and flexural strength when up to 2% of TAIC is integrated and irradiated by certain dose. The interface cohesiveness between straw powder and PBS is strengthened after radiation. (authors)

  10. Plasma preparation and low-temperature sintering of spherical TiC-Fe composite powder

    Institute of Scientific and Technical Information of China (English)

    Jian-jun Wang; Jun-jie Hao; Zhi-meng Guo; Song Wang

    2015-01-01

    A spherical Fe matrix composite powder containing a high volume fraction (82vol%) of fine TiC reinforcement was produced us-ing a novel process combining in situ synthesis and plasma techniques. The composite powder exhibited good sphericity and a dense struc-ture, and the fine sub-micron TiC particles were homogeneously distributed in theα-Fe matrix. A TiC–Fe cermet was prepared from the as-prepared spherical composite powder using powder metallurgy at a low sintering temperature;the product exhibited a hardness of HRA 88.5 and a flexural strength of 1360 MPa. The grain size of the fine-grained TiC and special surface structure of the spherical powder played the key roles in the fabrication process.

  11. Damping behavior of polymer composites with high volume fraction of NiMnGa powders

    Science.gov (United States)

    Sun, Xiaogang; Song, Jie; Jiang, Hong; Zhang, Xiaoning; Xie, Chaoying

    2011-03-01

    Polymer composites inserted with high volume fraction (up to 70 Vol%) of NiMnGa powders were fabricated and their damping behavior was investigated by dynamic mechanical analysis. It is found that the polymer matrix has little influence on the transformation temperatures of NiMnGa powders. A damping peak appears for NiMnGa/epoxy resin (EP) composites accompanying with the martensitic transformation or reverse martensitic transformation of NiMnGa powders during cooling or heating. The damping capacity for NiMnGa/EP composites increases linearly with the increase of volume fraction of NiMnGa powders and, decreases dramatically as the test frequency increases. The fracture strain of NiMnGa/EP composites decrease with the increase of NiMnGa powders.

  12. Structural comparison of sintering products made of "TiC + Ti" composite powders and "Ti + C" powder mixtures

    Science.gov (United States)

    Krinitcyn, Maksim G.; Pribytkov, Gennadii A.; Korosteleva, Elena N.; Firsina, Irina A.; Baranovskii, Anton V.

    2017-12-01

    In this study, powder composite materials comprised of TiC and Ti with different ratios are processed by sintering of Ti and C powder mixtures and self-propagating high-temperature synthesis (SHS) in "Ti+C" system followed by sintering. The microstructure and porosity of obtained composites are investigated and discussed. The dependence of porosity on sintering time is explained theoretically. Optimal regimes that enable to obtain the most homogeneous structure with the least porosity are described.

  13. The effect Of Fine UO2 Powder Composition On Density Of UO2 pellet Compaction

    International Nuclear Information System (INIS)

    Widjaksana; Mutiara, E.

    1998-01-01

    This research has been done to solve it. The work was done through making variation on the fine powder composition from 0% up to 50% and variation on compacting pressure from 1 MP up to 5 MP. Each variation combination was replicated eight times. The result showed that the data were within confidence interval of the density and the ANOVA showed that the parameters affected the density. The affect of them was showed in the various correlation. The maximum density was reached at the range of fine powder composition between 20% and 30%. When Heckel theory was applied to the data, the conclusion showed that the fine powder composition did not affect the mechanical strength of material, but when Smith theory was applied, the conclusion showed that the fine powder composition affect the compressibility of powder. The maximum compressibility of powder was reached at the range of fine powder composition between 20% and 30%

  14. Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

    Science.gov (United States)

    Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

    2017-11-29

    Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced ( p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

  15. Fabrication of metal matrix composites by powder metallurgy: A review

    Science.gov (United States)

    Manohar, Guttikonda; Dey, Abhijit; Pandey, K. M.; Maity, S. R.

    2018-04-01

    Now a day's metal matrix components are used in may industries and it finds the applications in many fields so, to make it as better performable materials. So, the need to increase the mechanical properties of the composites is there. As seen from previous studies major problem faced by the MMC's are wetting, interface bonding between reinforcement and matrix material while they are prepared by conventional methods like stir casting, squeeze casting and other techniques which uses liquid molten metals. So many researchers adopt PM to eliminate these defects and to increase the mechanical properties of the composites. Powder metallurgy is one of the better ways to prepare composites and Nano composites. And the major problem faced by the conventional methods are uniform distribution of the reinforcement particles in the matrix alloy, many researchers tried to homogeneously dispersion of reinforcements in matrix but they find it difficult through conventional methods, among all they find ultrasonic dispersion is efficient. This review article is mainly concentrated on importance of powder metallurgy in homogeneous distribution of reinforcement in matrix by ball milling or mechanical milling and how powder metallurgy improves the mechanical properties of the composites.

  16. LDRD FY 2014 Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    Anita Gianotto; Dena Tomchak

    2013-08-01

    As required by DOE Order 413.2B the FY 2014 Program Plan is written to communicate ares of investment and approximate amounts being requested for the upcoming fiscal year. The program plan also includes brief highlights of current or previous LDRD projects that have an opportunity to impact our Nation's current and future energy challenges.

  17. Selected Examples of LDRD Projects Supporting Test Ban Treaty Verification and Nonproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Al-Ayat, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Walter, W. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-02-23

    The Laboratory Directed Research and Development (LDRD) Program at the DOE National Laboratories was established to ensure the scientific and technical vitality of these institutions and to enhance the their ability to respond to evolving missions and anticipate national needs. LDRD allows the Laboratory directors to invest a percentage of their total annual budget in cutting-edge research and development projects within their mission areas. We highlight a selected set of LDRD-funded projects, in chronological order, that have helped provide capabilities, people and infrastructure that contributed greatly to our ability to respond to technical challenges in support of test ban treaty verification and nonproliferation.

  18. Development and characterization of composites PEAD recycled / gravel powder

    International Nuclear Information System (INIS)

    Sousa, P.V.B de; Goncalves, A.P.B.; Guimaraes, D.H.; Miranda, C.S.; Neto, J.L.M.S.; Carvalho, R.F.; Jose, N.M.

    2014-01-01

    The polymeric composites are heterogeneous materials multiphase, formed by at least one continuous phase and a discontinuous. The matrix used was recycled high density polyethylene (HDPE) and the load used was the residue of crushed stone dust generated by the process of crushing rocks, stocked in the quarries, no final destination, which changes the landscape and provides many environmental problems. With the aim of adding value to a new commercial waste and mitigate the environmental impact work proposes to develop polymeric composites for application in construction. Were prepared of recycled HDPE composites reinforced with three compositions 5,10 and 20% of powder aggregates with two different granulometries. The samples were prepared by pressing and characterized by FTIR analysis, DRX, DSC and TG. It has been observed that increasing the content of grit powder showed significant improvements in thermal and structural properties of the material. (author)

  19. Preparation of fine powdered composite for latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Fořt, Jan, E-mail: jan.fort.1@fsv.cvut.cz; Trník, Anton, E-mail: anton.trnik@fsv.cvut.cz; Pavlíková, Milena, E-mail: milena.pavlikova@fsv.cvut.cz; Pavlík, Zbyšek, E-mail: pavlikz@fsv.cvut.cz [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic); Pomaleski, Marina, E-mail: marina-pomaleski@fsv.cvut.cz [Faculty of Civil Engineering, Architecture and Urbanism, University of Campinas, R. Saturnino de Brito 224, 13083-889 Campinas – SP (Brazil)

    2016-07-07

    Application of latent heat storage building envelope systems using phase-change materials represents an attractive method of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. This study deals with a preparation of a new type of powdered phase change composite material for thermal energy storage. The idea of a composite is based upon the impregnation of a natural silicate material by a reasonably priced commercially produced pure phase change material and forming the homogenous composite powdered structure. For the preparation of the composite, vacuum impregnation method is used. The particle size distribution accessed by the laser diffraction apparatus proves that incorporation of the organic phase change material into the structure of inorganic siliceous pozzolana does not lead to the clustering of the particles. The compatibility of the prepared composite is characterized by the Fourier transformation infrared analysis (FTIR). Performed DSC analysis shows potential of the developed composite for thermal energy storage that can be easily incorporated into the cement-based matrix of building materials. Based on the obtained results, application of the developed phase change composite can be considered with a great promise.

  20. Chemical Composition and Quality Characteristics of Wheat Bread Supplemented with Leafy Vegetable Powders

    Directory of Open Access Journals (Sweden)

    T. V. Odunlade

    2017-01-01

    Full Text Available The study investigated the effect of supplementation of the leaf powders of Telfairia occidentalis, Amaranthus viridis, and Solanum macrocarpon on the chemical composition and the quality characteristics of wheat bread. The bread samples were supplemented with each of the vegetable leaf powders at 1%, 2%, and 3% during preparation. The bread samples were assayed for proximate composition, mineral composition, physical, sensory, and antioxidant properties using standard methods. The addition of vegetable powders significantly increased the protein (9.50 to 13.93%, fibre (1.81 to 4.00%, ash (1.05 to 2.38%, and fat (1.27 to 2.00%. Supplementation with vegetable powder however significantly decreased (p<0.05 the carbohydrate and moisture contents. Significant (p<0.05 increases were recorded for all evaluated minerals as the level of vegetable powder increased. Supplementation with vegetable powder caused significant decrease in total phenolic content, percentage DPPH inhibition, metal chelating ability, ferric reducing antioxidant power, and total antioxidant capacity. Sensory results showed that there was significant decrease in sensory qualities with increasing supplementation. This therefore suggests that bread supplemented with vegetable powder could have more market penetration if awareness is highly created.

  1. Preparation of magnesium metal matrix composites by powder metallurgy process

    Science.gov (United States)

    Satish, J.; Satish, K. G., Dr.

    2018-02-01

    Magnesium is the lightest metal used as the source for constructional alloys. Today Magnesium based metal matrix composites are widely used in aerospace, structural, oceanic and automobile applications for its light weight, low density(two thirds that of aluminium), good high temperature mechanical properties and good to excellent corrosion resistance. The reason of designing metal matrix composite is to put in the attractive attributes of metals and ceramics to the base metal. In this study magnesium metal matrix hybrid composite are developed by reinforcing pure magnesium with silicon carbide (SiC) and aluminium oxide by method of powder metallurgy. This method is less expensive and very efficient. The Hardness test was performed on the specimens prepared by powder metallurgy method. The results revealed that the micro hardness of composites was increased with the addition of silicon carbide and alumina particles in magnesium metal matrix composites.

  2. Processing, properties and applications of composites using powder-coated epoxy towpreg technology

    Science.gov (United States)

    Bayha, T. D.; Osborne, P. P.; Thrasher, T. P.; Hartness, J. T.; Johnston, N. J.; Marchello, J. M.; Hugh, M. K.

    1993-01-01

    Composite manufacturing using the current prepregging technology of impregnating liquid resin into three-dimensionally reinforced textile preforms can be a costly and difficult operation. Alternatively, using polymer in the solid form, grinding it into a powder, and then depositing it onto a carbon fiber tow prior to making a textile preform is a viable method for the production of complex textile shapes. The powder-coated towpreg yarn is stable, needs no refrigeration, contains no solvents and is easy to process into various woven and braided preforms for later consolidation into composite structures. NASA's Advanced Composites Technology (ACT) program has provided an avenue for developing the technology by which advanced resins and their powder-coated preforms may be used in aircraft structures. Two-dimensional braiding and weaving studies using powder-coated towpreg have been conducted to determine the effect of resin content, towpreg size and twist on textile composite properties. Studies have been made to customize the towpreg to reduce friction and bulk factor. Processing parameters have been determined for three epoxy resin systems on eight-harness satin fabric, and on more advanced 3-D preform architectures for the downselected resin system. Processing effects and the resultant mechanical properties of these textile composites will be presented and compared.

  3. In situ synthesis of NiAl–NbB2 composite powder through combustion synthesis

    International Nuclear Information System (INIS)

    Shokati, Ali Akbar; Parvin, Nader; Sabzianpour, Naser; Shokati, Mohammad; Hemmati, Ali

    2013-01-01

    Highlights: ► A Novel NiAl matrix composite powder with 0–40 wt.% NbB 2 was synthesized. ► Composite powders were synthesized by thermal explosion reaction of Ni–Al–Nb–B system. ► Microhardness of NiAl considerably increased with raising NbB 2 content. ► Synthesized composite powders is a good candidate as precursor for thermal barrier application. - Abstract: Synthesis of a novel NiAl matrix composite powder reinforced with 0–40 wt.% NbB 2 by combustion synthesis in thermal explosion mode was investigated. The elemental powders of Ni, Al, Nb, and amorphous boron were used as starting material. For all compositions final products consisted of only the NiAl and NbB 2 phases. Coarser NbB 2 with a relatively uniform distribution in NiAl matrix was formed with rising NbB 2 content. Microhardness of NiAl considerably increased from 377 ± 13 HV 0.05 to 866 ± 81 HV 0.05 for NiAl with 40 wt.% NbB 2 . High microhardness, proper size and distribution of NbB 2 in NiAl matrix make it a good candidate as precursor for thermal spray application.

  4. LDRD 149045 final report distinguishing documents.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Scott A.

    2010-09-01

    This LDRD 149045 final report describes work that Sandians Scott A. Mitchell, Randall Laviolette, Shawn Martin, Warren Davis, Cindy Philips and Danny Dunlavy performed in 2010. Prof. Afra Zomorodian provided insight. This was a small late-start LDRD. Several other ongoing efforts were leveraged, including the Networks Grand Challenge LDRD, and the Computational Topology CSRF project, and the some of the leveraged work is described here. We proposed a sentence mining technique that exploited both the distribution and the order of parts-of-speech (POS) in sentences in English language documents. The ultimate goal was to be able to discover 'call-to-action' framing documents hidden within a corpus of mostly expository documents, even if the documents were all on the same topic and used the same vocabulary. Using POS was novel. We also took a novel approach to analyzing POS. We used the hypothesis that English follows a dynamical system and the POS are trajectories from one state to another. We analyzed the sequences of POS using support vector machines and the cycles of POS using computational homology. We discovered that the POS were a very weak signal and did not support our hypothesis well. Our original goal appeared to be unobtainable with our original approach. We turned our attention to study an aspect of a more traditional approach to distinguishing documents. Latent Dirichlet Allocation (LDA) turns documents into bags-of-words then into mixture-model points. A distance function is used to cluster groups of points to discover relatedness between documents. We performed a geometric and algebraic analysis of the most popular distance functions and made some significant and surprising discoveries, described in a separate technical report.

  5. Effects of air-polishing powders on color stability of composite resins.

    Science.gov (United States)

    Güler, Ahmet Umut; Duran, Ibrahim; Yücel, Ali Çağin; Ozkan, Pelin

    2011-10-01

    The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re

  6. Effects of air-polishing powders on color stability of composite resins

    Directory of Open Access Journals (Sweden)

    Ahmet Umut Güler

    2011-10-01

    Full Text Available OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex. The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder. A standard air-polishing unit (ProSmile Handly was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300. Color differences (∆E* between the 2 color measurements (baseline and after 24 h storage were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p.05 and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7. Air-polishing applications increased the color change for all composite resin restorative materials

  7. Long-Acting Composite Systems Based on Powdered Medicinal Plants and Nanosilica

    Directory of Open Access Journals (Sweden)

    Turov, V.V.

    2017-03-01

    Full Text Available The state of water in the powdered plant materials (calendula, hibiscus and their composite systems with A-300 nanosilicas having different bulk density has been studied by low-temperature 1H NMR spectroscopy method. The change in bulk density has been found to significantly affect the radius of inner cavities in fibrillar space of plant components. The composite systems based on wetting-drying compaction of nanosilica and plant powder have been showed to form a mix with high interaction energy of heterogeneous particles. This results in the effective retention of plant bioactive complex by composite, which enables the development of long-acting herbal drugs.

  8. Influence of Rubber Powders on Foaming Behavior and Mechanical Properties of Foamed Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    HE Yue

    2017-02-01

    Full Text Available Polypropylene/rubber powders composites with different kinds of rubber powders were foamed by injection molding machine equipped with volume-adjustable cavity. The effect of dispersity of rubber powders and crystallization behavior of composites on the foaming behavior and mechanical properties was investigated. The results show that the addition of rubber powders can improve the cell structure of foamed PP with fine and uniform cell distribution. And cell density and size of PP/PP-MAH/NBR foams are 7.64×106cell/cm3 and 29.78μm respectively, which are the best among these foams. Combining cell structures with mechanical properties, notch impact strength of PP/PP-MAH/CNBR composites increases approximately by 2.2 times while tensile strength is reduced just by 26% compared with those of the pure PP. This indicates that PP/PP-MAH/CNBR composites are ideal foamed materials.

  9. 2014 SRNL LDRD Annual Report, Rev. 0

    Energy Technology Data Exchange (ETDEWEB)

    Mcwhorter, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-15

    Laboratory Directed Research and Development is a congressionally authorized program that provides the ‘innovation inspiration’ from which many of the Laboratory’s multi-discipline advancements are made in both science and engineering technology. The program is the backbone for insuring that scientific, technical and engineering capabilities can meet current and future needs. It is an important tool in reducing the probability of technological surprise by allowing laboratory technical staff room to innovate and keep abreast of scientific breakthroughs. Drawing from the synergism among the EM and NNSA missions, and work from other federal agencies ensures that LDRD is the key element in maintaining the vitality of SRNL’s technical programs. The LDRD program aims to position the Laboratory for new business in clean energy, national security, nuclear materials management and environmental stewardship by leveraging the unique capabilities of the Laboratory to yield foundational scientific research in core business areas, while aligning with SRS strategic initiatives and maintaining a vision for ultimate DOE applications.

  10. One step HIP canning of powder metallurgy composites

    Science.gov (United States)

    Juhas, John J. (Inventor)

    1990-01-01

    A single step is relied on in the canning process for hot isostatic pressing (HIP) powder metallurgy composites. The binders are totally removed while the HIP can of compatible refractory metal is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

  11. Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders

    Directory of Open Access Journals (Sweden)

    Heikki SARJAS

    2012-03-01

    Full Text Available Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial  cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co. To estimate the properties of  recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338

  12. Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder

    OpenAIRE

    Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana

    2010-01-01

    Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin conten...

  13. Development of new metal matrix composite electrodes for electrical discharge machining through powder metallurgy process

    Directory of Open Access Journals (Sweden)

    C. Mathalai Sundaram

    2014-12-01

    Full Text Available Electrical discharge machining (EDM is one of the widely used nontraditional machining methods to produce die cavities by the erosive effect of electrical discharges. This method is popular due to the fact that a relatively soft electrically conductive tool electrode can machine hard work piece. Copper electrode is normally used for machining process. Electrode wear rate is the major drawback for EDM researchers. This research focus on fabrication of metal matrix composite (MMC electrode by mixing copper powder with titanium carbide (TiC and Tungsten carbide (WC powder through powder metallurgy process, Copper powder is the major amount of mixing proportion with TiC and WC. However, this paper focus on the early stage of the project where powder metallurgy route was used to determine suitable mixing time, compaction pressure and sintering and compacting process in producing EDM electrode. The newly prepared composite electrodes in different composition are tested in EDM for OHNS steel.

  14. Wear mechanisms in powder metallurgy high speed steels matrix composites

    International Nuclear Information System (INIS)

    Gordo, E.; Martinez, M. A.; Torralba, J. M.; Jimenez, J. A.

    2001-01-01

    The development of metal matrix composites has a major interest for automotive and cutting tools industries since they possess better mechanical properties and wear resistance than corresponding base materials. One of the manufacturing methods for these materials includes processing by powder metallurgy techniques. in this case, blending of both, base material and reinforcement powders constitute the most important process in order to achieve a homogeneous distribution of second phase particles. in the present work, composite materials of M3/2 tool steel reinforced with 2.5,5 and 8 vol% of niobium carbide have been prepared. In order to ensure a homogeneous mix, powders of both materials were mixed by dry high-energy mechanical milling at 200 r.p.m. for 40 h. After a recovering annealing, two routes for consolidate were followed die pressing and vacuum sintering, and hot isostatic pressing (HIP). Pin-on-disc tests were carried out to evaluate wear behaviour in all the materials. Results show that ceramic particles additions improve wear resistance of base material. (Author) 9 refs

  15. Al/ B4C Composites with 5 and 10 wt% Reinforcement Content Prepared by Powder Metallurgy

    International Nuclear Information System (INIS)

    Yusof Abdullah; Mohd Reusmaazran Yusof; Azali Muhammad; Nadira Kamarudin; Wilfred Sylvester Paulus; Roslinda Shamsudin; Nasrat Hannah Shudin; Nurazila Mat Zali

    2012-01-01

    The preparation, physical and mechanical properties of Al/ B 4 C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B 4 C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/ B 4 C composites prepared by powder metallurgy was high. (Author)

  16. The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

    International Nuclear Information System (INIS)

    Emamian, Ali; Corbin, Stephen F.; Khajepour, Amir

    2012-01-01

    Highlights: ► The novel idea was to develop Fe-TiC containing high volume fraction of TiC. ► Increased TiC volume fraction enhanced clad hardness profile. ► Both, laser conditions and fed powder compositions affected the clad microstructure. ► Hardness and TiC volume fraction was maximized by control over melt pool composition. ► Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

  17. The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

    Energy Technology Data Exchange (ETDEWEB)

    Emamian, Ali, E-mail: aemamian@uwaterloo.ca [Research Associate and Postdoctoral fellow in the Department of Mechanics and Mechatronics, University of Waterloo, 200 University West, Waterloo, N2L 4 3G1 (Canada); Corbin, Stephen F. [Professor and Canada Research Chair in the Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, P.O. Box 15000, B3H 5 4R2 (Canada); Khajepour, Amir [Professor and Canada Research Chair in the Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The novel idea was to develop Fe-TiC containing high volume fraction of TiC. Black-Right-Pointing-Pointer Increased TiC volume fraction enhanced clad hardness profile. Black-Right-Pointing-Pointer Both, laser conditions and fed powder compositions affected the clad microstructure. Black-Right-Pointing-Pointer Hardness and TiC volume fraction was maximized by control over melt pool composition. Black-Right-Pointing-Pointer Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

  18. Study of geometry angles forming a coaxial nozzle to performance of laser fusion powder composition

    Directory of Open Access Journals (Sweden)

    Павло Васильович Кондрашев

    2017-06-01

    Full Text Available The main purpose of scientific and experimental research, as reflected in this work is the search for solutions and approaches aimed at improving process performance laser alloying powder composition focused laser radiation. Priori information analysis showed the complexity of the process of laser powder fusion tracks from the physical point of view with a lot of technological impacts. Therefore, in this paper we used the method of experimental design, which will allow a more accurate experimental results compared with other methods of research. Based on the experimental screening were identified most significant technological factors influence. These are: powder mass flow, the geometric configuration of the delivery means of powder composition in the area of laser processing, the speed of movement of the substrate. To study the process performance laser alloying powder compositions were applied methods of mathematical statistics, namely, was elected symmetric quasi-D-optimal plan Pisochynskoho for 3 technological factors influence that has good statistical properties and sold regression equation of second order. As a result of the measures was received mathematical model of laser powder fusion focused laser radiation in a second order polynomial. The technique demonstrated the productivity of the process of laser powder fusion focused laser radiation, obtained by using a mathematical model of the process.

  19. Microwave reflection properties of planar anisotropy Fe50Ni50 powder/paraffin composites

    International Nuclear Information System (INIS)

    Wei Jian-Qiang; Zhang Zhao-Qi; Han Rui; Wang Tao; Li Fa-Shen

    2012-01-01

    The reflection properties of planar anisotropy Fe 50 Ni 50 powder/paraffin composites have been studied in the microwave frequency range. The permeability of Fe 50 Ni 50 powder/paraffin composites is greatly enhanced by introducing the planar anisotropy, and can be further enhanced by using a rotational orientation method. The complex permeability can be considered as the superposition of two types of magnetic resonance. The resonance peak at high frequency is attributed to the natural resonance, while the peak at low frequency is attributed to the domain-wall resonance. The simulated results of the microwave reflectivity show that the matching thickness, peak frequency, permeability, and permittivity are closely related to the quarter wavelength matching condition. The Fe 50 Ni 50 powder/paraffin composites can be attractive candidates for thinner microwave absorbers in the L-band (1–2 GHz). (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Effect of zirconia content and powder processing mechanical properties of gelcasted ZTA composite

    International Nuclear Information System (INIS)

    Khoshkalam, M.; Faghihi-Sani, M.A.; Nojoomi, A.

    2013-01-01

    Addition of fine zirconia particles in the alumina matrix in order to produce ZTA composite is a well-known method for improving the mechanical properties of alumina ceramics such as flexural strength and fracture toughness. Increasing homogeneity and reducing alumina grain size are two key factors for achieving proper mechanical properties in this ceramic matrix composite. In this work two batches of ZTA powder precursor were prepared through mixing of alumina and zirconia by ball milling and in situ synthesis of ZTA composite via solution combustion method. The bending strength testing samples were fabricated through gel-casting process. The effects of different powder processing methods as well as zirconia contents on microstructural homogeneity and mechanical properties of ZTA composites were investigated. The samples produced by solution combustion synthesized powder yielded higher homogeneity, finer microstructure and higher flexural strength. Results showed an upswing in the fracture toughness for the synthesized samples even up to 20 vol% zirconia, while the mixed samples depicted optimum fracture toughness in 10 vol% zirconia content. (author)

  1. Multi-attribute criteria applied to electric generation energy system analysis LDRD.

    Energy Technology Data Exchange (ETDEWEB)

    Kuswa, Glenn W.; Tsao, Jeffrey Yeenien; Drennen, Thomas E.; Zuffranieri, Jason V.; Paananen, Orman Henrie; Jones, Scott A.; Ortner, Juergen G. (DLR, German Aerospace, Cologne); Brewer, Jeffrey D.; Valdez, Maximo M.

    2005-10-01

    This report began with a Laboratory-Directed Research and Development (LDRD) project to improve Sandia National Laboratories multidisciplinary capabilities in energy systems analysis. The aim is to understand how various electricity generating options can best serve needs in the United States. The initial product is documented in a series of white papers that span a broad range of topics, including the successes and failures of past modeling studies, sustainability, oil dependence, energy security, and nuclear power. Summaries of these projects are included here. These projects have provided a background and discussion framework for the Energy Systems Analysis LDRD team to carry out an inter-comparison of many of the commonly available electric power sources in present use, comparisons of those options, and efforts needed to realize progress towards those options. A computer aid has been developed to compare various options based on cost and other attributes such as technological, social, and policy constraints. The Energy Systems Analysis team has developed a multi-criteria framework that will allow comparison of energy options with a set of metrics that can be used across all technologies. This report discusses several evaluation techniques and introduces the set of criteria developed for this LDRD.

  2. Final report on LDRD project ''proliferation-resistant fuel cycles''

    International Nuclear Information System (INIS)

    Brown, N W; Hassberger, J A.

    1999-01-01

    This report provides a summary of LDRD work completed during 1997 and 1998 to develop the ideas and concepts that lead to the Secure, Transportable, Autonomous Reactor (STAR) program proposals to the DOE Nuclear Energy Research Initiative (NERI). The STAR program consists of a team of three national laboratories (LLNL, ANL, and LANL), three universities, (UC Berkeley, TAMU, and MIT) and the Westinghouse Research Center. Based on the LLNL work and their own efforts on related work this team prepared and integrated a package of twelve proposals that will carry the LDRD work outlined here into the next phase of development. We are proposing to develop a new nuclear system that meets stringent requirements for a high degree of safety and proliferation resistance, and also deals directly with the related nuclear waste and spent fuel management issues

  3. Idaho National Laboratory LDRD Annual Report FY 2012

    Energy Technology Data Exchange (ETDEWEB)

    Dena Tomchak

    2013-03-01

    This report provides a glimpse into our diverse research and development portfolio, wwhich encompasses both advanced nuclear science and technology and underlying technologies. IN keeping with the mission, INL's LDRD program fosters technical capabilities necessary to support current and future DOE-Office of Nuclear Energy research and development needs.

  4. Microstructure/processing relationships in high-energy high-rate consolidated powder composites of Nb-stabilized Ti3Al+TiAl

    Energy Technology Data Exchange (ETDEWEB)

    Persad, C.; Lee, B.; Hou, C.; Eliezer, Z.; Marcus, H.L.

    1989-01-01

    A new approach to powder processing is employed in forming titanium aluminide composites. The processing consists of internal heating of a customized powder blend by a fast electrical discharge of a homopolar generator. The high-energy high-rate '1MJ in 1s' pulse permits rapid heating of an electrically conducting powder mixture in a cold wall die. This short time at temperature approach offers the opportunity to control phase transformations and the degree of microstructural coarsening not readily possible with standard powder-processing approaches. This paper describes the consolidation results of titanium aluminide-based powder-composite materials. The focus of this study was the definition of microstructure/processing relationships for each of the composite constituents, first as monoliths and then in composite forms. Non-equilibrium phases present in rapidly solidified TiAl powders are transformed to metastable intermediates en route to the equilibrium gamma phase.

  5. Comparison of Two Powder Processing Techniques on the Properties of Cu-NbC Composites

    Directory of Open Access Journals (Sweden)

    B. D. Long

    2014-01-01

    Full Text Available An in situ Cu-NbC composite was successfully synthesized from Cu, Nb, and C powders using ball milling and high pressure torsion (HPT techniques. The novelty of the new approach, HPT, is the combination of high compaction pressure and large shear strain to simultaneously refine, synthesize, and consolidate composite powders at room temperature. The HPTed Cu-NbC composite was formed within a short duration of 20 min without Fe contamination from the HPT’s die. High porosity of 3–9%, Fe and niobium oxidations, from grinding media and ethanol during ball milling led to low electrical conductivity of the milled Cu-NbC composite. The electrical conductivity of the HPTed Cu-NbC composite showed a value 50% higher than that of milled Cu-NbC composite of the same composition.

  6. The influence of powder particle size on properties of Cu-Al2O3 composites

    Directory of Open Access Journals (Sweden)

    Rajković V.

    2009-01-01

    Full Text Available Inert gas atomized prealloyed copper powder containing 2 wt.% Al (average particle size ≈ 30 μm and a mixture consisting of copper (average particle sizes ≈ 15 μm and 30 μm and 4 wt.% of commercial Al2O3 powder particles (average particle size ≈ 0.75 μm were milled separately in a high-energy planetary ball mill up to 20 h in air. Milling was performed in order to strengthen the copper matrix by grain size refinement and Al2O3 particles. Milling in air of prealloyed copper powder promoted formation of finely dispersed nano-sized Al2O3 particles by internal oxidation. On the other side, composite powders with commercial micro-sized Al2O3 particles were obtained by mechanical alloying. Following milling, powders were treated in hydrogen at 400 0C for 1h in order to eliminate copper oxides formed on their surface during milling. Hot-pressing (800 0C for 3 h in argon at pressure of 35 MPa was used for compaction of milled powders. Hot-pressed composite compacts processed from 5 and 20 h milled powders were additionally subjected to high temperature exposure (800°C for 1 and 5h in argon in order to examine their thermal stability. The results were discussed in terms of the effects of different size of starting powders, the grain size refinement and different size of Al2O3 particles on strengthening, thermal stability and electrical conductivity of copper-based composites.

  7. Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder.

    Science.gov (United States)

    Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana

    2011-02-01

    Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin content in pink powder decreased from 50.5 to 11.2 and 14.1 mg/100 g in samples packed in polyethylene (PE) and metalised polyester polyethylene laminated pouches respectively. Total polyphenol amount increased in both the powders irrespective of packaging material. Sorption isotherms indicated that both white and pink aril powders were hygroscopic and equilibrated at low relative humidity of 28 and 32%, respectively.

  8. An investigation on the compressibility of aluminum/nano-alumina composite powder prepared by blending and mechanical milling

    International Nuclear Information System (INIS)

    Razavi Hesabi, Z.; Hafizpour, H.R.; Simchi, A.

    2007-01-01

    The densification response of aluminum powder reinforced with 5 vol.% nanometric alumina particles (35 nm) during uniaxial compaction in a rigid die was studied. The composite powder was prepared by blending and mechanical milling procedures. To determine the effect of the reinforcement nanoparticles on the compressibility of aluminum powder, monolithic Al powder, i.e. without the addition of alumina, was also examined. It was shown that at the early stage of compaction when the rearrangement of particles is the dominant mechanism of the densification, disintegration of the nanoparticle clusters and agglomerates under the applied load contributes in the densification of the composite powder prepared by blending method. As the compaction pressure increases, however, the load partitioning effect of the nanoparticles decreases the densification rate of the powder mixture, resulting in a lower density compared to the monolithic aluminum. It was also shown that mechanical milling significantly impacts the compressibility of the unreinforced and reinforced aluminum powders. Morphological changes of the particles upon milling increase the contribution of particle rearrangement in densification whilst the plastic deformation mechanism is significantly retarded due to the work-hardening effect of the milling process. Meanwhile, the distribution of alumina nanoparticles is improved by mechanical milling, which in fact, affects the compressibility of the composite powder. This paper addresses the effect of mechanical milling and reinforcement nanoparticles on the compressibility of aluminum powder

  9. Composition and particle size of electrolytic copper powders prepared in water-containing dimethyl sulfoxide electrolytes

    Science.gov (United States)

    Mamyrbekova, Aigul'; Abzhalov, B. S.; Mamyrbekova, Aizhan

    2017-07-01

    The possibility of the electroprecipitation of copper powder via the cathodic reduction of an electrolyte solution containing copper(II) nitrate trihydrate and dimethyl sulfoxide (DMSO) is shown. The effect electrolysis conditions (current density, concentration and temperature of electrolyte) have on the dimensional characteristics of copper powder is studied. The size and shape of the particles of the powders were determined by means of electron microscopy; the qualitative composition of the powders, with X-ray diffraction.

  10. NMR study of nanophase Al/Al-oxide powder and consolidated composites

    International Nuclear Information System (INIS)

    Suits, B.H.; Apte, P.; Wilken, D.E.; Siegel, R.W.

    1994-10-01

    27 Al Nuclear Magnetic Resonance (NMR) measurements from aluminum powders and consolidated nanophase aluminum made from those powders are presented. The signals from the metal and surface oxidation are easily separated and are compared before and after consolidation. The results presented indicate that the oxide coating becomes the interface region within the nanophase composite material and that during consolidation the metal has undergone a deformation equivalent to that seen for bulk material under a compressive strain of between 4% and 8%

  11. Experimental Characterization of Aluminum-Based Hybrid Composites Obtained Through Powder Metallurgy

    Science.gov (United States)

    Marcu, D. F.; Buzatu, M.; Ghica, V. G.; Petrescu, M. I.; Popescu, G.; Niculescu, F.; Iacob, G.

    2018-06-01

    The paper presents some experimental results concerning fabrication through powder metallurgy (P/M) of aluminum-based hybrid composites - Al/Al2O3/Gr. In order to understand the mechanisms that occur during the P/M processes of obtaining Al/Al2O3/Gr composite, we correlated the physical characteristics with their micro-structural characteristics. The characterization was performed using analysis techniques specific for P/M process, SEM-EDS and XRD analyses. Micro-structural characterization of the composites has revealed fairly uniform distribution this resulting in good properties of the final composite material.

  12. Sintering of Cu–Al2O3 nano-composite powders produced by a thermochemical route

    Directory of Open Access Journals (Sweden)

    MARIJA KORAC

    2007-11-01

    Full Text Available This paper presents the synthesis of nano-composite Cu–Al2O3 powder by a thermochemical method and sintering, with a comparative analysis of the mechanical and electrical properties of the obtained solid samples. Nano-crystalline Cu–Al2O3 powders were produced by a thermochemical method through the following stages: spray-drying, oxidation of the precursor powder, reduction by hydrogen and homogenization. Characterization of powders included analytical electron microscopy (AEM coupled with energy dispersive spectroscopy (EDS, differenttial thermal and thermogravimetric (DTA–TGA analysis and X-ray diffraction (XRD analysis. The size of the produced powders was 20–50 nm, with a noticeable presence of agglomerates. The composite powders were characterized by a homogenous distribution of Al2O3 in a copper matrix. The powders were cold pressed at a pressure of 500 MPa and sintered in a hydrogen atmosphere under isothermal conditions in the temperature range from 800 to 900 °C for up to 120 min. Characterization of the Cu–Al2O3 sintered system included determination of the density, relative volume change, electrical and mechanical properties, examination of the microstructure by SEM and focused ion beam (FIB analysis, as well as by EDS. The obtained nano-composite, the structure of which was, with certain changes, presserved in the final structure, provided a sintered material with a homogenеous distribution of dispersoid in a copper matrix, with exceptional effects of reinforcement and an excellent combination of mechanical and electrical properties.

  13. Methane explosion suppression characteristics based on the NaHCO3/red-mud composite powders with core-shell structure.

    Science.gov (United States)

    Wang, Yan; Cheng, Yi-Shen; Yu, Ming-Gao; Li, Yao; Cao, Jian-Liang; Zheng, Li-Gang; Yi, Hong-Wei

    2017-08-05

    The NaHCO 3 /red-mud (RM) composite powders were successfully prepared by the solvent-anti-solvent method for methane explosion suppression. The RM was used as a carrier, and the NaHCO 3 was used as a loaded inhibitor. The NaHCO 3 /RM composite powders showed a special core-shell structure and excellent endothermic performance. The suppression properties of NaHCO 3 /RM composite for 9.5% CH 4 explosion were tested in a 20L spherical explosion vessel and a 5L Perspex duct. The results showed that the NaHCO 3 /RM composite powders displayed a much better suppression property than the pure RM or NaHCO 3 powders. The loading amount of NaHCO 3 has an intensive influence on the inhibition property of NaHCO 3 /RM composite powders. The best loaded content of NaHCO 3 is 35%. It exhibited significant inhibitory effect that the explosion max-pressure declined 44.9%, the max-pressure rise rate declined 96.3% and the pressure peak time delayed 366.7%, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Chemical and phase composition of powders obtained by electroerosion dispersion from alloys WC-Co

    International Nuclear Information System (INIS)

    Putintseva, M.N.

    2004-01-01

    A consideration is given to the dependence of chemical and phase compositions of dispersed powders on the conditions, the medium of electroerosion dispersing and the content of cobalt in an initial alloy. It is shown that dissociation of carbon from tungsten carbide proceeds even on dispersing in liquid hydrocarbon-containing media (kerosene and machine oil). The phase composition is determined to a large extent by a medium of dispersing and a cobalt content in the initial alloy. In all powders complex tungsten-cobalt carbides and even Co 7 W 6 intermetallic compounds are found [ru

  15. Chemical and Phase Composition of Powders Obtained by Electroerosion Dispersion from WC - Co Alloys

    Science.gov (United States)

    Putintseva, M. N.

    2004-03-01

    The dependence of the chemical and phase composition of dispersed powders on the mode and medium of electroerosion dispersion and the content of cobalt in the initial alloy is considered. It is shown that the dissociation of carbon from tungsten carbide occurs even in dispersion in liquid hydrocarbon-bearing media (kerosene and industrial oils). The phase composition is primarily determined by the dispersion medium and the content of cobalt in the initial alloy. Compound tungsten-cobalt carbides and even a Co7W6 intermetallic are determined in all the powders.

  16. Suspension plasma sprayed composite coating using amorphous powder feedstock

    International Nuclear Information System (INIS)

    Chen Dianying; Jordan, Eric H.; Gell, Maurice

    2009-01-01

    Al 2 O 3 -ZrO 2 composite coatings were deposited by the suspension plasma spray process using molecularly mixed amorphous powders. X-ray diffraction (XRD) analysis shows that the as-sprayed coating is composed of α-Al 2 O 3 and tetragonal ZrO 2 phases with grain sizes of 26 nm and 18 nm, respectively. The as-sprayed coating has 93% density with a hardness of 9.9 GPa. Heat treatment of the as-sprayed coating reveals that the Al 2 O 3 and ZrO 2 phases are homogeneously distributed in the composite coating

  17. Sintering, microstructure and properties of WC-AISI304 powder composites

    International Nuclear Information System (INIS)

    Marques, B.J.; Fernandes, C.M.; Senos, A.M.R.

    2013-01-01

    Highlights: ► Total replacement of Co binder by stainless steel AISI 304 in WC based composites. ► Processing conditions for WC–stainless steel composites. ► Mechanical behavior and oxidation resistance of WC–stainless steel composites. -- Abstract: Tungsten carbide–stainless steel (AISI 304) based composites were successfully prepared by powder metallurgy routes using vacuum sintering at a maximum temperature of 1500 °C. The effects of the binder amount (between 6 and 15 wt.%) on the phase composition, microstructure and mechanical properties, namely hardness and fracture toughness, were investigated. Appreciable amount of (M,W) 6 C up to 12 wt.% was detected, especially for the higher SS contents. However, a good compromise between toughness and hardness was observed. Besides that, improved oxidation resistance was noticed in WC–SS based composites compared with WC–Co composites. The results are discussed having in mind the correlation between chemical composition, phase composition, microstructure and mechanical behavior

  18. Characterizations of Polystyrene-Based Hybrid Particles Containing Hydrophobic Mg(OH2 Powder and Composites Fabricated by Employing Resultant Hybrid Particles

    Directory of Open Access Journals (Sweden)

    Shuichi Kimura

    2007-01-01

    unchanged, even when the ST-1 powder content increased from 10 to 50 phr. Furthermore, a composite fabricated by employing the hybrid particles achieved homogenous distribution of ST-1 powder and showed a higher oxygen index than that of a composite fabricated by directly mixing of PS pellets and ST-1 powder.

  19. FY07 LDRD Final Report Precision, Split Beam, Chirped-Pulse, Seed Laser Technology

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J W; Messerly, M J; Phan, H H; Crane, J K; Beach, R J; Siders, C W; Barty, C J

    2009-11-12

    The goal of this LDRD ER was to develop a robust and reliable technology to seed high-energy laser systems with chirped pulses that can be amplified to kilo-Joule energies and recompressed to sub-picosecond pulse widths creating extremely high peak powers suitable for petawatt class physics experiments. This LDRD project focused on the development of optical fiber laser technologies compatible with the current long pulse National Ignition Facility (NIF) seed laser. New technologies developed under this project include, high stability mode-locked fiber lasers, fiber based techniques for reduction of compressed pulse pedestals and prepulses, new compact stretchers based on chirped fiber Bragg gratings (CFBGs), new techniques for manipulation of chirped pulses prior to amplification and new high-energy fiber amplifiers. This project was highly successful and met virtually all of its goals. The National Ignition Campaign has found the results of this work to be very helpful. The LDRD developed system is being employed in experiments to engineer the Advanced Radiographic Capability (ARC) front end and the fully engineered version of the ARC Front End will employ much of the technology and techniques developed here.

  20. Densification behavior of aluminum alloy powder mixed with zirconia powder inclusion under cold compaction

    International Nuclear Information System (INIS)

    Ryu, Hyun Seok; Lee, Sung Chul; Kim, Ki Tae

    2002-01-01

    Densification behavior of composite powders was investigated during cold compaction. Experimental data were obtained for aluminum alloy powder mixed with zirconia powder inclusion under triaxial compression. The cap model with constraint factors was implemented into a finite element program(ABAQUS) to simulate compaction responses of composite powders during cold compaction. Finite element results were compared with experimental data for densification behavior of composite powders under cold isostatic pressing and die compaction. The agreements between experimental data and finite element calculations from the cap model with constraint factors were good

  1. 2013 SRNL LDRD Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    McWhorter, S. [Savannah River Site (SRS), Aiken, SC (United States)

    2014-03-07

    This report demonstrates the execution of our LDRD program within the objectives and guidelines outlined by the Department of Energy (DOE) through the DOE Order 413.2b. The projects described within the report align purposefully with SRNL’s strategic vision and provide great value to the DOE. The diversity exhibited in the research and development projects underscores the DOE Office of Environmental Management (DOE-EM) mission and enhances that mission by developing the technical capabilities and human capital necessary to support future DOE-EM national needs. As a multiprogram national laboratory, SRNL is applying those capabilities to achieve tangible results for the nation in National Security, Environmental Stewardship, Clean Energy and Nuclear Materials Management.

  2. Novel Composite Powders with Uniform TiB2 Nano-Particle Distribution for 3D Printing

    Directory of Open Access Journals (Sweden)

    Mengxing Chen

    2017-03-01

    Full Text Available It is reported that the ductility and strength of a metal matrix composite could be concurrently improved if the reinforcing particles were of the size of nanometers and distributed uniformly. In this paper, we revealed that gas atomization solidification could effectively disperse TiB2 nanoparticles in the Al alloy matrix due to its fast cooling rate and the coherent orientation relationship between TiB2 particles and α-Al. Besides, nano-TiB2 led to refined equiaxed grain structures. Furthermore, the composite powders with uniformly embedded nano-TiB2 showed improved laser absorptivity. The novel composite powders are well suited for selective laser melting.

  3. The choice of the conditions to receive the electrolytic zinc powders for metal-rich compositions

    Directory of Open Access Journals (Sweden)

    A. V. Patrushev

    2015-03-01

    Full Text Available In the work a method of obtaining highly dispersed zinc powders by electrolysis and comparison of the properties of zinc-rich compositions prepared using as a pigment zinc powders obtained by different methods is provided. Conducted measurements have shown that the electrical conductivity of zinc-rich coatings comprising electrolytic zinc powder does not inferior to the conductivity of the film with PZHD-0 powder obtained by the  evaporation-condensation method, despite the significant difference in the amount of zinc pigment. On the basis of the received data one can conclude that the use of electrolytic zinc powder as a pigment will significantly save zinc.

  4. Effects of extrusion cooking on the chemical composition and functional properties of dry bean powders

    Science.gov (United States)

    This study aimed to investigate the impacts of extrusion cooking on the chemical composition and functional properties of bean powders from four bean varieties. The raw bean powders were extruded under eight different conditions, and the extrudates were then dried and ground (particle size = 0.5 mm)...

  5. Effect of composition and heat treatment on the phase formation of mechanically alloyed Cr-B and Mo-B powders

    International Nuclear Information System (INIS)

    Wu, H M; Hu, C J; Pai, K Y

    2009-01-01

    Blended elemental Cr-B and Mo-B powders in atomic ratio of 67:33, 50:50, and 20:80 were subjected to mechanical alloying up to 60 h and subsequent heat treatment to investigate effect of composition and heat treatment on the phase formation of Cr-B and Mo-B powders. It was studied by X-ray diffraction and differential thermal analysis. Mechanical alloying these powder mixtures for 60 h leads essentially to a amorphous structure except for the Mo 20 B 80 powder, which creates a partially amorphous MoB 4 structure. Annealing at lower temperatures relieves the strains cumulative in the milled powders and creates no new phase. The structures obtained after annealing the milled powders at higher temperature vary and depend on the overall composition of the powder mixtures. Annealing the milled Mo-B powders having greater Mo content ends up with a dissociation reaction at higher temperature.

  6. [Study of relationship between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite powder].

    Science.gov (United States)

    Chai, Feng; Xu, Ling; Liao, Yun-mao; Chao, Yong-lie

    2003-07-01

    The fabrication of all-ceramic dental restorations is challenged by ceramics' relatively low flexural strength and intrinsic poor resistance to fracture. This paper aimed at investigating the relationships between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite (Al(2)O(3)-nZrO(2)). Al(2)O(3)-nZrO(2) ceramics powder (W) was processed by combination methods of chemical co-precipitation and ball milling with addition of different powder-sized ZrO(2). Field-emission scanning electron microscopy was used to determine the particle size distribution and characterize the particle morphology of powders. The matrix compacts were made by slip-casting technique and sintered to 1,450 degrees C and flexural strength and the fracture toughness of them were measured. 1. The particle distribution of Al(2)O(3)-nZrO(2) ceramics powder ranges from 0.02 - 3.5 micro m and among them the superfine particles almost accounted for 20%. 2. The ceramic matrix samples with addition of nZrO(2) (W) showed much higher flexural strength (115.434 +/- 5.319) MPa and fracture toughness (2.04 +/- 0.10) MPa m(1/2) than those of pure Al(2)O(3) ceramics (62.763 +/- 7.220 MPa; 1.16 +/- 0.02 MPa m(1/2)). The particle size of additive ZrO(2) may impose influences on mechanical properties of Al(2)O(3)-nZrO(2) ceramics matrix. Good homogeneity and reasonable powder-size gradation of ceramic powder can improve the mechanical properties of material.

  7. Exploration of cloud computing late start LDRD #149630 : Raincoat. v. 2.1.

    Energy Technology Data Exchange (ETDEWEB)

    Echeverria, Victor T.; Metral, Michael David; Leger, Michelle A.; Gabert, Kasimir Georg; Edgett, Patrick Garrett; Thai, Tan Q.

    2010-09-01

    This report contains documentation from an interoperability study conducted under the Late Start LDRD 149630, Exploration of Cloud Computing. A small late-start LDRD from last year resulted in a study (Raincoat) on using Virtual Private Networks (VPNs) to enhance security in a hybrid cloud environment. Raincoat initially explored the use of OpenVPN on IPv4 and demonstrates that it is possible to secure the communication channel between two small 'test' clouds (a few nodes each) at New Mexico Tech and Sandia. We extended the Raincoat study to add IPSec support via Vyatta routers, to interface with a public cloud (Amazon Elastic Compute Cloud (EC2)), and to be significantly more scalable than the previous iteration. The study contributed to our understanding of interoperability in a hybrid cloud.

  8. LDRD 2013 Annual Report: Laboratory Directed Research and Development Program Activities

    Energy Technology Data Exchange (ETDEWEB)

    Bookless, W. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2013-12-31

    This LDRD project establishes a research program led by Jingguang Chen, who has started a new position as a Joint Appointee between BNL and Columbia University as of FY2013. Under this project, Dr. Chen will establish a new program in catalysis science at BNL and Columbia University. The LDRD program will provide initial research funding to start research at both BNL and Columbia. At BNL, Dr. Chen will initiate laboratory research, including hiring research staff, and will collaborate with the existing BNL catalysis and electrocatalysis research groups. At Columbia, a subcontract to Dr. Chen will provide startup funding for his laboratory research, including initial graduate student costs. The research efforts will be linked under a common Catalysis Program in Sustainable Fuels. The overall impact of this project will be to strengthen the BNL catalysis science program through new linked research thrusts and the addition of an internationally distinguished catalysis scientist.

  9. Laser fabrication of Ti6Al4V/TiC composites using simultaneous powder and wire feed

    International Nuclear Information System (INIS)

    Wang, F.; Mei, J.; Jiang, H.; Wu, X.

    2007-01-01

    Composites of Ti-6Al-4V containing different volume fractions of TiC were manufactured using direct laser fabrication. Ti-6Al-4V wire and TiC powder were fed into the laser with the rate of powder feed being changed so that samples containing different volume fractions of TiC could be manufactured. Optical microscopy, scanning electron and transmission electron microscopy were used to characterise the microstructure of these samples. The room temperature tensile properties were measured also on some selected compositions together with their Young's moduli. In addition the change in wear resistance was studied as a function of TiC volume fraction using a standard wear test. These observations are discussed in terms of the advantages and difficulties of using simultaneous wire and powder feed systems and in terms of the value of this approach in obtaining data over a wide range of compositions for such a composite

  10. Investigation of Structure and Physico-Mechanical Properties of Composite Materials Based on Copper - Carbon Nanoparticles Powder Systems

    Directory of Open Access Journals (Sweden)

    Kovtun V.

    2015-04-01

    Full Text Available Physico-mechanical and structural properties of electrocontact sintered copper matrix- carbon nanoparticles composite powder materials are presented. Scanning electron microscopy revealed the influence of preliminary mechanical activation of the powder system on distribution of carbon nanoparticles in the metal matrix. Mechanical activation ensures mechanical bonding of nanoparticles to the surface of metal particles, thus giving a possibility for manufacture of a composite with high physico-mechanical properties.

  11. Design of powder metallurgy titanium alloys and composites

    International Nuclear Information System (INIS)

    Liu, Y.; Chen, L.F.; Tang, H.P.; Liu, C.T.; Liu, B.; Huang, B.Y.

    2006-01-01

    Low cost and good performance are two major factors virtually important for Ti alloy development. In this paper, we have studied the effects of alloying elements, thermo-mechanical treatment and particle reinforcement on microstructures and mechanical properties of powder metallurgy (PM) Ti alloys and their composites. Our results indicate that low cost PM Ti alloys and their composites with attractive properties can be fabricated through a single compaction-sintering process, although secondary treatments are required for high performance applications. Three new PM Ti alloys and one TiC/Ti composite of high performance are developed, and new design principles are also proposed. For design of PM Ti alloys, addition of alloying elements has the beneficial effect of enhanced sintering and/or improved mechanical properties. For example, Fe element accelerates the sintering process, Mo and Al are good candidates for solution strengthening, and rare earth elements effectively increase the material ductility by scavenging oxygen from the Ti matrix. For the design of Ti-based composites, in situ formation of strengthening particles and solid solution hardening of the matrix both should be considered simultaneously for alloy development. Cr 3 C 2 is found to be a very suitable additive for processing particle reinforced Ti composites

  12. Larnite powders and larnite/silica aerogel composites as effective agents for CO{sub 2} sequestration by carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A., E-mail: alberto.santos@uca.es [Departamento de Ciencias de la Tierra, Universidad de Cadiz, Puerto Real, 11510 Cadiz (Spain); Ajbary, M.; Morales-Florez, V. [Departamento de Fisica de la Materia Condensada, Universidad de Cadiz, Puerto Real, 11510 Cadiz (Spain); Kherbeche, A. [Universite Sidi Mohamed Ben Abdellah, Ecole Superieure de Technologie, Fes (Morocco); Pinero, M. [Departamento de Fisica Aplicada, Universidad de Cadiz, Puerto Real, 11510 Cadiz (Spain); Esquivias, L. [Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Instituto de Ciencias de Materiales de Sevilla (CSIC), Universidad de Sevilla, 41012 Sevilla (Spain)

    2009-09-15

    This paper presents the results of the carbonation reaction of two sample types: larnite (Ca{sub 2}SiO{sub 4}) powders and larnite/silica aerogel composites, the larnite acting as an active phase in a process of direct mineral carbonation. First, larnite powders were synthesized by the reaction of colloidal silica and calcium nitrate in the presence of ethylene glycol. Then, to synthesize the composites, the surface of the larnite powders was chemically modified with 3-aminopropyltriethoxysilane (APTES), and later this mixture was added to a silica sol previously prepared from tetraethylorthosilicate (TEOS). The resulting humid gel was dried in an autoclave under supercritical conditions for the ethanol. The textures and chemical compositions of the powders and composites were characterized.The carbonation reaction of both types of samples was evaluated by means of X-ray diffraction and thermogravimetric analysis. Both techniques confirm the high efficiency of the reaction at room temperature and atmospheric pressure. A complete transformation of the silicate into carbonate resulted after submitting the samples to a flow of pure CO{sub 2} for 15 min. This indicates that for this reaction time, 1 t of larnite could eliminate about 550 kg of CO{sub 2}. The grain size, porosity, and specific surface area are the factors controlling the reaction.

  13. Role of powder preparation route on microstructure and mechanical properties of Al-TiB2 composites fabricated by accumulative roll bonding (ARB)

    International Nuclear Information System (INIS)

    Askarpour, M.; Sadeghian, Z.; Reihanian, M.

    2016-01-01

    Accumulative roll bonding (ARB) was conducted up to seven cycles to fabricate Al-TiB 2 particulate metal matrix composites. The reinforcing particles were prepared and used in three different processing conditions: as-received TiB 2 , mixed TiB 2 -Al and in-situ synthesized TiB 2 -Al. The mixed TiB 2 -Al powder was produced by milling of TiB 2 with Al powder and in-situ synthesized TiB 2 -Al powder was prepared by mechanical alloying (MA) through inducing TiB 2 particles in the Al with various composition of 10, 20 and 30 wt% Al. Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to evaluate the microstructure of the produced composites. The composite obtained from the in-situ TiB 2 -Al powder showed the most uniform distribution of particles and exhibited the highest tensile strength of about 177 MPa in comparison with the composites reinforced with the as-received TiB 2 (156 MPa) and mixed TiB 2 -Al powder (160 MPa). After seven ARB cycles, an ultra-fine grained structure with the average size of about 300 nm was obtained in the composite reinforced with in-situ TiB 2 -Al powder. The appearance of dimples in tensile fracture surfaces revealed a ductile-type fracture in the produced composites.

  14. FEM modeling on the compaction of Fe and Al composite powders

    Directory of Open Access Journals (Sweden)

    Han P.

    2015-01-01

    Full Text Available The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1 With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2 When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3 Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4 The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.

  15. One-Pot Synthesis of CoSex -rGO Composite Powders by Spray Pyrolysis and Their Application as Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Park, Gi Dae; Kang, Yun Chan

    2016-03-14

    A simple one-pot synthesis of metal selenide/reduced graphene oxide (rGO) composite powders for application as anode materials in sodium-ion batteries was developed. The detailed mechanism of formation of the CoSe(x)-rGO composite powders that were selected as the first target material in the spray pyrolysis process was studied. The crumple-structured CoSe(x)-rGO composite powders prepared by spray pyrolysis at 800 °C had a crystal structure consisting mainly of Co0.85 Se with a minor phase of CoSe2. The bare CoSe(x) powders prepared for comparison had a spherical shape and hollow structure. The discharge capacities of the CoSe(x)-rGO composite and bare CoSe(x) powders in the 50th cycle at a constant current density of 0.3 A g(-1) were 420 and 215 mA h g(-1), respectively, and their capacity retentions measured from the second cycle were 80 and 46%, respectively. The high structural stability of the CoSe(x)-rGO composite powders for repeated sodium-ion charge and discharge processes resulted in superior sodium-ion storage properties compared to those of the bare CoSe(x) powders. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Effects of TiN nanoparticles on the microstructure and properties of W–30Cu composites prepared via electroless plating and powder metallurgy

    International Nuclear Information System (INIS)

    Huang, Li-Mei; Luo, Lai-Ma; Zhao, Mei-Ling; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Zan, Xiang; Wu, Yu-Cheng

    2015-01-01

    Highlights: • TiN-doped W–Cu composite was successfully prepared by electroless plating and powder metallurgy. • TiN-doped W–Cu significantly affected the microstructure and properties of the composites. • W–Cu composite with 0.25 wt.% TiN possesses the best comprehensive performance. - Abstract: W–30Cu/(0, 0.25, 0.5, 1, and 2) wt.% TiN composites were prepared via electroless plating with simplified pretreatment and powder metallurgy. The phase and morphology of W–Cu/TiN composite powders and sintered W–Cu/TiN samples were characterized via X-ray diffraction and field emission scanning electron microscopy. Transmission electron microscopy was performed to characterize the microstructure of the sintered W–Cu/TiN samples. The relative density, hardness, electrical conductivity, and compressive strength of the sintered samples were examined. Results showed that W–30Cu composite powders with a uniform structure can be obtained using W powder pretreated with nitric acid, ammonium fluoride, and hydrofluoric acid followed by electroless Cu plating. The addition of TiN nanoparticles significantly affected the microstructure and properties of the W–30Cu composites. A good combination of the compressive strength and hardness of the W–30Cu composite material can be obtained by incorporating the TiN additive at 0.25 wt.%. However, the relative density and electrical conductivity slightly decreased

  17. Composite with a metallic matrix Al-AlN: from the powder to the material; Composite a matrice metallique A1-A1N: de la poudre au materiau

    Energy Technology Data Exchange (ETDEWEB)

    Troadec, C.

    1996-05-09

    Two types of powders are used: a `composite` powder synthesized by direct nitridation of aluminium by nitrogen, and a `mixed` powder obtained by a mixture of Al and AlN powders. These two powders types are crushed in a high energetic planetary crusher under an Ar atmosphere, then they are sintered under solid phase hot pressure. Microstructure of these materials, studied by Tem and XED, is relatively heterogenous, with high density polycrystalline area and high porous nano-crystals area. Size of these porous area are higher in `mixed` powders, and is linked to AlN percentage and to the crushing time. High density area are composed of Al grains surrounded by AlN nano-crystals with Al{sub 2}O{sub 3} needles and few aluminium oxynitride crystals. Physicochemical and mechanical properties, wear and corrosion comportment differ in function of the initial powders (`mixed` or `composite`) and with the AlN percentage. These new materials have, at similar reinforcement concentration, equivalent properties to Al/SiC or Al/Al{sub 2}O{sub 3} materials. (A.B.) 112 refs.

  18. The effect of powder properties on sintering, microstructure, mechanical strength and degradability of beta-tricalcium phosphate/calcium silicate composite bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lin Kaili; Chang Jiang; Shen Ruxiang, E-mail: jchang@mail.sic.ac.c [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2009-12-15

    The effect of powder properties on sintering, microstructure, mechanical strength and degradability of beta-tricalcium phosphate/Calcium silicate (beta-Ca{sub 3}(PO{sub 4}){sub 2}/CaSiO{sub 3}, beta-TCP/CS) composite bioceramics was investigated. beta-TCP/CS composite powders with a weight ratio of 50:50 were prepared by three different methods: mechanical milling method (TW-A), two-step chemical precipitation method (TW-B) and in situ chemical co-precipitation method (TW-C), and then the three composite powders were uniaxially compacted at 30 MPa, followed by cold isostatic pressing into rectangular-prism-shaped specimens under a pressure of 200 MPa for 15 min, and then sintered at 1150 deg. C for 5 h. The TW-B powders with less agglomerative morphologies and uniform nano-size particles attained 96.14% relative density (RD). A uniform microstructure with about 120 nm grains was observed. Whereas, the samples obtained from TW-A and TW-C powders only reached a RD of 63.08% and 78.86%, respectively. The bending strength of the samples fabricated from TW-B reached 125 MPa, which was more than 3.7 and 1.5 times higher as compared with that of samples obtained from TW-A and TW-C powders, respectively. Furthermore, the degradability of the samples fabricated from TW-B powders was obviously lower than that of the samples fabricated from TW-A and TW-C powders.

  19. Nanoporous Silica Templated HeteroEpitaxy: Final LDRD Report.

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Koleske, Daniel; Rowen, Adam M.; Williams, John Dalton; Fan, Hongyou; Arrington, Christian Lew

    2006-11-01

    This one-year out-of-the-box LDRD was focused on exploring the use of porous growth masks as a method for defect reduction during heteroepitaxial crystal growth. Initially our goal was to investigate porous silica as a growth mask, however, we expanded the scope of the research to include several other porous growth masks on various size scales, including mesoporous carbon, and the UV curable epoxy, SU-8. Use of SU-8 as a growth mask represents a new direction, unique in the extensive literature of patterned epitaxial growth, and presents the possibility of providing a single step growth mask. Additional research included investigation of pore viability via electrochemical deposition into high aspect ratio photoresist patterns and pilot work on using SU-8 as a DUV negative resist, another significant potential result. While the late start nature of this project pushed some of the initial research goals out of the time table, significant progress was made. 3 Acknowledgements This work was performed in part at the Nanoscience @ UNM facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECS 03-35765). Sandia is multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United Stated Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000. This work was supported under the Sandia LDRD program (Project 99405). 4

  20. Role of powder preparation route on microstructure and mechanical properties of Al-TiB{sub 2} composites fabricated by accumulative roll bonding (ARB)

    Energy Technology Data Exchange (ETDEWEB)

    Askarpour, M.; Sadeghian, Z., E-mail: z.sadeghian@scu.ac.ir; Reihanian, M.

    2016-11-20

    Accumulative roll bonding (ARB) was conducted up to seven cycles to fabricate Al-TiB{sub 2} particulate metal matrix composites. The reinforcing particles were prepared and used in three different processing conditions: as-received TiB{sub 2}, mixed TiB{sub 2}-Al and in-situ synthesized TiB{sub 2}-Al. The mixed TiB{sub 2}-Al powder was produced by milling of TiB{sub 2} with Al powder and in-situ synthesized TiB{sub 2}-Al powder was prepared by mechanical alloying (MA) through inducing TiB{sub 2} particles in the Al with various composition of 10, 20 and 30 wt% Al. Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to evaluate the microstructure of the produced composites. The composite obtained from the in-situ TiB{sub 2}-Al powder showed the most uniform distribution of particles and exhibited the highest tensile strength of about 177 MPa in comparison with the composites reinforced with the as-received TiB{sub 2} (156 MPa) and mixed TiB{sub 2}-Al powder (160 MPa). After seven ARB cycles, an ultra-fine grained structure with the average size of about 300 nm was obtained in the composite reinforced with in-situ TiB{sub 2}-Al powder. The appearance of dimples in tensile fracture surfaces revealed a ductile-type fracture in the produced composites.

  1. Microstructure and properties of FeSiCr/PA6 composites by injection molding using FeSiCr powders by phosphating and coupling treatment

    Science.gov (United States)

    Wang, Lulu; Qiao, Liang; Zheng, Jingwu; Cai, Wei; Ying, Yao; Li, Wangchang; Che, Shenglei; Yu, Jing

    2018-04-01

    FeSiCr/PA6 composites were prepared by injection molding using the FeSiCr powders modified by different phosphating agents and KH550 coupling agent. The resistivity, impact strength, magnetic permeability and magnetic loss of the FeSiCr/PA6 composites were measured. The morphologies of different FeSiCr powders and the FeSiCr/PA6 composites were also observed by scanning electron microscope (SEM). The results showed that 1-Hydroxyethylidene-1,1-diphosphonic acid, phytic acid and H3PO4 could improve the electrical resistivity of FeSiCr powders by forming the dense phosphating layer except diphenylphosphinic acid. However, the resistivity of FeSiCr/PA6 composites using the FeSiCr powders treated by all the four phosphating agents had no obvious increase though the phosphating layer on the surface of FeSiCr powder came into being. The nylon insulation layer had much stronger influence than the phosphating layer on electrical resistivity of the composites. After adding appropriate KH550 coupling agent, the impact strengths of FeSiCr/PA6 composites were significantly improved, which may be associated with the tiny gap between FeSiCr powder and PA6 matrix. The effects of the phosphating agents on the magnetic permeability and loss of the FeSiCr/PA6 were small and the mechanism were also discussed.

  2. Synthesis, Characterization, and Photocatalytic Properties of Bamboo Charcoal/TiO2 Composites Using Four Sizes Powder

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2018-04-01

    Full Text Available Visible-light-active bamboo biochar/TiO2 composites were fabricated by the calcination method using C16H36O4Ti as the titanium source and bamboo powder with different sizes as the carbon source. The TiO2 nanoparticles were observed to disperse onto the surface of bamboo biochar fiber. The sizes of the bamboo powder played an important role in the microstructures and the properties of bamboo biochar/TiO2 composites. The bamboo biochar/TiO2 composites displayed the photocatalytic activities both under visible light irradiation and UV irradiation. The adsorption isotherms better fitted Freundlich isotherm models and the photodegradation reactions followed pseudo-first-order kinetics. Bamboo charcoal/TiO2 composites exhibited high stability after up to four cycles. This research could pave the way for high-value applications of biomass in the environmental field.

  3. In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

    Science.gov (United States)

    Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L

    2010-05-01

    Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability. Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Novel powder/solid composites possessing low Young’s modulus and tunable energy absorption capacity, fabricated by electron beam melting, for biomedical applications

    International Nuclear Information System (INIS)

    Ikeo, Naoko; Ishimoto, Takuya; Nakano, Takayoshi

    2015-01-01

    Highlights: • We fabricated novel porous composites by electron beam melting. • The composites consist of necked powder and melted solid framework. • Unmelted powder that is usually discarded was mechanically functionalized by necking. • The composites possess controllably low Young’s modulus and excellent toughness. • The composites would be promising for utilization in biomedical applications. - Abstract: A novel, hierarchical, porous composite from a single material composed of necked powder and melted solid, with tunable mechanical properties, is fabricated by electron beam melting and subsequent heat treatment. The composite demonstrates low Young’s modulus (⩽31 GPa) and excellent energy absorption capacity, both of which are necessary for use in orthopedic applications. To the best of our knowledge, this is the first report on the synthesis of a material combining controllably low Young’s modulus and excellent toughness

  5. Effect of Rare Earth Y on Properties of Nanosized 90W-7Ni-3Fe Composite Powder Fabricated by Spray Drying-Hydrogen Reduction

    Directory of Open Access Journals (Sweden)

    Y.-Z. Ma

    2008-01-01

    Full Text Available (W,Ni,Fe composite oxide powder synthesized by spray drying was reduced at 700∘C for 90 minutes in H2 atmosphere. The effect of rare earth Y on H2 reduction of (W,Ni,Fe composite oxide powder was studied. Phase composition, crystalline size, and particle morphology of the reduced powder have been measured by X-ray diffraction and scanning electron microscope (SEM. Fsss particle size and special surface area of the reduced powder were also measured and analyzed. The result showed that new phase Y(Ni0.75W0.25O3 appeared in the reduced powder and particle morphology was nearly spherical or polyhedron by Y additions. The higher the rare earth element content was, the bigger the influencing on particle morphology was. When the rare earth Y content was under 0.8%, with the increase of the rare earth element content, dBET, Fsss, and crystal sizes of the reduced powder decreased greatly.

  6. Final Report for the Virtual Reliability Realization System LDRD

    Energy Technology Data Exchange (ETDEWEB)

    DELLIN, THEODORE A.; HENDERSON, CHRISTOPHER L.; O' TOOLE, EDWARD J.

    2000-12-01

    Current approaches to reliability are not adequate to keep pace with the need for faster, better and cheaper products and systems. This is especially true in high consequence of failure applications. The original proposal for the LDRD was to look at this challenge and see if there was a new paradigm that could make reliability predictions, along with a quantitative estimate of the risk in that prediction, in a way that was faster, better and cheaper. Such an approach would be based on the underlying science models that are the backbone of reliability predictions. The new paradigm would be implemented in two software tools: the Virtual Reliability Realization System (VRRS) and the Reliability Expert System (REX). The three-year LDRD was funded at a reduced level for the first year ($120K vs. $250K) and not renewed. Because of the reduced funding, we concentrated on the initial development of the expertise system. We developed an interactive semiconductor calculation tool needed for reliability analyses. We also were able to generate a basic functional system using Microsoft Siteserver Commerce Edition and Microsoft Sequel Server. The base system has the capability to store Office documents from multiple authors, and has the ability to track and charge for usage. The full outline of the knowledge model has been incorporated as well as examples of various types of content.

  7. Influence of Metal-Coated Graphite Powders on Microstructure and Properties of the Bronze-Matrix/Graphite Composites

    Science.gov (United States)

    Zhao, Jian-hua; Li, Pu; Tang, Qi; Zhang, Yan-qing; He, Jian-sheng; He, Ke

    2017-02-01

    In this study, the bronze-matrix/x-graphite (x = 0, 1, 3 and 5%) composites were fabricated by powder metallurgy route by using Cu-coated graphite, Ni-coated graphite and pure graphite, respectively. The microstructure, mechanical properties and corrosive behaviors of bronze/Cu-coated-graphite (BCG), bronze/Ni-coated-graphite (BNG) and bronze/pure-graphite (BPG) were characterized and investigated. Results show that the Cu-coated and Ni-coated graphite could definitely increase the bonding quality between the bronze matrix and graphite. In general, with the increase in graphite content in bronze-matrix/graphite composites, the friction coefficients, ultimate density and wear rates of BPG, BCG and BNG composites all went down. However, the Vickers microhardness of the BNG composite would increase as the graphite content increased, which was contrary to the BPG and BCG composites. When the graphite content was 3%, the friction coefficient of BNG composite was more stable than that of BCG and BPG composites, indicating that BNG composite had a better tribological performance than the others. Under all the values of applied loads (10, 20, 40 and 60N), the BCG and BNG composites exhibited a lower wear rate than BPG composite. What is more, the existence of nickel in graphite powders could effectively improve the corrosion resistance of the BNG composite.

  8. Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios.

    Science.gov (United States)

    Wu, Dawei; Zhou, Qifa; Shung, Koping Kirk; Bharadwaja, Srowthi N; Zhang, Dongshe; Zheng, Haixing

    2009-05-08

    The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P(r), and transverse piezoelectric coefficient, e(31,) (f), increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm(2), a dielectric constant of 450 (at 1 kHz), and e(31,) (f) = -2.8 C/m(2). Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm(2), a dielectric constant of 1250 (at 1 kHz) and e(31,) (f) = -5.8 C/m(2).

  9. Black powder in gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

    2009-07-01

    Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

  10. A Study on the Manufacturing Properties of Crack Self-Healing Capsules Using Cement Powder for Addition to Cement Composites

    OpenAIRE

    Choi, Yun-Wang; Oh, Sung-Rok; Choi, Byung-Keol

    2017-01-01

    We fabricated crack self-healing capsules using cement powder for mixing into cement composites and evaluated the properties of the capsule manufacturing process in this study. The manufacture of the self-healing capsules is divided into core production processing of granulating cement in powder form and a coating process for creating a wall on the surfaces of the granulated cement particles. The produced capsules contain unhardened cement and can be mixed directly with the cement composite m...

  11. LDRD final report : robust analysis of large-scale combinatorial applications.

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Robert D.; Morrison, Todd (University of Colorado, Denver, CO); Hart, William Eugene; Benavides, Nicolas L. (Santa Clara University, Santa Clara, CA); Greenberg, Harvey J. (University of Colorado, Denver, CO); Watson, Jean-Paul; Phillips, Cynthia Ann

    2007-09-01

    Discrete models of large, complex systems like national infrastructures and complex logistics frameworks naturally incorporate many modeling uncertainties. Consequently, there is a clear need for optimization techniques that can robustly account for risks associated with modeling uncertainties. This report summarizes the progress of the Late-Start LDRD 'Robust Analysis of Largescale Combinatorial Applications'. This project developed new heuristics for solving robust optimization models, and developed new robust optimization models for describing uncertainty scenarios.

  12. Nano-composite powders Ag-SnO2 prepared by reactive milling sintering and microstructural evolution

    International Nuclear Information System (INIS)

    Lorrain, Nathalie

    2000-01-01

    This work aims at controlling the synthesis and the sintering of nano-composite powders Ag-SnO 2 in order to obtain a dense and nano-structured material for electrical contact as a substitute of the toxic compound Ag - CdO. The powder is prepared by reactive milling from silver oxide (Ag 2 O) and silver bronze (Ag 3 Sn) powders. This process leads to a fine dispersion of silver and tin oxide nanometer sized particles. We first studied the mechanisms of reaction promoted by milling in vacuum and in air. A two-stage oxidation of tin in Ag 3 Sn occurs: during forced contact with Ag 2 O, tin oxidises in SnO, then in SnO 2 . In air, gaseous oxygen also participates to the oxidation of tin in SnO 2 but the reaction is slower because of the formation of silver carbonates from a reaction of Ag 2 O with CO 2 .Then the sintering behaviour of the nano-composite powder as a function of the compacting pressure and of the heating rate has been studied. We show: (i) a diffusion of pure silver towards porosity and free surfaces (exo-diffusion) which destroys the nano-structure and (ii) a severe de-densification. We show that the origin of these phenomena is due to carbonates on to the Ag 2 O starting powder, which are incorporated, in the milled Ag-SnO 2 powder in course of milling; during sintering, decomposition gases generate internal stresses. Low stresses lead to a diffusional creep with exo-diffusion whereas high stresses induce an intensive de-densification by local plastic deformation but no exo-diffusion. A modelling shows that exo-diffusion is limited by heating very quickly a strongly compacted powder that contains a high quantity of carbonates. The experimental results confirm the predictions of the model. Finally, we propose solutions allowing a full densification and a process for decreasing the tin oxide concentration. (author) [fr

  13. Composition-dependent nanostructure of Cu(In,Ga)Se{sub 2} powders and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schnohr, C.S., E-mail: c.schnohr@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Kämmer, H.; Steinbach, T.; Gnauck, M. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Rissom, T.; Kaufmann, C.A.; Stephan, C. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Schorr, S. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin (Germany)

    2015-05-01

    Atomic-scale structural parameters of Cu(In,Ga)Se{sub 2} powders and polycrystalline thin films were determined as a function of the In and Cu contents using X-ray absorption spectroscopy. No difference in the two sample types is observed for the average bond lengths demonstrating the strong tendency towards bond length conservation typical for tetrahedrally coordinated semiconductors. In contrast, the bond length variation is significantly smaller in the thin films than in the powders, particularly for Cu-poor material. This difference in the nanostructure is proposed to originate from differences in the preparation conditions, most prominently from the different history of Cu composition. - Highlights: • Cu(In,Ga)Se{sub 2} powders and thin films are studied with X-ray absorption spectroscopy. • Structural parameters are determined as a function of the In and Cu contents. • The element-specific average bond lengths are identical for powders and thin films. • The Ga-Se/In-Se bond length variation is smaller for thin films than for powders. • The differences are believed to stem from the different history of the Cu content.

  14. Magnetic and microstructural properties of Fe{sub 3}O{sub 4}-coated Fe powder soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Jo Sunday, Katie [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States); Hanejko, Francis G. [Hoeganaes Corporation, Cinnaminson, NJ08077 (United States); Taheri, Mitra L., E-mail: mtaheri@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States)

    2017-02-01

    Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and possess high melting temperatures, thus providing adequate electrical barriers between metallic particles. In this work, iron powder was coated with Fe{sub 3}O{sub 4} particles via mechanical milling, then compacted and cured in an inert gas environment. We find density and coercivity to improve with increasing temperatures; however, core loss greatly increases, which is attributed to the formation of a more conductive iron-oxide phase and less resistive Fe volume. Our work begins to exemplify the unique qualities and potential for ferrite-based coatings using traditional powder metallurgy techniques and higher curing temperatures for electromagnetic devices. - Highlights: • Fe{sub 3}O{sub 4}-coated Fe powder was produced via mechanical milling, then compacted and cured into composite form. • SEM/EDS confirm Fe particles are individually isolated with iron-oxide coating material. • Larger particle sizes show improved core loss and coercivity measurements. • We report good magnetic properties for compaction at 800 MPa and a curing temperature of 700 °C.

  15. Microstructures and Properties of 40Cu/Ag(Invar) Composites Fabricated by Powder Metallurgy and Subsequent Thermo-Mechanical Treatment

    Science.gov (United States)

    Zhang, Xin; Huang, Yingqiu; Liu, Xiangyu; Yang, Lei; Shi, Changdong; Wu, Yucheng; Tang, Wenming

    2018-03-01

    Composites of 40Cu/Ag(Invar) were prepared via pressureless sintering and subsequent thermo-mechanical treatment from raw materials of electroless Ag-plated Invar alloy powder and electrolytic Cu powder. Microstructures and properties of the prepared composites were studied to evaluate the effect of the Ag layer on blocking Cu/Invar interfacial diffusion in the composites. The electroless-plated Ag layer was dense, uniform, continuous, and bonded tightly with the Invar alloy substrate. During sintering of the composites, the Ag layer effectively prevented Cu/Invar interfacial diffusion. During cold-rolling, the Ag layer was deformed uniformly with the Invar alloy particles. The composites exhibited bi-continuous network structure and considerably improved properties. After sintering at 775 °C and subsequent thermo-mechanical treatment, the 40Cu/Ag(Invar) composites showed satisfactory comprehensive properties: relative density of 99.0 pct, hardness of HV 253, thermal conductivity of 55.7 W/(m K), and coefficient of thermal expansion of 11.2 × 10-6/K.

  16. Copper-carbon and aluminum-carbon composites fabricated by powder metallurgy processes

    International Nuclear Information System (INIS)

    Silvain, Jean-François; Veillère, Amélie; Lu, Yongfeng

    2014-01-01

    The increase in both power and packing densities in power electronic devices has led to an increase in the market demand for effective heat-dissipating materials, with high thermal conductivity and thermal- expansion coefficient compatible with chip materials still ensuring the reliability of the power modules. In this context, metal matrix composites: carbon fibers and diamond-reinforced copper and aluminum matrix composites among them are considered very promising as a next generation of thermal-management materials in power electronic packages. These composites exhibit enhanced thermal properties compared to pure copper combined with lower density. This article presents the fabrication techniques of copper/carbon fibers and copper/diamond and aluminum/carbon fibers composite films by powder metallurgy and hot pressing. The thermal analyses clearly indicate that interfacial treatments are required in these composites to achieve high thermomechanical properties. Interfaces (through novel chemical and processing methods), when selected carefully and processed properly will form the right chemical/mechanical link between metal and carbon, enhancing all the desired thermal properties while minimizing the deleterious effect.

  17. Superplasticity in powder metallurgy aluminum alloys and composites

    International Nuclear Information System (INIS)

    Mishra, R.S.; Bieler, T.R.; Mukherjee, A.K.

    1995-01-01

    Superplasticity in powder metallurgy Al alloys and composites has been reviewed through a detailed analysis. The stress-strain curves can be put into 4 categories: classical well-behaved type, continuous strain hardening type, continuous strain softening type and complex type. The origin of these different types of is discussed. The microstructural features of the processed material and the role of strain have been reviewed. The role of increasing misorientation of low angle boundaries to high angle boundaries by lattice dislocation absorption is examined. Threshold stresses have been determined and analyzed. The parametric dependencies for superplastic flow in modified conventional aluminum alloys, mechanically alloyed alloys and Al alloy matrix composites is determined to elucidate the superplastic mechanism at high strain rates. The role of incipient melting has been analyzed. A stress exponent of 2, an activation energy equal to that for grain boundary diffusion and a grain size dependence of 2 generally describes superplastic flow in modified conventional Al alloys and mechanically alloyed alloys. The present results agree well with the predictions of grain boundary sliding models. This suggests that the mechanism of high strain rate superplasticity in the above-mentioned alloys is similar to conventional superplasticity. The shift of optimum superplastic strain rates to higher values is a consequence of microstructural refinement. The parametric dependencies for superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of 313 kJ/mol best describes the composites having SiC reinforcements. The role of shape of the reinforcement (particle or whisker) and processing history is addressed. The analysis suggests that the mechanism for superplasticity in composites is interface diffusion controlled grain boundary sliding

  18. LDRD project final report : hybrid AI/cognitive tactical behavior framework for LVC.

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevich, Donna D.; Xavier, Patrick Gordon; Brannon, Nathan Gregory; Hart, Brian E.; Hart, Derek H.; Little, Charles Quentin; Oppel, Fred John III; Linebarger, John Michael; Parker, Eric Paul

    2012-01-01

    This Lab-Directed Research and Development (LDRD) sought to develop technology that enhances scenario construction speed, entity behavior robustness, and scalability in Live-Virtual-Constructive (LVC) simulation. We investigated issues in both simulation architecture and behavior modeling. We developed path-planning technology that improves the ability to express intent in the planning task while still permitting an efficient search algorithm. An LVC simulation demonstrated how this enables 'one-click' layout of squad tactical paths, as well as dynamic re-planning for simulated squads and for real and simulated mobile robots. We identified human response latencies that can be exploited in parallel/distributed architectures. We did an experimental study to determine where parallelization would be productive in Umbra-based force-on-force (FOF) simulations. We developed and implemented a data-driven simulation composition approach that solves entity class hierarchy issues and supports assurance of simulation fairness. Finally, we proposed a flexible framework to enable integration of multiple behavior modeling components that model working memory phenomena with different degrees of sophistication.

  19. Strain Hardening Behaviour and Its Effect on Properties of ZrB2 Reinforced Al Composite Prepared by Powder Metallurgy Technique

    Science.gov (United States)

    Kaku, Sai Mahesh Yadav; Khanra, Asit Kumar; Davidson, M. J.

    2018-04-01

    Strain hardening behaviour has significant effect on altering the properties of materials. In the present study, Al-ZrB2 metal matrix composites are made through powder metallurgy route. Incremental weight percentage (wt%) of ZrB2 (0, 2, 4 and 6 wt%) are added to Aluminium matrix to produce different composites. The homogenous powder mixture is compacted and pressurelessly sintered. Sintering of composites is performed over a range of 450-575 °C. The optimized sintered condition is observed at 550 °C for 1 h in controlled atmosphere (argon gas flow). The sintered compacts are strained in incremental steps in different levels up to failure. A visible crack on the bulge of the powder preform is considered as the failure. Composites are strain hardened up to failure. To evaluate the effect of temperature on strain hardening, strain hardening is carried out at different temperatures. Composites are densified with the extent of straining and hardness increases with the increase of strain. Hardness increase with the increase in temperature is maintained during strain hardening. To evaluate the corrosion behaviour of Al-ZrB2 composite, potentiodynamic polarization study are performed on the strained composites. Corrosion rate decrease with the extent of straining.

  20. Low-temperature densification and excellent thermal properties of W–Cu thermal-management composites prepared from copper-coated tungsten powders

    International Nuclear Information System (INIS)

    Zhang, Lianmeng; Chen, Wenshu; Luo, Guoqiang; Chen, Pingan; Shen, Qiang; Wang, Chuanbin

    2014-01-01

    Highlights: • High-density (98.4%) W–20 wt.%Cu composites were low-temperature fabricated. • A highly pure Cu network and a homogenous microstructure formed in the composites. • The interfaces between W and Cu are well bonded with no spaces. • The composites have excellent thermal properties. -- Abstract: High-density W–20 wt.%Cu composites containing a Cu-network structure and exhibiting good thermal properties were fabricated by low-temperature hot-press sintering from high-purity copper-coated tungsten powders. The relative density of W–20 wt.%Cu composites sintered at 950 °C–100 MPa–2 h was 98.4%. The low-temperature densification of W–Cu composites occurs because the sintering mode of the coated particles involves only sintering of Cu to Cu, rather than both Cu to W and Cu to Cu, as required for conventional powder particles. The microstructure shows that a network of high-purity Cu extends throughout the composites, and that the W is distributed homogeneously; the interfaces between W and Cu show good contact. The composites have excellent thermal conductivity (239 W/(m K)) and a relatively low coefficient of thermal expansion (7.4 × 10 −6 /K), giving them some of the best properties reported to date for thermal-management materials. The excellent performance is mainly because of their structure, which arises from the characteristics of the high-purity copper-coated tungsten powders

  1. Synthesis and densification of Cu added Fe-based BMG composite powders by gas atomization and electrical explosion of wire

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.C., E-mail: jckimpml@ulsan.ac.k [University of Ulsan, School of Materials Science and Engineering, Ulsan 680-749 (Korea, Republic of); Ryu, H.J.; Kim, J.S. [University of Ulsan, School of Materials Science and Engineering, Ulsan 680-749 (Korea, Republic of); Kim, B.K.; Kim, Y.J. [Department of Powder Materials, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Kim, H.J. [Advanced Materials Division, Korea Institute of Industrial Technology, Incheon 406-130 (Korea, Republic of)

    2009-08-26

    In this study, the Fe-based (Fe-C-Si-B-P-Cr-Mo-Al) BMG powders were produced by the high pressure gas atomization process, and they were combined with the ductile Cu powders produced by the electrical explosion of wire (EEW). The Fe-based amorphous powders and Cu added BMG composite powders were compacted by the spark plasma sintering (SPS) processes into cylindrical shape. In the SPS press, the as-prepared powders were sintered at 793 K and 843 K. The relative density increased to 98% when the pressure increased up to 500 MPa by optimum control of the SPS process parameters. The micro-Vickers hardness was over 1100 Hv.

  2. Neurons to algorithms LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Rothganger, Fredrick H.; Aimone, James Bradley; Warrender, Christina E.; Trumbo, Derek

    2013-09-01

    Over the last three years the Neurons to Algorithms (N2A) LDRD project teams has built infrastructure to discover computational structures in the brain. This consists of a modeling language, a tool that enables model development and simulation in that language, and initial connections with the Neuroinformatics community, a group working toward similar goals. The approach of N2A is to express large complex systems like the brain as populations of a discrete part types that have specific structural relationships with each other, along with internal and structural dynamics. Such an evolving mathematical system may be able to capture the essence of neural processing, and ultimately of thought itself. This final report is a cover for the actual products of the project: the N2A Language Specification, the N2A Application, and a journal paper summarizing our methods.

  3. Nanoclay/Polymer Composite Powders for Use in Laser Sintering Applications: Effects of Nanoclay Plasma Treatment

    Science.gov (United States)

    Almansoori, Alaa; Majewski, Candice; Rodenburg, Cornelia

    2017-11-01

    Plasma-etched nanoclay-reinforced Polyamide 12 (PA12) powder is prepared with its intended use in selective laser sintering (LS) applications. To replicate the LS process we present a downward heat sintering (DHS) process, carried out in a hot press, to fabricate tensile test specimens from the composite powders. The DHS parameters are optimized through hot stage microscopy, which reveal that the etched clay (EC)-based PA12 (EC/PA12) nanocomposite powder melts at a temperature 2°C higher than that of neat PA12, and 1-3°C lower than that of the nonetched clay-based nanocompsite (NEC/PA12 composite). We show that these temperature differences are critical to successful LS. The distribution of EC and NEC onto PA12 is investigated by scanning electron microscopy (SEM). SEM images show clearly that the plasma treatment prevents the micron-scale aggregation of the nanoclay, resulting in an improved elastic modulus of EC/PA12 when compared with neat PA12 and NEC/PA12. Moreover, the reduction in elongation at break for EC/PA12 is less pronounced than for NEC/PA12.

  4. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  5. Effects of Polyethylene Grafted Maleic Anhydride on the Mechanical, Morphological, and Swelling Properties of Poly (Vinyl Chloride / Epoxidized Natural Rubber / Kenaf Core Powder Composites

    Directory of Open Access Journals (Sweden)

    Rohani Abdul Majid

    2014-10-01

    Full Text Available The effects of polyethylene grafted maleic anhydride (PE-g-MA on the properties of poly (vinyl chloride/epoxidized natural rubber (PVC/ENR kenaf core powder composites were studied, with four different loadings of kenaf core powder (5, 10, 15, and 20 phr. The tensile properties indicated that the strength and elongation at break of the composites exhibited an increase for samples with PE-g-MA. Morphological analysis using a scanning electron microscope (SEM showed better dispersion of kenaf fiber with the addition of PE-g-MA and less kenaf powder agglomeration. Furthermore, the swelling index indicated that composites with PE-g-MA showed lower toluene absorption than composites without PE-g-MA.

  6. Processing and properties of carbon nanofibers reinforced epoxy powder composites

    International Nuclear Information System (INIS)

    Palencia, C.; Mazo, M. A.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2011-01-01

    Commercially available CNFs (diameter 30–300 nm) have been used to develop both bulk and coating epoxy nanocomposites by using a solvent-free epoxy matrix powder. Processing of both types of materials has been carried out by a double-step process consisting in an initial physical premix of all components followed by three consecutive extrusions. The extruded pellets were grinded into powder and sieved. Carbon nanofibers powder coatings were obtained by electrostatic painting of the extruded powder followed by a curing process based in a thermal treatment at 200 °C for 25 min. On the other hand, for obtaining bulk carbon nanofibers epoxy composites, a thermal curing process involving several steps was needed. Gloss and mechanical properties of both nanocomposite coatings and bulk nanocomposites were improved as a result of the processing process. FE-SEM fracture surface microphotographs corroborate these results. It has been assessed the key role played by the dispersion of CNFs in the matrix, and the highly important step that is the processing and curing of the nanocomposites. A processing stage consisted in three consecutive extrusions has reached to nanocomposites free of entanglements neither agglomerates. This process leads to nanocomposite coatings of enhanced properties, as it has been evidenced through gloss and mechanical properties. A dispersion limit of 1% has been determined for the studied system in which a given dispersion has been achieved, as the bending mechanical properties have been increased around 25% compared with the pristine epoxy resin. It has been also demonstrated the importance of the thickness in the nanocomposite, as it involves the curing stage. The complex curing treatment carried out in the case of bulk nanocomposites has reached to reagglomeration of CNFs.

  7. Processing and properties of carbon nanofibers reinforced epoxy powder composites

    Science.gov (United States)

    Palencia, C.; Mazo, M. A.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2011-11-01

    Commercially available CNFs (diameter 30-300 nm) have been used to develop both bulk and coating epoxy nanocomposites by using a solvent-free epoxy matrix powder. Processing of both types of materials has been carried out by a double-step process consisting in an initial physical premix of all components followed by three consecutive extrusions. The extruded pellets were grinded into powder and sieved. Carbon nanofibers powder coatings were obtained by electrostatic painting of the extruded powder followed by a curing process based in a thermal treatment at 200 °C for 25 min. On the other hand, for obtaining bulk carbon nanofibers epoxy composites, a thermal curing process involving several steps was needed. Gloss and mechanical properties of both nanocomposite coatings and bulk nanocomposites were improved as a result of the processing process. FE-SEM fracture surface microphotographs corroborate these results. It has been assessed the key role played by the dispersion of CNFs in the matrix, and the highly important step that is the processing and curing of the nanocomposites. A processing stage consisted in three consecutive extrusions has reached to nanocomposites free of entanglements neither agglomerates. This process leads to nanocomposite coatings of enhanced properties, as it has been evidenced through gloss and mechanical properties. A dispersion limit of 1% has been determined for the studied system in which a given dispersion has been achieved, as the bending mechanical properties have been increased around 25% compared with the pristine epoxy resin. It has been also demonstrated the importance of the thickness in the nanocomposite, as it involves the curing stage. The complex curing treatment carried out in the case of bulk nanocomposites has reached to reagglomeration of CNFs.

  8. Small space object imaging : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Mark R.; Valley, Michael T.; Kearney, Sean Patrick

    2009-10-01

    We report the results of an LDRD effort to investigate new technologies for the identification of small-sized (mm to cm) debris in low-earth orbit. This small-yet-energetic debris presents a threat to the integrity of space-assets worldwide and represents significant security challenge to the international community. We present a nonexhaustive review of recent US and Russian efforts to meet the challenges of debris identification and removal and then provide a detailed description of joint US-Russian plans for sensitive, laser-based imaging of small debris at distances of hundreds of kilometers and relative velocities of several kilometers per second. Plans for the upcoming experimental testing of these imaging schemes are presented and a preliminary path toward system integration is identified.

  9. Use of Amino‐Functionalized CNTs and CVD Grown CNTs for Better Dispersion in Al Powder in the Fabrication of Composites

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, S. K.; Mathur, R. B. [National Physical Laboratory (CSIR), New Delhi‐1100 12 (India); Mamta,; Teotia, Satish [Guru Jambheshwar University of Science and Technology, Hisar (India); Chahal, Rajiv [Nanoscience and Nanotechnology, Panjab University, Chandigarh (India)

    2011-12-12

    We report an improved process for the better dispersion of multiwalled carbon nanotubes (MWCNTs) in Al powder used for the fabrication of Al‐matrix composites employing powder metallurgy process. For obtaining a better dispersion of MWCNTs in Al, we used two types of MWCNTs. In the first type, the MWCNTs were firstly functionalized by using ammonium bi‐carbonate and mix with Al powder using a high energy ball mill in the presence of a process control agent. In the second type we grew MWCNTs directly on Al powder using CVD. Various mechanical properties of the composites including micro hardness, compressive strength etc. were determined. It has been observed that using functionalized MWCNTs (fCNTs) and CVD grown MWCNTs, these properties were found to enhance significantly. The dispersion of functionalized CNTs was studied by SEM and the interfacial bonding between functionalized CNTs and Al matrix using high resolution transmission electron microscopy (HRTEM).

  10. Hydrogen absorption kinetics in powdered V + 80 wt.% LaNi5 composite

    International Nuclear Information System (INIS)

    Kumar, Sanjay; Tirpude, Amit; Taxak, Manju; Krishnamurthy, Nagaiyar

    2013-01-01

    Highlights: •Vanadium prevents the pulverization of LaNi 5 . •H absorption capacity LaNi 5 –V composite is higher than LaNi 5 . •H absorption kinetics of LaNi 5 –V composite is relatively faster than V and LaNi 5 . •Fermi energy level of LaNi 5 –V composite lowered by vanadium addition. -- Abstract: The hydrogen absorption behavior of V + 80 wt.% LaNi 5 composite, LaNi 5 and V has been investigated. The LaNi 5 –V composite was prepared by high energy ball-milling technique using high pure vanadium and LaNi 5 powder. Lattice expansion of the composite has been observed in X-ray analysis which indicates the solid solution formation. Presence of free V and traces of V 2 O 5 phase were also observed in the composite. The hydrogen absorption capacity and absorption kinetics of the composite showed improvement as compared to LaNi 5 . The improved kinetics of the composite has been co-related to the change in lattices parameter, Fermi energy level and catalytic property of vanadium. Integrity of the composite has found to be effective even after 20 numbers of hydriding and dehydriding cycles due to the presence of vanadium

  11. Final report on LDRD project : coupling strategies for multi-physics applications.

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Matthew Morgan; Moffat, Harry K.; Carnes, Brian; Hooper, Russell Warren; Pawlowski, Roger P.

    2007-11-01

    Many current and future modeling applications at Sandia including ASC milestones will critically depend on the simultaneous solution of vastly different physical phenomena. Issues due to code coupling are often not addressed, understood, or even recognized. The objectives of the LDRD has been both in theory and in code development. We will show that we have provided a fundamental analysis of coupling, i.e., when strong coupling vs. a successive substitution strategy is needed. We have enabled the implementation of tighter coupling strategies through additions to the NOX and Sierra code suites to make coupling strategies available now. We have leveraged existing functionality to do this. Specifically, we have built into NOX the capability to handle fully coupled simulations from multiple codes, and we have also built into NOX the capability to handle Jacobi Free Newton Krylov simulations that link multiple applications. We show how this capability may be accessed from within the Sierra Framework as well as from outside of Sierra. The critical impact from this LDRD is that we have shown how and have delivered strategies for enabling strong Newton-based coupling while respecting the modularity of existing codes. This will facilitate the use of these codes in a coupled manner to solve multi-physic applications.

  12. Extruded Al-Al2O3 composites formed in situ during consolidation of ultrafine Al powders: Effect of the powder surface area

    International Nuclear Information System (INIS)

    Balog, Martin; Simancik, Frantisek; Walcher, Martin; Rajner, Walter; Poletti, Cecilia

    2011-01-01

    Highlights: → 25 gas atomised Al 99.5% powders with particle size 2 O 3 dispersoids. → Compacts showed good thermal stability due to grain pinning of Al 2 O 3 dispersoids. - Abstract: Twenty-five samples of commercially available, gas-atomised Al (99.5%) powders with particle sizes 2 O 3 composites formed in situ during extrusion. The effect of particle size, surface area, oxygen content and atomisation atmosphere of the powder on the microstructure and mechanical properties of the extruded compacts were studied by Brunauer, Emmett, Teller (BET) analysis, hot gas extraction, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests. Thermal stability of the compacts and the individual strengthening mechanisms operating in the compacts were discussed. It was found that the properties of the compacts stemmed from the extraordinary grain boundary strengthening effect of the ultrafine-grained compacts due to their microstructures. The efficiency of the grain boundary strengthening was significantly enhanced by the presence of nano-metric Al 2 O 3 dispersoids introduced in situ. The strength of the compacts was closely related to the surface area of the powder particles. In addition, the entrapped gasses and chemically bonded humidity had a negative effect on the mechanical properties of the compacts.

  13. Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

    Directory of Open Access Journals (Sweden)

    Yu ZHONG

    2017-10-01

    Full Text Available Abstract Radio frequency heating (RFH provides higher efficiency and more uniform heating zone compared with conventional method. The aim of present work is to evaluate the effect of RFH (at 90 °C for 5 or 10 min on the changes in composition (protein oxidation and fat distribution, microstructure, flow characteristic and rehydration property of infant milk powder. The results indicate that the concentration of protein dityrosine was slightly enhanced, more free fat appeared on powder surfaces (> 50% increase, and porosity in powder matrix as tested by SEM was increased after RFH treatment. For powder flowability, raw sample had low cohesiveness (specific energy = 4.39 mJ/g, and RFH provided better flowability and decreased compressibility. Moreover, RFH had some negative impacts on wettability and solubility of powder particles with contact angle increase at least 5% and solubility decrease of 2%~4%, indicating worse rehydration abilities. Guggenheim-Anderson-de Boer (GAB model was applied to fit moisture vapor sorption isotherms, and longer RFH duration leading to higher c values (about 63% increase at 10 min. In addition, the RFH initiated browning reaction as CIE a* values increased from -1.8 to -1.3.

  14. Multi-target camera tracking, hand-off and display LDRD 158819 final report

    International Nuclear Information System (INIS)

    Anderson, Robert J.

    2014-01-01

    Modern security control rooms gather video and sensor feeds from tens to hundreds of cameras. Advanced camera analytics can detect motion from individual video streams and convert unexpected motion into alarms, but the interpretation of these alarms depends heavily upon human operators. Unfortunately, these operators can be overwhelmed when a large number of events happen simultaneously, or lulled into complacency due to frequent false alarms. This LDRD project has focused on improving video surveillance-based security systems by changing the fundamental focus from the cameras to the targets being tracked. If properly integrated, more cameras shouldn't lead to more alarms, more monitors, more operators, and increased response latency but instead should lead to better information and more rapid response times. For the course of the LDRD we have been developing algorithms that take live video imagery from multiple video cameras, identifies individual moving targets from the background imagery, and then displays the results in a single 3D interactive video. In this document we summarize the work in developing this multi-camera, multi-target system, including lessons learned, tools developed, technologies explored, and a description of current capability.

  15. Multi-target camera tracking, hand-off and display LDRD 158819 final report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Robert J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    Modern security control rooms gather video and sensor feeds from tens to hundreds of cameras. Advanced camera analytics can detect motion from individual video streams and convert unexpected motion into alarms, but the interpretation of these alarms depends heavily upon human operators. Unfortunately, these operators can be overwhelmed when a large number of events happen simultaneously, or lulled into complacency due to frequent false alarms. This LDRD project has focused on improving video surveillance-based security systems by changing the fundamental focus from the cameras to the targets being tracked. If properly integrated, more cameras shouldn't lead to more alarms, more monitors, more operators, and increased response latency but instead should lead to better information and more rapid response times. For the course of the LDRD we have been developing algorithms that take live video imagery from multiple video cameras, identifies individual moving targets from the background imagery, and then displays the results in a single 3D interactive video. In this document we summarize the work in developing this multi-camera, multi-target system, including lessons learned, tools developed, technologies explored, and a description of current capability.

  16. Multi-Target Camera Tracking, Hand-off and Display LDRD 158819 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Robert J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Robotic and Security Systems Dept.

    2014-10-01

    Modern security control rooms gather video and sensor feeds from tens to hundreds of cameras. Advanced camera analytics can detect motion from individual video streams and convert unexpected motion into alarms, but the interpretation of these alarms depends heavily upon human operators. Unfortunately, these operators can be overwhelmed when a large number of events happen simultaneously, or lulled into complacency due to frequent false alarms. This LDRD project has focused on improving video surveillance-based security systems by changing the fundamental focus from the cameras to the targets being tracked. If properly integrated, more cameras shouldn’t lead to more alarms, more monitors, more operators, and increased response latency but instead should lead to better information and more rapid response times. For the course of the LDRD we have been developing algorithms that take live video imagery from multiple video cameras, identify individual moving targets from the background imagery, and then display the results in a single 3D interactive video. In this document we summarize the work in developing this multi-camera, multi-target system, including lessons learned, tools developed, technologies explored, and a description of current capability.

  17. Using precipitated Cr on the surface of Cu-Cr alloy powders as catalyst synthesizing CNTs/Cu composite powders by water-assisted CVD

    Science.gov (United States)

    Zhou, Honglei; Liu, Ping; Chen, Xiaohong; Bi, Liming; Zhang, Ke; Liu, Xinkuan; Li, Wei; Ma, Fengcang

    2018-02-01

    Given that the conventional catalyst is easily soluble in the matrix to result in the poor performance of the CNTs/Cu composite materials, the Cr nano-particles precipitated on the surface of Cu-Cr particles are first used as catalysts to prepare the CNTs/Cu composite powders by means of water-assisted chemical vapor deposition in situ synthesis. The results show that the morphological difference of the precipitated Cr nano-particle is obvious with the change of solution and aging treatment, and the morphology, length and diameter of the synthetic CNTs are also different. The catalyst of Cr nano-particle has the best morphology and the synthesized CNTs had a good wettability with Cu particles when the Cu-Cr composite powders was solution-treated at 1023 K for 60 min and then was aged at 723 K for 120 min. The length, diameter, yield and purity of the synthesized CNTs can be also affected by the moisture content in the reaction gas. It is the most suitable for the growth of CNTs when the moisture content is 0.4%, and the high purity and defect-free CNTs with the smooth pipe wall, a diameter of 20 ˜ 30 nm and a length of up to 1800 nm can be obtained. The yield of CNTs with the moisture content of 0.4% reached to 138%, which was increased by 119% to compare with that without moisture. In this paper, a feasible technology was offered for the preparation of high performance CNTs/Cu composites.

  18. Production and properties of boride powders

    International Nuclear Information System (INIS)

    Klinskaya, N.A.; Koroleva, E.B.; Petrunichev, V.A.

    1990-01-01

    Results of plasma metallization of boride powders 40-80 μ diam. are presented. Peculiarities of changes of granulometric powder composition and of metallic cover on refractory cores were investigated. There are shown size- and compositional cores effects on metallization level of poders and on cover structure

  19. SHS synthesis of Si-SiC composite powders using Mg and reactants from industrial waste

    Science.gov (United States)

    Chanadee, Tawat

    2017-11-01

    Si-SiC composite powders were synthesized by self-propagating high-temperature synthesis (SHS) using reactants of fly ash-based silica, sawdust-based activated carbon, and magnesium. Fly ash-based silica and sawdust-based activated carbon were prepared from coal mining fly ash and Para rubber-wood sawdust, respectively. The work investigated the effects of the synthesis atmosphere (air and Ar) on the phase and morphology of the SHS products. The SHS product was leached by a two-step acid leaching processes, to obtain the Si-SiC composite powder. The SHS product and SHS product after leaching were characterized by X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectrometry. The results indicated that the SHS product synthesized in air consisted of Si, SiC, MgO, and intermediate phases (SiO2, Mg, Mg2SiO4, Mg2Si), whereas the SHS product synthesized in Ar consisted of Si, SiC, MgO and a little Mg2SiO4. The SiC content in the leached-SHS product was higher when Ar was used as the synthesis atmosphere. As well as affecting the purity, the synthesis atmospheres also affected the average crystalline sizes of the products. The crystalline size of the product synthesized in Ar was smaller than that of the product synthesized in air. All of the results showed that fly ash and sawdust could be effective waste-material reactants for the synthesis of Si-SiC composite powders.

  20. Composition influence on positron annihilation parameters in ZnO-based nanocrystal semiconductor powders

    Energy Technology Data Exchange (ETDEWEB)

    Damonte, L.C.; Hernandez Fenollosa, M.A.; Donderis, V.; Mari, B. [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Cami de Vera s/n, Valencia, 46071 (Spain)

    2007-07-01

    Zn{sub 1-x}Mg{sub x}O powders at various compositions were obtained by mechanical milling from the binary oxides. The progressive incorporation of Mg atoms into the ZnO lattice was monitored by X-ray diffraction (XRD). The evolution of annihilation parameters with milling time and composition were analyzed and related to the possible types of mechanical and substitutional induced defect present. It was concluded that the average lifetime constitute a useful parameter to sense the complete cation substitution in the wurtzite structure. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Composition influence on positron annihilation parameters in ZnO-based nanocrystal semiconductor powders

    International Nuclear Information System (INIS)

    Damonte, L.C.; Hernandez Fenollosa, M.A.; Donderis, V.; Mari, B.

    2007-01-01

    Zn 1-x Mg x O powders at various compositions were obtained by mechanical milling from the binary oxides. The progressive incorporation of Mg atoms into the ZnO lattice was monitored by X-ray diffraction (XRD). The evolution of annihilation parameters with milling time and composition were analyzed and related to the possible types of mechanical and substitutional induced defect present. It was concluded that the average lifetime constitute a useful parameter to sense the complete cation substitution in the wurtzite structure. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. A new approach to assess the chemical composition of powder deposits damaging the stone surfaces of historical monuments.

    Science.gov (United States)

    Fermo, Paola; Turrion, Raquel Gonzalez; Rosa, Mario; Omegna, Alessandra

    2015-04-01

    The issue of conservation of the monumental heritage worldwide is mainly related to atmospheric pollution that causes the degradation of stone surfaces. The powder deposits present on the stone monuments reflect the composition of the aerosol particulate matter (PM) to which the surfaces are exposed, so the chemical characterization of the outermost damaged layers is necessary in order to adopt mitigation measurements to reduce PM emissions. In the present paper, a new analytical approach is proposed to investigate the chemical composition of powder deposits present on Angera stone, a dolomitic rock used in the Richini courtyard, a masterpiece of Lombard Baroque and placed in Milan. Inorganic and organic components present in these deposits have been analyzed by IC (ion chromatography) and a new approach mainly bases on thermal analyses, respectively. Gypsum is the main inorganic constituent indicating a composition similar to that of black crusts, hard black patina covering the degraded building surfaces. Ammonium nitrate present in the powder is able to react with the stone substrate to form magnesium nitrate which can migrate into the porous stone. The carbonaceous fraction powder deposits (i.e. OC = Organic Carbon and EC = Elemental Carbon) have been quantified by a new simple thermal approach based on carbon hydrogen nitrogen (CHN) analysis. The presence of high concentration of EC confirms that the powder deposits are evolving to black crust. Low values of water-soluble organic carbon (WSOC, determined by total organic carbon-TOC), with respect to what is normally found in PM, may indicate a migration process of organic substances into the stone with a worsening of the conservation conditions. The presence of heavy metals of anthropogenic origin and acting as catalysts in the black crust formation process has been highlighted by SEM-EDS (electron microscopy coupled with an energy dispersive spectrometer) as well.

  3. A Case Study in Competitive Technical and Market Intelligence Support and Lessons Learned for the uChemLab LDRD Grand Challenge Project; TOPICAL

    International Nuclear Information System (INIS)

    SOUTHWELL, EDWIN T.; GARCIA, MARIE L.; MEYERS, CHARLES E.

    2001-01-01

    The(mu)ChemLab(trademark) Laboratory Directed Research and Development (LDRD) Grand Challenge project began in October 1996 and ended in September 2000. The technical managers of the(mu)ChemLab(trademark) project and the LDRD office, with the support of a consultant, conducted a competitive technical and market demand intelligence analysis of the(mu)ChemLab(trademark). The managers used this knowledge to make project decisions and course adjustments. CTI/MDI positively impacted the project's technology development, uncovered potential technology partnerships, and supported eventual industry partner contacts. CTI/MDI analysis is now seen as due diligence and the(mu)ChemLab(trademark) project is now the model for other Sandia LDRD Grand Challenge undertakings. This document describes the CTI/MDI analysis and captures the more important ''lessons learned'' of this Grand Challenge project, as reported by the project's management team

  4. Synthesis of high-performance Li2FeSiO4/C composite powder by spray-freezing/freeze-drying a solution with two carbon sources

    Science.gov (United States)

    Fujita, Yukiko; Iwase, Hiroaki; Shida, Kenji; Liao, Jinsun; Fukui, Takehisa; Matsuda, Motohide

    2017-09-01

    Li2FeSiO4 is a promising cathode active material for lithium-ion batteries due to its high theoretical capacity. Spray-freezing/freeze-drying, a practical process reported for the synthesis of various ceramic powders, is applied to the synthesis of Li2FeSiO4/C composite powders and high-performance Li2FeSiO4/C composite powders are successfully synthesized by using starting solutions containing both Indian ink and glucose as carbon sources followed by heating. The synthesized composite powders have a unique structure, composed of Li2FeSiO4 nanoparticles coated with a thin carbon layer formed by the carbonization of glucose and carbon nanoparticles from Indian ink. The carbon layer enhances the electrochemical reactivity of the Li2FeSiO4, and the carbon nanoparticles play a role in the formation of electron-conducting paths in the cathode. The composite powders deliver an initial discharge capacity of 195 and 137 mAh g-1 at 0.1 C and 1 C, respectively, without further addition of conductive additive. The discharge capacity at 1 C is 72 mAh g-1 after the 100th cycle, corresponding to approximately 75% of the capacity at the 2nd cycle.

  5. Development and characterization of composites PEAD recycled / gravel powder; Desenvolvimento e caracterizacao de compositos PEAD reciclado/po de brita

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, P.V.B de; Goncalves, A.P.B.; Guimaraes, D.H.; Miranda, C.S.; Neto, J.L.M.S.; Carvalho, R.F.; Jose, N.M., E-mail: patybritosousa@yahoo.com.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Programa de Pos-Graduacao em Engenharia Quimica

    2014-07-01

    The polymeric composites are heterogeneous materials multiphase, formed by at least one continuous phase and a discontinuous. The matrix used was recycled high density polyethylene (HDPE) and the load used was the residue of crushed stone dust generated by the process of crushing rocks, stocked in the quarries, no final destination, which changes the landscape and provides many environmental problems. With the aim of adding value to a new commercial waste and mitigate the environmental impact work proposes to develop polymeric composites for application in construction. Were prepared of recycled HDPE composites reinforced with three compositions 5,10 and 20% of powder aggregates with two different granulometries. The samples were prepared by pressing and characterized by FTIR analysis, DRX, DSC and TG. It has been observed that increasing the content of grit powder showed significant improvements in thermal and structural properties of the material. (author)

  6. Effect of heat absorbing powder addition on cell morphology of porous titanium composite manufactured by reactive precursor method

    International Nuclear Information System (INIS)

    Kobashi, Makoto; Kamiya, Yoshinori; Kanetake, Naoyuki

    2012-01-01

    Open-cell structured porous titanium/ceramics composite was synthesized by a reactive precursor method using titanium and boron carbide (B 4 C) as reactant powders. Pore morphology was controlled by adding heat absorbing powder (titanium diboride: TiB 2 ) in the Ti+B 4 C blended powder. The effects of molar blending ratio of titanium and B 4 C and the amount of heat absorbing powder addition on the cell morphology (either open or closed) were investigated. Fine and homogeneous open-cell structure was achieved by adding appropriate amount of heat absorbing agent powder (>15 vol%), and the relative density of the specimen after the reaction became closer to that of the precursor by increasing TiB 2 volume fraction. When the volume fraction of TiB 2 addition was 20%, the open-cell fraction was maintained as 1.0 regardless of the relative density of the precursor.

  7. Structure and characteristics of functional powder composite materials obtained by spark plasma sintering

    Science.gov (United States)

    Oglezneva, S. A.; Kachenyuk, M. N.; Kulmeteva, V. B.; Ogleznev, N. B.

    2017-07-01

    The article describes the results of spark plasma sintering of ceramic materials based on titanium carbide, titanium carbosilicide, ceramic composite materials based on zirconium oxide, strengthened by carbon nanostructures and composite materials of electrotechnical purpose based on copper with addition of carbon structures and titanium carbosilicide. The research shows that the spark plasma sintering can achieve relative density of the material up to 98%. The effect of sintering temperature on the phase composition, density and porosity of the final product has been studied. It was found that with addition of carbon nanostructures the relative density and hardness decrease, but the fracture strength of ZrO2 increases up to times 2. The relative erosion resistance of the electrodes made of composite copper-based powder materials, obtained by spark plasma sintering during electroerosion treatment of tool steel exceeds that parameter of pure copper up to times 15.

  8. The influence of concentration of Nd-Fe-B powder in composite coating of optical fiber to the sensibility to external magnetic field

    Directory of Open Access Journals (Sweden)

    Radojević Vesna J.

    2005-01-01

    Full Text Available Multi-mode optical fiber with magnetic composite coating was investigated as an optical fiber sensor element (OFMSE for magnetic field sensing The composite coating was formed with dispersions of permanent magnet powder of Nd-Fe-B in poly (ethylene-co-vinyl acetate-EVA solutions in toluene. The influence of the applied external magnetic field on the change of intensity of the light signal propagate trough developed optical fibers sensor element was investigated. In this paper the influence of the content of magnetic powder in the composite coating on the optical propagation characteristics of optical fiber were particularly investigated.

  9. STUDIES ON NATURAL WEATHERING OF RATTAN POWDER-FILLED NATURAL RUBBER COMPOSITES

    Directory of Open Access Journals (Sweden)

    Komethi Muniandy,

    2012-07-01

    Full Text Available This article investigates the effect of natural weathering on mechanical and morphological properties of rattan powder-filled natural rubber (NR composites as a function of filler loading and silane coupling agent. The rattan powder samples in the range of 0 to 30 phr were compounded with NR using a laboratory size two-roll mill. The natural weathering test was carried out for six months. The degradation of the samples was evaluated by performing a tensile test, a Fourier transform infrared spectroscopy (FTIR, and a scanning electron microscopy (SEM test. The results indicated that after natural weathering, an increase in stress at 100% elongation (M100 can be seen for samples without the silane coupling agent, whilst M100 was reduced for samples with silane coupling agent. A drastic reduction in tensile strength and elongation at break were observed for all samples due to the photo-oxidation process that occurred during the degradation of the samples. The extent of degradation on the samples’ surfaces and the presence of oxygenated products were confirmed by SEM and FTIR studies, respectively.

  10. Effects of gamma irradiation and ozone treatment on microbial decontamination and fatty acid compositions of aloe and pollen powders

    International Nuclear Information System (INIS)

    Yook, H.S.; Chung, Y.J.; Kim, J.O.; Kwon, O.J.; Byun, M.W.

    1997-01-01

    The comparative effects of gamma irradiation and ozone treatment on the microbial inactivation and fatty acid composition were investigated for improving hygienic quality of aloe and pollen powders. Gamma irradiation at 10 kGy resulted in sterilizing total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of aloe and pollen powders. The compositions of fatty acid were not significantly changed by gamma irradiation up to 10 kGy. However, ozone treatment markedly decreased unsaturated fatty acids by approximately 20-80% in contents, whereas it significantly increased saturated fatty acids (p<0.05)

  11. LDRD Report: Topological Design Optimization of Convolutes in Next Generation Pulsed Power Devices.

    Energy Technology Data Exchange (ETDEWEB)

    Cyr, Eric C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); von Winckel, Gregory John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kouri, Drew Philip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardiner, Thomas Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ridzal, Denis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shadid, John N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, Sean [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    This LDRD project was developed around the ambitious goal of applying PDE-constrained opti- mization approaches to design Z-machine components whose performance is governed by elec- tromagnetic and plasma models. This report documents the results of this LDRD project. Our differentiating approach was to use topology optimization methods developed for structural design and extend them for application to electromagnetic systems pertinent to the Z-machine. To achieve this objective a suite of optimization algorithms were implemented in the ROL library part of the Trilinos framework. These methods were applied to standalone demonstration problems and the Drekar multi-physics research application. Out of this exploration a new augmented Lagrangian approach to structural design problems was developed. We demonstrate that this approach has favorable mesh-independent performance. Both the final design and the algorithmic performance were independent of the size of the mesh. In addition, topology optimization formulations for the design of conducting networks were developed and demonstrated. Of note, this formulation was used to develop a design for the inner magnetically insulated transmission line on the Z-machine. The resulting electromagnetic device is compared with theoretically postulated designs.

  12. ELASTO-PLASTIC DEFORMATION OF COMPOSITE POWDERS WITH LAYERED CARBON AND CARBIDE-FORMING ELEMENT COATING

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2012-01-01

    Full Text Available Coating structure formation under magnetron spraying of titanium and carbon cathodes and combined cathodes, namely cobalt (EP 131 – nickel, tungsten – carbon have been investigated under conditions of carbide separate synthesis within the temperature range of 650–1200 °C. Usage of cobalt and nickel particles as matrix material leads to their rapid thermal expansion under heating during sintering process in the dilatometer. Subsequent plastic deformation of sintered samples provides obtaining a composite powder material that is a composite with framing structure of cobalt, titanium and tungsten carbides in the coatings.

  13. Composition powders of the system TiC-TiB2

    International Nuclear Information System (INIS)

    Degrave, I.E.; Udalov, Yu.P.

    2000-01-01

    The ceramic composition on TiC-TiB 2 base is proposed for substitution of scarce and expensive tungsten carbide for manufacturing metallo-ceramic articles. The technology of TiC and TiB 2 powder production from the mixture of oxides and carbon-bearing reducing agents is developed. Saccharose is recommended to be used as a reductant. Carbon tetrachloride vapors are introduced into the reaction volume to accelerate the synthesis. The purification of the product from residual carbon is performed in high frequency glow discharge with the use of air as a plasma forming gas. Microstructural studies show that the product obtained constitutes submicron TiC particles in a TiB 2 matrix [ru

  14. Time resolved fluorescence of cow and goat milk powder

    Science.gov (United States)

    Brandao, Mariana P.; de Carvalho dos Anjos, Virgílio; Bell., Maria José V.

    2017-01-01

    Milk powder is an international dairy commodity. Goat and cow milk powders are significant sources of nutrients and the investigation of the authenticity and classification of milk powder is particularly important. The use of time-resolved fluorescence techniques to distinguish chemical composition and structure modifications could assist develop a portable and non-destructive methodology to perform milk powder classification and determine composition. This study goal is to differentiate milk powder samples from cows and goats using fluorescence lifetimes. The samples were excited at 315 nm and the fluorescence intensity decay registered at 468 nm. We observed fluorescence lifetimes of 1.5 ± 0.3, 6.4 ± 0.4 and 18.7 ± 2.5 ns for goat milk powder; and 1.7 ± 0.3, 6.9 ± 0.2 and 29.9 ± 1.6 ns for cow's milk powder. We discriminate goat and cow powder milk by analysis of variance using Fisher's method. In addition, we employed quadratic discriminant analysis to differentiate the milk samples with accuracy of 100%. Our results suggest that time-resolved fluorescence can provide a new method to the analysis of powder milk and its composition.

  15. THz transceiver characterization : LDRD project 139363 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Nordquist, Christopher Daniel; Wanke, Michael Clement; Cich, Michael Joseph; Reno, John Louis; Fuller, Charles T.; Wendt, Joel Robert; Lee, Mark; Grine, Albert D.

    2009-09-01

    LDRD Project 139363 supported experiments to quantify the performance characteristics of monolithically integrated Schottky diode + quantum cascade laser (QCL) heterodyne mixers at terahertz (THz) frequencies. These integrated mixers are the first all-semiconductor THz devices to successfully incorporate a rectifying diode directly into the optical waveguide of a QCL, obviating the conventional optical coupling between a THz local oscillator and rectifier in a heterodyne mixer system. This integrated mixer was shown to function as a true heterodyne receiver of an externally received THz signal, a breakthrough which may lead to more widespread acceptance of this new THz technology paradigm. In addition, questions about QCL mode shifting in response to temperature, bias, and external feedback, and to what extent internal frequency locking can improve stability have been answered under this project.

  16. Modeling of wear behavior of Al/B_4C composites produced by powder metallurgy

    International Nuclear Information System (INIS)

    Sahin, Ismail; Bektas, Asli; Guel, Ferhat; Cinci, Hanifi

    2017-01-01

    Wear characteristics of composites, Al matrix reinforced with B_4C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B_4C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

  17. Extruded Al-Al{sub 2}O{sub 3} composites formed in situ during consolidation of ultrafine Al powders: Effect of the powder surface area

    Energy Technology Data Exchange (ETDEWEB)

    Balog, Martin, E-mail: martin.balog@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava (Slovakia); Simancik, Frantisek [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava (Slovakia); Walcher, Martin; Rajner, Walter [NMD - New Materials Development GmbH, St. Pantaleon (Austria); Poletti, Cecilia [Institute of Materials Science and Welding, Graz University of Technology, Kopernikusgasse 24/I, A8010 Graz (Austria)

    2011-11-25

    Highlights: {yields} 25 gas atomised Al 99.5% powders with particle size <10 {mu}m were hot extruded. {yields} The strength of compacts was closely related to powder surface area. {yields} Grain boundary strengthening was enhanced by the presence of in situ Al{sub 2}O{sub 3} dispersoids. {yields} Compacts showed good thermal stability due to grain pinning of Al{sub 2}O{sub 3} dispersoids. - Abstract: Twenty-five samples of commercially available, gas-atomised Al (99.5%) powders with particle sizes <10 {mu}m were hot extruded into Al-Al{sub 2}O{sub 3} composites formed in situ during extrusion. The effect of particle size, surface area, oxygen content and atomisation atmosphere of the powder on the microstructure and mechanical properties of the extruded compacts were studied by Brunauer, Emmett, Teller (BET) analysis, hot gas extraction, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests. Thermal stability of the compacts and the individual strengthening mechanisms operating in the compacts were discussed. It was found that the properties of the compacts stemmed from the extraordinary grain boundary strengthening effect of the ultrafine-grained compacts due to their microstructures. The efficiency of the grain boundary strengthening was significantly enhanced by the presence of nano-metric Al{sub 2}O{sub 3} dispersoids introduced in situ. The strength of the compacts was closely related to the surface area of the powder particles. In addition, the entrapped gasses and chemically bonded humidity had a negative effect on the mechanical properties of the compacts.

  18. Rapid Strengthening of Full-Sized Concrete Beams with Powder-Actuated fastening Systems and Fiber-Reinforced Polymer (FRP) Composite Materials

    National Research Council Canada - National Science Library

    Bank, Lawrence

    2002-01-01

    A research study was conducted to determine if the method of retrofitting reinforced concrete beams with powder-actuated fasteners and composite materials was applicable to full-scale flexural members...

  19. A Study on the Manufacturing Properties of Crack Self-Healing Capsules Using Cement Powder for Addition to Cement Composites

    Directory of Open Access Journals (Sweden)

    Yun-Wang Choi

    2017-01-01

    Full Text Available We fabricated crack self-healing capsules using cement powder for mixing into cement composites and evaluated the properties of the capsule manufacturing process in this study. The manufacture of the self-healing capsules is divided into core production processing of granulating cement in powder form and a coating process for creating a wall on the surfaces of the granulated cement particles. The produced capsules contain unhardened cement and can be mixed directly with the cement composite materials because they are protected from moisture by the wall material. Therefore, the untreated cement is present in the form of a capsule within the cement composite, and hydration can be induced by moisture penetrating the crack surface in the event of cracking. In the process of granulating the cement, it is important to obtain a suitable consistency through the kneading agent and to maintain the moisture barrier performance of the wall material. We can utilize the results of this study as a basis for advanced self-healing capsule technology for cement composites.

  20. Study on titanium-magnesium composites with bicontinuous structure fabricated by powder metallurgy and ultrasonic infiltration.

    Science.gov (United States)

    Jiang, S; Huang, L J; An, Q; Geng, L; Wang, X J; Wang, S

    2018-05-01

    Titanium-magnesium (Ti-Mg) composites with bicontinuous structure have been successfully fabricated by powder metallurgy and ultrasonic infiltration for biomaterial potential. In the composites, Ti phase is distributed continuously by sintering necks, while Mg phase is also continuous, distributing at the interconnected pores surrounding the Ti phase. The results showed that the fabricated Ti-Mg composites exhibited low modulus and high strength, which are very suitable for load bearing biomedical materials. The composites with 100 µm and 230 µm particle sizes exhibited Young's modulus of 37.6 GPa and 23.4 GPa, 500.7 MPa and 340 MPa of compressive strength and 631.5 MPa and 375.2 MPa of bending strength, respectively. Moreover, both of the modulus and strength of the composites increase with decreasing of Ti particle sizes. In vitro study has been done for the preliminary evaluation of the Ti-Mg composites. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. RESEARCH REGARDING THE CHEMICAL COMPOSITION OF POWDER MILK WITH NUTRIENTS

    Directory of Open Access Journals (Sweden)

    Liviu Giurgiulescu

    2009-06-01

    Full Text Available Powdered milk is a manufactured dairy product made by evaporating milk to dryness. This product has incomposition powder apple, powder carrots, rice flour and corn flour, vitamins, minerals.One purpose of drying milk is to preserve it; milk powder has a far longer self life than liquid milk and does notneed to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for economy oftransportation. Milk powders contain all twenty standards amino acids and are high insoluble vitamins and minerals.The typical average amounts of major nutrients in the un reconstituted in 100 g milk are (by weight 12,7g protein,68,2g carbohydrates (predominantly lactose, calcium 427g , potassium g, vitamins11g, Inappropriate storageconditions (high relative humidity and high ambient temperature can significantly degrade the nutritive value ofmilk powder.

  2. The wear properties of in-situ 7075 Al-Ti composites produced by powder metallurgy route

    Energy Technology Data Exchange (ETDEWEB)

    Ay, H.; Özyurek, D.; Yıldırım, M., E-mail: musayildirim@karabuk.edu.tr [Karabük University, Technology Faculty, Department of Manufacturing Engineering / Karabuk (Turkey); Bostan, B. [Gazi University, Technology Faculty, Department of Metallurgy and Materials Engineering (Turkey)

    2016-04-21

    In this study, the wear properties of in-situ 7075 Al-Ti composites produced by powder metallurgy route were investigated. Different amount of Ti (2, 4, 6 %) added to gas atomized 7075 Al alloy powders and they were mixed in turbula with 47rpm for 45 minutes. Then the mixed powders were pre-shaped by press under 600 MPa pressure. The samples were cooled in the furnace after sintered at 580 °C for 4 hours in the atmosphere controlled furnace. Standard metallographic process such as grinding, polishing and etching were applied to sintered samples. The hardness values were measured. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) examines were carried out. The wear tests were performed in a pin-on disc type wear apparatus with 1 ms{sup −1} sliding speed at six different sliding distance (500-3000 m) under 30 N loads. As a result of studies, hardness values were increased with increasing Ti content, in addition the weight losses were decreased with increasing Ti amount.

  3. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    International Nuclear Information System (INIS)

    Wang Lingqian; Zhou Jiansong; Yu Youjun; Guo Chun; Chen Jianmin

    2012-01-01

    NiCr + Cr 3 C 2 + Ag + BaF 2 /CaF 2 composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si 3 N 4 ball. The morphologies of the wear debris, worn surfaces of both samples and the Si 3 N 4 ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

  4. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    Science.gov (United States)

    Wang, Lingqian; Zhou, Jiansong; Yu, Youjun; Guo, Chun; Chen, Jianmin

    2012-06-01

    NiCr + Cr3C2 + Ag + BaF2/CaF2 composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si3N4 ball. The morphologies of the wear debris, worn surfaces of both samples and the Si3N4 ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

  5. Main group adducts of carbon dioxide and related chemistry (LDRD 149938).

    Energy Technology Data Exchange (ETDEWEB)

    Barry, Brian M. (University of New Mexico, Albuquerque, NM); Kemp, Richard Alan; Stewart, Constantine A.; Dickie, Diane A. (University of New Mexico, Albuquerque, NM)

    2010-11-01

    This late-start LDRD was broadly focused on the synthetic attempts to prepare novel ligands as complexing agents for main group metals for the sequestration of CO{sub 2}. In prior work we have shown that certain main group (p block elements) metals such as tin and zinc, when ligated to phosphinoamido- ligands, can bind CO{sub 2} in a novel fashion. Rather than simple insertion into the metal-nitrogen bonds to form carbamates, we have seen the highly unusual complexation of CO{sub 2} in a mode that is more similar to a chemical 'adduct' rather than complexation schemes that have been observed previously. The overarching goal in this work is to prepare more of these complexes that can (a) sequester (or bind) CO{sub 2} easily in this adduct form, and (b) be stable to chemical or electrochemical reduction designed to convert the CO{sub 2} to useful fuels or fuel precursors. The currently used phosphinoamido- ligands appear at this point to be less-stable than desired under electrochemical reduction conditions. This instability is believed due to the more delicate, reactive nature of the ligand framework system. In order to successfully capture and convert CO{sub 2} to useful organics, this instability must be addressed and solved. Work described in the late-start LDRD was designed to screen a variety of ligand/metal complexes that a priori are believed to be more stable to polar solvents and possible mild hydrolytic conditions than are the phosphinoamido-ligands. Results from ligand syntheses and metal complexation studies are reported.

  6. Preparation and electrochemical characterization of size controlled SnO2-RuO2 composite powder for monolithic hybrid battery

    International Nuclear Information System (INIS)

    Jeon, Young-Ah; No, Kwang-Soo; Choi, Sun Hee; Ahn, Jae pyong; Yoon, Young Soo

    2004-01-01

    Tin oxide (SnO 2 ) powders with a particle size of ∼20 nm were synthesized by a gas condensation method. Ruthenium oxide was loaded by an incipient-wetness method, in which an aqueous solution of RuCl 3 was added to the manufactured SnO 2 powder in an amount that was just sufficient to wet completely the powder. And then, the resulting solution was obtained after freeze-drying to synthesis the smallest particle. The as-synthesized SnO 2 powder with 1.5 wt.% ruthenium oxide (RuO 2 ) exhibited well-developed facets and had a very uniform particle size. The first discharge capacity was lower than comparing to commercial powder because of forming the second phase, but showed good cyclability. A maximum specific electrode capacitance of ∼20 F/g and a maximum specific power of ∼80 W/kg were achieved by manufactured SnO 2 with 1.5 wt.% RuO 2 . This result indicated that the synthesized SnO 2 -RuO 2 composite powder of nano-size scale is candidate for use in fabricating monolithic hybrid batteries using suitable electrolyte as well

  7. Fabrication of TiC-TiO{sub 2} composite powders by thermal plasma oxidation of titanium carbide powder; Tanka chitan funmatsu no plasma sanka hanno ni yori seiseishita TiC-TiO{sub 2} fukugo funmatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishigaki, T.; Li, Y.; Haneda, H. [National institute for Research Inorganic materials, Tsukuba (Japan); Kataoka, E. [Showa Cabot Supermetals K.K., Tokyo (Japan)

    2000-09-15

    TiC-TiO{sub 2} composite powders were prepared by in-flight oxidation of titanium carbide powder in RF induction thermal plasmas. Original titanium carbide powder of 20 - 38 {mu}m in particle size was axially injected into the center of argon-oxygen plasma. The powders were partially spheroidized and evaporated through the plasma treatment. X-ray diffraction of plasma-treated powders showed the formation of titanium dioxides, both rutile and anatase phases. The phase content of the plasma-prepared powders strongly depended on the plasma conditions, such as the plasma generating pressure and the oxygen flow rate in plasma generating gas. Especially, the increase of oxygen flow rate in plasma gas gave rise to the increase of heat transfer from plasma to powder particles, exothermic heat of oxidation reaction and cooling rate of plasma, giving the increase of spheroidization ratio, formation ratio of titanium dioxides, and content of anatase phases. (author)

  8. Anti-carburizing Coating for Resin Sand Casting of Low Carbon Steel Based on Composite Silicate Powder Containing Zirconium

    Directory of Open Access Journals (Sweden)

    Zhan Chunyi

    2018-01-01

    Full Text Available This paper studied the structure and properties of anticarburizing coating based on composite silicate powder containing zirconium by X-ray diffraction analyzer, thermal expansion tester, digital microscope and other equipment. It is introduced that the application example of the coating in the resin-sand casting of ZG1Cr18Ni9Ti stainless steel impeller. The anti-carburizing effect of the coating on the surface layer of the cast is studied by using direct reading spectrometer and spectrum analyzer. The change of the micro-structure of the coating after casting and cooling is observed by scanning electron microscope. The analysis of anti-carburizing mechanism of the coating is presented. The results indicate that the coating possesses excellent suspension property, brush ability, permeability, levelling property and crackresistance. The coating exhibits high strength and low gas evolution. Most of the coating could be automatically stripped off flakily when the casting was shaken out. The casting possesses excellent surface finish and antimetal penetration effect. The carburizing layer thickness of the stainless steel impeller casting with respect to allowable upper limit of carbon content is about 1mm and maximum carburizing rate is 23.6%. The anticarburizing effect of casting surface is greatly improved than that of zircon powder coating whose maximum carburizing rate is 67.9% and the carburizing layer thickness with respect to allowable upper limit of carbon content is greater than 2mm. The composite silicate powder containing zirconium coating substantially reduces the zircon powder which is expensive and radioactive and mainly dependent on imports. The coating can be used instead of pure zircon powder coating to effectively prevent metal-penetration and carburizing of resin-sand-casting surface of low carbon steel, significantly improve the foundry production environment and reduce the production costs.

  9. Influence of Co and W powders on viscosity of composite solders during soldering of specially shaped diamond-abrasive tools

    Science.gov (United States)

    Sokolov, E. G.; Aref’eva, S. A.; Svistun, L. I.

    2018-03-01

    The influence of Co and W powders on the structure and the viscosity of composite solders Sn-Cu-Co-W used for the manufacture of the specially shaped diamond tools has been studied. The solders were obtained by mixing the metallic powders with an organic binder. The mixtures with and without diamonds were applied to steel rollers and shaped substrates. The sintering was carried out in a vacuum at 820 ° C with time-exposure of 40 minutes. The influence of Co and W powders on the viscosity solders was evaluated on the basis of the study of structures and according to the results of sintering specially shaped diamond tools. It was found that to provide the necessary viscosity and to obtain the uniform diamond-containing layers on the complex shaped surfaces, Sn-Cu-Co-W solder should contain 27–35 vol % of solid phase. This is achieved with a total solder content of 24–32 wt % of cobalt powder and 7 wt % of tungsten powder.

  10. Characterize and Model Final Waste Formulations and Offgas Solids from Thermal Treatment Processes - FY-98 Final Report for LDRD 2349

    Energy Technology Data Exchange (ETDEWEB)

    Kessinger, Glen Frank; Nelson, Lee Orville; Grandy, Jon Drue; Zuck, Larry Douglas; Kong, Peter Chuen Sun; Anderson, Gail

    1999-08-01

    The purpose of LDRD #2349, Characterize and Model Final Waste Formulations and Offgas Solids from Thermal Treatment Processes, was to develop a set of tools that would allow the user to, based on the chemical composition of a waste stream to be immobilized, predict the durability (leach behavior) of the final waste form and the phase assemblages present in the final waste form. The objectives of the project were: • investigation, testing and selection of thermochemical code • development of auxiliary thermochemical database • synthesis of materials for leach testing • collection of leach data • using leach data for leach model development • thermochemical modeling The progress toward completion of these objectives and a discussion of work that needs to be completed to arrive at a logical finishing point for this project will be presented.

  11. Modeling of wear behavior of Al/B{sub 4}C composites produced by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Ismail; Bektas, Asli [Gazi Univ., Ankara (Turkey). Dept. of Industrial Design Engineering; Guel, Ferhat; Cinci, Hanifi [Gazi Univ., Ankara (Turkey). Dept. of Materials and Metallurgy Engineering

    2017-06-01

    Wear characteristics of composites, Al matrix reinforced with B{sub 4}C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B{sub 4}C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

  12. Powder processing and spheroidizing with thermal inductively coupled plasma

    International Nuclear Information System (INIS)

    Nutsch, G.; Linke, P.; Zakharian, S.; Dzur, B.; Weiss, K.-H.

    2001-01-01

    Processing of advanced powder materials for the spraying industry is one of the most promising applications of the thermal RF inductively coupled plasma. By selecting the feedstock carefully and adjusting the RF plasma parameters, unique materials with high quality can be achieved. Powders injected in the hot plasma core emerge with modified shapes, morphology, crystal structure and chemical composition. Ceramic oxide powders such as Al 2 O 3 , ZrO 2 , SiO 2 are spheroidized with a high spheroidization rate. By using the RF induction plasma spheroidizing process tungsten melt carbide powders are obtained with a high spheroidization rate at high feeding rates by densification of agglomerated powders consisting of di-tungsten carbide and monocarbide with a definite composition. This kind of ball-like powders is particularly suited for wear resistant applications. (author)

  13. Equal channel angular pressing of powder processed Al6061/SiC nano metal matrix composites and study of its wear properties

    Science.gov (United States)

    Bongale, Arunkumar M.; Kumar, Satish

    2018-03-01

    Nano Metal Matrix Composites were fabricated by a novel approach by combining powder metallurgy and equal channel angular pressing (ECAP) using aluminium alloy 6061 (Al6061) as matrix phase and 2, 4 and 6 wt% of silicon carbide nanoparticles (SiCnp) as reinforcements. Alloying elements of Al6061 in their elemental form are blended together using high energy planetary ball mill and calculated wt% of SiCnp were mixed with it. Thus formed composite powder mixture is compacted in a uniaxial compaction die and then subjected to ECAP up to three passes. Density and porosity of samples were estimated using Archimedes’ principle. Pin on disc setup is used to evaluate the wear properties of the composites under different speed and loading conditions. Tests revealed that increase in wt% of SiCnp reduces the wear rate of the composites whereas increasing the load and speed increases wear rate of the composite samples. SEM micrographs of worn surfaces indicated different types of wear mechanism responsible for wear of the specimens under different testing conditions. Also, wt% of SiCnp and the number of passes through ECAP were found to increase the hardness value of the composite material.

  14. A novel approach using powder metallurgy for strengthened RABiTS composite substrates for coated superconductors

    International Nuclear Information System (INIS)

    Suo Hongli; Zhao Yue; Liu Min; Ye Shuai; Zhu YongHua; He Dong; Ma Lingji; Ji Yuan; Zhou Meiling

    2008-01-01

    We report on the development of mechanically strengthened, highly textured Ni-5 at.%W/Ni-12 at.%W composite materials prepared by a powder metallurgical approach as promising weakly magnetic substrates for coated superconductors. The key configuration of this composite substrate consists of a thin, sharp cubic textured Ni-5 at.%W layer on a Ni-12 at.%W alloy core, thus providing a mechanical reinforcement while decreasing the saturation magnetization of the whole substrate. The composite substrates have a sharp cubic texture at the top Ni-5 at.%W outer layer and their yield strength reaches 272 MPa, exceeding that of the commercially used Ni5W substrates by a factor of 1.6. The saturation magnetization of the composite substrate Ni5W/Ni12W/Ni5W is substantially reduced when compared to that of pure Ni and Ni-5 at.%W substrates, respectively

  15. Cast AlSi9Cu4 alloy with hybride strenghtened by Fe{sub x}Al{sub y}-Al{sub 2}O{sub 3} composite powder

    Energy Technology Data Exchange (ETDEWEB)

    Piatkowski, J [Department of Materials Technology, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland); Formanek, B, E-mail: jaroslaw.piatkowski@polsl.pl, E-mail: boleslaw.formanek@polsl.pl [Department of Materials Science, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    The main objective of the study was to develop a technology of dispersion strenghtened hypoeutectic Al-Si alloy. The article presented the materials and technology conception for producing aluminium matrix composite AlSi9Cu4Fe alloy with hybride reinforcement of Al{sub x}Fe{sub y} intermetallic and aluminium oxide powders. Composite powder obtained in mechanical agllomerisation mixture of elemental powders. Changes in the structure were confirmed by TA and ATD thermal analyses plotting the solidification curves, which showed a decrease in temperature T{sub liq} compared to the unmodified alloy and an exothermic effect originating from the crystallisation of eutectics with alloying elements. The examinations carried out by SEM and BSE as well as the determination of local chemical composition by EDX technique have characterised the structure of the alloy as containing some binary Al-Si-Al-Cu and Al-Fe eutectics and multicomponent eutectics.

  16. Sintering by infiltration of loose mixture of powders, a method for metal matrix composite elaboration

    International Nuclear Information System (INIS)

    Constantinescu, V.; Orban, R.; Colan, H.

    1993-01-01

    Starting from the observation that Sintering by Infiltration of Loose Mixture of Powders confers large possibilities for both complex shaped and of large dimensions Particulate Reinforced Metal Matrix Composite components elaboration, its mechanism comparative with those of the classical melt infiltration was investigated. Appropriate measures in order to prevent an excessive hydrostatic flow of the melt and, consequently, reinforcement particle dispersion, as well as to promote wetting in both infiltration and liquid phase sintering stages of the process were established as necessary. Some experimental results in the method application to the fusion tungsten carbide and diamond reinforced metal matrix composite elaboration are, also, presented. (orig.)

  17. Final LDRD report : advanced plastic scintillators for neutron detection.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Mascarenhas, Nicholas; O' Bryan, Greg; Mrowka, Stanley

    2010-09-01

    This report summarizes the results of a one-year, feasibility-scale LDRD project that was conducted with the goal of developing new plastic scintillators capable of pulse shape discrimination (PSD) for neutron detection. Copolymers composed of matrix materials such as poly(methyl methacrylate) (PMMA) and blocks containing trans-stilbene (tSB) as the scintillator component were prepared and tested for gamma/neutron response. Block copolymer synthesis utilizing tSBMA proved unsuccessful so random copolymers containing up to 30% tSB were prepared. These copolymers were found to function as scintillators upon exposure to gamma radiation; however, they did not exhibit PSD when exposed to a neutron source. This project, while falling short of its ultimate goal, demonstrated the possible utility of single-component, undoped plastics as scintillators for applications that do not require PSD.

  18. Utilization of Construction Waste Composite Powder Materials as Cementitious Materials in Small-Scale Prefabricated Concrete

    OpenAIRE

    Cuizhen Xue; Aiqin Shen; Yinchuan Guo; Tianqin He

    2016-01-01

    The construction and demolition wastes have increased rapidly due to the prosperity of infrastructure construction. For the sake of effectively reusing construction wastes, this paper studied the potential use of construction waste composite powder material (CWCPM) as cementitious materials in small-scale prefabricated concretes. Three types of such concretes, namely, C20, C25, and C30, were selected to investigate the influences of CWCPM on their working performances, mechanical properties, ...

  19. Efficient Probability of Failure Calculations for QMU using Computational Geometry LDRD 13-0144 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ebeida, Mohamed Salah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Vicente J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rushdi, Ahmad A. [Univ. of Texas, Austin, TX (United States); Abdelkader, Ahmad [Univ. of Maryland, College Park, MD (United States)

    2015-09-01

    This SAND report summarizes our work on the Sandia National Laboratory LDRD project titled "Efficient Probability of Failure Calculations for QMU using Computational Geometry" which was project #165617 and proposal #13-0144. This report merely summarizes our work. Those interested in the technical details are encouraged to read the full published results, and contact the report authors for the status of the software and follow-on projects.

  20. Advances in allogenic bone graft processing and usage: preparation and evaluation of chitosan-demineralized cancellous bone powder composite scaffolds as a bone graft substitute

    International Nuclear Information System (INIS)

    Yongyudh Vajaradul

    2008-01-01

    Full text: Demineralized bone matrix (DBM) is currently used by surgeons. It usually exists as a lyophilized powder which is difficult to handle and operated. In this study, we try to improve these disadvantages by combining DBM with a biomaterial. It focuses on a natural biodegradable polymer, chitosan, to act as a temporary matrix for bone growth that easily prepare in any size and shape by using tissue engineering knowledge to get a proper temporary matrix. Thus, the development of chitosan-demineralized bone powder composite scaffold is an alternative way. Polymeric scaffold has been demonstrated to have great potential for tissue engineering because the scaffold or three dimension (3D) construct provides the necessary support for cells to proliferate, extracellular matrix deposition and vascularization of neo-tissue. Moreover, chitosan, a natural cationic polymer which its structural is similar to extracellular matrix glycosaminoblycans, is biodegradable, biocompatible, non-antigenic and biofunctional. It can enhance osteoblast cells proliferation and mineral matrix deposition in culture. The first study was to fabricate and analyze composite scaffold composed of either chitosan-demineralized cancellous bone powders or chitosan-demineralized cancellous cartilage bone powders in a ratio 50:50 and 70:30 w/w (chitosan : bone powders) based on physical properties composing of average pore diameter, mechanical integrity and swelling property. Secondly, scaffolds were evaluated in term of biological properties composing of their ability to support neo osteogenesis, including assessments of cell attachment and viability, cell morphology, and the biosynthesis of extracellular matrix. Results indicated that chitosan-demineralized cancellous bone powder composite scaffolds possessing an interconnecting, porous structure could be easily created through a simple freezing and lyophilization process. (Author)

  1. Preparation of superconductor precursor powders

    Science.gov (United States)

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  2. Compositionally graded Ti6Al4V + TiC made by direct laser fabrication using powder and wire

    International Nuclear Information System (INIS)

    Wang, F.; Mei, J.; Wu Xinhua

    2007-01-01

    Ti6Al4V reinforced with TiC has been fabricated as compositionally graded material by direct laser fabrication using TiC powder and Ti6Al4V wire which were fed simultaneously into the laser focal point. The microstructure along the length of the sample has been characterised using X-ray diffraction and scanning electron microscopy. The results show that the composition along the length changes as expected from the imposed changes in feed rate when allowance is made for the different capture efficiency for the powder and the wire. Some unmelted TiC has been observed in regions where the TiC fraction was high, but along most of the length of the samples TiC was completely melted and formed primary TiC, eutectic TiC and secondary TiC. Some preliminary tribological properties of the compositionally graded material were obtained using a sliding wear test which showed that the tribological properties of Ti6Al4V are improved by the reinforced TiC particles with the optimum frictional behaviour being found with approximately 24 vol% of TiC

  3. Synthesis of vanadium oxide powders by evaporative decomposition of solutions

    International Nuclear Information System (INIS)

    Lawton, S.A.; Theby, E.A.

    1995-01-01

    Powders of the vanadium oxides V 2 O 4 , V 6 O 13 , and V 2 O 5 were produced by thermal decomposition of aqueous solutions of vanadyl sulfate hydrate in atmospheres of N 2 , H 2 mixed with N 2 , or air. The composition of the oxide powder was determined by the reactor temperature and gas composition. Residual sulfur concentrations in powders produced by decomposition at 740 C were less than 1 at.%, and these powders consisted of hollow, roughly spherical aggregates of particles less than 1 microm in diameter

  4. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lingqian [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong, E-mail: jszhou@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yu Youjun; Guo Chun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2012-06-15

    NiCr + Cr{sub 3}C{sub 2} + Ag + BaF{sub 2}/CaF{sub 2} composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si{sub 3}N{sub 4} ball. The morphologies of the wear debris, worn surfaces of both samples and the Si{sub 3}N{sub 4} ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

  5. Treatment of refractory powders by a novel, high enthalpy dc plasma

    Science.gov (United States)

    Pershin, L.; Mitrasinovic, A.; Mostaghimi, J.

    2013-06-01

    Thermophysical properties of CO2-CH4 mixtures at high temperatures are very attractive for materials processing. In comparison with argon, at the same temperature, such a mixture possesses much higher enthalpy and higher thermal conductivity. At high temperatures, CO2-CH4 mixture has a complex composition with strong presence of CO which, in the case of powder treatment, could reduce oxidation. In this work, a dc plasma torch with graphite cathode was used to study the effect of plasma gas composition on spheroidization of tungsten carbide and alumina powders. Two different gas compositions were used to generate the plasma while the torch current was kept at 300 A. Various techniques were employed to assess the average concentration of carbides and oxides and the final shape of the treated powders. Process parameters such as input power and plasma gas composition allow controlling the degree of powder oxidation and spheroidization of high melting point ceramic powders.

  6. Treatment of refractory powders by a novel, high enthalpy dc plasma

    International Nuclear Information System (INIS)

    Pershin, L; Mitrasinovic, A; Mostaghimi, J

    2013-01-01

    Thermophysical properties of CO 2 –CH 4 mixtures at high temperatures are very attractive for materials processing. In comparison with argon, at the same temperature, such a mixture possesses much higher enthalpy and higher thermal conductivity. At high temperatures, CO 2 –CH 4 mixture has a complex composition with strong presence of CO which, in the case of powder treatment, could reduce oxidation. In this work, a dc plasma torch with graphite cathode was used to study the effect of plasma gas composition on spheroidization of tungsten carbide and alumina powders. Two different gas compositions were used to generate the plasma while the torch current was kept at 300 A. Various techniques were employed to assess the average concentration of carbides and oxides and the final shape of the treated powders. Process parameters such as input power and plasma gas composition allow controlling the degree of powder oxidation and spheroidization of high melting point ceramic powders. (paper)

  7. Magnetomechanical properties of composites and fibers made from thermoplastic elastomers (TPE) and carbonyl iron powder (CIP)

    Science.gov (United States)

    Schrödner, Mario; Pflug, Günther

    2018-05-01

    Magnetoactive elastomers (MAE) made from composites of five thermoplastic elastomers (TPE) of different stiffness with carbonyl iron powder (CIP) as magnetic component were investigated. The composites were produced by melt blending of the magnetic particles with the TPEs in a twin-screw extruder. The resulting materials were characterized by ac permeability testing, stress-strain measurements with and without external magnetic field and magnetically controlled bending of long cylindrical rods in a homogenous magnetic field. The magnetic field necessary for deflection of the rods decreases with decreasing modulus and increasing iron particle content. This effect can be used e.g. for magnetically controlled actuation. Some highly filled MAE show a magnetic field induced increase of Young's modulus. Filaments could be spun from some of the composites.

  8. Lignocellulose nanofibers prepared by ionic liquid pretreatment and subsequent mechanical nanofibrillation of bagasse powder: Application to esterified bagasse/polypropylene composites.

    Science.gov (United States)

    Ninomiya, Kazuaki; Abe, Megumi; Tsukegi, Takayuki; Kuroda, Kosuke; Tsuge, Yota; Ogino, Chiaki; Taki, Kentaro; Taima, Tetsuya; Saito, Joji; Kimizu, Mitsugu; Uzawa, Kiyoshi; Takahashi, Kenji

    2018-02-15

    In the present study, we examined the efficacy of choline acetate (ChOAc, a cholinium ionic liquid))-assisted pretreatment of bagasse powder for subsequent mechanical nanofibrillation to produce lignocellulose nanofibers. Bagasse sample with ChOAc pretreatment and subsequent nanofibrillation (ChOAc/NF-bagasse) was prepared and compared to untreated control bagasse sample (control bagasse), bagasse sample with nanofibrillation only (NF-bagasse) and with ChOAc pretreatment only (ChOAc-bagasse). The specific surface area was 0.83m 2 /g, 3.1m 2 /g, 6.3m 2 /g, and 32m 2 /g for the control bagasse, ChOAc-bagasse, NF-bagasse, and the ChOAc/NF-bagasse, respectively. Esterified bagasse/polypropylene composites were prepared using the bagasse samples. ChOAc/NF-bagasse exhibited the best dispersion in the composites. The tensile toughness of the composites was 0.52J/cm 3 , 0.73J/cm 3 , 0.92J/cm 3 , and 1.29J/cm 3 for the composites prepared using control bagasse, ChOAc-bagasse, NF-bagasse, and ChOAc/NF-bagasse, respectively. Therefore, ChOAc pretreatment and subsequent nanofibrillation of bagasse powder resulted in enhanced tensile toughness of esterified bagasse/polypropylene composites. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effect of powder geometry on densification

    International Nuclear Information System (INIS)

    Spasskij, M.R.; Spasskaya, I.A.; Shatalova, I.G.; Shchukin, E.D.

    1979-01-01

    The effect of particle shape and size composition on the processes of powder vibratory compacting is considered. Using microstress measurements in compacted structures of conglomerated and disintegrated tungsten powders as well as powder strength testing the existence of a zone of transition from a structural deformation to a plastic one has been shown. The formation of phase interparticle contacts of practically stable strength (approximately 5-6 dyn) is a characteristic feature of the zone. The width of the transition zone greatly depends upon geometrical powder properties; 55-65 % for conglomerated tungsten, 63-66 % for integrated tungsten

  10. Characterization of powdered fish heads for bone graft biomaterial applications.

    Science.gov (United States)

    Oteyaka, Mustafa Ozgür; Unal, Hasan Hüseyin; Bilici, Namık; Taşçı, Eda

    2013-01-01

    The aim of this study was to define the chemical composition, morphology and crystallography of powdered fish heads of the species Argyrosomus regius for bone graft biomaterial applications. Two sizes of powder were prepared by different grinding methods; Powder A (coarse, d50=68.5 µm) and Powder B (fine, d50=19.1 µm). Samples were analyzed using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), thermogravimetry (TG), and energy dispersive X-ray spectroscopy (EDS). The powder was mainly composed of aragonite (CaCO3) and calcite (CaCO3). The XRD pattern of Powder A and B matched standard aragonite and calcite patterns. In addition, the calcium oxide (CaO) phase was found after the calcination of Powder A. Thermogravimetry analysis confirmed total mass losses of 43.6% and 47.3% in Powders A and B, respectively. The microstructure of Powder A was mainly composed of different sizes and tubular shape, whereas Powder B showed agglomerated particles. The high quantity of CaO and other oxides resemble the chemical composition of bone. In general, the powder can be considered as bone graft after transformation to hydroxyapatite phase.

  11. Electroactive thermoset shape memory polymer nanocomposite filled with nanocarbon powders

    International Nuclear Information System (INIS)

    Leng, Jinsong; Lan, Xin; Liu, Yanju; Du, Shanyi

    2009-01-01

    This paper concerns an electroactive thermoset styrene-based shape memory polymer (SMP) nanocomposite filled with nanosized (30 nm) carbon powders. With an increase of the incorporated nanocarbon powders of the SMP composite, its glass transition temperature (T g ) decreases and storage modulus increases. Due to the high micro-porosity and homogeneous distributions of nanocarbon powders in the SMP matrix, the SMP composite shows good electrical conductivity with a percolation of about 3.8%. This percolation threshold is slightly lower than that of many other carbon-based conductive polymer composites. Consequently, due to the relatively high electrical conductivity, a sample filled with 10 vol% nanocarbon powders shows a good electroactive shape recovery performance heating by a voltage of 30 V above a transition temperature of 56–69 °C

  12. Optimization of the composition of the powdered cereal sprouts mixtures

    Directory of Open Access Journals (Sweden)

    Tumbas-Šaponjac Vesna T.

    2016-01-01

    Full Text Available Sprouts of cereals have received significant attention as functional food due to their nutritional and functional value. Consumption of sprouts has become increasingly popular among people interested in improving and maintaining their health status by changing dietary habits. Cereal grains contain several classes of phytochemicals, i.e. phenolics, chlorophylls, and carotenoids. However, their nutritional and chemical profile is altered and improved during germination. The purpose of this study was to find the best ratio of the powdered wheat (WS, oat (OS and barley (BS sprouts for designing the cereal sprout mixture (CSM with the highest total phenolic content (TPh and antioxidant capacity (AC, using Simplex-Centroid experimental design and response surface methodology (RSM. Single- and multi-response optimizations showed that OS did not contribute to TPh or AC values of CSM and, therefore, was not included in any of the compositions of the optimized CSM. Single-response optimizations showed that the highest TPh was found for CSM containing 82% BS and 18% WS, while the best AC was found for pure BS. The predicted ratio of cereal sprout powders in CSM obtained by multi-response optimization was: 96% BS and 4% WS. This mixture possessed the highest predicted TPh and AC (372.32 mg GAE/100 g, 549.99 μmol TE/100 g, respectively, which was confirmed to be in accordance with the experimental values. Based on the results obtained in this study, a designed CSM is proposed as a convenient ingredient of functional food products, dietary supplements and nutraceuticals.

  13. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

    Energy Technology Data Exchange (ETDEWEB)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-04-08

    A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  14. Reuse of scrap of Al and steel SAE 1045 in metal composite as alternative of recycling route powder metallurgy

    International Nuclear Information System (INIS)

    Souza, V.E.S.; Masieiro, F.R.S.; Lourenco, J.M.; Felipe, R.C.T.S.

    2009-01-01

    Full text: The process of powder metallurgy in the production of parts through application of pressure on the selected ceramic or metal powders, which are subjected to a temperature of sintering for to occur consolidation of the components. The metal-mechanical industry is responsible for the generation of inputs from their manufacturing processes. This work aims to re-use of chips of Al and SAE 1045 steel by powder metallurgy of this is a viable and effective. This work is in the manufacture of a composite using Al 6060 metal matrix and steel 1045 as reinforcement (30%, 40%, 50%), under different compaction pressures (250MPa, 400MPa and 600MPa), analyzing the influence of compressibility in hardness of the compressed. The samples were sintered at a temperature of 500 ° C in an oven using resistive atmosphere of hydrogen for 45 minutes. After the procedures of the powder metallurgy technique were analyzed of the optical microscopy, x-ray diffraction, MEV and Rockwell hardness, which was found to be evaluated as not diffusibility between the steel and aluminum. (author)

  15. LDRD final report : mesoscale modeling of dynamic loading of heterogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dingreville, Remi Philippe Michel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Voth, Thomas Eugene [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Furnish, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    Material response to dynamic loading is often dominated by microstructure (grain structure, porosity, inclusions, defects). An example critically important to Sandia's mission is dynamic strength of polycrystalline metals where heterogeneities lead to localization of deformation and loss of shear strength. Microstructural effects are of broad importance to the scientific community and several institutions within DoD and DOE; however, current models rely on inaccurate assumptions about mechanisms at the sub-continuum or mesoscale. Consequently, there is a critical need for accurate and robust methods for modeling heterogeneous material response at this lower length scale. This report summarizes work performed as part of an LDRD effort (FY11 to FY13; project number 151364) to meet these needs.

  16. Peculiarities of powder metallurgy of vanadium and its alloys

    International Nuclear Information System (INIS)

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

    1987-01-01

    Literature data on preparation of vanadium powder and powder materials on the vanadium base are generalized. Application of powder metallurgy engineering, allowing simulaneously to introduce practically any strengthening and solid-lubricating components as well as to alloy vanadium, permits undoubtedly to develop composite materials on the vanadium base

  17. Preparation techniques for ceramic waste form powder

    International Nuclear Information System (INIS)

    Hash, M.C.; Pereira, C.; Lewis, M.A.

    1997-01-01

    The electrometallurgical treatment of spent nuclear fuels result in a chloride waste salt requiring geologic disposal. Argonne National Laboratory (ANL) is developing ceramic waste forms which can incorporate this waste. Currently, zeolite- or sodalite-glass composites are produced by hot isostatic pressing (HIP) techniques. Powder preparations include dehydration of the raw zeolite powders, hot blending of these zeolite powders and secondary additives. Various approaches are being pursued to achieve adequate mixing, and the resulting powders have been HIPed and characterized for leach resistance, phase equilibria, and physical integrity

  18. Mineral, amino acid, and hormonal composition of chicken eggshell powder and the evaluation of its use in human nutrition

    NARCIS (Netherlands)

    Schaafsma, A; Pakan, [No Value; Hofstede, GJH; Muskiet, FAJ; Van Der Veer, E; De Vries, PJF

    2000-01-01

    Chicken eggshell powder (ESP) might be an attractive source of Ca for human nutrition. To study its nutritional value, we analyzed minerals, amino acids, and hormones in commercially available Slovakian ESP. The mineral composition was compared with three Dutch ESP samples that differed in feed and

  19. Modelling the Peak Elongation of Nylon6 and Fe Powder Based Composite Wire for FDM Feedstock Filament

    Science.gov (United States)

    Garg, Harish Kumar; Singh, Rupinder

    2017-10-01

    In the present work, to increase the application domain of fused deposition modelling (FDM) process, Nylon6-Fe powder based composite wire has been prepared as feed stock filament. Further for smooth functioning of feed stock filament without any change in the hardware and software of the commercial FDM setup, the mechanical properties of the newly prepared composite wire must be comparable/at par to the existing material i.e. ABS, P-430. So, keeping this in consideration; an effort has been made to model the peak elongation of in house developed feedstock filament comprising of Nylon6 and Fe powder (prepared on single screw extrusion process) for commercial FDM setup. The input parameters of single screw extruder (namely: barrel temperature, temperature of the die, speed of the screw, speed of the winding machine) and rheological property of material (melt flow index) has been modelled with peak elongation as the output by using response surface methodology. For validation of model the result of peak elongation obtained from the model equation the comparison was made with the results of actual experimentation which shows the variation of ±1 % only.

  20. Ceramic compositions based on nano forsterite/nano magnesium aluminate spinel powders

    International Nuclear Information System (INIS)

    Khattab, R.M.; Wahsh, M.M.S.; Khalil, N.M.

    2015-01-01

    According to the wide applications in the field of chemical and engineering industries, forsterite (Mg_2SiO_4)/spinel (MgAl_2O_4) ceramic compositions were the matter of interest of several research works during the last three decades. This work aims at preparation and characterization of improved ceramic bodies based on forsterite and spinel nano powders through controlling the forsterite and spinel contents in the prepared mixes. These prepared ceramic compositions have been investigated through measuring the densification parameters, cold crushing strength as well as volume resistively. Nano spinel was added from 0 to 30 mass% on expense of nano forsterite matrix and fired at 1550 °C for 2 h. The phase composition of the fired samples was examined using x-ray diffraction (XRD) technique. The microstructure of some selected samples was shown using scanning electron microscope (SEM). A pronounced improvement in the sintering, mechanical properties and volume resistively were achieved with increasing of nano spinel addition up to 15 mass%. This is due to the improvement in the matrix of the prepared forsterite/spinel bodies as a result of well distribution of spinel in the forsterite matrix as depicted by SEM analysis. - Highlights: • Ceramic compositions based on nano forsterite/nano-MgAl_2O_4 spinel were synthesized. • CCS was improved (333.78 MPa) through 15 mass% of nano-MgAl_2O_4 spinel addition. • Volume resistivity was enhanced to 203*10"1"3 Ohm cm with 15 mass% of spinel addition. • Beyond 15 mass% spinel, CCS and volume resistivity were decreased.

  1. Material Evaluation and Process Optimization of CNT-Coated Polymer Powders for Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Shangqin Yuan

    2016-10-01

    Full Text Available Multi-walled carbon nanotubes (CNTs as nano-reinforcements were introduced to facilitate the laser sintering process and enhance the thermal and mechanical properties of polymeric composites. A dual experimental-theoretical method was proposed to evaluate the processability and predict the process parameters of newly developed CNT-coated polyamide 12 (CNTs/PA12 powders. The thermal conductivity, melt viscosity, phase transition and temperature-dependent density and heat capacity of PA12 and CNTs/PA12 powders were characterized for material evaluation. The composite powders exhibited improved heat conduction and heat absorption compared with virgin polymer powders, and the stable sintering range of composite powders was extended and found to be favourable for the sintering process. The microstructures of sintered composites revealed that the CNTs remained at the powder boundaries and formed network architectures, which instantaneously induced the significant enhancements in tensile strength, elongation at break and toughness without sacrificing tensile modulus.

  2. High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

  3. Plasma metallization of refractory carbide powders

    International Nuclear Information System (INIS)

    Koroleva, E.B.; Klinskaya, N.A.; Rybalko, O.F.; Ugol'nikova, T.A.

    1986-01-01

    The effect of treatment conditions in plasma on properties of produced metallized powders of titanium, tungsten and chromium carbides with the main particle size of 40-80 μm is considered. It is shown that plasma treatment permits to produce metallized powders of carbide materials with the 40-80 μm particle size. The degree of metallization, spheroidization, chemical and phase composition of metallized carbide powders are controlled by dispersivity of the treated material, concentration of a metal component in the treated mixtures, rate of plasma flow and preliminary spheroidization procedure

  4. Influence of Ultrafine 2CaO·SiO₂ Powder on Hydration Properties of Reactive Powder Concrete.

    Science.gov (United States)

    Sun, Hongfang; Li, Zishanshan; Memon, Shazim Ali; Zhang, Qiwu; Wang, Yaocheng; Liu, Bing; Xu, Weiting; Xing, Feng

    2015-09-17

    In this research, we assessed the influence of an ultrafine 2CaO·SiO₂ powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM), mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength) with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO₂. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO₂ powder has the potential to improve the performance of a reactive powder cementitious system.

  5. Cheese powder as an ingredient in emulsion sausages

    DEFF Research Database (Denmark)

    Chen, Xiang; Ruiz Carrascal, Jorge; Petersen, Mikael Agerlin

    2017-01-01

    Different types of cheese powder were added to meat emulsion sausages in order to address its influence on chemical composition, volatile compounds profile and sensory properties, and its potential to reduce salt content through boosting saltiness. Addition of cheese powder to emulsion sausages...... modified their profile of volatile compounds. Blue cheese increased some ketones, alcohols, and esters, while brown cheese brought typical Maillard reaction compounds. Overall, addition of cheese powders to sausages enhanced the intensity of flavour traits. A mixture of hard and blue cheese powder showed...... the highest effect on boosting saltiness, while brown cheese powder showed the strongest umami and meat flavour boosting effect, and sausages with added blue cheese powder showed a more intense aftertaste. Hardness significantly increased due to the addition of blue cheese powder. Addition of cheese powder...

  6. Building more powerful less expensive supercomputers using Processing-In-Memory (PIM) LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Richard C.

    2009-09-01

    This report details the accomplishments of the 'Building More Powerful Less Expensive Supercomputers Using Processing-In-Memory (PIM)' LDRD ('PIM LDRD', number 105809) for FY07-FY09. Latency dominates all levels of supercomputer design. Within a node, increasing memory latency, relative to processor cycle time, limits CPU performance. Between nodes, the same increase in relative latency impacts scalability. Processing-In-Memory (PIM) is an architecture that directly addresses this problem using enhanced chip fabrication technology and machine organization. PIMs combine high-speed logic and dense, low-latency, high-bandwidth DRAM, and lightweight threads that tolerate latency by performing useful work during memory transactions. This work examines the potential of PIM-based architectures to support mission critical Sandia applications and an emerging class of more data intensive informatics applications. This work has resulted in a stronger architecture/implementation collaboration between 1400 and 1700. Additionally, key technology components have impacted vendor roadmaps, and we are in the process of pursuing these new collaborations. This work has the potential to impact future supercomputer design and construction, reducing power and increasing performance. This final report is organized as follow: this summary chapter discusses the impact of the project (Section 1), provides an enumeration of publications and other public discussion of the work (Section 1), and concludes with a discussion of future work and impact from the project (Section 1). The appendix contains reprints of the refereed publications resulting from this work.

  7. Characterization of the properties of thermoplastic elastomers containing waste rubber tire powder

    International Nuclear Information System (INIS)

    Zhang Shuling; Xin Zhenxiang; Zhang Zhenxiu; Kim, Jin Kuk

    2009-01-01

    The aim of this research was to recycle waste rubber tires by using powdering technology and treating the waste rubber tire powder with bitumen. It has been proven that the elongation at break, thermal stability and processing flowability of composites of polypropylene (PP), waste rubber tire powder (WRT) and bitumen composites are better than those of PP/WRT composite. A comparative study has been made to evaluate the influence of bitumen content and different compatibilizers on the properties of PP/WRT/bitumen composites, using a universal testing machine (UTM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and a capillary rheometer. The results suggested that the properties of PP/WRT/bitumen composites were dependent on the bitumen content and the kind of compatibilizer used

  8. Terahertz spectral signatures :measurement and detection LDRD project 86361 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Michael Clement; Brener, Igal; Lee, Mark

    2005-11-01

    LDRD Project 86361 provided support to upgrade the chemical and material spectral signature measurement and detection capabilities of Sandia National Laboratories using the terahertz (THz) portion of the electromagnetic spectrum, which includes frequencies between 0.1 to 10 THz. Under this project, a THz time-domain spectrometer was completed. This instrument measures sample absorption spectra coherently, obtaining both magnitude and phase of the absorption signal, and has shown an operating signal-to-noise ratio of 10{sub 4}. Additionally, various gas cells and a reflectometer were added to an existing high-resolution THz Fourier transform spectrometer, which greatly extend the functionality of this spectrometer. Finally, preliminary efforts to design an integrated THz transceiver based on a quantum cascade laser were begun.

  9. Tracking of Nuclear Production using Indigenous Species: Final LDRD Report

    International Nuclear Information System (INIS)

    Alam, Todd Michael; Alam, Mary Kathleen; McIntyre, Sarah K.; Volk, David; Neerathilingam, Muniasamy; Luxon, Bruce A.; Ansari, G. A. Shakeel

    2009-01-01

    Our LDRD research project sought to develop an analytical method for detection of chemicals used in nuclear materials processing. Our approach is distinctly different than current research involving hardware-based sensors. By utilizing the response of indigenous species of plants and/or animals surrounding (or within) a nuclear processing facility, we propose tracking 'suspicious molecules' relevant to nuclear materials processing. As proof of concept, we have examined TBP, tributylphosphate, used in uranium enrichment as well as plutonium extraction from spent nuclear fuels. We will compare TBP to the TPP (triphenylphosphate) analog to determine the uniqueness of the metabonomic response. We show that there is a unique metabonomic response within our animal model to TBP. The TBP signature can further be delineated from that of TPP. We have also developed unique methods of instrumental transfer for metabonomic data sets.

  10. Tracking of Nuclear Production using Indigenous Species: Final LDRD Report

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Electronic and Nanostructured Materials; Alam, Mary Kathleen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Energetics Characterization Dept.; McIntyre, Sarah K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Electronic and Nanostructured Materials; Volk, David [Univ. of Texas, Galveston, TX (United States). Medical Branch; Neerathilingam, Muniasamy [Univ. of Texas, Galveston, TX (United States). Medical Branch; Luxon, Bruce A. [Univ. of Texas, Galveston, TX (United States). Medical Branch; Ansari, G. A. Shakeel [Univ. of Texas, Galveston, TX (United States). Medical Branch

    2009-10-01

    Our LDRD research project sought to develop an analytical method for detection of chemicals used in nuclear materials processing. Our approach is distinctly different than current research involving hardware-based sensors. By utilizing the response of indigenous species of plants and/or animals surrounding (or within) a nuclear processing facility, we propose tracking 'suspicious molecules' relevant to nuclear materials processing. As proof of concept, we have examined TBP, tributylphosphate, used in uranium enrichment as well as plutonium extraction from spent nuclear fuels. We will compare TBP to the TPP (triphenylphosphate) analog to determine the uniqueness of the metabonomic response. We show that there is a unique metabonomic response within our animal model to TBP. The TBP signature can further be delineated from that of TPP. We have also developed unique methods of instrumental transfer for metabonomic data sets.

  11. Retrospective on the Seniors' Council Tier 1 LDRD portfolio.

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, William Parker

    2012-04-01

    This report describes the Tier 1 LDRD portfolio, administered by the Seniors Council between 2003 and 2011. 73 projects were sponsored over the 9 years of the portfolio at a cost of $10.5 million which includes $1.9M of a special effort in directed innovation targeted at climate change and cyber security. Two of these Tier 1 efforts were the seeds for the Grand Challenge LDRDs in Quantum Computing and Next Generation Photovoltaic conversion. A few LDRDs were terminated early when it appeared clear that the research was not going to succeed. A great many more were successful and led to full Tier 2 LDRDs or direct customer sponsorship. Over a dozen patents are in various stages of prosecution from this work, and one project is being submitted for an R and D 100 award.

  12. Chemical compositions of spherical titanium powders prepared by RF induction plasma

    International Nuclear Information System (INIS)

    Gu Zhongtao; Jin Yuping; Ye Gaoying

    2012-01-01

    Spherical titanium powders were prepared by RF induction plasma technology. The particle size is essentially un- changed, while the particle size distribution is relatively narrow after spheroidization processing. X-ray diffraction (XRD) random testing of the spherical titanium powders shows no structure and phase changes. The content of O, H, N and C decreases, while the content of Ti increases slightly. It indicates that spheroidization with RF plasma can enhance powder purity. (authors)

  13. Application of powder metallurgy and hot rolling processes for manufacturing aluminum/alumina composite strips

    Energy Technology Data Exchange (ETDEWEB)

    Zabihi, Majed, E-mail: m.zabihi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Toroghinejad, Mohammad Reza, E-mail: toroghi@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shafyei, Ali, E-mail: shafyei@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2013-01-10

    In this study, aluminum matrix composites (AMC) with 2, 4, 6 and 10 wt% alumina were produced using powder metallurgy (PM), mechanical milling (MM) and vacuum hot pressing (VHP) techniques; then, this was followed by the hot-rolling process. During hot rolling, AMCs with 6 and 10 wt% Al{sub 2}O{sub 3} were fractured whereas strip composites with 2 and 4 wt% Al{sub 2}O{sub 3} were produced successfully. Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and hardness tests, respectively. Microscopic evaluations of the hot-rolled composites showed a uniform distribution of alumina particles in the aluminum matrix. It was found that with increasing alumina content in the matrix, tensile strength (TS) and hardness increased and the percentage of elongation also decreased. Scanning electron microscope (SEM) was used to investigate aluminum/alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test. SEM observations demonstrated that the failure mode in the hot-rolled Al-2 wt% Al{sub 2}O{sub 3} composite strips is a typical ductile fracture, while the failure mode was shear ductile fracture with more flat surfaces in Al-4 wt% Al{sub 2}O{sub 3} strips.

  14. Liquid phase surface melting of AA8011 aluminum alloy by addition of Al/Al{sub 2}O{sub 3} nano-composite powders synthesized by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Sohi, M. Heydarzadeh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Hojjatzadeh, S.M.H., E-mail: Hojatzadeh@yahoo.com [Department of Welding, Science and Research Branch, Azad University, Tehran (Iran, Islamic Republic of); Moosavifar, Sh. S.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Aluminum matrix composite layers reinforced with alumina particles were fabricated. • Non milled powders caused porosity in the microstructures because of poor wettability. • The ball milling of powders was significantly improved the wettability of nano ceramic particles. • The micro hardness of the layers was approximately 3 times greater than that of the base metal. - Abstract: Poor wettability of particles is an obstacle in formation of sound composite layer via surface melting. Pre-coating of particles with metallic material by different techniques, such as ball milling may enhance the wettability of the particles with molten metal. In this study, composite surface layers containing Al{sub 2}O{sub 3} particles were fabricated on the surface of AA8011 aluminum substrates by tungsten inert gas (TIG) surface melting using preplaced layers of Al/Al{sub 2}O{sub 3} powder mixtures in two different forms: (1) a mixture of 40 wt% Al and 60 wt% of 50 nm Al{sub 2}O{sub 3} powders and (2) a mixture obtained by mechanical alloying of 40 wt% Al and 60 wt% of 60 μm Al{sub 2}O{sub 3} powders. Morphology evolution of powders during ball milling and the microstructure of the fabricated composite layers were studied through conventional characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Microhardness measurements were also performed across the alloyed zone. The results indicated that the layer fabricated by the second route showed a defect free structure with a more uniform distribution of Al{sub 2}O{sub 3} particles in comparison with the layer obtained by the first route. It was also noticed that the uniform dispersion of Al{sub 2}O{sub 3} particles in the fabricated layer increased the hardness to 133 HV which was over 3 times of that of the base metal.

  15. Ultrafine hydrogen storage powders

    Science.gov (United States)

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  16. Development of semiindustrial technology for electrolytic powder production

    International Nuclear Information System (INIS)

    Suchkov, A.B.; Kovalev, B.F.; Zhbanov, A.M.; Rabinovich, E.M.; Sozina, A.L.

    1978-01-01

    The technology of the production of Fe, Mn, Cr, W pure metal powders by electrolysis of industrial waste in molten chloride-fluoride media with the addition of lower chlorides of refining metal was tested in laboratory and then in industrial electrolysers (2kA). The cathode deposit was subjected to hydrometallurgical treatment. Approximate technological parameters of electrorefining are presented. A high-temperature (700-1000 deg C) hydrogen annealing was applied to increase the quality and to change physicochemical and technological characteristics of electrolytic powders. The data on the chemical composition of Mowders are presented, testifying to their high purity. It is shown that electrolytic powders are not uniform in granulometric composition (from 1 to 100 μm), their particles being characterized mainly by the dendrite structure

  17. Influence of Ultrafine 2CaO·SiO2 Powder on Hydration Properties of Reactive Powder Concrete

    Directory of Open Access Journals (Sweden)

    Hongfang Sun

    2015-09-01

    Full Text Available In this research, we assessed the influence of an ultrafine 2CaO·SiO2 powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM, mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO2. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO2 powder has the potential to improve the performance of a reactive powder cementitious system.

  18. Predictive Simulation of Process Windows for Powder Bed Fusion Additive Manufacturing: Influence of the Powder Bulk Density.

    Science.gov (United States)

    Rausch, Alexander M; Küng, Vera E; Pobel, Christoph; Markl, Matthias; Körner, Carolin

    2017-09-22

    The resulting properties of parts fabricated by powder bed fusion additive manufacturing processes are determined by their porosity, local composition, and microstructure. The objective of this work is to examine the influence of the stochastic powder bed on the process window for dense parts by means of numerical simulation. The investigations demonstrate the unique capability of simulating macroscopic domains in the range of millimeters with a mesoscopic approach, which resolves the powder bed and the hydrodynamics of the melt pool. A simulated process window reveals the influence of the stochastic powder layer. The numerical results are verified with an experimental process window for selective electron beam-melted Ti-6Al-4V. Furthermore, the influence of the powder bulk density is investigated numerically. The simulations predict an increase in porosity and surface roughness for samples produced with lower powder bulk densities. Due to its higher probability for unfavorable powder arrangements, the process stability is also decreased. This shrinks the actual parameter range in a process window for producing dense parts.

  19. EFFECT OF THE Si POWDER ADDITIONS ON THE PROPERTIES OF SiC COMPOSITES

    Directory of Open Access Journals (Sweden)

    GUOGANG XU

    2012-09-01

    Full Text Available By means of transient plastic phase process, the SiC silicon carbide kiln furniture materials were produced through adding Si powder to SiC materials. At the condition of the same additions of SiO2 powder, the effect of the Si powder additions on properties of silicon carbide materials after sintered at 1450°C for 3 h in air atmosphere was studied by means of SEM and other analysis methods. The results showed that silicon powder contributes to both sintering by liquid state and plastic phase combination to improve the strength of samples. When the Si powder additions is lower than 3.5 %, the density and strength of samples increase and porosity decrease with increasing Si powder additions. However when the Si powder additions is higher than 3.5 %, the density and strength of samples decrease and porosity increase with increasing Si powder additions. With increasing of Si additions, the residual strength of sample after thermal shocked increased and linear change rate decreased, and get to boundary value when Si additions is 4.5 %. The results also indicated that at the same sintering temperature, the sample with 3.5 % silicon powder has maximum strength.

  20. Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

    Science.gov (United States)

    Dellacorte, Christopher; Sliney, Harold E.

    1989-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  1. Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

    Science.gov (United States)

    Dellacorte, Christopher; Sliney, Harold E.

    1990-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  2. 210Pb content in natural gas pipeline residues ('black-powder') and its correlation with the chemical composition

    International Nuclear Information System (INIS)

    Godoy, Jose Marcus; Carvalho, Franciane; Cordilha, Aloisio; Matta, Luiz Ernesto; Godoy, Maria Luiza

    2005-01-01

    The present work was carried out to assess the 210 Pb content in 'black-powder' found in pigging operations on gas pipelines in Brazil, in particular, on the Campos Basin gas pipeline. Additionally, the chemical composition of such deposits was determined and an eventual correlation with 210 Pb concentration evaluated. Typical 'black-powder' generated in the natural gas pipeline from Campos Basin oilfield contains mainly iron oxide (∼81%) and residual organic matter (∼9%). The 210 Pb content ranges from 4.9 to 0.04 kBq kg -1 and seems to be inversely correlated with the distance to the platforms. On the other hand, 226 Ra concentration is higher on the pipeline branch between the platform and the onshore installations. 228 Ra was only observed in few samples, in particular, in the samples with the highest 226 Ra content

  3. Microstructural investigation of aluminum-graphene nano platelets composites prepared by powder metallurgy

    Science.gov (United States)

    Sreearravind, M.; Peddavarapu, Sreehari; Raghuraman, S.

    2018-04-01

    Recently, Graphene has attracted a large variety of scientific communities due to its inimitable properties. Typically, Graphene Nanoplatelets (GNPs) are ideal reinforcements for the production of nanocomposites due to its excellent mechanical properties for strength enhancement. This paper reports the Aluminum-Graphene Nanoplatelets (Al/GNPs) composites synthesized through powder metallurgy method. The microstructural investigation was carried out to study the GNPs integration on the Al matrix. For this study, the samples Al-2wt% GNPs, Al-3wt% GNPs and Al- 4wt% GNPs are high-energy ball milled at 200rpm and sintered at 500°C,550°C, and 600°C. Microstructural characterization is carried out with optical microscopy, Scanning electron microscopy. Rockwell hardness test is conducted to evaluate the hardness behavior in Al/GNPs. Microstructural analysis revealed the homogeneous dispersion of GNPs in the Al matrix in all the samples. It is observed that the existence of the graphene nanoparticles and the rise of their concentrations in the aluminum matrix (2 wt.% to 4 wt.%) as reinforcement in addition to rising the sintering temperature (450°C to 600°C) greatly improve the mechanical properties of Al/GNPs composites.

  4. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

    Science.gov (United States)

    Ning, C Q; Zhou, Y

    2002-07-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

  5. Composite cement mortars based on marine sediments and oyster shell powder

    Directory of Open Access Journals (Sweden)

    Ez-zaki, H.

    2016-03-01

    Full Text Available Additions of dredged marine sediments and oyster shell powder (OS as cement substitute materials in mortars are examined by several techniques. The sediments have high water and chloride contents and calcite, quartz, illite and kaolinite as principal minerals. The OS powders are entirely composed of calcium carbonate and traces of other impurities. Four mixtures of treated sediments and OS powders at 650 °C and 850 °C are added to Portland cement at 8%, 16% and 33% by weight. The hydration of composite pastes is followed by calorimetric tests, the porosity accessible to water, the bulk density, the permeability to gas, the compressive strength and the accelerated carbonation resistance are measured. In general, the increase of addition amounts reduced the performance of mortars. However, a reduction of gas permeability was observed when the addition was up to 33%. Around 16% of addition, the compressive strength and carbonation resistance were improved.En este trabajo se ha valorado la sustitución de cemento en morteros por sedimentos marinos dragados y polvo de concha de ostra (OS. Los sedimentos tienen altos contenidos de agua, cloruros, calcita, cuarzo, illita y caolinita como minerales principales. Los polvos OS están compuestos de carbonato cálcico y trazas de otras impurezas. Se añadieron a un cemento Portland, cuatro mezclas de los sedimentos y polvos de OS tratados a 650 °C y 850 °C en proporciones del 8%, 16% y 33% en peso. La hidratación de pastas se estudió a través de calorimetría. Se estudió además la porosidad accesible al agua, densidad aparente, permeabilidad al gas, resistencia a compresión y carbonatación acelerada. En general, un aumento en la adición produjo una reducción del rendimiento de los morteros. Se observó, sin embargo, una reducción de la permeabilidad a los gases con porcentajes de adición de hasta el 33%. Con valores del 16% de sustitución, mejoraron las resistencias mecánicas y la

  6. Synthesis, mechanical properties and corrosion behavior of powder metallurgy processed Fe/Mg2Si composites for biodegradable implant applications.

    Science.gov (United States)

    Sikora-Jasinska, M; Paternoster, C; Mostaed, E; Tolouei, R; Casati, R; Vedani, M; Mantovani, D

    2017-12-01

    Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg 2 Si particles were proposed. The initial powders were prepared by different combinations of mixing and milling processes, and finally consolidated by hot rolling. The influence of the microstructure on mechanical properties and corrosion behavior of Fe/Mg 2 Si was investigated. Scanning electron microscopy and X-ray diffraction were used for the assessment of the composite structure. Tensile and hardness tests were performed to characterize the mechanical properties. Potentiodynamic and static corrosion tests were carried out to investigate the corrosion behavior in a pseudo-physiological environment. Samples with smaller Mg 2 Si particles showed a more homogenous distribution of the reinforcement. Yield and ultimate tensile strength increased when compared to those of pure Fe (from 400MPa and 416MPa to 523MPa and 630MPa, respectively). Electrochemical measurements and immersion tests indicated that the addition of Mg 2 Si could increase the corrosion rate of Fe even twice (from 0.14 to 0.28mm·year -1 ). It was found that the preparation method of the initial composite powders played a major role in the corrosion process as well as in the corrosion mechanism of the final composite. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

    International Nuclear Information System (INIS)

    Bohlouli-Zanjani, Golnaz; Wen, John Z.; Hu, Anming; Persic, John; Ringuette, Sophie; Zhou, Y. Norman

    2013-01-01

    Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites

  8. Final LDRD report :ultraviolet water purification systems for rural environments and mobile applications.

    Energy Technology Data Exchange (ETDEWEB)

    Banas, Michael Anthony; Crawford, Mary Hagerott; Ruby, Douglas Scott; Ross, Michael P.; Nelson, Jeffrey Scott; Allerman, Andrew Alan; Boucher, Ray

    2005-11-01

    We present the results of a one year LDRD program that has focused on evaluating the use of newly developed deep ultraviolet LEDs in water purification. We describe our development efforts that have produced an LED-based water exposure set-up and enumerate the advances that have been made in deep UV LED performance throughout the project. The results of E. coli inactivation with 270-295 nm LEDs are presented along with an assessment of the potential for applying deep ultraviolet LED-based water purification to mobile point-of-use applications as well as to rural and international environments where the benefits of photovoltaic-powered systems can be realized.

  9. Sintered FeCuRe Alloys Produced from Commercially Available Powders

    Directory of Open Access Journals (Sweden)

    Borowiecka-Jamrozek J.

    2017-09-01

    Full Text Available This paper discusses the mechanical properties of materials fabricated from commercially available powders designed for use as a metal matrix of diamond-impregnated composites. The powders with the catalogue numbers CSA and CSA800 produced in China were tested under laboratory conditions. The specimens were fabricated in a graphite mould using hot pressing. The materials were analysed for density, porosity, hardness and static tensile strength. A scanning electron microscope (SEM was employed to observe the microstructure and fracture surfaces of the specimens. The experimental data was used to determine how the chemical composition of the powders and the process parameters affected the microstructure and properties of the materials. The properties of the sintered materials produced from the Chinese powders were compared with the properties reported for specimens fabricated from cobalt powder (Co SMS. Even though the hot pressed CSA and CSA800 powders had inferior mechanical properties to their cobalt analogue, they seem well-suited for general-purpose diamond-impregnated tools with less demanding applications.

  10. High-performance biodegradable polylactide composites fabricated using a novel plasticizer and functionalized eggshell powder.

    Science.gov (United States)

    Kong, Junjun; Li, Yi; Bai, Yungang; Li, Zonglin; Cao, Zengwen; Yu, Yancun; Han, Changyu; Dong, Lisong

    2018-06-01

    A novel polyester poly(diethylene glycol succinate) (PDEGS) was synthesized and evaluated as a plasticizer for polylactide (PLA) in this study. Meanwhile, an effective sustainable filler, functionalized eggshell powder (FES) with a surface layer of calcium phenyphosphonate was also prepared. Then, PLA biocomposites were prepared from FES and PDEGS using a facile melt blending process. The addition of 15 wt% PDEGS as plasticizer showed good miscibility with PLA macromolecules and increased the chain mobility of PLA. The crystallization kinetics of PLA composites revealed that the highly effective nucleating FES significantly improved the crystallization ability of PLA at both of non-isothermal and isothermal conditions. In addition, the effective plasticizer and well-dispersed FES increased the elongation at break from 6% of pure PLA to over 200% for all of the plasticized PLA composites. These biodegradable PLA biocomposites, coupled with excellent crystallization ability and tunable mechanical properties, demonstrate their potential as alternatives to traditional commodity plastics. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Effect of Fe-Mn addition on microstructure and magnetic properties of NdFeB magnetic powders

    Science.gov (United States)

    Kurniawan, C.; Purba, A. S.; Setiadi, E. A.; Simbolon, S.; Warman, A.; Sebayang, P.

    2018-03-01

    In this paper, the effect of Fe-Mn alloy addition on microstructures and magnetic properties of NdFeB magnetic powders was investigated. Varied Fe-Mn compositions of 1, 5, and 10 wt% were mixed with commercial NdFeB type MQA powders for 15 minutes using shaker mill. The characterizations were performed by powder density, PSA, XRD, SEM, and VSM. The Fe-Mn addition increased the powder density of NdFeB/Fe-Mn powders. On the other side, particle size distribution slightly decreased as the Fe-Mn composition increases. Magnetic properties of NdFeB/Fe-Mn powders changed with the increasing of Fe-Mn content. SEM analysis showed the particle size of NdFeB/Fe-Mn powder was smaller as the Fe-Mn composition increases. It showed that NdFeB/Fe-Mn particles have different size and shape for NdFeB and Fe-Mn particles separately. The optimum magnetic properties of NdFeB/Fe-Mn powder was achieved on the 5 wt% Fe-Mn composition with remanence M r = 49.45 emu/g, coercivity H c = 2.201 kOe, and energy product, BH max = 2.15 MGOe.

  12. Effect of surface energy on powder compactibility.

    Science.gov (United States)

    Fichtner, Frauke; Mahlin, Denny; Welch, Ken; Gaisford, Simon; Alderborn, Göran

    2008-12-01

    The influence of surface energy on the compactibility of lactose particles has been investigated. Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity. All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders. The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.

  13. Self-compacting concrete containing different powders at elevated temperatures - Mechanical properties and changes in the phase composition of the paste

    International Nuclear Information System (INIS)

    Bakhtiyari, S.; Allahverdi, A.; Rais-Ghasemi, M.; Zarrabi, B.A.; Parhizkar, T.

    2011-01-01

    Fire resistance of self-compacting concretes (SCC) containing limestone and quartz powders, with two different compressive strengths, were evaluated and compared with normal concretes (NC). The residual mechanical strengths of the mixes at different temperatures were measured. The changes in the phase composition of the cement pastes at high temperatures were examined with thermal analysis and X-ray diffractometry methods. The SCC mixes showed a higher susceptibility to spalling at high temperatures but the NC mixes suffered much more from loss of the mechanical strengths. Both the powder types and the compressive strength notably influenced the fire behavior of the SCC. The quartz powder accelerated the hydration of the SCC cement paste at high temperatures, up to 500 o C. However, the quartz-contained SCC showed the highest risk of spalling among all the mixes. The results showed that the thermal analysis could be a useful device for evaluating the fire behavior of building materials.

  14. Self-compacting concrete containing different powders at elevated temperatures - Mechanical properties and changes in the phase composition of the paste

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtiyari, S., E-mail: bakhtiyari@bhrc.ac.ir [School of Chemical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Allahverdi, A., E-mail: ali.allahverdi@iust.ac.ir [Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Rais-Ghasemi, M., E-mail: raissghasemi@bhrc.ac.ir [Dep. of Concrete Technology, Building and Housing Research Center (BHRC), Tehran (Iran, Islamic Republic of); Zarrabi, B.A., E-mail: zarrabi@chalmers.se [Fire Technology Dep., SP Technical Research Institute of Sweden (Sweden); Parhizkar, T., E-mail: parhizkar@bhrc.ac.ir [Dep. of Concrete Technology, Building and Housing Research Center (BHRC), Tehran (Iran, Islamic Republic of)

    2011-02-20

    Fire resistance of self-compacting concretes (SCC) containing limestone and quartz powders, with two different compressive strengths, were evaluated and compared with normal concretes (NC). The residual mechanical strengths of the mixes at different temperatures were measured. The changes in the phase composition of the cement pastes at high temperatures were examined with thermal analysis and X-ray diffractometry methods. The SCC mixes showed a higher susceptibility to spalling at high temperatures but the NC mixes suffered much more from loss of the mechanical strengths. Both the powder types and the compressive strength notably influenced the fire behavior of the SCC. The quartz powder accelerated the hydration of the SCC cement paste at high temperatures, up to 500 {sup o}C. However, the quartz-contained SCC showed the highest risk of spalling among all the mixes. The results showed that the thermal analysis could be a useful device for evaluating the fire behavior of building materials.

  15. Preparation of Cu and Fly Ash Composite by Powder Metallurgy Technique

    International Nuclear Information System (INIS)

    Chew, P. Y.; Lim, P. S.; Ng, M. C.; Zahi, S.; You, A. H.

    2011-01-01

    Cu and Fly Ash (FA) mixtures with different weight percentages were prepared. Pellets of the mixture powder were produced with the dimension of 17.7 mm in diameter and 10-15 mm in height. These different composites were compacted at a constant pressure of 280 MPa. One of the selected weight percentages was then compacted to form into pellet and sintered at different temperatures which were at 900, 950 and 1000 deg. C respectively for 2 hours. Density of green pellet was measured before sintered in furnace. After sintering, all the pellets with different temperatures were re-weighed and sintered density were calculated. The densification of the green and sintered pellets was required to be measured as one of the parameter in selection of the best material properties. Porosity of the pellet shall not be ignored in order to analyze the close-packed particles stacking in the pellet. SEM micrograph had been captured to observe the presence of pores and agglomeration of particles in the sample produced.

  16. Development of a cryogenic EOS capability for the Z Pulsed Radiation Source: Goals and accomplishments of FY97 LDRD project

    International Nuclear Information System (INIS)

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-03-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. This report describes progress during the period 2/97-11/97 on the FY97 LDRD project ''Cryogenic EOS Capabilities on Pulsed Radiation Sources (Z Pinch)''. The goal of this project is the development of a general purpose cryogenic target system for precision EOS and shock physics measurements at liquid helium temperatures on the Z accelerator Z-pinch pulsed radiation source. Activity during the FY97 LDRD phase of this project has focused on development of a conceptual design for the cryogenic target system based on consideration of physics, operational, and safety issues, design and fabrication of principal system components, construction and instrumentation of a cryogenic test facility for off-line thermal and optical testing at liquid helium temperatures, initial thermal testing of a cryogenic target assembly, and the design of a cryogenic system interface to the Z pulsed radiation source facility. The authors discuss these accomplishments as well as elements of the project that require further work

  17. Experimental Determination of Ballistic Performance of Composite Material Kevlar 29 and Alumina Powder/ Epoxy by Spherical Projectile

    Directory of Open Access Journals (Sweden)

    Luay Hashem Abbud

    2016-12-01

    Full Text Available In this study, a response of hybrid composite laminate woven fiber Kevlar29 – Al2O3 Powder/ Epoxy subjected to high velocity impact loading is presented. The energy absorbed due to impact of small rigid projectile on composite materials targets is determined experimentally. The energy absorbed due to impact of hemispherical projectiles on the developed composite laminates is investigated. The results revealed the maximum ballistic limit at impact velocity is found to be 390.87 ± 6 m/s for an the 18 mm target thickness. The ballistic limit velocity predictions are based on the theoretical method presented from another article. The initial velocity and residual velocity results showed good is agreement compared with the predicted results of Ipson and Recht equations. With 5.4 % of accuracy based on the experimental value for the theoretical model for ballistic limit velocity.

  18. Synthesis and sintering of nanocrystalline hydroxyapatite powders by citric acid sol-gel combustion method

    International Nuclear Information System (INIS)

    Han Yingchao; Li Shipu; Wang Xinyu; Chen Xiaoming

    2004-01-01

    The citric acid sol-gel combustion method has been used for the synthesis of nanocrystalline hydroxyapatite (HAP) powder from calcium nitrate, diammonium hydrogen phosphate and citric acid. The phase composition of HAP powder was characterized by X-ray powder diffraction analysis (XRD). The morphology of HAP powder was observed by transmission electron microscope (TEM). The HAP powder has been sintered into microporous ceramic in air at 1200 deg. C with 3 h soaking time. The microstructure and phase composition of the resulting HAP ceramic were characterized by scanning electron microscope (SEM) and XRD, respectively. The physical characterization of open porosity and flexural strength have also been carried out

  19. Features of the incorporation of single and double based powders within emulsion explosives

    Science.gov (United States)

    Ribeiro, J. B.; Mendes, R.; Tavares, B.; Louro, C.

    2014-05-01

    In this work, features of the thermal and detonation behaviour of compositions resulting from the mixture of single and double based powders within ammonium nitrate based emulsion explosives are shown. Those features are portrayed through results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential thermal analysis [DTA] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the "gap-test". DTA/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical species and so of the compatibility of the components of the compositions. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with powder than for the one with sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have been shown to be higher for the powdered compositions than for the sole emulsion explosive. Shock sensitivity assessments have ended-up with a slightly bigger sensitivity for the compositions with double based powder when compared to the single based compositions or to the sole emulsion.

  20. Features of the incorporation of single and double based powders within emulsion explosives

    International Nuclear Information System (INIS)

    Ribeiro, J B; Mendes, R; Tavares, B; Louro, C

    2014-01-01

    In this work, features of the thermal and detonation behaviour of compositions resulting from the mixture of single and double based powders within ammonium nitrate based emulsion explosives are shown. Those features are portrayed through results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential thermal analysis [DTA] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the g ap-test . DTA/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical species and so of the compatibility of the components of the compositions. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with powder than for the one with sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have been shown to be higher for the powdered compositions than for the sole emulsion explosive. Shock sensitivity assessments have ended-up with a slightly bigger sensitivity for the compositions with double based powder when compared to the single based compositions or to the sole emulsion.

  1. Nano-scale analysis of titanium dioxide fingerprint-development powders

    International Nuclear Information System (INIS)

    Reynolds, A J; Jones, B J; Sears, V; Bowman, V

    2008-01-01

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO 2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO 2 particles and efficacy of print development.

  2. Nano-scale analysis of titanium dioxide fingerprint-development powders

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A J; Jones, B J [Experimental Techniques Centre, Brunei University, Kingston Lane, Uxbridge, Middlesex, UB8 3PH (United Kingdom); Sears, V; Bowman, V [Fingerprint and Footwear Forensics, Home Office Scientific Development Branch, Sandridge, St Albans, Hertfordshire, AL4 9HQ (United Kingdom)], E-mail: b.j.jones@physics.org

    2008-08-15

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO{sub 2} particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO{sub 2} particles and efficacy of print development.

  3. In situ synthesis of Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite by vacuum sintering mechanically alloyed TiAl powder coated with CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin (China); Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology, IL (United States); Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-11-25

    Highlights: •Using zwitterionic surfactant to enhance the dispersion of the CNTs on the powder surface. •CNTs as carbon source decreased the formation temperature of Ti{sub 2}AlC. •Al{sub 2}O{sub 3} was generated in situ from the oxygen atoms introduced in the drying procedure. •Nanosized Ti{sub 3}Al was precipitated at 1250 °C and distribute in the TiAl matrix homogeneously. •Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite was synthesized in situ by sintering pre-alloy Ti–Al coated with CNTs. -- Abstract: Bulk Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were in situ synthesized by vacuum sintering mechanically alloyed Ti–50 at.% Al powders coated with carbon nanotubes (CNTs). The pre-alloyed Ti–50 at.% Al powder was obtained by ball milling Ti and Al powders. The multi-walled carbon nanotubes as the carbon resource were covered on the surface of the pre-alloyed powders by immersing them into a water solution containing the CNTs. A zwitterionic surfactant was used to enhance the dispersion of the CNTs on the powder surface. The samples were cold pressed and sintered in vacuum at temperatures from 950 to 1250 °C, respectively. The results show that the reaction of forming Ti{sub 2}AlC can be achieved below 950 °C, which is 150 °C lower than in the Ti–Al–TiC system and 250 °C lower than for the Ti–Al–C system due to the addition of CNTs. Additionally, the reinforcement of Al{sub 2}O{sub 3} particles was introduced in situ in Ti{sub 2}AlC/TiAl by the drying process and subsequent sintering of the composite powders. Dense Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were obtained by sintering at 1250 °C and exhibited a homogeneous distribution of Ti{sub 2}AlC, Al{sub 2}O{sub 3} and precipitated Ti{sub 3}Al particles and a resulting high hardness.

  4. Effects of Partial Replacement of Eggshell Powder by Halloysite Nanotubes on the Properties of Polyvinyl Alcohol Composites

    Science.gov (United States)

    Alias, N. F.; Ismail, H.

    2018-06-01

    Polyvinyl alcohol (PVA)/eggshell powder (ESP) were prepared via solution casting method. The effects of gradual replacement of ESP by halloysite nanotubes (HNTs) were investigated based on tensile properties, physical properties and biodegradability. The main objective is to study the effect of hybrid fillers and also to compare the properties of PVA/ESP composite with conventional filler, HNT. The tensile properties decreased with increasing HNT loading. Scanning electron microscopy (SEM) studies showed that agglomeration of filler were present throughout the composites. Due to the presence of hydroxyl group on the outer and inner surface of HNT, the water absorption and water vapor transmisibility were found to increase with increasing HNTs loading. The biodegradability of film filled with HNT is lower compared to the film filled with ESP.

  5. Strength Improvement of Clay Soil by Using Stone Powder

    OpenAIRE

    Ahmed Sameer Abdulrasool

    2015-01-01

    Soil stabilization with stone powder is a good solution for the construction of subgrade for road way and railway lines, especially under the platforms and mostly in transition zones between embankments and rigid structures, where the mechanical properties of supporting soils are very influential. Stone powder often has a unique composition which justifies the need for research to study the feasibility of using this stone powder type for ground improvement applications. This paper presents re...

  6. Weldability of powder-metallurgy molybdenum with low oxygen content

    International Nuclear Information System (INIS)

    Hiraoka, Yutaka; Okada, Masatoshi

    1987-01-01

    Relationships between the formation of weld pores and the chemical compositions in powder-metallurgy molybdenum were investigated. It is suggested that almost 100% of Ca and Mg form oxides. In contrast, Fe, Ni, Cr and Al, Si only partly form oxides. A powder-metallurgy molybdenum containing less than 84 at.ppm oxygen did not show any large weld pores. The reduction of the oxygen content was achieved by purifying the molybdenum powder. (orig.) [de

  7. Powder injection molding of HA/Ti6Al4V composite using palm stearin as based binder for implant material

    International Nuclear Information System (INIS)

    Arifin, Amir; Sulong, Abu Bakar; Muhamad, Norhamidi; Syarif, Junaidi; Ramli, Mohd Ikram

    2015-01-01

    Highlights: • Fabrication of HA/Ti6Al4V composite using powder injection molding. • Rheological results show that palm stearin is suitable as binder. • Resulted mechanical properties in between titanium alloy and HA values. • Micro porous enable accelerated bioactivity based on in vitro test. - Abstract: Titanium alloy (Ti6Al4V) and hydroxyapatite (HA) are well-known materials applied in implants. Ti6Al4V shows good mechanical properties and corrosion resistance, whereas HA possesses excellent biocompatibility and bioactivity but weak mechanical properties. The combination of the Ti6Al4V and HA properties is expected to produce a superior material for bio-implants. This study aimed to analyze the feasibility of fabricating HA/Ti6Al4V composites through powder injection molding (PIM) using palm stearin as base binder. In this study, 90 wt% Ti6Al4V and 10 wt% HA were mixed with the palm stearin and polyethylene binder system. The HA/Ti6Al4V feedstock showed pseudoplastic properties, suggesting its suitability for PIM. Flexural test revealed that the strength of the sintered composite ranges from 67.12 MPa to 112.97 MPa and its Young’s modulus ranges from 39.28 GPa to 44.25 GPa. The X-ray diffraction patterns and energy-dispersive X-ray spectra of the composite showed that the HA decomposed and formed secondary phases. Isotropic porous structure was observed on the sintered sample because of HA decomposition. Results showed that the palm stearin can be used as based binder in fabricating HA/Ti6Al4V composites via PIM. The mechanical properties of the sintered composites are nearly similar to those of the human bone. In addition, the increase in weight of the sintered composite during in vitro tests indicated the nucleation and growth of the Ca–P phase, which exhibited the biocompatibility of the fabricated HA/Ti6Al4V composite

  8. Composite material dosimeters

    Science.gov (United States)

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  9. PREPARATION OF WC-Co POWDER BY DIRECT REDUCTION AND CARBONIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhonglai Yi; Gangqin Shao; Xinglong Duan; Peng Sun; Xiaoliang Shi; Zhen Xiong; Jingkun Guo

    2005-01-01

    A new approach to produce superfine WC-Co powder by direct reduction and carbonization is proposed.Water-soluble salts containing W and Co were used as raw materials. Tungsten and cobalt oxide powder (CoWO4/WO3)was first formed by a spray-pyrolysis technique, which was then mixed with carbon black and converted to WC-Co composite powder at 950℃ for 4 h in N2 atmosphere. The resulting powder has a particle size of 100-300 nm.

  10. Microstructural Development in Al-Si Powder During Rapid Solidification

    Energy Technology Data Exchange (ETDEWEB)

    Genau, Amber Lynn [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Powder metallurgy has become an increasingly important form of metal processing because of its ability to produce materials with superior mechanical properties. These properties are due in part to the unique and often desirable microstructures which arise as a result of the extreme levels of undercooling achieved, especially in the finest size powder, and the subsequent rapid solidification which occurs. A better understanding of the fundamental processes of nucleation and growth is required to further exploit the potential of rapid solidification processing. Aluminum-silicon, an alloy of significant industrial importance, was chosen as a model for simple eutectic systems displaying an unfaceted/faceted interface and skewed coupled eutectic growth zone, Al-Si powder produced by high pressure gas atomization was studied to determine the relationship between microstructure and alloy composition as a function of powder size and atomization gas. Critical experimental measurements of hypereutectic (Si-rich) compositions were used to determine undercooling and interface velocity, based on the theoretical models which are available. Solidification conditions were analyzed as a function of particle diameter and distance from nucleation site. A revised microstructural map is proposed which allows the prediction of particle morphology based on temperature and composition. It is hoped that this work, by providing enhanced understanding of the processes which govern the development of the solidification morphology of gas atomized powder, will eventually allow for better control of processing conditions so that particle microstructures can be optimized for specific applications.

  11. Suitability of Polyvinyl Waste Powder as Partial Replacement for ...

    African Journals Online (AJOL)

    B Up to 50% by weight of cement was replaced with PWP at interval of 10%. The parameters investigated are: the chemical composition of polyvinyl waste powder (PWP) and the setting times of cement-polyvinyl paste. Also investigated in concrete containing polyvinyl powder were: workability, density, compressive strength ...

  12. Obtainment, machining and wear of metal matrix composites processed by powder metallurgy

    International Nuclear Information System (INIS)

    Jesus, Edilson Rosa Barbosa de.

    1998-01-01

    The aim of this investigation was the obtainment of metal matrix composites (MMC) by the route of powder metallurgy, and the valuation of these materials with relation to their machining and wear characteristics. Firstly, were obtained pure commercial aluminium matrix composites materials, with 5, 10 and 15% volumetric fraction of silicon carbide particles. Was also obtained a material without reinforcement particles in order to verify by comparison, the influence of addition of reinforcement particles. The obtained materials were characterized physics (hydrostatic density), mechanics (hardness and tensile tests) and microstructurally (optical microscopy and scanning electron microscopy). The results showed a homogeneous distribution of reinforcement particles in the composite, and improvement in the mechanical properties, mainly tensile strength (UTS) in comparison to the unreinforced material. After, tests were made to verify the materials behavior during machining and to check the performance of several tool materials (cemented carbide, ceramics and polycrystalline diamond). In these tests, values of the cutting force were measured by instrumented tool-holders. Phenomena such as tool wear, built-up edge formation and mechanism of chip formation were also observed and evaluated. The results from the cemented carbide tool tests, were utilised for the machinability index determination of each material. These results were applied to the Taylor equation and the equation constants for each material and test conditions were determined. The results showed that the inclusion of silicon carbide particles made extremely difficult the machining of the composites, and only with diamond tool, satisfactory results were obtained. At last, wear tests were performed to verify the influence of the reinforcement particles in the characteristics of wear resistance of the materials. The results obtained were utilized in the wear coefficient determination for each material. The

  13. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  14. Polymer quenched prealloyed metal powder

    Science.gov (United States)

    Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  15. In situ preparation of (TiB + TiC + Nd2O3)/Ti composites by powder metallurgy

    International Nuclear Information System (INIS)

    Lu Junqiang; Qin Jining; Lu Weijie; Liu Yang; Gu Jiajun; Zhang Di

    2009-01-01

    Titanium matrix composites reinforced with multiple ceramic particulates TiB, TiC and Nd 2 O 3 were prepared by powder metallurgy utilizing the chemical reactions among Ti, B 4 C, NdB 6 and oxygen in Ti powder. The thermodynamic feasibility of the in situ reaction has been calculated. The phases were identified by X-ray diffraction (XRD). The result shows that multiple ceramic phases TiB, TiC and Nd 2 O 3 particulates have been synthesized. The microstructures were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), backscattered electron microscopy and transmission electron microscope (TEM). The results show that the reinforcements are distributed uniformly in the matrix alloy and grow in different shapes. TiB grows in needle shape; TiC and Nd 2 O 3 grow in equiaxed or near-equiaxed shapes. The addition of NdB 6 is beneficial to grain refinement, grain-boundary purification and porosity reduction

  16. A study of the oriented composites with the conductive segregated structure obtained via solid-phase processing of the UHMWPE reactor powder mixed with the carbon nanofillers

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Oleg V. [Moscow Institute of Physics and Technology (State University,) Institutskiy per., Dolgoprudny, Moscow Region, 141700 (Russian Federation); N.S. Enikolopov Institute of Synthetic Polymer Materials of RAS, Profsoyuznaya st., Moscow, 117393 (Russian Federation); Kechek’yan, Alexander S.; Shevchenko, Vitaly G.; Kurkin, Tikhon S.; Golubev, Evgeny K.; Ozerin, Alexander N. [N.S. Enikolopov Institute of Synthetic Polymer Materials of RAS, Profsoyuznaya st., Moscow, 117393 (Russian Federation); Karpushkin, Evgeny A.; Sergeev, Vladimir G. [Moscow State University, Chemical Department, Leninskie Gori, Moscow, 119234 (Russian Federation)

    2016-05-18

    Electrically conductive oriented polymer nano-composites of different compositions, based on the reactor powder of ultra-high-molecular-weight polyethylene (UHMWPE) with a special morphology, filled with particles of nanostructured graphite (NG), multi-walled carbon nanotubes (MWCNTs), and electrically conductive carbon black (CB), were investigated. Polymer composites were obtained via compaction of the mechanical mixture of the polymer and filler powder, followed by uniaxial deformation of the material under homogeneous shear (HS) conditions (all of the processing stages were conducted at room temperature). Resulted composites possess a high tensile strength, high level of the electrical conductivity and low percolation threshold, owing it to the formation of the segregated conductive structure, The influence of the type of nanosized carbon filler, degree of the deformation under HS condition, temperature and etc. on the electrical conductivity and mechanical properties of strengthened conductive composites oriented under homogeneous shear conditions was investigated. Changes in the electrical conductivity of oriented composite materials during reversible “tension–shrinkage” cycles along the orientation axis direction were studied. A theoretical approach, describing the process of transformation of the conductive system as a response on polymer phase deformation and volume change, was proposed, based on the data received from the analysis of the conductivity behavior during the uniaxial deformation and thermal treatment of composites.

  17. Shock compression behavior of bi-material powder composites with disparate melting temperatures

    International Nuclear Information System (INIS)

    Sullivan, Kyle T.; Swift, Damian; Barham, Matthew; Stölken, James; Kuntz, Joshua; Kumar, Mukul

    2014-01-01

    Laser driven experiments were used to investigate the shock compression behavior of powder processed Bismuth/Tungsten (Bi/W) composite samples. The constituents provide different functionality to the composite behavior as Bi could be shock melted at the pressures attained in this work, while the W could not. Samples were prepared by uniaxial pressing, and the relative density was measured as a function of particle size, applied pressure, and composition for both hot and cold pressing conditions. This resulted in sample densities between 73% and 99% of the theoretical maximum density, and also noticeable differences in microstructure in the hot and cold pressed samples. The compression waves were generated with a 1.3 × 1.3 mm square spot directly onto the surface of the sample, using irradiances between 10 12 and 10 13  W/cm 2 , which resulted in calculated peak pressures between 50 and 150 GPa within a few micrometers. Sample recovery and post-mortem analysis revealed the formation of a crater on the laser drive surface, and the depth of this crater corresponded to the depth to which the Bi had been melted. The melt depth was found to be primarily a function of residual porosity and composition, and ranged from 167 to 528 μm. In general, a higher porosity led to a larger melt depth. Direct numerical simulations were performed, and indicated that the observed increase in melt depth for low-porosity samples could be largely attributed to increased heating associated with work done for pore collapse. However, the relative scaling was sensitive to composition, with low volume fraction Bi samples exhibiting a much stronger dependence on porosity than high Bi content samples. Select samples were repeated using an Al foil ablator, but there were no noticeable differences ensuring that the observed melting was indeed pressure-driven and was not a result of direct laser heating. The resultant microstructures and damage near the spall surface were also investigated

  18. Automated Algorithms for Quantum-Level Accuracy in Atomistic Simulations: LDRD Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Aidan Patrick; Schultz, Peter Andrew; Crozier, Paul; Moore, Stan Gerald; Swiler, Laura Painton; Stephens, John Adam; Trott, Christian Robert; Foiles, Stephen Martin; Tucker, Garritt J. (Drexel University)

    2014-09-01

    This report summarizes the result of LDRD project 12-0395, titled "Automated Algorithms for Quantum-level Accuracy in Atomistic Simulations." During the course of this LDRD, we have developed an interatomic potential for solids and liquids called Spectral Neighbor Analysis Poten- tial (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected on to a basis of hyperspherical harmonics in four dimensions. The SNAP coef- ficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. Global optimization methods in the DAKOTA software package are used to seek out good choices of hyperparameters that define the overall structure of the SNAP potential. FitSnap.py, a Python-based software pack- age interfacing to both LAMMPS and DAKOTA is used to formulate the linear regression problem, solve it, and analyze the accuracy of the resultant SNAP potential. We describe a SNAP potential for tantalum that accurately reproduces a variety of solid and liquid properties. Most significantly, in contrast to existing tantalum potentials, SNAP correctly predicts the Peierls barrier for screw dislocation motion. We also present results from SNAP potentials generated for indium phosphide (InP) and silica (SiO 2 ). We describe efficient algorithms for calculating SNAP forces and energies in molecular dynamics simulations using massively parallel computers

  19. Plasma spheroidization and cladding of powders

    Energy Technology Data Exchange (ETDEWEB)

    Petrunichev, V.A.; Averin, V.V.; Sorokin, L.M.; Koroleva, E.B.

    1987-02-01

    With reference to experimental results for nickel and chromium alloys, it is shown that complex alloy powders can be spheroidized in plasma discharges using an argon plasma with hydrogen. The spheroidizing process is accompanied by the reduction of surface oxides, with uniform element distribution within the particles; the granulometric composition of the particles is preserved. It is also shown that plasma technology can be used for producing metal-clad oxide and carbide powders, which improve the performance of cermets and coatings.

  20. Cellular Energy Absorbing TRIP-Steel/Mg-PSZ Composite: Honeycomb Structures Fabricated by a New Extrusion Powder Technology

    Directory of Open Access Journals (Sweden)

    Ulrich Martin

    2010-01-01

    Full Text Available Lightweight linear cellular composite materials on basis of austenite stainless TRIP- (TRansformation Induced Plasticity- steel as matrix with reinforcements of MgO partially stabilized zirconia (Mg-PSZ are described. Two-dimensional cellular materials for structural applications are conventionally produced by sheet expansion or corrugation processes. The presented composites are fabricated by a modified ceramic extrusion powder technology. Characterization of the microstructure in as-received and deformed conditions was carried out by optical and scanning electron microscopy. Magnetic balance measurements and electron backscatter diffraction (EBSD were used to identify the deformation-induced martensite evolution in the cell wall material. The honeycomb composite samples exhibit an increased strain hardening up to a certain engineering compressive strain and an extraordinary high specific energy absorption per unit mass and unit volume, respectively. Based on improved property-to-weight ratio such linear cellular structures will be of interest as crash absorbers or stiffened core materials for aerospace, railway, or automotive applications.

  1. Ascorbic acid and mineral elements composition of powdered ...

    African Journals Online (AJOL)

    Different types of powdered antimalarial and blood-enriching (haematinic) recipes are used in traditional health system of Southwestern Nigeria. Two of these from Ogbomoso (that is Maloff-HB and Haematol-B, respectively) were recently named following a quantitative definition of their botanical constituents. However ...

  2. Effect of annealing on the composition and structure of TiC and TaC powders

    International Nuclear Information System (INIS)

    Vavrda, J.; Blazhikova, J.

    1979-01-01

    Effect of annealing (1300-2000 deg C) upon lattice parameters and composition of TiC and TaC powders has been investigated. It is established that the lowest deviation from stoichiometric composition of TiC and TaC is the result of annealing the samples, placed in graphite crucibles, in the medium of pure argon. It is shown, that the processes of decarbonizing and crystal defect formation produce decisive effect upon recrystallization of titanium and tantalum carbides. Using the methods of X-ray diffraction and scanning electron microscopy significant difference is detected in structural changes in TiC at high temperature heat treatment compared to recrystallization processes in metals. Singled out are the following stages of the process: carbide decarbonizing and arizing of lattice distortions connected with it; progressing disorientation of mosaic blocks, connected with the increase in stresses of the second kind and subsequent gragmentation of big crystals; relief in fragmentated crystals

  3. Emerging Applications Using Magnesium Alloy Powders: A Feasibility Study

    Science.gov (United States)

    Tandon, Rajiv; Madan, Deepak

    The use of powder metallurgy offers a potential processing route based on tailored compositions and unique microstructures to achieve high performance in magnesium alloys. This paper highlights recent advances in the production, qualification, and characterization of gas atomized AZ91E, WE43 and Elektron21 alloy powders. Transmission electron microscopy (TEM) was used to understand the bulk and surface structure of the atomized powder. The potential for using these magnesium alloy powders for emerging applications involves establishing compatibility with viable consolidation processes such as cold spray, laser assisted deposition, forging and extrusion. This study summarizes the preliminary results for various ongoing investigations using WE43 powder as an example. Results show that powder metallurgy processed WE43 results in comparable properties to those obtained from cast and wrought and offers potential for improvement.

  4. The influence of powder composition and sintering temperature on transformation kinetics, structure and mechanical properties of hot-pressed silicon nitride

    International Nuclear Information System (INIS)

    Knoch, H.; Ziegler, G.

    1977-01-01

    The strength at room temperature of hot-pressed silicon nitride is strongly dependent on the structure which in turn depends on powder composition and process parameters. Connections between production conditions (MgO content, pressing temperature, pressing time), structure (α/β content and morphology), and the properties at room temperature are discussed. The growth of oblong β grains - as a direct result of phase transition from α- to β-Si 3 N 4 - results in microstructural meshing and thus in a higher strength. Optimum mechanical properties are achieved after full phase transformation and with a microstructure as fine as possible. The direct connection between strength and transformed β fraction indicates a possible way for a relatively fast determination of optimum properties for a given initial powder. (orig.) [de

  5. Final report on LDRD project: Simulation/optimization tools for system variability analysis

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Bierbaum; R. F. Billau; J. E. Campbell; K. D. Marx; R. J. Sikorski; B. M. Thompson; S. D. Wix

    1999-10-01

    >This work was conducted during FY98 (Proposal Number 98-0036) and FY99 (Proposal Number 99-0818) under the auspices of the Sandia National Laboratories Laboratory-Directed Research and Development (LDRD) program. Electrical simulation typically treats a single data point in the very large input space of component properties. For electrical simulation to reach its full potential as a design tool, it must be able to address the unavoidable variability and uncertainty in component properties. Component viability is strongly related to the design margin (and reliability) of the end product. During the course of this project, both tools and methodologies were developed to enable analysis of variability in the context of electrical simulation tools. Two avenues to link relevant tools were also developed, and the resultant toolset was applied to a major component.

  6. Gas Release Behavior of Cu-TiH2 Composite Powder and Its Application as a Blowing Agent to Fabricate Aluminum Foams with Low Porosity and Small Pore Size

    Science.gov (United States)

    Cheng, Ying; Li, Yanxiang; Chen, Xiang; Liu, Zhiyong; Zhou, Xu; Wang, Ningzhen

    2018-03-01

    Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH2 composite powder prepared by ball milling preoxidized TiH2 with Cu powder was used as a blowing agent. Its gas release behavior was characterized by thermogravimetric analysis and differential scanning calorimetry. The results show that the ball milling treatment can advance the gas release process and slow the gas release rate at the same time. All these changes are favorable to the reduction of porosity and pore size. Such Cu-TiH2 composite powder provides an alternative way to fabricate aluminum foams with low porosity and small pore size.

  7. Gas Release Behavior of Cu-TiH2 Composite Powder and Its Application as a Blowing Agent to Fabricate Aluminum Foams with Low Porosity and Small Pore Size

    Science.gov (United States)

    Cheng, Ying; Li, Yanxiang; Chen, Xiang; Liu, Zhiyong; Zhou, Xu; Wang, Ningzhen

    2018-06-01

    Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH2 composite powder prepared by ball milling preoxidized TiH2 with Cu powder was used as a blowing agent. Its gas release behavior was characterized by thermogravimetric analysis and differential scanning calorimetry. The results show that the ball milling treatment can advance the gas release process and slow the gas release rate at the same time. All these changes are favorable to the reduction of porosity and pore size. Such Cu-TiH2 composite powder provides an alternative way to fabricate aluminum foams with low porosity and small pore size.

  8. The preparation of UO2 powder: effect of ammonium uranate properties

    International Nuclear Information System (INIS)

    Woolfrey, J.L.

    1978-01-01

    Ammonium uranate (AU) powders were precipitated from a uranyl nitrate solution with gaseous ammonia. The decomposition of the powders in hydrogen was studied to determine those properties of AU which affect the decomposition reactions and influence the properties of the final UO 2 powder. The thermal decomposition was affected by the initial composition (ammonia and nitrate content) and the morphology of the AU powders. The amount of self-reduction increased with increasing combined ammonia content and decreased with increasing nitrate content. The specific surface area of the decomposed powder increased with increasing total ammonia content and initial surface area of the precursor AU powder. Thermal treatment of the decomposed powder can be used to modify such effects and, in commercial powder production, is used to control the properties of the final UO 2 powder. (Auth.)

  9. Remarkable improvement of the wear resistance of poly(vinylidene difluoride) by incorporating polyimide powder and carbon nanofibers

    Science.gov (United States)

    Min, Chunying; Liu, Dengdeng; Shen, Chen; Zhang, Qiaqia; Shen, Xiaojuan; Zhang, Kan

    2017-10-01

    Poly(vinylidene difluoride) (PVDF) composites reinforced via adding different fillers have attracted wide attention in the field of dielectric materials, but few have been reported in the tribological area. In this paper, the effect of polyimide (PI) powder and carbon nanofibers (CF) as reinforcement phases on the friction and wear performance of PVDF composites has been investigated. It was found that PI powder enhances the mechanical and tribological properties of PVDF and especially as the content of the PI powder reaches 5 wt%. In addition, CF and PI exhibited synergistic effect on the tribological properties of PVDF. With PVDF containing 5 wt% PI powder and 20 wt% CF, the friction and wear behavior of the PVDF composite showed the best performance. PVDF, PI powder and CF can form a consistent network structure, which prevents the polymer molecular chains from moving or deformation, decreasing the wear loss of PVDF composites.

  10. Choosing the optimal Pareto composition of the charge material for the manufacture of composite blanks

    Science.gov (United States)

    Zalazinsky, A. G.; Kryuchkov, D. I.; Nesterenko, A. V.; Titov, V. G.

    2017-12-01

    The results of an experimental study of the mechanical properties of pressed and sintered briquettes consisting of powders obtained from a high-strength VT-22 titanium alloy by plasma spraying with additives of PTM-1 titanium powder obtained by the hydride-calcium method and powder of PV-N70Yu30 nickel-aluminum alloy are presented. The task is set for the choice of an optimal charge material composition of a composite material providing the required mechanical characteristics and cost of semi-finished products and items. Pareto optimal values for the composition of the composite material charge have been obtained.

  11. Quantitative phase analysis using the whole-powder-pattern decomposition method. Pt. 1. Solution from knowledge of chemical compositions

    International Nuclear Information System (INIS)

    Toraya, H.; Tusaka, S.

    1995-01-01

    A new procedure for quantitative phase analysis using the whole-powder-pattern decomposition method is proposed. The procedure consists of two steps. In the first, the whole powder patterns of single-component materials are decomposed separately. The refined parameters of integrated intensity, unit cell and profile shape for respective phases are stored in computer data files. In the second step, the whole powder pattern of a mixture sample is fitted, where the parameters refined in the previous step are used to calculate the profile intensity. The integrated intensity parameters are, however, not varied during the least-squares fitting, while the scale factors for the profile intensities of individual phases are adjusted instead. Weight fractions are obtained by solving simultaneous equations, coefficients of which include the scale factors and the mass-absorption coefficients calculated from chemical formulas of respective phases. The procedure can be applied to all mixture samples, including those containing an amorphous material, if single-component samples with known chemical compositions and their approximate unit-cell parameters are provided. The procedure has been tested by using two-to five-component samples, giving average deviations of 1 to 1.5%. Optimum refinement conditions are discussed in connection with the accuracy of the procedure. (orig.)

  12. Integrated computer control system CORBA-based simulator FY98 LDRD project final summary report

    International Nuclear Information System (INIS)

    Bryant, R M; Holloway, F W; Van Arsdall, P J.

    1999-01-01

    The CORBA-based Simulator was a Laboratory Directed Research and Development (LDRD) project that applied simulation techniques to explore critical questions about distributed control architecture. The simulator project used a three-prong approach comprised of a study of object-oriented distribution tools, computer network modeling, and simulation of key control system scenarios. This summary report highlights the findings of the team and provides the architectural context of the study. For the last several years LLNL has been developing the Integrated Computer Control System (ICCS), which is an abstract object-oriented software framework for constructing distributed systems. The framework is capable of implementing large event-driven control systems for mission-critical facilities such as the National Ignition Facility (NIF). Tools developed in this project were applied to the NIF example architecture in order to gain experience with a complex system and derive immediate benefits from this LDRD. The ICCS integrates data acquisition and control hardware with a supervisory system, and reduces the amount of new coding and testing necessary by providing prebuilt components that can be reused and extended to accommodate specific additional requirements. The framework integrates control point hardware with a supervisory system by providing the services needed for distributed control such as database persistence, system start-up and configuration, graphical user interface, status monitoring, event logging, scripting language, alert management, and access control. The design is interoperable among computers of different kinds and provides plug-in software connections by leveraging a common object request brokering architecture (CORBA) to transparently distribute software objects across the network of computers. Because object broker distribution applied to control systems is relatively new and its inherent performance is roughly threefold less than traditional point

  13. The most essential tendencies in development of powder metallurgy

    International Nuclear Information System (INIS)

    Fedorchenko, I.M.

    1989-01-01

    A progress in the sphere of creation and application of new types of powder materials is characterized. The materials are as follows: structural, tribotechnical, composite, reinforced, precipitation-hardened, refractory, tool, materials based on light metals and others. A number of important problems whose solution will promote a further development of powder metallurgy are formulated

  14. Development of Oxide Dispersion Strengthened (ODS) Ferritic Steel Through Powder Forging

    Science.gov (United States)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-04-01

    Oxide dispersion strengthened (ODS) ferritic steels are candidates for cladding tubes in fast breeder nuclear reactors. In this study, an 18%Cr ODS ferritic steel was prepared through powder forging route. Elemental powders with a nominal composition of Fe-18Cr-2 W-0.2Ti (composition in wt.%) with 0 and 0.35% yttria were prepared by mechanical alloying in a Simoloyer attritor under argon atmosphere. The alloyed powders were heated in a mild steel can to 1473 K under flowing hydrogen atmosphere. The can was then hot forged. Steps of sealing, degassing and evacuation are eliminated by using powder forging. Heating ODS powder in hydrogen atmosphere ensures good bonding between alloy powders. A dense ODS alloy with an attractive combination of strength and ductility was obtained after re-forging. On testing at 973 K, a loss in ductility was observed in yttria-containing alloy. The strength and ductility increased with increase in strain rate at 973 K. Reasons for this are discussed. The ODS alloy exhibited a recrystallized microstructure which is difficult to achieve by extrusion. No prior particle boundaries were observed after forging. The forged compacts exhibited isotropic mechanical properties. It is suggested that powder forging may offer several advantages over the traditional extrusion/HIP routes for fabrication of ODS alloys.

  15. LDRD final report : a lightweight operating system for multi-core capability class supercomputers.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Suzanne Marie; Hudson, Trammell B. (OS Research); Ferreira, Kurt Brian; Bridges, Patrick G. (University of New Mexico); Pedretti, Kevin Thomas Tauke; Levenhagen, Michael J.; Brightwell, Ronald Brian

    2010-09-01

    The two primary objectives of this LDRD project were to create a lightweight kernel (LWK) operating system(OS) designed to take maximum advantage of multi-core processors, and to leverage the virtualization capabilities in modern multi-core processors to create a more flexible and adaptable LWK environment. The most significant technical accomplishments of this project were the development of the Kitten lightweight kernel, the co-development of the SMARTMAP intra-node memory mapping technique, and the development and demonstration of a scalable virtualization environment for HPC. Each of these topics is presented in this report by the inclusion of a published or submitted research paper. The results of this project are being leveraged by several ongoing and new research projects.

  16. Composite materials formed with anchored nanostructures

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  17. Multi-Layered Effects of Fe on EMI Shielding of Sn-Al Hotel Architectural Powder

    Directory of Open Access Journals (Sweden)

    Hung Fei-Shuo

    2016-01-01

    Full Text Available No evident effect in shielding efficiency is observed when the electromagnetic wave-absorbing coating materials were applied in single layers because of the dispersing nature of the powder. When increased to two-layer coating, shielding effects were evident at both high and low frequencies, with greater shielding efficiency at low frequencies over high frequencies. It is worth noting that when increased to three-layer coating, as the weight percentage of powdered Fe increased from 5% to 8% , the shielding efficiency of the powdered-Fe composite material was raised to −35 dB This shows that, as the weight percentage gets higher, the powder shows the resonance phenomenon of permeability spectrum, and at high frequencies, the electromagnetic wave shielding efficiency of the composite materials were greatly increased. As the weight percentage of the powered Fe were increased to 8% , we were unable to spread the powder evenly in the epoxy because of the dispersing characteristic in the electromagnetic properties of Fe and the anisotropic and heterogeneous nature of a powered composite material. During production, the powder aggregates often resulted in greater heterogeneity in the materials and consequently, lowered shielding efficiency at 3GHz.

  18. High yttria ferritic ODS steels through powder forging

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Deepak [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Prakash, Ujjwal, E-mail: ujwalfmt@iitr.ac.in [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Dabhade, Vikram V. [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Laha, K.; Sakthivel, T. [Mechanical Metallurgy Group, IGCAR, Kalpakkam, Tamilnadu 603102 (India)

    2017-05-15

    Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y{sub 2}O{sub 3} (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility. - Highlights: •ODS steels with yttria contents beyond the conventional limit of 0.5 wt% were fabricated by powder forging in a hydrogen atmosphere. •All the alloys exhibited significant ductility. •This may be attributed to improved inter-particle bonding due to reduction of surface oxides by hydrogen. •Strength in excess of 300 MPa was obtained at 973 K for 0.5%, 1% and 1.5% yttria ODS alloys. •Powder forging is a promising route to fabricate ODS steels and permits development of compositions with up to 1.5% yttria.

  19. Advances in food powder agglomeration engineering.

    Science.gov (United States)

    Cuq, B; Gaiani, C; Turchiuli, C; Galet, L; Scher, J; Jeantet, R; Mandato, S; Petit, J; Murrieta-Pazos, I; Barkouti, A; Schuck, P; Rondet, E; Delalonde, M; Dumoulin, E; Delaplace, G; Ruiz, T

    2013-01-01

    Food powders are used in everyday life in many ways and offer technological solutions to the problem of food production. The natural origin of food powders, diversity in their chemical composition, variability of the raw materials, heterogeneity of the native structures, and physicochemical reactivity under hydrothermal stresses contribute to the complexity in their behavior. Food powder agglomeration has recently been considered according to a multiscale approach, which is followed in the chapter layout: (i) at the particle scale, by a presentation of particle properties and surface reactivity in connection with the agglomeration mechanisms, (ii) at the mechanisms scale, by describing the structuration dynamics of agglomerates, (iii) at the process scale, by a presentation of agglomeration technologies and sensors and by studying the stress transmission mode in the powder bed, and finally (iv) by an integration of the acquired knowledge, thanks to a dimensional analysis carried out at each scale. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Gas adsorption during storage of plutonium dioxide powders

    International Nuclear Information System (INIS)

    Cuillerdier, C.; Cossonnet, C.; Germain, M.

    1984-10-01

    Adsorption phenomena occuring in plutonium dioxide containers are studied for the determination of safe conditions for storage and transportation of plutonium dioxide powders. Adsorption on dried PuO 2 of air individual gases, influence of powder isotopic composition, chemisorption, effect of moisture are determined. Adsorption of dry air obeys an Elovich's law for its kinetics it is greatly exchange by α radiolysis. Pressure in the container can be reduced by storage under dry inert gas (Ar), decreasing the PuO 2 load and using powder containing preadsorbed water or wet air then radiolysis may occur (H 2 formation)

  1. High-efficiency high-energy Ka source for the critically-required maximum illumination of x-ray optics on Z using Z-petawatt-driven laser-breakout-afterburner accelerated ultrarelativistic electrons LDRD .

    Energy Technology Data Exchange (ETDEWEB)

    Sefkow, Adam B.; Bennett, Guy R.

    2010-09-01

    Under the auspices of the Science of Extreme Environments LDRD program, a <2 year theoretical- and computational-physics study was performed (LDRD Project 130805) by Guy R Bennett (formally in Center-01600) and Adam B. Sefkow (Center-01600): To investigate novel target designs by which a short-pulse, PW-class beam could create a brighter K{alpha} x-ray source than by simple, direct-laser-irradiation of a flat foil; Direct-Foil-Irradiation (DFI). The computational studies - which are still ongoing at this writing - were performed primarily on the RedStorm supercomputer at Sandia National Laboratories Albuquerque site. The motivation for a higher efficiency K{alpha} emitter was very clear: as the backlighter flux for any x-ray imaging technique on the Z accelerator increases, the signal-to-noise and signal-to-background ratios improve. This ultimately allows the imaging system to reach its full quantitative potential as a diagnostic. Depending on the particular application/experiment this would imply, for example, that the system would have reached its full design spatial resolution and thus the capability to see features that might otherwise be indiscernible with a traditional DFI-like x-ray source. This LDRD began FY09 and ended FY10.

  2. Final LDRD report : development of advanced UV light emitters and biological agent detection strategies.

    Energy Technology Data Exchange (ETDEWEB)

    Figiel, Jeffrey James; Crawford, Mary Hagerott; Banas, Michael Anthony; Farrow, Darcie; Armstrong, Andrew M.; Serkland, Darwin Keith; Allerman, Andrew Alan; Schmitt, Randal L.

    2007-12-01

    We present the results of a three year LDRD project which has focused on the development of novel, compact, ultraviolet solid-state sources and fluorescence-based sensing platforms that apply such devices to the sensing of biological and nuclear materials. We describe our development of 270-280 nm AlGaN-based semiconductor UV LEDs with performance suitable for evaluation in biosensor platforms as well as our development efforts towards the realization of a 340 nm AlGaN-based laser diode technology. We further review our sensor development efforts, including evaluation of the efficacy of using modulated LED excitation and phase sensitive detection techniques for fluorescence detection of bio molecules and uranyl-containing compounds.

  3. Influence of Heavy Metal Powders on Rheological Properties of Poly(Lactic Acid)

    Science.gov (United States)

    Lebedev, S. M.; Gefle, O. S.; Amitov, E. T.; Berchuk, D. Yu.; Zhuravlev, D. V.

    2017-08-01

    Main properties of poly(lactic acid) (PLA) and composite materials on its basis filled with tungsten and lead powders are investigated. An anomalous decrease of the viscosity of melts of poly(lactic acid)/tungsten and poly(lactic acid)/lead composites is detected. The methods of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and IR spectroscopy are used for investigation. It is shown that the temperature at which the composites filled with tungsten and lead begin to melt decreases by more than 8 and 3°C in comparison with neat PLA. Our investigations show impossibility of preparing radiation resistant polymer composites based on PLA filled with tungsten and lead powders.

  4. Advances in Powder Metallurgy Soft Magnetic Composite Materials

    Directory of Open Access Journals (Sweden)

    Bureš R.

    2017-06-01

    Full Text Available Powder metallurgy has grown with the expansion of various industry. Automotive industry had the most strong influence. Today, more than 90% of PM products are used in the transportation industry. Development of new materials such as magnetic materials is expected to meet the new trends of automotive industry, electric and hybrid vehicles.

  5. Features of the Valorization of Single and Double Based Powders for Codetonation in Emulsion Explosives

    Science.gov (United States)

    Ribeiro, Jose; Mendes, Ricardo; Tavares, Bruno; Louro, Cristina

    2013-06-01

    In this work, features of the thermal and detonation behavior of compositions resulting from the mixture of single and double based gun powder within ammonium nitrate (AN) based emulsion explosives are shown. That includes results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential scanning calorimetry [DSC] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the ``gap-test''. DSC/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical specimens and so of the capability of the composition components. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with gun powder than for the sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have shown to be higher for the powdered compositions than for the pure emulsion explosive. Shock sensitivity assessment have ended-up with a slightly bigger sensitivity for the compositions with double based gun powder when compared to the single based compositions or to the pure emulsion.

  6. Sol-Gel Synthesis Of Aluminoborosilicate Powders

    Science.gov (United States)

    Bull, Jeffrey; Leiser, Daniel; Selvaduray, Guna

    1992-01-01

    Application of sol-gel process to synthesis of aluminoborosilicate powders shows potential for control of microstructures of materials. Development of materials having enhanced processing characteristics prove advantageous in extending high-temperature endurance of fibrous refractory composite insulation made from ceramic fibers.

  7. Microstructural properties of electrochemically prepared Ni–Fe–W powders

    International Nuclear Information System (INIS)

    Ribić-Zelenović, L.; Ćirović, N.; Spasojević, M.; Mitrović, N.; Maričić, A.; Pavlović, V.

    2012-01-01

    A nanostructured Ni–Fe–W powder was obtained by electrodeposition from ammonium citrate electrolyte within the current density range of 500–1000 mA cm −2 at the electrolyte temperature of 50 °C–70 °C. XRD analysis shows that the powder contains an amorphous matrix having embedded nanocrystals of the FCC solid solution of iron and tungsten in nickel, with an average crystal grain size of 3.4 nm, a high internal microstrain value and a high density of chaotically distributed dislocations. EDS analysis exhibits that the chemical composition of the Ni–24%Fe–11%W powder does not depend upon current density and electrolyte temperature due to the diffusion control of the process of codeposition of nickel, iron and tungsten. SEM micrographs show that the electrodeposition results in the formation of two particle shapes: large cauliflower-like particles and small dendrite particles. The cauliflower-like particles contain deep cavities at hydrogen evolution sites. Cavity density increases with increasing deposition current density. Smaller powder particles are formed at higher temperatures and at higher current densities. During the first heating, relative magnetic permeability decreases reaching the Curie temperature at about 350 °C and after cooling exhibits a 12% increase due to the performed relaxation process. Following the second heating to 500 °C, the magnetic permeability of the powder is about 5% lower than that of the as-prepared powder due to crystallization of the amorphous phase of the powder and the crystal grain growth in FCC phase. - Highlights: ► Electrodeposition Ni–Fe–W powder from ammonium citrate electrolyte (500–1000 mA cm −2 ). ► Powder contains amorphous matrix and embedded nanocrystals 3.4 nm. ► Chemical composition Ni–24%Fe–11%W do not depend upon current density and electrolyte temperature. ► Two particle shapes: large cauliflower-like particles and small dendrite particles. ► Smaller powder particles are

  8. Microstructural properties of electrochemically prepared Ni-Fe-W powders

    Energy Technology Data Exchange (ETDEWEB)

    Ribic-Zelenovic, L. [Faculty of Agronomy, University of Kragujevac, Cacak (Serbia); Cirovic, N. [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Spasojevic, M. [Faculty of Agronomy, University of Kragujevac, Cacak (Serbia); Mitrovic, N., E-mail: nmitrov@tfc.kg.ac.rs [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Maricic, A. [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Pavlovic, V. [Faculty of Agriculture, University of Belgrade, Belgrade (Serbia)

    2012-07-16

    A nanostructured Ni-Fe-W powder was obtained by electrodeposition from ammonium citrate electrolyte within the current density range of 500-1000 mA cm{sup -2} at the electrolyte temperature of 50 Degree-Sign C-70 Degree-Sign C. XRD analysis shows that the powder contains an amorphous matrix having embedded nanocrystals of the FCC solid solution of iron and tungsten in nickel, with an average crystal grain size of 3.4 nm, a high internal microstrain value and a high density of chaotically distributed dislocations. EDS analysis exhibits that the chemical composition of the Ni-24%Fe-11%W powder does not depend upon current density and electrolyte temperature due to the diffusion control of the process of codeposition of nickel, iron and tungsten. SEM micrographs show that the electrodeposition results in the formation of two particle shapes: large cauliflower-like particles and small dendrite particles. The cauliflower-like particles contain deep cavities at hydrogen evolution sites. Cavity density increases with increasing deposition current density. Smaller powder particles are formed at higher temperatures and at higher current densities. During the first heating, relative magnetic permeability decreases reaching the Curie temperature at about 350 Degree-Sign C and after cooling exhibits a 12% increase due to the performed relaxation process. Following the second heating to 500 Degree-Sign C, the magnetic permeability of the powder is about 5% lower than that of the as-prepared powder due to crystallization of the amorphous phase of the powder and the crystal grain growth in FCC phase. - Highlights: Black-Right-Pointing-Pointer Electrodeposition Ni-Fe-W powder from ammonium citrate electrolyte (500-1000 mA cm{sup -2}). Black-Right-Pointing-Pointer Powder contains amorphous matrix and embedded nanocrystals 3.4 nm. Black-Right-Pointing-Pointer Chemical composition Ni-24%Fe-11%W do not depend upon current density and electrolyte temperature. Black

  9. Manufacturing of superconductive silver/ceramic composites

    DEFF Research Database (Denmark)

    Seifi, Behrouz; Bech, Jakob Ilsted; Eriksen, Morten

    2000-01-01

    Manufacturing of superconducting metal/ceramic composites is a rather new discipline within materials forming processes. High Temperature SuperConductors, HTSC, are manufactured applying the Oxide-Powder-In-Tube process, OPIT. A ceramic powder containing lead, calcium, bismuth, strontium, and cop......Manufacturing of superconducting metal/ceramic composites is a rather new discipline within materials forming processes. High Temperature SuperConductors, HTSC, are manufactured applying the Oxide-Powder-In-Tube process, OPIT. A ceramic powder containing lead, calcium, bismuth, strontium...

  10. Microstructural and Mechanical Study of Inconel 625 – Tungsten Carbide Composite Coatings Obtained by Powder Laser Cladding

    Directory of Open Access Journals (Sweden)

    Huebner J.

    2017-06-01

    Full Text Available This study focuses on the investigation of fine (~0.54 μm tungsten carbide particles effect on structural and mechanical properties of laser cladded Inconel 625-WC composite. Three powder mixtures with different Inconel 625 – WC weight ratio (10, 20 and 30 weight % of WC were prepared. Coatings were made using following process parameters: laser beam diameter ø ≈ 500 μm, powder feeder rotation speed – 7 m/min, scanning velocity – 10 m/min, laser power – 220 W changed to 320 W, distance between tracks – 1 mm changed to 0.8 mm. Microstructure and hardness were investigated. Coatings produced by laser cladding were crack and pore free, chemically and structurally homogenous. High cooling rate during cladding process resulted in fine microstructure of material. Hardness improved with addition of WC from 396.3 ±10.5 HV for pure Inconel 625, to 469.9 ±24.9 HV for 30 weight % of WC. Tungsten carbide dissolved in Inconel 625 which allowed formation of intergranular eutectic that contains TCP phases.

  11. Effects of Diatomite–Limestone Powder Ratio on Mechanical and Anti-Deformation Properties of Sustainable Sand Asphalt Composite

    Directory of Open Access Journals (Sweden)

    Yongchun Cheng

    2018-03-01

    Full Text Available Diatomite has gained more and more interest as a new resource, since it has potential as a favorable alternative to mineral filler in the construction of asphalt pavement compared with ordinary limestone powder. In this paper, the mechanical and anti-deformation properties of sand asphalt composites with various proportions of diatomite were investigated by a uniaxial compression failure test, a uniaxial compression repeated creep test, and a low-temperature splitting test in order to determine the optimal replacement content of ordinary limestone powder. Five groups of sand asphalts with various volume ratios of diatomite to limestone (0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25, and 1:0 were determined by the simplex-lattice mixture design (SLD method. The results reveal that the compression strength, anti-deformation properties, and low-temperature crack resistance of sand asphalts are improved through the use of diatomite. Furthermore, the optimal ratio (0.327:0.673 of limestone to diatomite is determined by the SLD method, according to secant modulus and creep strain results.

  12. Tungsten and tungsten alloys by powder metallurgy

    International Nuclear Information System (INIS)

    Belhadjhamida, A.; German, R.M.

    1991-01-01

    Tungsten has a historical link with powder metallurgy and there is continued progress in expanding the available compositions and processing options. This paper starts with an introduction to the history of tungsten powder metallurgy and use this as a basis for analyzing some of the current trends. The literature base in tungsten processing is expanding and includes new alloys, microstructures, and processing routes. A few examples will be emphasize here to produce a frame work for this program, including description of sintering mechanisms for tungsten, liquid phase sintering advances, hot consolidation fundamentals, and options for complex shaping using powder injection modeling. For this base, subsequent presentations will expand on these fundamental advances

  13. Development of engineered cementitious composites with limestone powder and blast furnace slag

    NARCIS (Netherlands)

    Zhou, J.; Qian, S.; Sierra Beltran, M.G.; Ye, G.; Van Breugel, K.; Li, V.C.

    2009-01-01

    Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy

  14. Synthesis and characterization of Yb and Er based monosilicate powders and durability of plasma sprayed Yb2SiO5 coatings on C/C–SiC composites

    International Nuclear Information System (INIS)

    Khan, Zuhair S.; Zou Binglin; Huang Wenzhi; Fan Xizhi; Gu Lijian; Chen Xiaolong; Zeng Shuibing; Wang Chunjie; Cao Xueqiang

    2012-01-01

    Highlights: ► Ultra-pure rare-earth monosilicate powders based on Er and Yb have been fabricated by solid-state reaction. ► Spray-drying treatment results in powders with free flowing characteristics and rounded surface morphologies. ► CTEs are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 . ► Plasma spraying has been used to deposit Yb 2 SiO 5 coatings on C/C–SiC substrate. ► Coatings remain strongly intact with the substrate on thermal cycling between ∼400 °C and 1500 °C in gas burner rig experiment. - Abstract: Rare-earth silicates such as Yb 2 SiO 5 and Er 2 SiO 5 are promising environmental barrier coating materials for ceramic matrix composites. In this work, Yb 2 SiO 5 and Er 2 SiO 5 ceramic powders have been synthesized by solid-state reaction using Yb 2 O 3 , Er 2 O 3 and SiO 2 as starting materials. The fabricated powders were subjected to spray drying treatment for subsequent synthesis of coatings by plasma spraying. The spray drying resulted in well-dispersed and spherical powder particles with good flowability. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and differential scanning calorimetry (TGA/DSC) and dilatometry were applied to study the microstructural and thermal characteristics of the powders. Ultra-high purity monosilicate powders formed as a result of heating treatments at 1400 °C in a box furnace for 20 h. TG/DSC revealed the genesis temperatures of the silicate formation (low temperature polymorphs) and also showed that the solid-state reactions to form Yb and Er based monosilicates proceeded without any weight-loss in the tested temperature range. The values of coefficients of thermal expansion (CTE) of the fabricated compounds are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 by dilatometric measurements. Besides these studies, coating formation by plasma spraying of spray-dried Yb 2 SiO 5 powders on the ceramic

  15. Preparation and characterization of polyurethane - Fe powder composites

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Bureš, R.; Fáberová, M.; Trchová, Miroslava; Strachota, Adam; Kaprálková, Ludmila

    2011-01-01

    Roč. 11, 3/4 (2011), s. 290-299 ISSN 1335-8987 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethanes * polybutadiene diol * Fe powder Subject RIV: CD - Macromolecular Chemistry http://www.imr.saske.sk/pmp/issue/3-4-2011/PMP_Vol11_No3-4_p_290-299.pdf

  16. Food powders flowability characterization: theory, methods, and applications.

    Science.gov (United States)

    Juliano, Pablo; Barbosa-Cánovas, Gustavo V

    2010-01-01

    Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.

  17. Structural investigations of zirconia powders obtained by hf-plasmochemical denitration

    International Nuclear Information System (INIS)

    Dedov, N.V.; Ivanov, Yu.F.; Dorda, F.A.; Paul', A.V.; Zav'yalov, A.V.; Koneva, N.A.; Korobtsev, V.P.; Kutyavin, E.M.; Mazin, V.I.; Matyukha, V.A.

    1992-01-01

    Results are presented of structural and physicochemical investigations of unstabilized and stabilized (using yttria, magnesia, calcium oxide and alumina) zirconia, obtained from nitrate solutions on pilot HF-plasmochemical equipment with an electric rating of 63 kW. The phase composition of the ultradispersed powder is shown. Morphological and grain-size analyses were carried out on the EM-125K electron diffraction microscope. specimens were prepared by applying powder to a carbon film obtained in a VUP-4 vacuum cell. The phase composition was studied by x-ray analysis on the DRON-3 diffractometer. These studies established that the main morphological constituents of the ZrO 2 powder are polycrystalline hollow spheres and fragments of films. The average sizes (diameter) of the spheres in 0.77 μ (mean square deviation σ n = 0.57μ) and for the grains in them 31 nm (σ n = 9.5 nm). There exists a certain correlation between the dimensions of the polycrystalline spheres and their grain structure - the coarser the powders, the larger the grains observed

  18. Microstructure and High Temperature Oxidation Property of Fe-Cr-B Based Metal/Ceramic Composite Manufactured by Powder Injection Molding Process

    Science.gov (United States)

    Joo, Yeun-Ah; Kim, Young-Kyun; Yoon, Tae-Sik; Lee, Kee-Ahn

    2018-03-01

    This study investigated the microstructure and high temperature oxidation property of Fe-Cr-B metal/ceramic composite manufactured using powder injection molding process. Observations of initial microstructure showed a unique structure where α-Fe and (Cr, Fe)2B form a continuous three-dimensional network. High temperature oxidation tests were performed at 900, 1000 and 1100 °C, for 24 h, and the oxidation weight gain according to each temperature condition was 0.13, 0.84 and 6.4 mg/cm2, respectively. The oxidation results according to time at 900 and 1000 °C conditions represented parabolic curves, and at 1100 °C condition formed a rectilinear curve. Observation and phase analysis results of the oxides identified Cr2O3 and SiO2 at 900 and 1000 °C. In addition to Cr2O3 and SiO2, CrBO3 and FeCr2O4 formed due to phase decomposition of boride were identified at 1100 °C. Based on the findings above, this study suggested the high temperature oxidation mechanism of Fe-Cr-B metal/ceramic composite manufactured using powder injection molding, and the possibility of its application as a high temperature component material was also discussed.

  19. Antioxidant Potential of Fruit Juice with Added Chokeberry Powder (Aronia melanocarpa)

    OpenAIRE

    Jana Šic Žlabur; Nadica Dobričević; Stjepan Pliestić; Ante Galić; Daniela Patricia Bilić; Sandra Voća

    2017-01-01

    The purpose of this study was to determine the possibility of using chokeberry powder as a supplement in apple juice to increase the nutritional value of the final product with the aim of developing a new functional food product. Also, to determine the influence of ultrasound assisted extraction on the bioactive compounds content, nutritional composition and antioxidant potential of apple juice with added chokeberry powder. The juice samples with added chokeberry powder had higher antioxidant...

  20. Powder-metallurgy superalloy strengthened by a secondary gamma phase.

    Science.gov (United States)

    Kotval, P. S.

    1971-01-01

    Description of experiments in which prealloyed powders of superalloy compositions were consolidated by extrusion after the strengthening by precipitation of a body-centered tetragonal gamma secondary Ni3 Ta phase. Thin foil electron microscopy showed that the mechanical properties of the resultant powder-metallurgy product were correlated with its microstructure. The product exhibited high strength at 1200 F without loss of ductility, after thermomechanical treatment and aging.

  1. Spheroidization by Plasma Processing and Characterization of Stainless Steel Powder for 3D Printing

    Science.gov (United States)

    Ji, Lina; Wang, Changzhen; Wu, Wenjie; Tan, Chao; Wang, Guoyu; Duan, Xuan-Ming

    2017-10-01

    Stainless steel 316L (SS 316L) powder was spheroidized by plasma processing to improve its suitability for powder 3D printing. The obtained spheroidized (sphero) powder was characterized in terms of its crystalline phases, elemental composition, morphology, particle size and distribution, light absorption, and flow properties. The elemental composition of the sphero powder met the Chinese standard for SS 316L except for its Si content. The volume fraction of ferrite increased after plasma processing. Furthermore, plasma processing was shown to not only reduce the mean size of the particles in the size range of 10 to 100 μm but also generate particles in the size range of 0.1 to 10 μm. The smaller particles filled the voids among larger particles, increasing the powder density. The light absorption was also increased owing to enhanced internal reflection. Although the basic flow energy decreased after plasma processing, the flow function (FF) value was smaller for the sphero powder, indicating a lower flowability of the sphero powder. However, the density of SS 316L pieces printed with commercial and sphero powders was 98.76 pct and 98.16 pct of the SS 316L bulk density, respectively, indicating the suitability of the sphero powder for 3D printing despite an FF below 10.

  2. Electromagnetic characterization of strontium ferrite powders in series 2000, SU8 polymer

    Science.gov (United States)

    Sholiyi, Olusegun; Williams, John

    2014-12-01

    In this article, electromagnetic characterization of strontium hexaferrite powders and composites with SU8 was carried out to determine their compatibility with micro and millimeter wave fabrications. The structures of both powders and their composites were scanned with electron microscope to produce the SEM images. Two powder sizes (0.8-1.0 μm and 3-6 μm), were mixed with SU8, spin cast and patterned on wafer, and then characterized using energy dispersive x-ray spectrometry, ferromagnetic resonance (FMR) and vibrating sample magnetometry. In this investigation, FMRs of the samples were determined at 60 GHz while their complex permittivity and permeability were determined using rectangular waveguide method of characterization between 26.5 and 40 GHz frequency range. The results obtained show no adverse effects on the electromagnetic properties of the composites except some slight shift in the resonant frequencies due to anisotropic field of the samples.

  3. Thermal conductivity of glass copper-composite

    International Nuclear Information System (INIS)

    Kinoshita, Makoto; Terai, Ryohei; Haidai, Haruki

    1980-01-01

    Glass-metal composites are to be one of the answers for promoting thermal conduction in the glassy solids containing high-level radioactive wastes. In order to investigate the effect of metal addition on thermal conductivity of glasses, glass-copper composites were selected, and the conductivities of the composites were measured and discussed in regards to copper content and microstructure. Fully densified composites were successfully prepared by pressure sintering of the powder mixtures of glass and copper at temperatures above the yield points of the constituent glasses if the copper content was not so much. The conductivity was measured by means of a comparative method, in which the thermal gradient of the specimen was compared with that of quartz glass as standard under thermally steady state. Measurements were carried out at around 50 0 C. The thermal conductivity increased with increasing content of copper depending on the kind of copper powder used. The conductivities of the composites of the same copper content differed considerably each another. Fine copper powder was effective on increasing conductivity, and the conductivity became about threefold of that of glass by mixing the fine copper powder about 10 vol%. For the composites containing the fine copper powder less than 5 vol%, the conductivity obeyed so-called logarithmic rule, one of the mixture rules of conductivity, whereas for composites containing more than 5 vol%, the conductivity remarkably increased apart from the rule. This fact suggests that copper becomes continuous in the composite when the copper content increased beyond 5 vol%. For the composites containing coarse copper powder, the conductivity was increased not significantly, and obeyed an equation derived from the model in which conductive material dispersed in less conductive one. (author)

  4. Phase evolution in Al-Ni-(Ti, Nb, Zr) powder blends by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, A. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur (India); Manna, I. [Metallurgical and Materials Engineering Department, I.I.T., Kharagpur 721302 (India); Chattopadhyay, P.P. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur (India)], E-mail: c.partha@mailcity.com

    2007-08-25

    Mechanical alloying of Al-rich Al-Ni-ETM (ETM = Ti, Nb, Zr) elemental powder blends by planetary ball milling yielded amorphous and/or nanocrystalline products after ball milling for suitable duration. Powder samples collected at different stages of ball milling have been examined by X-ray diffraction, differential scanning caloremetry and high-resolution transmission electron microscopy to examine the solid-state phase evolution. Powder blends having nominal composition of Al{sub 80}Ni{sub 10}Ti{sub 10} and Al{sub 80}Ni{sub 10}Nb{sub 10} yielded predominantly amorphous products, while the other alloys formed composite microstructures comprising nanaocrystalline and amorphous solid solutions. The amorphous Al{sub 80}Ni{sub 10}Ti{sub 10} alloy was mixed with different amounts of Al powder, and subjected to warm rolling after consolidation within the Al-cans with or without intermediate annealing for 10 min at 500 K to obtain sheet of 2.5 mm thickness. Notable improvement in mechanical properties has been achieved for the composite sheets in comparison to the pure Al.

  5. Preparation and characterization of functional fabrics from bamboo charcoal/silver and titanium dioxide/silver composite powders and evaluation of their antibacterial efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fu-Chu, E-mail: yfc580629@yahoo.com.tw [Army Command Headquarters, MND, Taoyuan, Taiwan (China); Wu, Kuo-Hui [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, NDU, No. 190, Sanyuan 1st Street, Tahsi, Taoyuan 335, Taiwan (China); Huang, Jen-Wei [Department of Physics, Chinese Military Academy, Fengshan, Kaohsiung, Taiwan (China); Horng, Deng-Nan; Liang, Chia-Feng [Department of Chemistry, Chinese Military Academy, Fengshan, Kaohsiung, Taiwan (China); Hu, Ming-Kuan [School of Pharmacy, National Defense Medical Center, Taipei, Taiwan (China)

    2012-07-01

    Bamboo charcoal supporting silver (BC/Ag) and titanium dioxide supporting silver (TiO{sub 2}/Ag) were prepared by activation and chemical reduction. The BC/Ag and TiO{sub 2}/Ag composites were characterized by silver particle size and distribution and antibacterial properties. The pore and surface properties were studied in terms of BET volumetric measurement with nitrogen adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antibacterial effects of the BC/Ag and TiO{sub 2}/Ag composite powders were assessed from the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs), and an excellent antibacterial performance was discovered. Moreover, these composite powders were deposited via immersion coating onto fabrics (nonwoven and carbon fibers) to improve the antibacterial efficacy and to act as a biologically-protective material. The antibacterial activities of the fabrics supported by BC/Ag and TiO{sub 2}/Ag were studied in zone of inhibition and plate counting tests against Gram-positive Staphylococcus aureus ME/GM/TC Resistant, Bacillus subtilis, Candida albicans, Gram-negative Pseudomonas aeruginosae (CTZ and EM and GM) Res. Clin. Isol., Escherichia coli Juhl, and Klebsiella pneumoniae. The results showed that fabric-BC/Ag and fabric-TiO{sub 2}/Ag possess a strong antibacterial activity and an inhibitory effect on the growth of these bacteria and are therefore believed to have great potential for use as antibacterial fabrics.

  6. Pengaruh One Direction Pre-Tension pada Reinforcement Fibre terhadap Kekuatan Tarik dan Impact Fibre-Powder Reinforcement Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Gilang Gumilar

    2017-12-01

    Full Text Available Nowadays, industrial manufacturing needs environmentally and friendly material and has special properties which are difficult to obtain from the metal material. Composite is one of the alternative materials that can be used to meet those needs. A structural composite material consisting of a combination of two or more elements bonded material at the macroscopic level. This study was conducted to determine the effect of pre-tension one direction on a hybrid composite reinforcement against tensile strength and impact strength. Composite materials prepared by C-Glass fiber types woven rovings, coconut shell powder and vinyl ester resin. manufacturing composite using hand lay-up methods. The variation of the tension given 0N, 50N, 100N, 150N, and 200N. A tensile test based on the reference standard ASTM D 3039 while testing the impact based on ASTM D 6110-04. The results were obtained giving tension to the hybrid composite reinforcement increases tensile strength and impact strength of the material. The lowest tensile strength of the composite obtained in 0N treatment (without treatment ranged 71,58N / mm², and the greatest tensile strength is obtained in the pre-tension 200N, ranging from 106.05 N / mm2. As for the lowest impact on specimens obtained without treatment ranges 1,34J / mm2 and provision of pre-tension 200N biggest impact strength values obtained, ranging 15,09J / mm2.

  7. Surface chemical state of Ti powders and its alloys: Effect of storage conditions and alloy composition

    Energy Technology Data Exchange (ETDEWEB)

    Hryha, Eduard, E-mail: hryha@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Shvab, Ruslan [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Bram, Martin; Bitzer, Martin [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), D-52425 Jülich (Germany); Nyborg, Lars [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden)

    2016-12-01

    Highlights: • Powder particles of Ti, NiTi and Ti6Al4V are covered by homogeneous Ti-oxide layer. • Thickness of the Ti-oxide layer is in the range of 2.9 to 4.2 nm in as-atomized state. • Exposure to the air results in immediate oxide thickness increase of up to 30%. • Oxide thickness increase of only 15% during storage for 8 years. • High passivation of the Ti, NiTi and Ti6Al4V powder surface by Ti-oxide layer. - Abstract: High affinity of titanium to oxygen in combination with the high surface area of the powder results in tremendous powder reactivity and almost inevitable presence of passivation oxide film on the powder surface. Oxide film is formed during the short exposure of the powder to the environment at even a trace amount of oxygen. Hence, surface state of the powder determines its usefulness for powder metallurgy processing. Present study is focused on the evaluation of the surface oxide state of the Ti, NiTi and Ti6Al4V powders in as-atomized state and after storage under air or Ar for up to eight years. Powder surface oxide state was studied by X-ray photoelectron spectroscopy (XPS) and high resolution scanning electron microscopy (HR SEM). Results indicate that powder in as-atomized state is covered by homogeneous Ti-oxide layer with the thickness of ∼2.9 nm for Ti, ∼3.2 nm and ∼4.2 nm in case of Ti6Al4V and NiTi powders, respectively. Exposure to the air results in oxide growth of about 30% in case of Ti and only about 10% in case of NiTi and Ti6Al4V. After the storage under the dry air for two years oxide growth of only about 3-4% was detected in case of both, Ti and NiTi powders. NiTi powder, stored under the dry air for eight years, indicates oxide thickness of about 5.3 nm, which is about 30% thicker in comparison with the as-atomized powder. Oxide thickness increase of only ∼15% during the storage for eight years in comparison with the powder, shortly exposed to the air after manufacturing, was detected. Results indicate a

  8. Fabricating solid carbon porous electrodes from powders

    Science.gov (United States)

    Kaschmitter, James L.; Tran, Tri D.; Feikert, John H.; Mayer, Steven T.

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  9. Controlling fundamentals in high-energy high-rate pulsed power materials processing of powdered tungsten, titanium aluminides, and copper-graphite composites. Final technical report, 1 Jun 87-31 Aug 90

    Energy Technology Data Exchange (ETDEWEB)

    Persad, C.; Marcus, H.L.; Bourell, D.L.; Eliezer, Z.; Weldon, W.F.

    1990-10-01

    This study was conducted to determine the controlling fundamentals in the high-energy high-rate (1 MJ in 1s) processing of metal powders. This processing utilizes a large electrical current pulse to heat a pressurized powder mass. The current pulse was provided by a homopolar generator. Simple short cylindrical shapes were consolidated so as to minimize tooling costs. Powders were subjected to current densities of 5 kA/cm2 to 25 kA/cm2 under applied pressures ranging from 70 MPa to 500 MPa. Disks with diameters of 25 mm to 70 mm, and thicknesses of 1 mm to 10 mm were consolidated. Densities of 75% to 99% of theoretical values were obtained in powder consolidates of tungsten, titanium aluminides, copper-graphite, and other metal-ceramic composites. Extensive microstructural characterization was performed to follow the changes occuring in the shape and microstructure of the various powders. The processing science has at its foundation the control of the duration of elevated temperature exposure during powder consolidation.

  10. Electromagnetic characterization of strontium ferrite powders in series 2000, SU8 polymer

    International Nuclear Information System (INIS)

    Sholiyi, Olusegun; Williams, John

    2014-01-01

    In this article, electromagnetic characterization of strontium hexaferrite powders and composites with SU8 was carried out to determine their compatibility with micro and millimeter wave fabrications. The structures of both powders and their composites were scanned with electron microscope to produce the SEM images. Two powder sizes (0.8–1.0 μm and 3–6 μm), were mixed with SU8, spin cast and patterned on wafer, and then characterized using energy dispersive x-ray spectrometry, ferromagnetic resonance (FMR) and vibrating sample magnetometry. In this investigation, FMRs of the samples were determined at 60 GHz while their complex permittivity and permeability were determined using rectangular waveguide method of characterization between 26.5 and 40 GHz frequency range. The results obtained show no adverse effects on the electromagnetic properties of the composites except some slight shift in the resonant frequencies due to anisotropic field of the samples. (paper)

  11. Antioxidant and antimicrobial activities of squid ink powder

    OpenAIRE

    Fatimah Zaharah, M.Y.; Rabeta, M.S.

    2017-01-01

    Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assa...

  12. Combustion synthesis of AlB2-Al2O3 composite powders with AlB2 nanowire structures

    Science.gov (United States)

    Yang, Pan; Xiao, Guoqing; Ding, Donghai; Ren, Yun; Yang, Shoulei; Lv, Lihua; Hou, Xing

    2018-05-01

    Using of Al and B2O3 powders as starting materials, and Mg-Al alloy as additives, AlB2-Al2O3 composite powders with AlB2 nanowire structures were successfully fabricated via combustion synthesis method in Ar atmosphere at a pressure of 1.5 MPa. The effect of different amount of Mg-Al alloy on the phase compositions and morphology of the combustion products was investigated. The results revealed that AlB2 and Al2O3 increased, whereas Al decreased with the content of Mg-Al alloy increasing. The impurities MgAl2O4 and AlB12 would exist in the sample with adding of 18 wt% Mg-Al alloy. Interestingly, FESEM/TEM/EDS results showed that AlB2 nanowires were observed in the products when the content of Mg-Al alloy is 6 wt% and 12 wt%. The more AlB2 nanowires can be found as the content of Mg-Al alloy increased. And the yield of AlB2 nanowires with the diameter of about 200 nanometers (nm) and the length up to several tens of micrometers (μm) in the combustion product is highest when the content of Mg-Al alloy is 12 wt%. The vapor, such as Mg-Al (g), B2O2 (g), AlO (g) and Al2O (g), produced during the process of combustion synthesis, reacted with each other to yield AlB2 nanowires by vapor-solid (VS) mechanism and the corresponding model was also proposed.

  13. Nanocarbon materials obtained of coniferous trees in the composition of black powder

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

    Full Text Available Obtained black powders from coniferous wood. The carbon content of up to 90% can be used in warfare, pyrotechnics and industries. In the Republic of Kazakhstan does not produce gunpowder. In the energy-intensive materials laboratory, developed industrial black powders (ordinary, composed of components produced in the republic of Kazakhstan. Sulfur, activated carbon, based on apricot seeds and rice husks, softwood sawdust, which have lower costs than their foreign counterparts.

  14. Chemical Composition and Antioxidant Properties of Powders Obtained from Different Plum Juice Formulations.

    Science.gov (United States)

    Michalska, Anna; Wojdyło, Aneta; Łysiak, Grzegorz P; Figiel, Adam

    2017-01-17

    Among popular crops, plum ( Prunus domestica L.) has received special attention due to its health-promoting properties. The seasonality of this fruit makes it impossible to consume it throughout the year, so new products in a powder form may offer an alternative to fresh consumption and may be used as high-quality natural food ingredients. A 100% plum (cultivar "Valor") juice was mixed with three different concentrations of maltodextrin or subjected to sugars removal by amberlite-XAD column, and dried using the freeze, spray, and vacuum (40, 60, and 80 °C) drying techniques. The identification and quantification of phenolic acids, flavonols, and anthocyanins in plum powders was performed by LC-MS QTof and UPLC-PDA, respectively. l-ascorbic acid, hydroxymethylfurfural, and antioxidant capacity were measured by the Trolox equivalent antioxidant capacity (TEAC) ABTS and ferric reducing antioxidant potential (FRAP) methods in order to compare the influence of the drying methods on product quality. The results indicated that the profile of polyphenolic compounds in the plum juice powders significantly differed from the whole plum powders. The drying of a sugar free plum extract resulted in higher content of polyphenolic compounds, l-ascorbic acid and antioxidant capacity, but lower content of hydroxymethylfurfural, regardless of drying method applied. Thus, the formulation of plum juice before drying and the drying method should be carefully selected in order to obtain high-quality powders.

  15. Strength Improvement of Clay Soil by Using Stone Powder

    Directory of Open Access Journals (Sweden)

    Ahmed Sameer Abdulrasool

    2015-05-01

    Full Text Available Soil stabilization with stone powder is a good solution for the construction of subgrade for road way and railway lines, especially under the platforms and mostly in transition zones between embankments and rigid structures, where the mechanical properties of supporting soils are very influential. Stone powder often has a unique composition which justifies the need for research to study the feasibility of using this stone powder type for ground improvement applications. This paper presents results from a comprehensive laboratory study carried out to investigate the feasibility of using stone powder for improvement of engineering properties of clays. The stone powder contains bassanite (CaSO4. ½ H2O, and Calcite (CaCO3. Three percentages are used for stone powder (1%, 3% and 5% by dry weight of clay. Several tests are made to investigate the soil behavior after adding the stone powder (Atterberg limits, Standard Proctor density, Grain size distribution, Specific gravity, Unconfined Compressive test, and California bearing ratio test. Unconfined Compressive tests conducted at different curing. The samples are tested under both soaked and unsoaked condition. Chemical tests and X-ray diffraction analyses are also carried out. Stone powder reacts with clay producing decreasing in plasticity and The curves of grain size distribution are shifted to the coarse side as the stone powder percentage increase; the soil becomes more granular, and also with higher strength.

  16. Correlations between the in vitro and in vivo bioactivity of the Ti/HA composites fabricated by a powder metallurgy method.

    Science.gov (United States)

    Ning, Congqin; Zhou, Yu

    2008-11-01

    Ti/HA composites were successfully prepared by a powder metallurgy method and the effect of phase composition on the in vitro and in vivo bioactivity of the Ti/HA composites was investigated in the present study. The correlations between the in vitro and in vivo biological behaviors were highlighted. The results showed that the in vitro and in vivo bioactivity of the Ti/HA composites was dependent on their phase composition. The in vitro bioactivity of the Ti/HA composites was evaluated in simulated body fluid with ion concentrations similar to those of human plasma. After immersion in the simulated body fluid for a certain time, apatite precipitations formed on the surface of the composites with an initial titanium content of 50 and 70 wt.%, and no apatite was found on the surface of the composite with 30% titanium. Ti(2)O was responsible for the apatite formation on the surfaces of the composites. For in vivo analysis, Ti/HA cylinders were implanted in the metaphases of the rabbit femur. At the early stage of implantation, the new bone formed on the surface of the composite with 30% titanium was much less than that on the surfaces of the composites with 50% and 70% titanium. All the Ti/HA composites formed a chemical bone-bonding interface with the host bone by 6 months after implantation. The Ti/HA composites formed the bone-bonding interface with the surrounding bone through an apatite layer. The results in the present study suggested that the in vivo results agreed well with the in vitro results.

  17. Tensile Properties and Fracture Behavior of a Powder-Thixoformed 2024Al/SiCp Composite at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Pubo Li

    2017-10-01

    Full Text Available In the present work, the tensile properties and fracture behavior of a 2024Al composite reinforced with 10 vol % SiCp and fabricated via powder thixoforming (PT were studied at temperatures ranging from 25 °C to 300 °C with a strain rate of 0.05 s−1, as well as the PT 2024 alloy. The results indicated that the tensile strengths of both the PT materials were all decreased with increasing the temperature, but the decrease rate of the composite was smaller than that of the 2024 alloy, and the composite exhibited higher tensile strength than that of the 2024 alloy at all of the employed testing temperatures due to the strengthening role of SiCp. Increasing temperature was beneficial for enhancing the ductility of materials, and the maximum elongation was reached at 250 °C. The elongation decrease over 250 °C was attributed to the cavity formation due to the debonding of the SiCp/Al interface and the fracturing of the matrix between SiCp. The fracture of the composite at room temperature initiated from the fracture of SiCp and the debonding of the SiCp/Al interface, but that at high temperatures was dominated by void nucleation and growth in the matrix besides the interface debonding.

  18. Laser Processing Technology using Metal Powders

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jeong-Hwan; Moon, Young-Hoon [Pusan National University, Busan (Korea, Republic of)

    2012-03-15

    The purpose of this paper is to review the state of laser processing technology using metal powders. In recent years, a series of research and development efforts have been undertaken worldwide to develop laser processing technologies to fabricate metal-based parts. Layered manufacturing by the laser melting process is gaining ground for use in manufacturing rapid prototypes (RP), tools (RT) and functional end products. Selective laser sintering / melting (SLS/SLM) is one of the most rapidly growing rapid prototyping techniques. This is mainly due to the processes's suitability for almost any materials, including polymers, metals, ceramics and many types of composites. The interaction between the laser beam and the powder material used in the laser melting process is one of the dominant phenomena defining feasibility and quality. In the case of SLS, the powder is not fully melted during laser scanning, therefore the SLS-processed parts are not fully dense and have relatively low strength. To overcome this disadvantage, SLM and laser cladding (LC) processes have been used to enable full melting of the powder. Further studies on the laser processing technology will be continued due to the many potential applications that the technology offers.

  19. Fat properties during homogenization, spray-drying, and storage affect the physical properties of dairy powders.

    Science.gov (United States)

    Vignolles, M L; Lopez, C; Madec, M N; Ehrhardt, J J; Méjean, S; Schuck, P; Jeantet, R

    2009-01-01

    Changes in fat properties were studied before, during, and after the drying process (including during storage) to determine the consequences on powder physical properties. Several methods were combined to characterize changes in fat structure and thermal properties as well as the physical properties of powders. Emulsion droplet size and droplet aggregation depended on the homogenizing pressures and were also affected by spray atomization. Aggregation was usually greater after spray atomization, resulting in greater viscosities. These processes did not have the same consequences on the stability of fat in the powders. The quantification of free fat is a pertinent indicator of fat instability in the powders. Confocal laser scanning microscopy permitted the characterization of the structure of fat in situ in the powders. Powders from unhomogenized emulsions showed greater free fat content. Surface fat was always overrepresented, regardless of the composition and process parameters. Differential scanning calorimetry melting experiments showed that fat was partially crystallized in situ in the powders stored at 20 degrees C, and that it was unstable on a molecular scale. Thermal profiles were also related to the supramolecular structure of fat in the powder particle matrix. Powder physical properties depended on both composition and process conditions. The free fat content seemed to have a greater influence than surface fat on powder physical properties, except for wettability. This study clearly showed that an understanding of fat behavior is essential for controlling and improving the physical properties of fat-filled dairy powders and their overall quality.

  20. Production of rare earth polishing powders in Russia

    International Nuclear Information System (INIS)

    Kosynkin, V.D.; Ivanov, E.N.; Kotrekhov, V.A.; Shtutza, M.G.; Grabko, A.I.

    1998-01-01

    Full text: Russia is a potent producer of polishing powders made of rare earth material presented as an extensive and well developed base. Considering the reserves, the facilities predisposition and the polishing agent (cerium dioxide) content the chief mineral source is loparite, apatite and monazite. The production of rare earth polishing powders is based on specially developed continuous technological processes, corrosion-proof equipment, ensuring a high and stable production quality. A special attention is paid to the radiation safety of the powders. The initial material for the rare earth polishing powders based on loparite is the fusion cake of rare earth chlorides obtained at that mineral chlorination. The technology of the polishing powder production from the REE fusion cake includes the following stages: dissolution of the REE fusion cake chlorides; - thorough cleaning of the REE fusion cake chlorides from radioactive and non-rare-earth impurities; chemical precipitation of REE carbonates, obtaining middlings with proper material and granulometric composition, thermal treatment of precipitated carbonates followed with the operations of drying and roasting; classification of roasted oxides, obtaining end products - polishing powders. The production of fluorine-containing powders includes the stage of their fluorination after the stage of carbonate precipitation. The stabilizing doping can be introduced both into the middlings during one of the technological process of powders manufacturing and into the end product. Rare earth polishing powders are manufactured in Russia by the Share Holding Company 'Chepetz Mechanical Plant' (ChMP Co.), the city of Glasov. The plant produces a number of polishing materials, such as; polishing powder Optinol, containing at least 50% by mass of cerium dioxide, used in the mass production of optical and other articles; polishing powder Optinol-10 with doping to improve the sedimentary and aggregate stability of the solid phase

  1. Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder

    Directory of Open Access Journals (Sweden)

    Jeon Byoungjun

    2015-06-01

    Full Text Available 316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.

  2. Study on the sterilization of egg white powder by irradiation

    International Nuclear Information System (INIS)

    Fu Lixin; Meng Lifen; Zhao Xiaonan; Xu Dechun; Hu Shaoxin; Chen Changdong; Pei Ying

    2011-01-01

    The article studied the killing microorganism result, the influence of main essential nutrient and sense organ of egg white powder by Co-60 γ-ray irradiation. The microorganism index of the egg white powder samples can meet the government food 1 sanitation standard by 4 kGy irradiation, and the killing microorganism rare can reach 100%. The irradiation dose from 4 to 10 kGy has little influence to the egg white powder protein, crude fiber and amino acids contrasting to comparison, and the sensory quality such as color and luster, scent has little change below 6 kGy irradiation. Compositing the result of physical chemistry and sense organ, the optimal irradiation dose of egg white powder killing microorganism is 4 to 6 kGy. (authors)

  3. Enhancing micronutrient content of beverage powder by incorporating malted finger millet

    Directory of Open Access Journals (Sweden)

    Jaya Tripathi

    2014-12-01

    Full Text Available Introduction: There is growing interest in the role of the micronutrients in optimizing health, and in prevention or treatment of disease. Micronutrients play a central part in metabolism and in the maintenance of tissue function, an adequate intake therefore is necessary. Rationale: This research work was concerned with the development of micronutrient especially calcium rich instant health beverage powder from malted finger millet (Eleusine coracana and gurhal powder (Hibiscus rosa- sinensis. Aims & Objectives: In this study attempts have been made to investigate that whether the extruded malted finger millet flour and hibiscus flower powder has improved the nutritional and phytochemical quality of instant health beverage powder without deteriorating their sensory properties and whether it can be a supplement for calcium deficit sedentary women. Materials and methods: Instant health beverage powder was prepared by adding malted and extruded finger millet with glucose, hibiscus flower powder, citric acid and vanilla essence. All the ingredients were mixed well. Prior to consumption this powder was dissolved in water and stirred well manually. Further Instant health beverage powder was assessed for nutritional composition. Results: Results shows that beverage powder has very high content of protein (12.25 % and calcium (96.5 % along with highly beneficial neutraceutical properties as compared with the health drinks available in market, it is because of enhanced antioxidant activity resulted due to the incorporation of gurhal leaf powder and malting of the finger millet. Conclusion: This study may prove as a potential step to utilise malted finger millet as a supplement for calcium deficit women. The nutritional composition was found sufficient enough to meet approximately one fourth of RDA of Protein and Calcium as prescribed by NIN, India for sedentary women who are the main sufferers of calcium deficiencies in various life stages

  4. MECHANICAL, ELECTRICAL, AND THERMAL PROPERTIES OF MALEIC ANHYDRIDE MODIFIED RICE HUSK FILLED PVC COMPOSITES

    OpenAIRE

    Navin Chand; Bhajan Das Jhod

    2008-01-01

    Unmodified and modified rice husk powder filled PVC composites were prepared having different amounts of rice husk powder. Mechanical, thermal, and electrical properties of these composites were determined. The tensile strength of rice husk powder PVC composites having 0, 10, 20, 30, and 40 weight percent of rice husk powder was found to be 33.9, 19.4, 18.1, 14.6, and 9.5 MPa, respectively. Adding of maleic anhydride- modified rice husk powder improved the tensile strength of rice husk powder...

  5. Experimental and numerical studies on laser-based powder deposition of slurry erosion resistant materials

    Science.gov (United States)

    Balu, Prabu

    Slurry erosion (the removal of material caused by the randomly moving high velocity liquid-solid particle mixture) is a serious issue in crude oil drilling, mining, turbines, rocket nozzles, pumps, and boiler tubes that causes excessive downtime and high operating costs as a result of premature part failure. The goal of this research is to enhance the service life of high-value components subjected to slurry erosion by utilizing the concept of functionally graded metal-ceramic composite material (FGMCCM) in which the favorable properties of metal (toughness, ductility, etc.) and ceramic (hardness) are tailored smoothly to improve erosion resistance. Among the potential manufacturing processes, such as the laser-based powder deposition (LBPD), the plasma transferred arc (PTA), and the thermal spray the LBPD process offers good composition and microstructure control with a high deposition rate in producing the FGMCCM. This research focuses on the development of nickel-tungsten carbide (Ni-WC) based FGMCCM using the LBPD process for applications the above mentioned. The LBPD of Ni-WC involves the introduction of Ni and WC powder particle by an inert gas into the laser-formed molten pool at the substrate via nozzles. The LBPD of Ni-WC includes complex multi-physical interactions between the laser beam, Ni-WC powder, substrate, and carrier and shielding gases that are governed by a number of process variables such as laser power, scanning speed, and powder flow rate. In order to develop the best Ni-WC based slurry erosion resistant material using the LBPD process, the following challenges associated with the fabrication and the performance evaluation need to be addressed: 1) flow behavior of the Ni-WC powder and its interaction with the laser, 2) the effect of the process variables, the material compositions, and the thermo-physical properties on thermal cycles, temperature gradient, cooling rate, and residual stress formation within the material and the subsequent

  6. Preparation of reactive and refractory metal powders (Paper No. 25)

    International Nuclear Information System (INIS)

    Sundaram, C.V.; Sharma, B.P.; Krishnan, T.S.

    1979-01-01

    In devising processes for the preparation of refractory and reactive metal powders, one has to reckon with many relevant factors. The choice of specific flowsheets is governed by the characteristics of the metal compounds and the reducing agents, the purity required and achievable in the as-reduced powder, the need for further refining of the metal, the possibilities of chemical/physical/mechanical comminution of the purified metal without contamination, and the end application of the powder metal. Micron size zirconium powder used as trigger material in photo-flash bulbs and detonator compositions, tantalum powder of controlled particle size and high purity for the production of electrolytic capacitors, and beryllium metal powder for the preparation of hot pressed powder metallurgy components are illustrative of the variety of reactive metal powders for industrial applications. The work carried out at the Bhabha Atomic Research Centre, Bombay, on the preparation of special metal powders, with particular emphasis on Group IV and V metals and also beryllium is presented. Reduction of metal oxides with alkaline earth metals/hydrides, reduction of metal halides with sodium/magnesium, vacuum arc and electron beam melt purification followed by comminution by hydrogen embrittlement/mechanical comminution are among the processes discussed. (auth.)

  7. Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

    International Nuclear Information System (INIS)

    Zhang, H.J.; Zhang, H.T.; Wu, X.W.; Wang, Z.L.; Jia, Q.L.; Jia, X.L.

    2006-01-01

    Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO 4 aqueous solution by electroless plating method. The factors including concentration of NiSO 4 , bathing temperature, ratio of hydrazine hydrate to NiSO 4 , the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way

  8. Syntheses and characterizations of LiFePO4 powders

    OpenAIRE

    Jugović, Dragana; Kuzmanović, Maja; Mitrić, Miodrag; Cvjetićanin, Nikola; Uskoković, Dragan

    2011-01-01

    The olivine type compositions LiMPO4 (M = Fe, Mn, Co) are among the most attractive materials for the positive electrode of lithium-ion battery. The benefits of using LiFePO4 are excellent cycle life, high structural stability, low cost and environmental friendliness. Here will be presented our efforts to obtain LiFePO4 powders through several synthesis methods. The differences in phase purity, microstructure, morphology, and electrochemical performances of synthesized powders were investigat...

  9. Dispersion of carbon nanotubes in hydroxyapatite powder by in situ chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Haipeng; Wang Lihui; Liang, Chunyong; Wang Zhifeng; Zhao Weimin

    2010-01-01

    In the present work, we use chemical vapor deposition of methane to disperse carbon nanotubes (CNTs) within hydroxyapatite (HA) powder. The effect of different catalytic metal particles (Fe, Ni or Co) on the morphological and structural development of the powder and dispersion of CNTs in HA powder was investigated. The results show that the technique is effective in dispersing the nanotubes within HA powder, which simultaneously protects the nanotubes from damage. The results can have important and promising speculations for the processing of CNT-reinforced HA-matrix composites in general.

  10. Plasma Treatment of Agave Fiber Powder and Its Effect on the Mechanical and Thermal Properties of Composites Based on Polyethylene

    Directory of Open Access Journals (Sweden)

    Florentino Soriano Corral

    2016-01-01

    Full Text Available Composites based on low-density polyethylene (LDPE were prepared with Agave fiber powder (AFP that was coated by plasma polymerization process using ethylene gas. Treated and pristine AFP were analyzed by infrared spectroscopy, scanning electron microscopy, and contact water angle for the assessment of surface properties. The polymer composites were prepared by melt mixing using 0, 5, 10, and 20 wt% of AFP and their mechanical and thermal properties were measured. Dispersion evaluation in water confirmed that the AFP treated changed from hydrophilic to hydrophobic behavior and it was also corroborated with water contact angle tests. The addition of treated and untreated AFP (200 mesh at 20 wt% promotes an increase of Young’s modulus of the composites of up to 60% and 32%, respectively, in relation to the neat matrix. Also, an increase of crystallinity of LDPE was observed by the addition of treated and untreated AFP; however no significant effect on the crystallization temperature was observed in LDPE containing AFP.

  11. Chemical Composition and Antioxidant Properties of Powders Obtained from Different Plum Juice Formulations

    Directory of Open Access Journals (Sweden)

    Anna Michalska

    2017-01-01

    Full Text Available Among popular crops, plum (Prunus domestica L. has received special attention due to its health-promoting properties. The seasonality of this fruit makes it impossible to consume it throughout the year, so new products in a powder form may offer an alternative to fresh consumption and may be used as high-quality natural food ingredients. A 100% plum (cultivar “Valor” juice was mixed with three different concentrations of maltodextrin or subjected to sugars removal by amberlite-XAD column, and dried using the freeze, spray, and vacuum (40, 60, and 80 °C drying techniques. The identification and quantification of phenolic acids, flavonols, and anthocyanins in plum powders was performed by LC-MS QTof and UPLC-PDA, respectively. l-ascorbic acid, hydroxymethylfurfural, and antioxidant capacity were measured by the Trolox equivalent antioxidant capacity (TEAC ABTS and ferric reducing antioxidant potential (FRAP methods in order to compare the influence of the drying methods on product quality. The results indicated that the profile of polyphenolic compounds in the plum juice powders significantly differed from the whole plum powders. The drying of a sugar free plum extract resulted in higher content of polyphenolic compounds, l-ascorbic acid and antioxidant capacity, but lower content of hydroxymethylfurfural, regardless of drying method applied. Thus, the formulation of plum juice before drying and the drying method should be carefully selected in order to obtain high-quality powders.

  12. Microstructural evolution of ferritic steel powder during mechanical alloying with iron oxide

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Yuren; Liu, Yong; Liu, Donghua; Tang, Bei [Central South Univ., State Key Lab. of Powder Metallurgy, Changsha (China); Liu, C.T. [The Hong Kong Polytechnic Univ., Dept. of Mechanical Engineering, Hong Kong (China)

    2011-02-15

    Mechanical alloying of mixed powders is of great importance for preparing oxide dispersion strengthened ferritic steels. In this study, the microstructural evolution of ferritic steel powder mixed with TiH{sub x}, YH{sub 2} and Fe{sub 2}O{sub 3} in the process of mechanical alloying is systematically investigated by using X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy and microhardness tests. It is found that titanium, yttrium hydrides and iron oxide are completely dissolved during milling, and homogeneous element distribution can be achieved after milling for 12 h. The disintegration of the composite powder particles occurs at 24 h and reaches the balance of welding and fracturing after 36 h. The oxygen content increases sharply with the disintegration of powder particles due to the absorption of oxygen at the solid/gas interface from the milling atmosphere, which is the main source of extra oxygen in the milled powder. Grain refinement down to nanometer level occurs due to the severe plastic deformation of particles; however, the grain size does not change much with further disintegration of particles. The hardness increases with milling time and then becomes stable during further milling. The study indicates that the addition of iron oxide and hydrides may be more beneficial for the dispersion and homogenization of chemical compositions in the powder mixture, thus shortening the mechanical alloying process. (orig.)

  13. High yttria ferritic ODS steels through powder forging

    Science.gov (United States)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

  14. Characteristics of Inconel Powders for Powder-Bed Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Quy Bau Nguyen

    2017-10-01

    Full Text Available In this study, the flow characteristics and behaviors of virgin and recycled Inconel powder for powder-bed additive manufacturing (AM were studied using different powder characterization techniques. The results revealed that the particle size distribution (PSD for the selective laser melting (SLM process is typically in the range from 15 μm to 63 μm. The flow rate of virgin Inconel powder is around 28 s·(50 g−1. In addition, the packing density was found to be 60%. The rheological test results indicate that the virgin powder has reasonably good flowability compared with the recycled powder. The inter-relation between the powder characteristics is discussed herein. A propeller was successfully printed using the powder. The results suggest that Inconel powder is suitable for AM and can be a good reference for researchers who attempt to produce AM powders.

  15. Synergistic Removal of Humic Acid in Water by Coupling Adsorption and Photocatalytic Degradation Using TiO2/Coconut Shell Powder Composite

    Directory of Open Access Journals (Sweden)

    Jong Kyu Kim

    2016-01-01

    Full Text Available The feasibility of applying nanoscale TiO2/coconut shell powder (TCNSP composite to remove HA in aqueous solution was evaluated, and the optimization of the photocatalytic systems using newly developed TCNSP composite was performed. The developed TCNSP composite has high specific surface area (i.e., 454 m2/g and great porosity (i.e., 66.9% with pore size of less than 5 μm. High removal efficiencies (≥95% of HA were observed due to the significant synergistic effects by coupling adsorption and photocatalytic reaction of TCNSP composite. As the initial concentration of HA increased, the degradation rate (Kapp decreased due to HA sorption saturation to the surface of TCNSP composite and the photon interception by HA molecules in aqueous solution. Since the increased loading amount of TCNSP composite enhanced the number of active sites, Kapp values increased until the optimum loading amount of TCNSP composite. As pH values increased, HA removal efficiency decreased due to increasing electrostatic repulsion between HA and TCNSP composite. Based on the response surface methodology, higher HA removal efficiencies were obtained with acidic condition, longer reaction time, and appropriated loading amount of TCNSP. Further pilot-scale study is in progress using TCNSP composite combined with UVC to remove HA from large amounts of surface water (i.e., 200 m3/d.

  16. Structure, mechanical and corrosion properties of powdered stainless steel Kh13

    International Nuclear Information System (INIS)

    Radomysel'skij, I.D.; Napara-Volgina, S.G.; Orlova, L.N.; Apininskaya, L.M.

    1982-01-01

    Structure, mechanical and corrosion properties are studied for compact powdered stainless steel, Grade Kh13, produced from prealloyed powder and a mixture of chromium and iron powders by hot vacuum pressing (HVP) following four schemes: HVP of unsintered billets; HVP of presintered billets; HVP of unsintered billets followed by diffusion annealing; HVP of sintered billets followed by diffusion annealing. Analysis of the structure, mechanical and corrosion properties of Kh13 steel produced according to the four schemes confirmed that production of this steel by the HVP method without presintering of porous billets and diffusion annealing of compact stampings is possible only when prealloyed powder of particular composition is used as a starting material

  17. Mechanical characterisation of superconducting BSCCO powder and numerical modelling of the OPIT process

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Eriksen, Morten; Toussaint, F.

    2000-01-01

    Silver/BSCCO composite superconducting tapes are produced using BSCCO-2212 ceramic powder. The manufacturing process implies a large number of forming operations including drawing and rolling. The numerical simulation of the flat rolling process is of a great interest to anticipate the shape...... of the silver/composite tape. In order to achieve these goals, the plastic properties of superconducting BSCCO-2212 ceramic powder are investigated with three mechanical tests. Results obtained from diametrical, uniaxial and die compaction tests are used to fit the parameters of the Drucker...

  18. Improvement of cytocompatibility of polylactide by filling with marine algae powder

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung-Yi [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Yang, Ming-Chien, E-mail: myang@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Hsu, Yi-Chiang [Graduate Institute of Medical Science, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan (China); Innovative Research Center of Medicine, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan (China)

    2015-05-01

    This work evaluated the cytocompatibility, thermal and mechanical properties of composites of polylactide (PLA) and marine algae powder (MAP). To improve the thermal and mechanical properties of PLA–MAP composites, glycidyl methacrylate (GMA) was used as the compatibilizer for the blending of PLA and MAP. The PLA-g-GMA/MAP composites exhibited superior mechanical properties, attributing to higher compatibility between the polymer and MAP, comparing to PLA/MAP composites. The dispersion of MAP in the PLA-g-GMA matrix was highly homogeneous as a result of etherification. The lower melt torque of the PLA-g-GMA/MAP composites also made them more processable than PLA/MAP. To assess the cytocompatibility, normal human foreskin fibroblasts (FBs) were seeded onto each type of the composites. Results of FB proliferation, collagen production, and cytotoxicity assays indicated greater cytocompatibility for the PLA/MAP composites than for the PLA-g-GMA/MAP composites. Furthermore, both PLA/MAP and PLA-g-GMA/MAP composites were more cytocompatible than pure PLA. - Highlights: • PLA was grafted with GMA to form ether bond with marine algae powder (MAP). • Composites of PLA-g-GMA and MAP exhibited cytocompatibility with fibroblasts. • PLA-g-GMA/MAP composites exhibited mechanical properties superior to PLA/MAP. • PLA-g-GMA/MAP composites were more processable than PLA/MAP.

  19. Improvement of cytocompatibility of polylactide by filling with marine algae powder

    International Nuclear Information System (INIS)

    Wu, Tung-Yi; Yang, Ming-Chien; Hsu, Yi-Chiang

    2015-01-01

    This work evaluated the cytocompatibility, thermal and mechanical properties of composites of polylactide (PLA) and marine algae powder (MAP). To improve the thermal and mechanical properties of PLA–MAP composites, glycidyl methacrylate (GMA) was used as the compatibilizer for the blending of PLA and MAP. The PLA-g-GMA/MAP composites exhibited superior mechanical properties, attributing to higher compatibility between the polymer and MAP, comparing to PLA/MAP composites. The dispersion of MAP in the PLA-g-GMA matrix was highly homogeneous as a result of etherification. The lower melt torque of the PLA-g-GMA/MAP composites also made them more processable than PLA/MAP. To assess the cytocompatibility, normal human foreskin fibroblasts (FBs) were seeded onto each type of the composites. Results of FB proliferation, collagen production, and cytotoxicity assays indicated greater cytocompatibility for the PLA/MAP composites than for the PLA-g-GMA/MAP composites. Furthermore, both PLA/MAP and PLA-g-GMA/MAP composites were more cytocompatible than pure PLA. - Highlights: • PLA was grafted with GMA to form ether bond with marine algae powder (MAP). • Composites of PLA-g-GMA and MAP exhibited cytocompatibility with fibroblasts. • PLA-g-GMA/MAP composites exhibited mechanical properties superior to PLA/MAP. • PLA-g-GMA/MAP composites were more processable than PLA/MAP

  20. Chemical vapor composites (CVC)

    International Nuclear Information System (INIS)

    Reagan, P.

    1993-01-01

    The Chemical Vapor Composite, CVC trademark , process fabricates composite material by simply mixing particles (powders and or fibers) with CVD reactants which are transported and co-deposited on a hot substrate. A key feature of the CVC process is the control provided by varing the density, geometry (aspect ratio) and composition of the entrained particles in the matrix material, during deposition. The process can fabricate composite components to net shape (± 0.013 mm) on a machined substrate in a single step. The microstructure of the deposit is described and several examples of different types of particles in the matrix are illustrated. Mechanical properties of SiC composite material fabricated with SiC powder and fiber will be presented. Several examples of low cost ceramic composite products will be shown. (orig.)

  1. AC magnetic properties of the soft magnetic composites based on Supermalloy nanocrystalline powder prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Neamtu, B.V., E-mail: bogdan.neamtu@stm.utcluj.ro [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Geoffroy, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Grenoble Electrical Engineering, University J. Fourier, BP 46, F-38402 Saint-Martin d' Heres Cedex (France); Chicinas, I. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Isnard, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Nanocrystalline soft magnetic composites were obtained. Black-Right-Pointing-Pointer The cutting frequency of the produced nanocrystalline SMC exceeds 100 kHz. Black-Right-Pointing-Pointer A long annealing at low temperature leads to an improvement of the permeability (12%). - Abstract: The preparation and characterization of the nanocrystalline soft magnetic composite core based on Supermalloy powder obtained via mechanical alloying route are presented. The AC magnetic properties of the compacts were determined in frequency range from 100 Hz to 100 kHz for flux densities of 0.05 and 0.1 T. Composite materials were obtained by covering the Supermalloy particles with a polymer binder, then compacted into toroidal shape and finally polymerized. It is found that an increase of the compacting pressure from 600 MPa to 800 MPa leads to an increase of the compacts permeability by more than 8%. Also, reducing the polymer content from 2 wt.% to 0.5 wt.% leads to an increase of the magnetic losses (at 100 kHz and 0.1 T) by 380%. The removal of the stresses induced during compaction has been accomplished by a heat treatment at 170 Degree-Sign C for 120 h. This leads to a significant increase (12%) of the relative initial permeability of the compacts.

  2. Preparation and Characterization of Nano-structured Ceramic Powders Synthesized by Emulsion Combustion Method

    International Nuclear Information System (INIS)

    Takatori, Kazumasa; Tani, Takao; Watanabe, Naoyoshi; Kamiya, Nobuo

    1999-01-01

    The emulsion combustion method (ECM), a novel powder production process, was originally developed to synthesize nano-structured metal-oxide powders. Metal ions in the aqueous droplets were rapidly oxidized by the combustion of the surrounding flammable liquid. The ECM achieved a small reaction field and a short reaction period to fabricate the submicron-sized hollow ceramic particles with extremely thin wall and chemically homogeneous ceramic powder. Alumina, zirconia, zirconia-ceria solid solutions and barium titanate were synthesized by the ECM process. Alumina and zirconia powders were characterized to be metastable in crystalline phase and hollow structure. The wall thickness of alumina was about 10 nm. The zirconia-ceria powders were found to be single-phase solid solutions for a wide composition range. These powders were characterized as equiaxed-shape, submicron-sized chemically homogeneous materials. The powder formation mechanism was investigated through the synthesis of barium titanate powder with different metal sources

  3. The influence of structural changes on electrical and magnetic characteristics of amorphous powder of the nixmoy alloy

    Directory of Open Access Journals (Sweden)

    Ribić-Zelenović Lenka

    2006-01-01

    Full Text Available Nickel and molybdenum alloy powder was electrodeposited on a titanium cathode from a NiSO4⋅7H2O and (NH46 Mo7O24⋅4H2O ammonium solution. The desired chemical composition, structure, size and shape of particles in the powder samples were achieved by an appropriate choice of electrolysis parameters (current density, composition and temperature of the solution, cathode material and electrolysis duration. Metal coatings form in the current density range 15 mA cm-2powders form. The chemical composition of powder samples depends on the current density of electrodeposition. The molybdenum content in the powder increases with the increase of current density (in the low current density range, while in the higher current density range the molybdenum content in the alloy decreases with the increase of the current density of deposition. Smaller sized particles form at higher current density. X-ray analysis, differential scanning calorimetric and measurements of the temperature dependence of electric resistance and magnetic permeability of the powder samples were all used to establish a predominantly amorphous structure of the powder samples formed at the current density of j≥70mA cm-2. The crystalline particle content in the powder samples increases with the decrease of the current density of deposition. Powder heating causes structural changes. The process of thermal stabilization of nickel and molybdenum amorphous powders takes place in the temperature interval from 463K to 573K and causes a decrease in electrical resistance and increase in magnetic permeability. The crystallization temperature depends on the value of current density of powder electrodeposition. Powder formed at j=180 mA cm-2 begins to crystallize at 573K, while the powder deposited at j=50 mA cm-2 begins to crystallize at 673K. Crystallization of the powder causes a decrease in electric resistivity and magnetic

  4. Effects of Aluminum Powder on Ignition Performance of RDX, HMX, and CL-20 Explosives

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Mao

    2018-01-01

    Full Text Available As a kind of high explosives, aluminized explosive cannot release the energy maximumly, which is a key problem. Using DTA-TG equipment, the ignition performance of three kinds of aluminized explosives (RDX, HMX, and CL-20 with different mass percentages of aluminum powder (0%, 10 wt.%, 20 wt.%, and 30 wt.% was investigated. The results showed that the energy release of the HMX/Al composite explosive with 10 wt.%, 20 wt.%, and 30 wt.% aluminum powder was only equivalent to 80%, 65%, and 36% of pure HMX, respectively. It was similar to RDX/Al and CL-20/Al composite explosives, except the CL-20/Al mixture with 10% aluminum powder. Rather than participating in the ignition and combustion, the aluminum powder does effect the complete reaction of RDX, HMX, and CL-20 in the initial stage of ignition or in the lower temperature area of the boundary.

  5. Study of microcellular injection-molded polypropylene/waste ground rubber tire powder blend

    International Nuclear Information System (INIS)

    Xin, Zhen Xiang; Zhang, Zhen Xiu; Pal, Kaushik; Byeon, Jong Ung; Lee, Sung Hyo; Kim, Jin Kuk

    2010-01-01

    Microcellular polypropylene/waste ground rubber tire powder blend processing was performed on an injection-molding machine with a chemical foaming agent. The molded samples produced based on the design of experiments (DOE) matrices were subjected to tensile testing and scanning electron microscope (SEM) analyses. Molding conditions and waste ground rubber tire (WGRT) powder have been found to have profound effects on the cell structures and mechanical properties of polypropylene (PP) and waste ground rubber tire powder composite samples. The result shows that microcellular PP/WGRT blend samples exhibit smaller cell size and higher cell density compare with polypropylene resin. Among the molding parameters studied, chemical foaming agent weight percentage has the most significant effect on cell size, cell density, and tensile strength. The results also suggest that tensile strength of microcellular PP/WGRT composites is sensitive to weight reduction, and skin thickness.

  6. Effect of filler loading and silane modification on the biodegradability of SBR composites reinforced with peanut shell powder

    Science.gov (United States)

    Shaniba, V.; Balan, Aparna K.; Sreejith, M. P.; Jinitha, T. V.; Subair, N.; Purushothaman, E.

    2017-06-01

    The development of biocomposites and their applications are important in material science due to environmental and sustainability issues. The extent of degradation depends on the nature of reinforcing filler, particle size and their modification. In this article, we tried to focus on the biodegradation of composites of Styrene Butadiene Rubber (SBR) reinforced with Peanut Shell Powder (PSP) by soil burial test. The composites of SBR with untreated PSP (UPSP) and silane modified PSP (SPSP) of 10 parts per hundred rubber (phr) and 20 phr filler loading in two particle size were buried in the garden soil for six months. The microbial degradation were assessed through the measurement of weight loss, tensile strength and hardness at definite period. The study shows that degradation increases with increase in filler loading and particle size. The chemical treatment of filler has been found to resist the degradation. The analysis of morphological properties by the SEM also confirmed biodegradation process by the microorganism in the soil.

  7. Development of titanium based biocomposite by powder metallurgy processing with in situ forming of Ca-P phases

    Energy Technology Data Exchange (ETDEWEB)

    Karanjai, Malobika [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India)]. E-mail: malobika@arci.res.in; Sundaresan, Ranganathan [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India); Rao, Gummididala Venkata Narasimha [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India); Mohan, Tallapragada Raja Rama [Metallurgical Engineering and Materials Science Department, Indian Institute of Technology, Powai, Mumbai 400076, Maharashtra (India); Kashyap, Bhagwati Prasad [Metallurgical Engineering and Materials Science Department, Indian Institute of Technology, Powai, Mumbai 400076, Maharashtra (India)

    2007-02-25

    Composites of titanium and calcium-phosphorus phases were developed by powder metallurgy processing and evaluated for bioactivity. Titanium hydride powder and precursors of calcium and phosphorus in the form of calcium carbonate and di-ammonium hydrogen orthophosphate were mixed in different proportions, compacted and calcined in different atmospheres. The calcined compacts were subsequently crushed, recompacted and sintered in vacuum. In situ formation of bioactive phases like hydroxylapatite, tricalcium phosphate and calcium titanate during the calcination and sintering steps was studied using X-ray diffraction. The effect of calcination atmosphere on density, interconnected porosity, phase composition and modulus of rupture of sintered composites was examined. The sintered composites were immersed in simulated body fluid for 7 days to observe their in vitro behaviour with XRD and FTIR spectroscopic identification of deposits. Composites with 10 wt% precursors sintered from vacuum calcined powder gave the best results in terms of bioactive phases, density and strength.

  8. Niobium-base superalloys via powder metallurgy technology

    International Nuclear Information System (INIS)

    Loria, E.A.

    1987-01-01

    This paper provides some insight into an area that has been neglected, namely the possibility of developing high-strength, niobium-base alloys by improved oxidation resistance via the consolidation of rapidly solidified powders. Powder metallurgy (P/M) is an attractive processing technique because of its flexibility and versatility, and it may provide the alloys with properties and workability not obtainable via metal casting. A critical review of both U.S. and Russian literature is presented along with suggestions on the most promising compositions and processing techniques available to meet these competing goals. Previous work on many niobium alloys reveals that long term properties are retained well above those obtained on nickel-base superalloys. Cast and wrought alloys extend specific strength beyond 1200 0 C (2200 0 F), but lack oxidation resistance. Remarkable oxidation resistance is obtained, however, on miniature castings of certain ternary alloys which are too brittle for any processing. A better understanding of the oxidation mechanism is necessary before the proper P/M (RST) approach is taken on compositions which could provide compatibility between the two competing goals through grain refinement and a homogeneous distribution of the contributory phases. Finally, ways to up-scale production of Nb powder are discussed, including thermodynamic feasibility for the direct reduction of NbCl/sub 5/ in a 1.5 MW plasma reactor

  9. Formation of Al3Ti/Mg composite by powder metallurgy of Mg–Al–Ti system

    Directory of Open Access Journals (Sweden)

    Zi R Yang et al

    2008-01-01

    Full Text Available An in situ titanium trialuminide (Al3Ti-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg–Al–Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC, x-ray diffractometry (XRD, scanning electron microscopy (SEM and energy-dispersive x-ray spectroscopy (EDS. Al3Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg–Al–Ti system, Al3Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg–Al–Ti system is almost the same as that of the Al–Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

  10. Formation of Al3Ti/Mg composite by powder metallurgy of Mg-Al-Ti system.

    Science.gov (United States)

    Yang, Zi R; Qi Wang, Shu; Cui, Xiang H; Zhao, Yu T; Gao, Ming J; Wei, Min X

    2008-07-01

    An in situ titanium trialuminide (Al 3 Ti)-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg-Al-Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC), x-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Al 3 Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg-Al-Ti system, Al 3 Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg-Al-Ti system is almost the same as that of the Al-Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

  11. Direct laser sintering of metal powders: Mechanism, kinetics and microstructural features

    International Nuclear Information System (INIS)

    Simchi, A.

    2006-01-01

    In the present work, the densification and microstructural evolution during direct laser sintering of metal powders were studied. Various ferrous powders including Fe, Fe-C, Fe-Cu, Fe-C-Cu-P, 316L stainless steel, and M2 high-speed steel were used. The empirical sintering rate data was related to the energy input of the laser beam according to the first order kinetics equation to establish a simple sintering model. The equation calculates the densification of metal powders during direct laser sintering process as a function of operating parameters including laser power, scan rate, layer thickness and scan line spacing. It was found that when melting/solidification approach is the mechanism of sintering, the densification of metals powders (D) can be expressed as an exponential function of laser specific energy input (ψ) as ln(1 - D) = -Kψ. The coefficient K is designated as 'densification coefficient'; a material dependent parameter that varies with chemical composition, powder particle size, and oxygen content of the powder material. The mechanism of particle bonding and microstructural features of the laser sintered powders are addressed

  12. Effect of complex alloying of powder materials on properties of laser melted surface layers

    International Nuclear Information System (INIS)

    Tesker, E.I.; Gur'ev, V.A.; Elistratov, V.S.; Savchenko, A.N.

    2001-01-01

    Quality and properties of laser melted surface layers produced using self-fluxing powder mixture of Ni-Cr-B-Si system and the same powders with enhanced Fe content alloyed with Co, Ti, Nb, Mo have been investigated. Composition of powder material is determined which does not cause of defect formation under laser melting and makes possible to produce a good mechanical and tribological properties of treated surface [ru

  13. Study on Quality Aggregate Construction Powder

    International Nuclear Information System (INIS)

    Myat Ko; Kyaw Naing; Thazin Lwin; Khin Mar Tun

    2008-03-01

    This research work deals with a view to promote cement replacement materials i-e aggregate construction powder, also known as building powder or construction powder . It has been used as lime substituent in construction work in Myanmar since 1990's. It is mixed with other construction materials such as cement, sand, etc. and used in plastering, tiling, arranging bricks and smoothing the face of the buildings.This work also deals with some aspects in physical properties of four different aggregate construction powder samples such as Moe Hein, Man Thiri, Shwe Taung and Kyauk Sue. In addition, these four different samples were characterized by using spectroscopic methods such as ED-XRF, AAS, FT-IR and XRD. In support of the finding by the analytical assays of Moe Hein aggregate construction powder, it indicated the percent composition of the presence of SiO2 12.13%, Al2O3 7.40%, Fe2O3 0.94%, CaO 41.00%,MgO 1.50% total sulphur 1.15%, chloride 1.49%, carbonate 43.63% and sulphate 3.44%. The analytical assays of Sin Min cement, Kyant cement, brick powder and pozzolan were also carried out in this research work. The mixing between various ratios of Moe Hein and Kyant cement as well as Sin Min II cement were done and their mechanical strengths such as setting time, tensile strength and compressive strength of each sample were studied. The quality of mixing ratio 50:50 of Moe Hein and Kyant cement was found to be comparable to the ASTM standard type II Protland cement which is for general use.

  14. Synthesis of Uranium nitride powders using metal uranium powders

    International Nuclear Information System (INIS)

    Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

    2012-01-01

    Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

  15. Making Self-Lubricating Parts By Powder Metallurgy

    Science.gov (United States)

    Sliney, Harold E.; Dellacorte, Christopher

    1990-01-01

    Compositions and parameters of powder-metallurgical fabrication processes determined for new class of low-friction, low-wear, self-lubricating materials. Used in oxidizing or reducing atmospheres in bearings and seals, at temperatures from below 25 degrees C to as high as 900 degrees C. Thick parts made with minimal waste.

  16. LDRD final report: photonic analog-to-digital converter (ADC) technology; TOPICAL

    International Nuclear Information System (INIS)

    Bowers, M; Deri, B; Haigh, R; Lowry, M; Sargis, P; Stafford, R; Tong, T

    1999-01-01

    We report on an LDRD seed program of novel technology development (started by an FY98 Engineering Tech-base project) that will enable extremely high-fidelity analog-to-digital converters for a variety of national security missions. High speed (l0+ GS/s ), high precision (l0+ bits) ADC technology requires extremely short aperture times ((approx)1ps ) with very low jitter requirements (sub 10fs ). These fundamental requirements, along with other technological barriers, are difficult to realize with electronics: However, we outline here, a way to achieve these timing apertures using a novel multi-wavelength optoelectronic short-pulse optical source. Our approach uses an optoelectronic feedback scheme with high optical Q to produce an optical pulse train with ultra-low jitter ( sub 5fs) and high amplitude stability ( and lt;10(sup 10)). This approach requires low power and can be integrated into an optoelectronic integrated circuit to minimize the size. Under this seed program we have demonstrated that the optical feedback mechanism can be used to generate a high Q resonator. This has reduced the technical risk for further development, making it an attractive candidate for outside funding

  17. Mechanical strength and thermophysical properties of PM212: A high temperature self-lubricating powder metallurgy composite

    Science.gov (United States)

    Edwards, Phillip M.; Sliney, Harold E.; Dellacorte, Christopher; Whittenberger, J. Daniel; Martineau, Robert R.

    1990-01-01

    A powder metallurgy composite, PM212, composed of metal bonded chromium carbide and solid lubricants is shown to be self-lubricating to a maximum application temperature of 900 C. The high temperature compressive strength, tensile strength, thermal expansion and thermal conductivity data needed to design PM212 sliding contact bearings and seals are reported for sintered and isostatically pressed (HIPed) versions of PM212. Other properties presented are room temperature density, hardness, and elastic modulus. In general, both versions appear to have adequate strength to be considered as sliding contact bearing materials, but the HIPed version, which is fully dense, is much stronger than the sintered version which contains about 20 percent pore volume. The sintered material is less costly to make, but the HIPed version is better where high compressive strength is important.

  18. Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

    Science.gov (United States)

    Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

    2015-12-01

    This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated.

  19. Synthesis of Amorphous Powders of Ni-Si and Co-Si Alloys by Mechanical Alloying

    Science.gov (United States)

    Omuro, Keisuke; Miura, Harumatsu

    1991-05-01

    Amorphous powders of the Ni-Si and Co-Si alloys are synthesized by mechanical alloying (MA) from crystalline elemental powders using a high energy ball mill. The alloying and amorphization process is examined by X-ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. For the Ni-Si alloy, it is confirmed that the crystallization temperature of the MA powder, measured by DSC, is in good agreement with that of the powder sample prepared by mechanical grinding from the cast alloy ingot products of the same composition.

  20. Microstructure and mechanical properties of Al-Mg-Si-Cu matrix composites reinforced with AINp. processed by extrusion of powders

    International Nuclear Information System (INIS)

    Ortiz, J. L.; Amigo, V.; Salvador, M. D.; Perz, C. R.

    2000-01-01

    This article presents an experimental investigation on the structure and mechanical properties of an Al-Mg-Si-Cu P/M alloy reinforced with 5%, 10% and 15% aluminum nitride, produced by extrusion of cold compacted powders mixtures. Mechanical properties in as extruded and T6 conditions are compared. Differential Scanning Calorimetry and Dilatometric analysis were conducted to gain further insight into the precipitation process of these materials. Low cost 6061 Al/AINp composites can be produced with rate and small porosity by extrusion of cold compacted shapes without canning. The mechanical properties of the MMCs obtained by this process have limitations for high particles fractions because of clustering effects. All materials are always harder than the matrix and shows a similar behavior during aging processes but kinetics is changed. Potential applications of dilatometric techniques in the aging investigations of aluminum alloys and aluminum matrix composites have been established. (Author) 23 refs

  1. Ultrafine yttria-stabilized zirconia powders prepared by pyrolysis of a metal-oxalate-cellulose complex

    Energy Technology Data Exchange (ETDEWEB)

    Solov`eva, L.V.; Bashmakov, I.A.; Kaputskii, F.N. [Research Institute of Physicochemical Problems, Minsk (Belarus)] [and others

    1995-12-01

    Preparation of high-purity submicron powders with uniform particles is a key stage in the fabrication of high-quality ceramics. For this purpose, chemical methods are commonly used. Recently, pyrolysis of salt-cellulose compositions has gained acceptance for the preparation of mixed oxide powders. This method ensures control of the morphology and particle size of the resultant powders. In this work, the authors present an environmentally safe method for preparing ZrO{sub 2}-based powders from metal-oxalate-cellulose complexes (MOCC) used as precursors instead of soluble metal salts physisorbed on the cellulose surface. The powders obtained by this method feature higher dispersity than their commercially available analogs.

  2. Net Shape Rapid Manufacturing Using Nano Encapsulated Powders, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this STTR is to determine the capability of Net Shape LENS processing with Nano-coated powders. The unique composites produced using regualr...

  3. Results on powder injection molding of Ni[sub 3]Al and application to other intermetallic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.M.

    1992-01-01

    Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni[sub 3]Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

  4. Results on powder injection molding of Ni{sub 3}Al and application to other intermetallic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.M.

    1992-12-31

    Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni{sub 3}Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

  5. Microstructure and corrosion of Pd-modified Ti alloys produced by powder metallurgy

    International Nuclear Information System (INIS)

    Ashworth, M.A.; Davenport, A.J.; Ward, R.M.; Hamilton, H.G.C.

    2010-01-01

    A method for the fabrication of titanium alloy parts with enhanced corrosion resistance by a powder metallurgy route is presented in this paper. Commercial purity titanium powders modified with Pd have been hot isostatically pressed (HIPped) and the microstructure and distribution of the noble metal characterised by optical and scanning electron microscopy. The electrochemistry of the HIPped alloy has been assessed and the effect of powder size fraction evaluated. Results show that the phase composition and electrochemistry of the HIPped Pd-modified alloy is equivalent to that of wrought grade 7 Ti.

  6. Evaluation of powder metallurgical processing routes for multi-component niobium silicide-based high-temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Seemueller, Hans Christoph Maximilian

    2016-03-22

    Niobium silicide-based composites are potential candidates to replace nickel-base superalloys for turbine applications. The goal of this work was to evaluate the feasibility and differences in ensuing properties of various powder metallurgical processing techniques that are capable of manufacturing net-shape turbine components. Two routes for powder production, mechanical alloying and gas atomization were combined with compaction via hot isostatic pressing and powder injection molding.

  7. Effect of incorporation of pumpkin (Cucurbita moshchata) powder and guar gum on the rheological properties of wheat flour

    OpenAIRE

    Kundu, Himani; Grewal, Raj Bala; Goyal, Ankit; Upadhyay, Neelam; Prakash, Saurabh

    2012-01-01

    The present study was carried out to study the effect of incorporation of fibre rich pumpkin powder and guar gum on the farinographic characteristics of wheat flour. The flour and pumpkin powder were assessed for proximate composition, total dietary fibre, minerals and β-carotene. Pumpkin powder contained appreciable amount of fibre, minerals and β-carotene. The effects of incorporation of different levels of pumpkin powder and guar gum along with pumpkin powder on farinographic characteristi...

  8. Performance ratio hardness characteristics polystyrene-metal composite materials

    International Nuclear Information System (INIS)

    Klepikov, V.F.; Prokhorenko, E.M.; Lytvynenko, V.V.; Zakharchenko, A.A.; Hazhmuradov, M.A.

    2015-01-01

    The methods of measuring the hardness of layered polystyrene-metallic composite materials. It is proposed to use powder-like tungsten and powder-like steel as radiation-protective layer. A measurement of the hardness of composites of different composition, and given its dependence on the particle size and their form. The possibility of increasing the hardness of the composites reinforced with metallic additives. Radiation-protective characteristics were calculated for the studied species of composite materials. Influence of the quantitative composition of the metal components is studied on the change of the absorbed dose of gamma radiation

  9. Antioxidant Potential of Fruit Juice with Added Chokeberry Powder (Aronia melanocarpa

    Directory of Open Access Journals (Sweden)

    Jana Šic Žlabur

    2017-12-01

    Full Text Available The purpose of this study was to determine the possibility of using chokeberry powder as a supplement in apple juice to increase the nutritional value of the final product with the aim of developing a new functional food product. Also, to determine the influence of ultrasound assisted extraction on the bioactive compounds content, nutritional composition and antioxidant potential of apple juice with added chokeberry powder. The juice samples with added chokeberry powder had higher antioxidant capacity, irrespective of the extraction technique used. Apple juice samples with added chokeberry powder treated with high intensity ultrasound had significantly higher content of all analyzed bioactive compounds. The application of high intensity ultrasound significantly reduced the extraction time of the plant material. A positive correlation between vitamin C content, total phenols, flavonoids and anthocyanins content and antioxidant capacity was determined in juice samples with added chokeberry powder treated with high intensity ultrasound.

  10. Antioxidant Potential of Fruit Juice with Added Chokeberry Powder (Aronia melanocarpa).

    Science.gov (United States)

    Šic Žlabur, Jana; Dobričević, Nadica; Pliestić, Stjepan; Galić, Ante; Bilić, Daniela Patricia; Voća, Sandra

    2017-12-05

    The purpose of this study was to determine the possibility of using chokeberry powder as a supplement in apple juice to increase the nutritional value of the final product with the aim of developing a new functional food product. Also, to determine the influence of ultrasound assisted extraction on the bioactive compounds content, nutritional composition and antioxidant potential of apple juice with added chokeberry powder. The juice samples with added chokeberry powder had higher antioxidant capacity, irrespective of the extraction technique used. Apple juice samples with added chokeberry powder treated with high intensity ultrasound had significantly higher content of all analyzed bioactive compounds. The application of high intensity ultrasound significantly reduced the extraction time of the plant material. A positive correlation between vitamin C content, total phenols, flavonoids and anthocyanins content and antioxidant capacity was determined in juice samples with added chokeberry powder treated with high intensity ultrasound.

  11. Low-Pressure and Low-Temperature Hydriding-Pulverization-Dehydriding Method for Producing Shape Memory Alloy Powders

    Science.gov (United States)

    Murguia, Silvia Briseño; Clauser, Arielle; Dunn, Heather; Fisher, Wendy; Snir, Yoav; Brennan, Raymond E.; Young, Marcus L.

    2018-04-01

    Shape memory alloys (SMAs) are of high interest as active, adaptive "smart" materials for applications such as sensors and actuators due to their unique properties, including the shape memory effect and pseudoelasticity. Binary NiTi SMAs have shown the most desirable properties, and consequently have generated the most commercial success. A major challenge for SMAs, in particular, is their well-known compositional sensitivity. Therefore, it is critical to control the powder composition and morphology. In this study, a low-pressure, low-temperature hydriding-pulverization-dehydriding method for preparing well-controlled compositions, size, and size distributions of SMA powders from wires is presented. Starting with three different diameters of as-drawn martensitic NiTi SMA wires, pre-alloyed NiTi powders of various well-controlled sizes are produced by hydrogen charging the wires in a heated H3PO4 solution. After hydrogen charging for different charging times, the wires are pulverized and subsequently dehydrided. The wires and the resulting powders are characterized using scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction. The relationship between the wire diameter and powder size is investigated as a function of hydrogen charging time. The rate of diameter reduction after hydrogen charging of wire is also examined. Finally, the recovery behavior due to the shape memory effect is investigated after dehydriding.

  12. Lactose hydrolysis and milk powder production: technological aspects

    Directory of Open Access Journals (Sweden)

    Jansen Kelis Ferreira Torres

    2017-06-01

    Full Text Available The food industry has the challenge and the opportunity to develop new products with reduced or low lactose content in order to meet the needs of a growing mass of people with lactose intolerance. The manufacture of spray dried products with hydrolyzed lactose is extremely challenging. These products are highly hygroscopic, which influence the productivity and conservation of the powders, not to mention the undesirable and inevitable technological problem of constant clogging of drying chambers. The aim of this study was to evaluate the effect of different levels (0%, 25%, 50%, 75% and > 99% of enzymatic lactose hydrolysis on the production and storage of whole milk powder. The samples were processed in a pilot plant and characterized in relation to their composition analysis; to their degree of hydrolysis of lactose; and to their sorption isotherms. The results indicated the hydrolysis of lactose may affect the milk powder production due to a higher extent of powder adhesion within the spray dryer chambers and due to a higher tendency to absorb water during storage.

  13. Synthesis of yttria powders by electrospray pyrolysis

    International Nuclear Information System (INIS)

    Rulison, A.J.; Flagan, R.C.

    1994-01-01

    Electrospray atomization of high-concentration (∼400 g/L) chemical precursor solutions was applied to the synthesis of yttria powders. Conditions were found which led to high-quality powders, composed of dense, spheroidal, submicrometer, and nanocrystalline oxide particles. The precursor solutions were hydrated yttrium nitrates dissolved in n-propyl alcohol at concentrations ranging from 44.1 to 455 g/L. Electrospray atomization produced submicrometer precursor droplets which were dispersed in air and carried through an electric furnace for thermal decomposition at 500 C for several seconds residence time. X-ray powder diffraction patterns indicated the expected cubic phase. Transmission electron micrographs showed that the particle structure varied with solution composition, ranging from hollow, inflated spheres for 6-hydrated nitrates to dense spheroids for 5-hydrated nitrates. The use of 6-hydrated nitrates in the solutions appeared to form particle surfaces which were impermeable to alcohol vapor evolved during thermal decomposition, leading to hollow, inflated spheres

  14. Homogenization of compacted blends of Ni and Mo powders

    International Nuclear Information System (INIS)

    Lanam, R.D.; Yeh, F.C.H.; Rovsek, J.E.; Smith, D.W.; Heckel, R.W.

    1975-01-01

    The homogenization behavior of compacted blends of Ni and Mo powders was studied primarily as a function of temperature, mean compact composition, and Mo powder particle size. All compact compositions were in the Ni-rich terminal solid-solution range; temperatures were between 950 and 1200 0 C (in the region of the phase diagram where only the Mo--Ni intermediate phase forms); average Mo particle sizes ranged from 8.4 mu m to 48 mu m. Homogenization was characterized in terms of the rate of decrease of the amounts of the Mo-rich terminal solid-solution phase and the Mo--Ni intermediate phase. The experimental results were compared to predictions based upon the three-phase, concentric-sphere homogenization model. In general, agreement between experimental data and model predictions was fairly good for high-temperature treatments and for compact compositions which were not close to the solubility limit of Mo in Ni. Departures from the model are discussed in terms of surface diffusion contributions to homogenization and non-uniform mixing effects. (U.S.)

  15. Investigation into the production of metastable Nb3Ge powder via the rotating electrode process

    International Nuclear Information System (INIS)

    McCormick, J.P.

    1977-12-01

    The production of metastable Nb 3 Ge powder via the rotating electrode process (REP) employing ''splat cooling'' was investigated. An electrode capable of withstanding the thermal shock of the electric arc used in REP was produced through powder metallurgy techniques. The effect of various parameters involved in the rotating electrode process was studied in correlation with process control and crystal structure, microstructure and compositional analyses of the powder produced. Superconducting transition temperature measurements were made on the powder both as-produced and after annealing experiments

  16. Plasma Methods of Obtainment of Multifunctional Composite Materials, Dispersion-Hardened by Nanoparticles

    Science.gov (United States)

    Sizonenko, O. N.; Grigoryev, E. G.; Pristash, N. S.; Zaichenko, A. D.; Torpakov, A. S.; Lypian, Ye. V.; Tregub, V. A.; Zholnin, A. G.; Yudin, A. V.; Kovalenko, A. A.

    2017-09-01

    High voltage electric discharge (HVED) in disperse system "hydrocarbon liquid - powder" due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10-6 to 10-7 m) and nanosized (from 10-7 to 10-9 m) composite powders of hardening phases. Spark plasma sintering (SPS) of powder mixtures allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10-20 %), hardness and wear-resistance (by 30-60 %) of obtained materials.

  17. Electroactive properties of flexible piezoelectric composites

    Directory of Open Access Journals (Sweden)

    Sakamoto Walter Katsumi

    2001-01-01

    Full Text Available A flexible piezoelectric composite with 0-3 connectivity, made from Lead Zirconate Titanate (PZT powder and vegetable-based polyurethane (PU, was doped with small amount of semiconductor powder. As a result a composite with 0-0-3 connectivity was obtained. The nature of absorption and steady state electrical conduction and the dielectric behaviour have been studied for this ceramic/polymer composite. The dielectric loss processes of the composite were observed to be dominated by those the polymer. Adding a semiconductor phase in the composite the electrical conductivity can be controlled and a continuous electric flux path could be created between the PZT grains. This composite may be poled at low voltage and in shorter time compared with composites without a conductive phase.

  18. Preparation of copper and silicon/copper powders by a gas ...

    Indian Academy of Sciences (India)

    Administrator

    aCentre for Materials Research, Department of Imaging and Applied Physics, ... Copper powder; Si/Cu composite particle; gas evaporation–condensation method; characteriza- tion. .... from the liquid metal surface, the mixed vapour of copper.

  19. Microstructure development of in situ porous TiO/Cu composites

    International Nuclear Information System (INIS)

    Qin, Q.D.; Huang, B.W.; Li, W.; Shao, F.

    2016-01-01

    An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti_2CO and Cu powder. Ti_2CO powder is produced by the carbothermic reduction of titanium dioxide (TiO_2) at 1000 °C. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. As the volume fraction of TiO increases, the size of TiO becomes more fine. Scanning electron microscopy (SEM) of the fracture morphology indicates that TiO particles and the Cu matrix are connected by a Cu–Ti phase. - Highlights: • An porous TiO/Cu composite is successfully prepared by powder metallurgy technology. • The porosity of composites lies in the range between 10.2% and 35.2%. • The TiO particles and the Cu matrix are connected by a Cu-Ti phase.

  20. Ti-Mg alloy powder synthesis via mechanochemical reduction of TiO 2 by elemental magnesium

    CSIR Research Space (South Africa)

    Mushove, T

    2009-04-01

    Full Text Available This paper reports the preliminary results of an investigation on the synthesis of a Ti-Mg alloy powder through mechanochemical processing of TiO 2 and Mg powders. TiO 2 was mixed with elemental Mg according to a nominal stoichiometric composition...

  1. Effect of intense vibration treatment on the powder fine structure and reaction ability during sintering

    International Nuclear Information System (INIS)

    Pribytkov, G.A.; Chzhan Khajfen; Yuj Baokhaj; Khu Zoangchi

    2003-01-01

    Effects of a vibration grinding treatment of TiC-Ni and TiC-Ni-Cr titanium carbide-metal powder composition on the size of X-ray coherent scattering zones as well as the melt and crystallization temperatures under liquid-phase sintering have been investigated. Hardness and strength of composites sintered from the blends grinded for 4 h and more are found to be decreased that is explained by high porosity due to oxygen contamination of powder blends during a dry grinding treatment [ru

  2. Interface physics in microporous media : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Yaklin, Melissa A.; Knutson, Chad E.; Noble, David R.; Aragon, Alicia R.; Chen, Ken Shuang; Giordano, Nicholas J. (Purdue University, West Lafayette, IN); Brooks, Carlton, F.; Pyrak-Nolte, Laura J. (Purdue University, West Lafayette, IN); Liu, Yihong (Purdue University, West Lafayette, IN)

    2008-09-01

    This document contains a summary of the work performed under the LDRD project entitled 'Interface Physics in Microporous Media'. The presence of fluid-fluid interfaces, which can carry non-zero stresses, distinguishes multiphase flows from more readily understood single-phase flows. In this work the physics active at these interfaces has been examined via a combined experimental and computational approach. One of the major difficulties of examining true microporous systems of the type found in filters, membranes, geologic media, etc. is the geometric uncertainty. To help facilitate the examination of transport at the pore-scale without this complication, a significant effort has been made in the area of fabrication of both two-dimensional and three-dimensional micromodels. Using these micromodels, multiphase flow experiments have been performed for liquid-liquid and liquid-gas systems. Laser scanning confocal microscopy has been utilized to provide high resolution, three-dimensional reconstructions as well as time resolved, two-dimensional reconstructions. Computational work has focused on extending lattice Boltzmann (LB) and finite element methods for probing the interface physics at the pore scale. A new LB technique has been developed that provides over 100x speed up for steady flows in complex geometries. A new LB model has been developed that allows for arbitrary density ratios, which has been a significant obstacle in applying LB to air-water flows. A new reduced order model has been developed and implemented in finite element code for examining non-equilibrium wetting in microchannel systems. These advances will enhance Sandia's ability to quantitatively probe the rich interfacial physics present in microporous systems.

  3. Synergistic effects of iron powder on intumescent flame retardant polypropylene system

    Directory of Open Access Journals (Sweden)

    2009-06-01

    Full Text Available The effects of iron powder as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene composites (IFR-PP were studied. The thermogravimetric analysis (TGA and cone calorimeter (CONE were used to evaluate the synergistic effects of iron powder (Fe. The TGA data showed that Fe could enhance the thermal stability of the IFR-PP systems at high temperature and effectively increase the char residue formation. The CONE results revealed that Fe and IFR could clearly change the decomposition behavior of PP and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate (HRR, mass loss (ML, Mass loss rate (MLR, total heat release (THR, carbon monoxide and so on. Thus, a suitable amount of Fe plays a synergistic effect in the flame retardancy of IFR composites.

  4. Homogeneous forming technology of composite materials and its application to dispersion nuclear fuel

    International Nuclear Information System (INIS)

    Hong, Soon Hyun; Ryu, Ho Jin; Sohn, Woong Hee; Kim, Chang Kyu

    1997-01-01

    Powder metallurgy processing technique of metal matrix composites is reviewed and its application to process homogeneous dispersion nuclear fuel is considered. The homogeneous mixing of reinforcement with matrix powders is very important step to process metal matrix composites. The reinforcement with matrix powders is very important step to process metal matrix composites. The reinforcement can be ceramic particles, whiskers or chopped fibers having high strength and high modulus. The blended powders are consolidated into billets and followed by various deformation processing, such as extrusion, forging, rolling or spinning into final usable shapes. Dispersion nuclear fuel is a class of metal matrix composite consisted of dispersed U-compound fuel particles and metallic matrix. Dispersion nuclear fuel is fabricated by powder metallurgy process such as hot pressing followed by hot extrusion, which is similar to that of SiC/Al metal matrix composite. The fabrication of homogeneous dispersion nuclear fuel is very difficult mainly due to the inhomogeneous mixing characteristics of the powders from quite different densities between uranium alloy powders and aluminum powders. In order to develop homogeneous dispersion nuclear fuel, it is important to investigate the effect of powder characteristics and mixing techniques on homogeneity of dispersion nuclear fuel. An new quantitative analysis technique of homogeneity is needed to be developed for more accurate analysis of homogeneity in dispersion nuclear fuel. (author). 28 refs., 7 figs., 1tab

  5. Dry powder mixes comprising phase change materials

    Science.gov (United States)

    Salyer, I.O.

    1994-02-01

    Free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and in cementitious compositions of the type in which it is beneficial to use a PCM material. The silica-PCM mix can also be admixed with soil to provide a soil warming effect and placed about a tree, flower, or shrub. 2 figures.

  6. Study on synthesis of ultrafine Cu–Ag core–shell powders with high electrical conductivity

    International Nuclear Information System (INIS)

    Peng Yuhsien; Yang Chihhao; Chen Kuanting; Popuri, Srinivasa R.; Lee, Ching-Hwa; Tang, Bo-Shin

    2012-01-01

    Highlights: ► This synthesis method is relatively facile, novel and eco-friendly. ► Toxic agents were not used for chelating agent, reductant or dispersant in our method. ► The reaction can under room temperature for energy saving purpose. ► Cu–Ag core–shell powders with homogeneous cover-silver layer. ► The resistivity of Cu–Ag core–shell powders has the same value as the pure silver. - Abstract: Cu–Ag composite powders with high electrical conductivity were synthesized by electroless plating of silver sulfate, copper powders with eco-friendly sodium citrate as reducing agent, dispersant and chelating agent in an aqueous system. The influences of sodium citrate/Ag ratio on Ag coatings of Cu powders were investigated. Ag was formed a dense coating on the surface of Cu powders at a molar ratio of sodium citrate/Ag = 0.07/1. SEM showed an uniformity of Ag coatings on Cu powders. SEM-EDX also revealed that Cu cores were covered by Ag shells on the whole. The surface composition analysis by XPS indicated that without Cu or Ag atoms in the surface were oxidized. The resistivity measurements of Cu–Ag paste shows that they have closer resistivity as the pure silver paste's after 250 °C for 30 min heat-treatment (2.55 × 10 −4 Ω cm) and 350 °C for 30 min heat-treatment (1.425 × 10 −4 Ω cm).

  7. Grinding Si3N4 Powder In Si3N4 Equipment

    Science.gov (United States)

    Herbell, Thomas P.; Freedman, Marc R.; Kiser, James D.

    1989-01-01

    Three methods of grinding compared. Report based on study of grinding silicon nitride powder in preparation for sintering into solid ceramic material. Attrition, vibratory, and ball mills lined with reaction-bonded silicon nitride tested. Rates of reduction of particle sizes and changes in chemical compositions of powders measured so grinding efficiences and increases in impurity contents from wear of mills and media evaluated for each technique.

  8. Preparation and Properties of Epoxy Resin-Coated Micro-Sized Ferrosilicon Powder

    OpenAIRE

    Ku,Jiangang; Chen,Huihuang; He,Kui; Yan,Quanxiang

    2016-01-01

    Ferrosilicon powder surface coated with a dense epoxy resin membrane was prepared via coating precipitation methods using silane coupling agents as the modifier and epoxy resin as the coating agent. FTIR, FESEM, MPMS-XL, and TG-DSC were used to analyze the morphology, surface composition, magnetic property and thermostability of ferrosilicon powder before and after the modification and coating. The experimental results indicate that epoxy resin membranes of a certain thickness were successful...

  9. Effect of Remelting Duration on Microstructure and Properties of SiCp/Al Composite Fabricated by Powder-Thixoforming for Electronic Packaging

    Directory of Open Access Journals (Sweden)

    Siyu Cai

    2016-12-01

    Full Text Available In this work, a novel processing method called powder thixoforming was proposed to prepare composites reinforced with 50 vol % of SiC particles (SiCp that were used for electronic packaging in order to investigate the effects of remelting duration on its microstructure and properties. Optical Microscope (OM, Scanning Electron Microscope (SEM, X-ray Diffraction (XRD and Transmission Electron Microscope (TEM methods were applied for the material characterization and the corresponding physical and mechanical properties were examined in detail. The obtained results indicate that the remelting duration exerted a large effect on the microstructure as well as the SiCp/Al interfacial reaction. The density and hardness of the composite continuously increased with increasing remelting duration. The thermal conductivity (TC and bending strength (BS first increased during the initial 90 min and then decreased. The remelting duration exerted a limited influence on the coefficient of thermal expansion (CTE. The optimal TC, BS, and hardness of these composites were up to 135.79 W/(m·K, 348.53 MPa, and 105.23 HV, respectively, and the CTE was less than 6.5 ppm/K after the composites were remelted at 600 °C for 90 min. The properties of the composites could thus be controlled to conform to the application requirements for electronic packaging materials.

  10. Impurities enhance caking in lactose powder

    DEFF Research Database (Denmark)

    Carpin, M.; Bertelsen, H.; Dalberg, A.

    2017-01-01

    Caking of lactose and other dry ingredients is a common problem in the dairy and food industries. The lactose production process includes different purification steps, depending on the type of lactose produced. The aim of this study was therefore to investigate how the remaining impurities (i.......e. non-lactose components) affect the caking tendency of the final powder. The results from a combination of different methods, including dynamic vapor sorption, characterization of the physicochemical composition and assessment of caking with a ring shear tester, suggested humidity caking. Larger...... amounts of impurities in the lactose powder resulted in enhanced moisture sorption and greater caking tendency. These findings emphasize the importance of controlling the washing and purification steps throughout the production process in order to limit caking in the final product...

  11. [METHOD OF INCREASING MICROBIOLOGICAL PURITY OF POWDER FROM COCOA-VELLA].

    Science.gov (United States)

    Magomedov, G O; Cheremushkina, L V; Plotnikova, I V

    2015-01-01

    In the article there is described in detail the characteristic of the product of processing cocoa beans--cocoa-vella, there is presented a comparative analysis of the chemical composition, quality indices, the dispersive pattern, microbiological indices of the powder from the cocoa-vella in comparison to cocoa powder, obtained by traditional technology from the core of the cocoa beans. To improve the microbiological purity of the powder from the cocoa-vella there was suggested to be the modern and environmentally safe manner for the preparation of the powder The use of cocoa-vella disinfecting power by means of the electromagnetic field of ultrahigh frequency (RF EMF) was established to allow to obtain a product that meets the requirements of Technical Regulations of the Customs Union (TRCU 021/2011) on Food Safety. This work is of practical interest, since it helps to improve the safety of the powder from the cocoa-vella, and thus the quality of confectionery and food products based on it, which is relevant in terms of the management of a healthy diet.

  12. Microstructural and mechanical properties of titanium particulate reinforced magnesium composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Umeda, Junko; Kawakami, Masashi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Kondoh, Katsuyoshi, E-mail: kondoh@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Ayman, El-Sayed; Imai, Hisashi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan)

    2010-10-01

    Pure titanium (Ti) particulate reinforced pure magnesium (Mg) composite materials were fabricated via powder metallurgy route, and their microstructural and mechanical properties were evaluated. When using the elemental mixture of pure Mg and pure Ti powders and consolidating them by solid-state sintering process, no significant increase in tensile strength of the composites was obtained, because of poor bonding strength at the interface between {alpha}-Mg matrix and Ti particles. In particular, coarse magnesium oxide (MgO) particles of about 100 nm were formed via thermite reaction between TiO{sub 2} surface films of Ti particles and Mg raw powders and resulted in preventing the improvement of the mechanical properties of the composite material. On the other hand, when using the atomized pure Mg composite powders reinforced with Ti particulates, their extruded composite material showed obviously improved tensile strength and good elongation, compared to the extruded pure Mg powder material including no Ti particle. The obvious improvement in the tensile strength was due to the restriction of dislocation movement by Ti reinforcements under applied tensile load.

  13. Structure and hardness of TiAl-TiB2 composite prepared by hot isostatic pressing of mechanically alloyed powders. Mekanikaru aroingu funmatsu no HIP shoketsu ni yori sakuseishita TiAl/TiB2 fukugo zairyo no soshiki to kodo

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T; Shimakage, K [Muroran Inst. of Technology, Hokkaido (Japan). Faculty of Engineering; Miyakawa, S [Muroran Inst. of Technology, Hokkaido (Japan). Graduate Student

    1992-11-20

    The practical application of Ti-Al system intermetallic compounds is expected as an advanced light heat resistant material. TiAl group out of them, as for the specific strength, has an equivalent maximum working temperature as that of the nickel base alloy, which is utilized as a turbine material for the current aircraft, and moreover it is also said that it is superior in the creep and rupture properties to the latter. In this study, by mechanical alloying (MA) of each mixed powder of Ti-Al and Ti-B, by suing heptane as a grinding aid, each MA powder of the amorphous TiAl containing carbon and extremely fine compound TiB2 were prepared, and subsequently the true density sintering by the hot isostatic pressing (HIP) was performed, and by doing these, the preparation of TiAl/TiB2 system composite material with a high composite ratio of TiO2 was tried. Consequently, by the MA treatment of the mixed powder of Ti and B for more than 50 hours, the compound powder of TiB2 mixed with TiB could be prepared, and its hardness has shown the maximum value Hmv=l200 with a composition of TiAl/25 mol % TiB2. 14 refs., 10 figs., 2 tabs.

  14. Microstructure development of in situ porous TiO/Cu composites

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Q.D., E-mail: 58124812@qq.com [Department of Materials & Metallurgy Engineering, Guizhou Institute of Technology, No.1 Caiguan Road, Guiyang 550003 (China); 2011 Special Functional Materials Collaborative Innovation Center of Guizhou Province, No.1 Caiguan Road, Guiyang 550003 (China); Huang, B.W. [Department of Materials & Metallurgy Engineering, Guizhou Institute of Technology, No.1 Caiguan Road, Guiyang 550003 (China); 2011 Special Functional Materials Collaborative Innovation Center of Guizhou Province, No.1 Caiguan Road, Guiyang 550003 (China); Li, W. [Department of Materials Engineering, Zhengzhou Technology College, No. 81 Zhengshang Road, Zhengzhou, 450051 (China); Shao, F. [2011 Special Functional Materials Collaborative Innovation Center of Guizhou Province, No.1 Caiguan Road, Guiyang 550003 (China)

    2016-07-05

    An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti{sub 2}CO and Cu powder. Ti{sub 2}CO powder is produced by the carbothermic reduction of titanium dioxide (TiO{sub 2}) at 1000 °C. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. As the volume fraction of TiO increases, the size of TiO becomes more fine. Scanning electron microscopy (SEM) of the fracture morphology indicates that TiO particles and the Cu matrix are connected by a Cu–Ti phase. - Highlights: • An porous TiO/Cu composite is successfully prepared by powder metallurgy technology. • The porosity of composites lies in the range between 10.2% and 35.2%. • The TiO particles and the Cu matrix are connected by a Cu-Ti phase.

  15. The Specification of Cement Powders for Waste Encapsulation Processes at Sellafield site

    International Nuclear Information System (INIS)

    Angus, M.; Borwick, J.; Cann, G.; Hayes, M.; McLuckie, B.; Jowsey, J.

    2012-01-01

    Requirements are described for Portland Cement (CEM I), Ground Granulated Blast-furnace Slag (GGBS) and Fly Ash (FA) powders used for the encapsulation of Intermediate Level Radioactive Waste (ILW) in UK, with particular reference to Sellafield site encapsulation processes. Differences between the powders used by the UK nuclear industry and the equivalent British and European cement standards are explained. Research over the last 20 years to respond to changes in the performance of these powders is summarised and options for dealing with potential future changes are discussed. These include the use of special blends of GGBS to achieve the desired flow properties or alternatively poly-carboxylate super-plasticizers to produce grouts with consistent performance using cement powders with a wide range of composition. (authors)

  16. Mechanical properties of hexaferite based magnet composite of SrFe12019 and BaFe12O19 with natural rubber bonding agent

    International Nuclear Information System (INIS)

    Waluyo, T.; Herman, Y.A.; Sudirman; Ridwan

    2000-01-01

    Research on mechanical properties at magnet composite of SrFe 12 0 19 (SrM) and BaFe 12 O 19 (BaM)magnet powder with natural rubber bonding agent have been done. The natural rubber used was rubber made of latex without vulcanization, The SrM powder having average particle size of 1.6 μm and flat shaped. and the BaM powder having particle size of 1.2 μm and nodular shaped. The production of composite carried out in Labo Plastomill at 100 o C and mixer speed of 30 rpm for 7 minutes. The result obtained from Labo Plastomill then made into sheets. Mechanical properties of the composite tested were strain, elongation break and hardness, The results showed that the highest strain of the SrM composite obtained at composition of 70% vol of powder that is 2,22 MPa, and 3,84 MPa for BaM composite at 50% vol. of powder The elongation break of SrM composite decreased by increasing of powder volume fraction, that is 90% at the composition or 70% vol. of powder, and 370% for BaM composite at 50% vol. fraction of powder. The highest hardness for SrM composite obtained at composition of of 70% vol. of powder, that is 95 SHA. and for the BaM composite at 50% vol. of powder. that is 52 SHA

  17. The use of glass powder in making batako

    Science.gov (United States)

    Nursyamsi, N.; Indrawan, I.

    2018-02-01

    Along with the increase in construction materials, innovation is needed to lessen the use of them, and one of them is by using cement [1]. In this research, it is reduced by glass powder; the reason for using it as the substitution of cement is that some chemical elements in cement are similar to those in glass powder such as SiO2, A12o3, Fe2O3, and CaO. The glass powder used was the one who passed sieve no. 100 and was hampered in sieve no. 200. It passed sieve no. 200 with its composition of 0%, 10%, 15%, 20%, 25%, and 30% from the volume of the use of cement. The specimen would treat within 28 days before the testing of compressive strength, water absorption, and tensile strength [2]. The variation which produced optimum result would mix with the foaming agent as the material for reducing the weight of the specimen. After that, the test of compressive strength, water absorption, and tensile strength on the installment of batako walls were done. The data analyzed by using SNI 02-0349-1989[3] reference about concrete brick for wall installment. The variation of 20% of glass powder passing sieve no. 200 gave optimum result. A specimen of the variation on glass powder of 20% which passed sieve no. 200 and the foaming agent was higher than the compressive strength of the specimen which used glass powder substitution of 0% of passing sieve no. 200 and foaming agent. The compressive strength of batako walls which used the batako construction with glass powder substitution of 20% of passing sieve no. 200 and the foaming agent was also higher than the compressive strength of the assaying object which used glass powder substitution of 0% of passing sieve no. 200 and foaming agent.

  18. Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

    2015-03-23

    In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

  19. Glass-Graphite Composite Materials

    International Nuclear Information System (INIS)

    Mayzan, M.Z.H.; Lloyd, J.W.; Heath, P.G.; Stennett, M.C.; Hyatt, N.C.; Hand, R.J.

    2016-01-01

    A summary is presented of investigations into the potential of producing glass-composite materials for the immobilisation of graphite or other carbonaceous materials arising from nuclear power generation. The methods are primarily based on the production of base glasses which are subsequently sintered with powdered graphite or simulant TRISO particles. Consideration is also given to the direct preparation of glass-graphite composite materials using microwave technology. Production of dense composite wasteforms with TRISO particles was more successful than with powdered graphite, as wasteforms containing larger amounts of graphite were resistant to densification and the glasses tried did not penetrate the pores under the pressureless conditions used. Based on the results obtained it is concluded that the production of dense glassgraphite composite wasteforms will require the application of pressure. (author)

  20. Final LDRD report : science-based solutions to achieve high-performance deep-UV laser diodes.

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Andrew M.; Miller, Mary A.; Crawford, Mary Hagerott; Alessi, Leonard J.; Smith, Michael L.; Henry, Tanya A.; Westlake, Karl R.; Cross, Karen Charlene; Allerman, Andrew Alan; Lee, Stephen Roger

    2011-12-01

    We present the results of a three year LDRD project that has focused on overcoming major materials roadblocks to achieving AlGaN-based deep-UV laser diodes. We describe our growth approach to achieving AlGaN templates with greater than ten times reduction of threading dislocations which resulted in greater than seven times enhancement of AlGaN quantum well photoluminescence and 15 times increase in electroluminescence from LED test structures. We describe the application of deep-level optical spectroscopy to AlGaN epilayers to quantify deep level energies and densities and further correlate defect properties with AlGaN luminescence efficiency. We further review our development of p-type short period superlattice structures as an approach to mitigate the high acceptor activation energies in AlGaN alloys. Finally, we describe our laser diode fabrication process, highlighting the development of highly vertical and smooth etched laser facets, as well as characterization of resulting laser heterostructures.

  1. Phase composition, microstructure, and mechanical properties of porous Ti-Nb-Zr alloys prepared by a two-step foaming powder metallurgy method.

    Science.gov (United States)

    Rao, X; Chu, C L; Zheng, Y Y

    2014-06-01

    Porous Ti-Nb-Zr alloys with different porosities from 6.06 to 62.8% are prepared by a two-step foaming powder metallurgy method using TiH2, Nb, and Zr powders together with 0 to 50wt% of NH4HCO3. The effects of the amounts of Nb and Zr as well as the sintering temperature (1473 to 1673K) on their phase composition, porosity, morphology, and mechanical characteristics are investigated. By controlling the porosity, Nb and Zr concentrations as well as the sintering temperature, porous Ti-Nb-Zr alloys with different mechanical properties can be obtained, for example, the hardness between 290 and 63HV, the compressive strength between 1530.5 and 73.4MPa, and the elastic modulus between 10.8 and 1.2GPa. The mechanical properties of the sintered porous Ti-Nb-Zr alloys can be tailored to match different requirements for the human bones and are thus potentially useful in the hard tissue implants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Synthesis of nanocrystalline NiO/ZnO heterostructured composite powders by sol-gel auto combustion method and their characterizations

    Science.gov (United States)

    Tangcharoen, Thanit; Klysubun, Wantana; Kongmark, Chanapa

    2018-03-01

    Nanocrystalline NiO/ZnO heterostructured composite powders were prepared by the sol-gel auto combustion method, based on nickel and zinc nitrate precursors and using diethanolamine (DEA) as novel fuel. The composition of different NiO and ZnO ratios, ranging from 100/0, 95/5, 90/10, 80/20, 60/40, 50/50, 40/60, 20/80, 10/90, 5/95 to 0/100, were studied. The structural, chemical bonding, morphological, optical, and fluorescence properties including the local atomic structure of each calcined sample were systematically investigated by means of X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, and synchrotron X-ray absorption spectroscopy (XAS), respectively. For the ZnO concentration below 20%, both XRD and Raman spectroscopy results revealed only the NiO phase. This conformed to the observation of Zn K-edge and Ni K-edge X-ray absorption near edge structure (XANES). The Zn ions found in the samples of low ZnO concentration exhibited six-fold coordination with oxygen atoms rather than the four-fold coordination found in the wurtzite (WZ) structure of ZnO. In contrast, the Ni ions which are found in the samples of low NiO concentration (≤10%) are coordinated both tetrahedrally and octahedrally by four or six oxygen atoms, respectively, rather than the six-fold coordination which is usually observed for Ni ions in the rock salt (RS) form of NiO. All analytical results obtained from experimental XANES spectra were verified by the theoretical calculation of absorption spectra using the FEFF9.7 code. The UV-DRS results showed that there was an increase in the reflectance efficiency for both infrared and visible light conditions as the content of ZnO increases; meanwhile, the values for the energy gap (Eg) of all composite samples were higher than that of pure NiO and ZnO. In addition, the PL spectra revealed major blue emission bands observed at 490

  3. Effect of nickel addition on mechanical properties of powder forged Fe-Cu-C

    Science.gov (United States)

    Archana Barla, Nikki

    2018-03-01

    Fe-Cu-C system is very popular in P/M industry for its good compressibility and dimensional stability with high strength. Fe-Cu-C is a structural material and is used where high strength with high hardness is required. The composition of powder metallurgy steel plays a vital role in the microstructure and physical properties of the sintered component. Fe-2Cu-0.7C-Ni alloy with varying nickel composition (0%, 0.5%, 1.0%, 1.5%, 2.0%, and 3.0%) wt. % was prepared by powder metallurgy (P/M) sinter forging process. The present work discuss the effect of varying nickel content on microstructure and mechanical properties.

  4. Dry powder mixes comprising phase change materials

    Science.gov (United States)

    Salyer, Ival O.

    1992-01-01

    Free flowing, conformable powder-like mix of silica particles and a phase change material (p.c.m.) is disclosed. The silica particles have a critical size of about 7.times.10.sup.-3 to about 7.times.10.sup.-2 microns and the pcm must be added to the silica in an amount of 80 wt. % or less pcm per combined weight of silica and pcm. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and in cementitious compositions of the type in which it is beneficial to use a pcm material. The silica-pcm mix can also be admixed with soil to provide a soil warming effect and placed about a tree, flower, or shrub.

  5. Simple process to fabricate nitride alloy powders

    International Nuclear Information System (INIS)

    Yang, Jae Ho; Kim, Dong-Joo; Kim, Keon Sik; Rhee, Young Woo; Oh, Jang-Soo; Kim, Jong Hun; Koo, Yang Hyun

    2013-01-01

    Uranium mono-nitride (UN) is considered as a fuel material [1] for accident-tolerant fuel to compensate for the loss of fissile fuel material caused by adopting a thickened cladding such as SiC composites. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. Among them, a direct nitriding process of metal is more attractive because it has advantages in the mass production of high-purity powders and the reusing of expensive 15 N 2 gas. However, since metal uranium is usually fabricated in the form of bulk ingots, it has a drawback in the fabrication of fine powders. The Korea Atomic Energy Research Institute (KAERI) has a centrifugal atomisation technique to fabricate uranium and uranium alloy powders. In this study, a simple reaction method was tested to fabricate nitride fuel powders directly from uranium metal alloy powders. Spherical powder and flake of uranium metal alloys were fabricated using a centrifugal atomisation method. The nitride powders were obtained by thermal treating the metal particles under nitrogen containing gas. The phase and morphology evolutions of powders were investigated during the nitriding process. A phase analysis of nitride powders was also part of the present work. KAERI has developed the centrifugal rotating disk atomisation process to fabricate spherical uranium metal alloy powders which are used as advanced fuel materials for research reactors. The rotating disk atomisation system involves the tasks of melting, atomising, and collecting. A nozzle in the bottom of melting crucible introduces melt at the center of a spinning disk. The centrifugal force carries the melt to the edge of the disk and throws the melt off the edge. Size and shape of droplets can be controlled by changing the nozzle size, the disk diameter and disk speed independently or simultaneously. By adjusting the processing parameters of the centrifugal atomiser, a spherical and flake shape

  6. Nanometer, submicron and micron sized aluminum powder prepared by semi-solid mechanical stirring method with addition of ceramic particles

    International Nuclear Information System (INIS)

    Qin, X.H.; Jiang, D.L.; Dong, S.M.

    2004-01-01

    Composite powder, which is a mixture of Al/Al 2 O 3 composite particles and nanometer, submicron and micron sized aluminum powder, was prepared by semi-solid mechanical stirring method with addition of Al 2 O 3 ceramic particles. The ceramic particles have an average diameter of 80 μm and a volume fraction of 15% in the slurry. The methods used to measure the size distribution of particles greater than 50 μm and less than 50 μm were sieve analysis and photosedimentation, respectively. The surface morphology and transverse sections of the composite powder of different sizes were examined by scanning electron microscope (SEM), optical microscope and auger electron spectroscopy (AES). The results indicate that the composite powder prepared in present work have a wide size distribution ranging from less than 50-900 μm, and the aluminum particles and Al/Al 2 O 3 composite particles are separated and isolated. The particles greater than 200 μm and less than 50 μm are almost pure aluminum powder. The rate of conversion of ingot aluminum into particles less than 1 μm containing nanometer and submicron sizes is 1.777 wt.% in this work. The aluminum powder of different sizes has different shape and surface morphology, quasi-spherical in shape with rough surface for aluminum particles of micron scale, irregular in shape for aluminum particles of submicron scale, and quite close to a globular or an excellent globular in shape for aluminum particles of nanometer size. On the other hand, the surface of ceramic particle was coated by aluminum particles with maximum thickness less than 10 μm containing nanometer and submicron sizes as a single layer. It is suggested that the surface of ceramic particles can provide more nucleation sites for solidification of liquid aluminum and the nucleation of liquid aluminum can take place readily, grow and adhere on the surface of ceramic particles, although it is poorly wetted by the liquid aluminum and the semi-solid slurry can

  7. Low-temperature plasma spheroidizing of polydisperse powders of refractory materials

    International Nuclear Information System (INIS)

    Tsymbalist, M.M.; Rudenskaya, N.A.; Kuz'min, B.P.; Pan'kov, V.A.

    2003-01-01

    A model is developed for heating and melting of a spherical particle, when powder processing in low temperature plasma, with the aim of estimation of the dependence of the degree of fusion on particle size for various materials. Spheroidizing of various refractory material powders close in shape and size composition is experimentally performed. Experimental and calculation estimates of spheroidizing criteria for the materials studied are in a satisfactory agreement. The influence of basic physical properties of refractory materials and plasma processing parameters on the degree of particle spheroidizing is analyzed [ru

  8. Processing equipment for grinding of building powders

    Science.gov (United States)

    Fediuk, R. S.; Ibragimov, R. A.; Lesovik, V. S.; Pak, A. A.; Krylov, V. V.; Poleschuk, M. M.; Stoyushko, N. Y.; Gladkova, N. A.

    2018-03-01

    In the article questions of mechanical grinding up to nanosize of building powder materials are considered. In the process of mechanoactivation of the composite binder, active molecules of cement minerals arise when molecular packets are destroyed in the areas of defects and loosening of the metastable phase during decompensation of intermolecular forces. The process is accompanied by a change in the kinetics of hardening Portland cement. Mechanical processes in the grinding of mineral materials cause, together with an increase in their surface energy, the growth of the isobaric potential of the powders and, accordingly, their chemical activity, which also contributes to high adhesion strength when they come into contact with binders. Thus, a set of measures for mechanical activation allows more fully use the mass of components of the filled cement systems and regulate their properties. At relatively low costs, it is possible to provide an impressive and, importantly, easily repeatable in production conditions result. It is revealed that the use of a vario-planetary mill allows to achieve the best results on grinding the powder building materials.

  9. Zirconia-mullite obtained from co-precipitated zirconia-mullite composite powders by SPS

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.Z.; Li, Z.J.; Luo, X.D. [Univ. of Science and Technology Liaoning, Anshan (China). School of High Temperature Materials and Magnesium Resource Engineering; Gui, J.Y.; Xie, Z.P. [Tsinghua Univ., Beijing (China). School of Materials Science and Engineering

    2016-07-01

    The co-precipitation method is used to fabricate precursor powder. This powder is densified by means of the spark plasma sintering (SPS) technique at 1500 C with a holding time of 7 min to prepare zirconia-mullite samples. Their density measures up to 97 % of the theoretical density, and the sintered mullite compacts exhibit better strength properties (289 ± 12 MPa) and H{sub v} (9.99 GPa). The mode of fracture is changed with the addition of ZrO{sub 2} and extensive fine cleavages are observed on the grain surface. These cleavages join together to form steps, which can absorb more energy. The flexural strength of the samples is almost double that of pure mullite, which is related to the formation of cleavages.

  10. Amorphous metal composites

    International Nuclear Information System (INIS)

    Byrne, M.A.; Lupinski, J.H.

    1984-01-01

    This patent discloses an improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite

  11. Relationship of Powder Feedstock Variability to Microstructure and Defects in Selective Laser Melted Alloy 718

    Science.gov (United States)

    Smith, T. M.; Kloesel, M. F.; Sudbrack, C. K.

    2017-01-01

    Powder-bed additive manufacturing processes use fine powders to build parts layer by layer. For selective laser melted (SLM) Alloy 718, the powders that are available off-the-shelf are in the 10-45 or 15-45 micron size range. A comprehensive investigation of sixteen powders from these typical ranges and two off-nominal-sized powders is underway to gain insight into the impact of feedstock on processing, durability and performance of 718 SLM space-flight hardware. This talk emphasizes an aspect of this work: the impact of powder variability on the microstructure and defects observed in the as-fabricated and full heated material, where lab-scale components were built using vendor recommended parameters. These typical powders exhibit variation in composition, percentage of fines, roughness, morphology and particle size distribution. How these differences relate to the melt-pool size, porosity, grain structure, precipitate distributions, and inclusion content will be presented and discussed in context of build quality and powder acceptance.

  12. New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

    OpenAIRE

    Budding, A.; Vaneker, T.H.J.

    2013-01-01

    In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of applications, but this study solely focuses on the application for powder -based three-dimensional printing (e.g. SLS, 3DP). This research is primarily interested in powder compaction for creating membrane...

  13. Combustion of Na2B4O7 + Mg + C to synthesis B4C powders

    International Nuclear Information System (INIS)

    Jiang Guojian; Xu Jiayue; Zhuang Hanrui; Li Wenlan

    2009-01-01

    Boron carbide powder was fabricated by combustion synthesis (CS) method directly from mixed powders of borax (Na 2 B 4 O 7 ), magnesium (Mg) and carbon. The adiabatic temperature of the combustion reaction of Na 2 B 4 O 7 + 6 Mg + C was calculated. The control of the reactions was achieved by selecting reactant composition, relative density of powder compact and gas pressure in CS reactor. The effects of these different influential factors on the composition and morphologies of combustion products were investigated. The results show that, it is advantageous for more Mg/Na 2 B 4 O 7 than stoichiometric ratio in Na 2 B 4 O 7 + Mg + C system and high atmosphere pressure in the CS reactor to increase the conversion degree of reactants to end product. The final product with the minimal impurities' content could be fabricated at appropriate relative density of powder compact. At last, boron carbide without impurities could be obtained after the acid enrichment and distilled water washing.

  14. MICROSTRUCTURE AND WEAR PROPERTIES OF COMPOSITE COATINGS PRODUCED BY LASER CLADDING OF Ti-6Al-4V WITH GRAPHITE AND SILICON MIXED POWDERS

    OpenAIRE

    Y. S. TIAN; C. Z. CHEN; D. Y. WANG; Q. H. HUO; T. Q. LEI

    2005-01-01

    Composite coatings are fabricated by laser cladding of titanium alloy Ti-6Al-4V with graphite and silicon mixed powders. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) indicate that the coatings mainly consist of pre-eutectic TiC and eutectic Ti5Si3 compounds. Test results show that the coatings exhibit a higher microhardness and a lower friction coefficient compared with the as-received sample. EPMA micrographs show that the compounds' morphology in the top zone of the coat...

  15. Corrosion-resistant powder-metallurgy stainless steel powders and compacts therefrom

    International Nuclear Information System (INIS)

    Klar, E.; Ro, D.H.; Whitman, C.I.

    1980-01-01

    Disclosed is a process for improving the corrosion resistance of a stainless steel powder or compact thereof wherein the powder is produced by atomizing a melt of metals in an oxidizing environment whereby the resulting stainless steel powder is surface-enriched in silicon oxides. The process comprises adding an effective proportion of modifier metal to the melt prior to the atomization, the modifier metal selected from the group consisting of tin, aluminum, lead, zinc, magnesium, rare earth metals and like metals capable of enrichment about the surface of the resulting atomized stainless steel powder and effective under reductive sintering conditions in the depletion of the silicon oxides about the surface; and sintering the resulting atomized powder or a compact thereof under reducing conditions, the sintered powder or compact thereof being depleted in the silicon oxides and the corrosion resistance of the powder or compact thereof being improved thereby

  16. Powder compression mechanics of spray-dried lactose nanocomposites.

    Science.gov (United States)

    Hellrup, Joel; Nordström, Josefina; Mahlin, Denny

    2017-02-25

    The aim of this study was to investigate the structural impact of the nanofiller incorporation on the powder compression mechanics of spray-dried lactose. The lactose was co-spray-dried with three different nanofillers, that is, cellulose nanocrystals, sodium montmorillonite and fumed silica, which led to lower micron-sized nanocomposite particles with varying structure and morphology. The powder compression mechanics of the nanocomposites and physical mixtures of the neat spray-dried components were evaluated by a rational evaluation method with compression analysis as a tool, using the Kawakita equation and the Shapiro-Konopicky-Heckel equation. Particle rearrangement dominated the initial compression profiles due to the small particle size of the materials. The strong contribution of particle rearrangement in the materials with fumed silica continued throughout the whole compression profile, which prohibited an in-depth material characterization. However, the lactose/cellulose nanocrystals and the lactose/sodium montmorillonite nanocomposites demonstrated high yield pressure compared with the physical mixtures indicating increased particle hardness upon composite formation. This increase has likely to do with a reinforcement of the nanocomposite particles by skeleton formation of the nanoparticles. In summary, the rational evaluation of mechanical properties done by applying powder compression analysis proved to be a valuable tool for mechanical evaluation for this type of spray-dried composite materials, unless they demonstrate particle rearrangement throughout the whole compression profile. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Light extinction in metallic powder beds: Correlation with powder structure

    International Nuclear Information System (INIS)

    Rombouts, M.; Froyen, L.; Gusarov, A.V.; Bentefour, E.H.; Glorieux, C.

    2005-01-01

    A theoretical correlation between the effective extinction coefficient, the specific surface area, and the chord length distribution of powder beds is verified experimentally. The investigated powder beds consist of metallic particles of several tens of microns. The effective extinction coefficients are measured by a light-transmission technique at a wavelength of 540 nm. The powder structure is characterized by a quantitative image analysis of powder bed cross sections resulting in two-point correlation functions and chord length distributions. The specific surface area of the powders is estimated by laser-diffraction particle-size analysis and by the two-point correlation function. The theoretically predicted tendency of increasing extinction coefficient with specific surface area per unit void volume is confirmed by the experiments. However, a significant quantitative discrepancy is found for several powders. No clear correlation of the extinction coefficient with the powder material and particle size, and morphology is revealed, which is in line with the assumption of geometrical optics

  18. Antibacterial characteristics of CaCO3-MgO composites

    International Nuclear Information System (INIS)

    Yamamoto, Osamu; Ohira, Toshiaki; Alvarez, Kelly; Fukuda, Masayuki

    2010-01-01

    Dentifrices, such as tooth-paste, are pastes containing insoluble abrasives that aid in the removal of plaque from the teeth and help to polish them. Composite powders contributing to oral hygiene application, i.e., nano-scale MgO crystallite dispersed in CaCO 3 grain, were fabricated by the thermal decomposition of dolomite. The composite obtained by heating at 800 deg. C consisted of CaCO 3 grains including 20 nm MgO fine crystallite, being the purpose powder in this study. The antibacterial activity of these powders related to gram-positive and gram-negative bacteria was evaluated in vitro. The thermal decomposition above 800 deg. C resulted in the mixture of CaO and MgO. Antibacterial activity of the composite enhanced with increasing powder concentration. Though antibacterial action toward Staphylococcus aureus was greater than towards Escherichia coli, the death rate constant was identical in both bacteria. It can be concluded that the obtained composite possesses two functions able to improve the oral hygiene: as a tooth abrasive and as an antibacterial agent.

  19. Structure and hardness of a hard metal alloy prepared with a WC powder synthesized at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Costa, F.A. da [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil)], E-mail: francineac@yahoo.com; Medeiros, F.F.P. de [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil); Silva, A.G.P. da [Laboratorio de Materiais Avancados, UENF, 28015-620 Campos de Goytacazes, RJ (Brazil); Gomes, U.U. [Departamento de Fisica Teorica e Experimental, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil); Filgueira, M. [Laboratorio de Materiais Avancados, UENF, 28015-620 Campos de Goytacazes, RJ (Brazil); Souza, C.P. de [Laboratorio de Termodinamica e Reatores, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil)

    2008-06-25

    The structure and hardness of a WC-10 wt% Co alloy prepared with an experimental WC powder are compared with those of another alloy of the same composition produced under the same conditions and prepared with a commercial WC powder. The experimental WC powder was synthesized by a gas-solid reaction between APT and methane at low temperature and the commercial WC powder was conventionally produced by a solid-solid reaction between tungsten and carbon black. WC-10 wt% Co alloys with the two powders were prepared under the same conditions of milling and sintering. The structure of the sample prepared with the experimental WC powder is homogeneous and coarse grained. The structure of the sample prepared with the commercial powder is heterogeneous. Furthermore the size and shape of the WC grains are significantly different.

  20. Preparation of alumina-chromium composites by reactive hot-pressing Al + Cr2O3 based powders

    International Nuclear Information System (INIS)

    Osso, D.; Mocellin, A.; Caer, G. le; Pianelli, A.

    1993-01-01

    Chromium-Alumina based composites have been obtained by reactive sintering under load and vacuum of various powder blends. The starting mixtures have been prepared from commercially available aluminium metal, chromium and aluminium oxides, and a thermally unstable titanium compound respectively. Differential thermal analysis (DTA) and differential calorimetry (DSC) as well as X-ray diffraction were used to identify chemical transformations taking place within the system. Microstructure changes were observed via scanning electron microscopy (SEM) with an energy dispersive spectroscopy system (EDS). Chemical reactions in relevant binary subsystems have been investigated qualitatively in order to understand the course of events in the more complex quaternary mixtures. The possibilities of forming intermetallic phases in both the Al-Ti and Cr-Ti systems and of dissolving some Cr 2 O 3 into the product Al 2 O 3 phase have been considered. The influence of such parameters as thermal schedule and initial aluminium content on those side reactions and the resulting microstructures was investigated. (orig.)

  1. Synthesis and characterization of interpenetrating phase ceramic metal composites

    International Nuclear Information System (INIS)

    Kanwal, T.

    2011-01-01

    Alumina powder was sintered in MW furnace under vacuum, without vacuum and conventional sintering furnace at different temperatures followed by characterization to observe the effect of sintering mode. Zirconia-Nickel and Alumina-Nickel systems were selected to study the effect of metallic phase interconnectivity on the electrical and thermal behavior in interpenetrating phase composites (IPCs). In order to obtain the homogenous mixture of Alumina and Nick powders, a detailed investigation was performed on the de-agglomeration and prop mixing of powders. Sintering parameters were optimized for the homogenization o Alumina with Nickel in planetary ball mill without sticking of powders with jar.- Homogenization of Zirconia-Nickel and Alumina-Nickel powders was perform using planetary ball mill as well as pestle mortar. Compaction of composites was performed uniaxially and sintering was carried in microwave furnace, tubular furnace with Argon environment and in vacuum sintering furnace. Electrical and thermal behavior of microwave as well as conventionally sintered ZrO/sub 2/-Ni and Al/sub 2/O/sub 3/-Ni IPCs was also observed. Electrical behavior of Composites was characterized b determining the impedance of the composites. To find the percolation limit for both Alumina-Nickel and Zirconia-Nickel composite systems the real part of impedance was used. On the basis of electrical characterization, samples were selected for SEM, BET surface area and CTE analysis. SEM of selected samples was performed t observe the connectivity of Nickel in composites. Finally, the effect of percolation limit on thermal behavior of IPCs was investigated with the help of CTE. (author)

  2. Luminescent characteristics of praseodymium-doped zinc aluminate powders

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Perez, C.D.; Garcia-Hipolito, M.; Alvarez-Fregoso, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Coyoacan, DF (Mexico); Alvarez-Perez, M.A. [Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, Coyoacan, DF (Mexico); Ramos-Brito, F. [Laboratorio de Materiales Optoelectronicos, DIDe, Centro de Ciencias de Sinaloa, Av. De las Americas No. 2771 Nte. Col. Villa Universidad, Culiacan, Sinaloa (Mexico); Falcony, C. [Centro de Investigaciones y Estudios Avanzados del IPN, Departamento de Fisica, Mexico, DF (Mexico)

    2010-02-15

    In this research, we report the cathodoluminescence (CL) and preliminary photoluminescence (PL) properties of praseodymium-doped zinc aluminate powders. ZnAl{sub 2}O{sub 4}:Pr powders were synthesized by a very simple chemical process. X-ray diffraction spectra indicated a cubic spinel crystalline structure with an average crystallite size of 15 nm. CL properties of the powders were studied as a function of the praseodymium concentration and electron-accelerating potential. In this case, all the cathodoluminescent emission spectra showed main peaks located at 494, 535, 611, 646, and 733 nm, which were associated to the electronic transitions {sup 3}P{sub 0}{yields}{sup 3}H{sub 4}, {sup 3}P{sub 0}{yields}{sup 3}H{sub 5}, {sup 3}P{sub 0}{yields}{sup 3}H{sub 6}, {sup 3}P{sub 0}{yields}{sup 3}F{sub 2}, and {sup 3}P{sub 0}{yields}{sup 3}F{sub 4} of the Pr{sup 3+} ions, respectively. A quenching of the CL, with increasing doping concentration, was observed. Also, an increment on cathodoluminescent emission intensity was observed as the accelerating voltage increased. The PL emission spectrum showed similar characteristics to those of the CL spectra. The chemical composition of the powders, as determined by energy dispersive spectroscopy, is also reported. In addition, the surface morphology characteristics of the powders are shown. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Early stages of the mechanical alloying of TiC–TiN powder mixtures

    International Nuclear Information System (INIS)

    Mura, Giovanna; Musu, Elodia; Delogu, Francesco

    2013-01-01

    The present work focuses on the alloying behavior of TiC–TiN powder mixtures submitted to mechanical processing by ball milling. Accurate X-ray diffraction analyses indicate a progressive modification of the unit cell parameters of the TiC and TiN phases, suggesting the formation of TiC- and TiN-rich solid solutions with an increasingly larger content of solutes. Once the discrete character of the mechanical treatment is taken into due account, the smooth change of the unit cell parameters can be explained by a sequence of mutual dissolution stages related to individual collisions. At each collision, the average chemical composition of small amounts of TiC- and TiN-rich phases changes discontinuously. The discontinuous changes can be tentatively ascribed to local mass transport processes activated by the mechanical deformation of powders at collisions. -- Highlights: ► Mechanically processed TiC–TiN powder mixtures form two solid solutions. ► An analytical model was developed to describe the mechanical alloying kinetics. ► The amount of powder alloyed at collision was indirectly estimated. ► A few nanomoles of material participate in the alloying process at each collision. ► The chemical composition of the solid solutions was shown to change discontinuously.

  4. Effect of Limestone Powder on Microstructure of Ternary Cementitious System

    NARCIS (Netherlands)

    Zhang, Y.; Ye, G.

    2012-01-01

    The pressure to reach sustainability favours the development of ternary composite cement. The synergistic effect on mechanical behaviour at 28 days between limestone powder (LP) and pozzolanic additives, i.e. fly ash (FA) and blast furnace slag (BFS), has been documented. In order to better

  5. New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

    NARCIS (Netherlands)

    Budding, A.; Vaneker, Thomas H.J.

    2013-01-01

    In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of

  6. Spectrochemical analysis of powder using 355 nm Nd-YAG laser-induced low-pressure plasma.

    Science.gov (United States)

    Lie, Zener S; Pardede, M; Hedwig, R; Suliyanti, M M; Kurniawan, Koo Hendrik; Munadi; Lee, Yong-Inn; Kagawa, Kiichiro; Hattori, Isamu; Tjia, May On

    2008-04-01

    The applicability of spectrochemical analysis of minute amounts of powder samples was investigated using an ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A large variety of chemical powder samples of different composition were employed in the experiment. These included a mixture of copper(II) sulfate pentahydrate, zinc sulfide, and chromium(III) sulfate n-hydrate powders, baby powder, cosmetic powders, gold films, zinc supplement tablet, and muds and soils from different areas. The powder samples were prepared by pulverizing the original samples to an average size of around 30 microm in order to trap them in the tiny micro holes created on the surface of the quartz subtarget. It was demonstrated that in all cases studied, good quality spectra were obtained with low background, free from undesirable contamination by the subtarget elements and featuring ppm sensitivity. A further measurement revealed a linear calibration curve with zero intercept. These results clearly show the potential application of this technique for practical qualitative and quantitative spectrochemical analysis of powder samples in various fields of study and investigation.

  7. High-energy, high-rate consolidation of tungsten and tungsten-based composite powders

    Energy Technology Data Exchange (ETDEWEB)

    Raghunathan, S.K.; Persad, C.; Bourell, D.L.; Marcus, H.L. (Center for Materials Science and Engineering, Univ. of Texas, Austin (USA))

    1991-01-20

    Tungsten and tungsten-based heavy alloys are well known for their superior mechanical properties at elevated temperatures. However, unalloyed tungsten is difficult to consolidate owing to its very high melting temperature (3683 K). The additions of small amounts of low-melting elements such as iron, nickel, cobalt and copper, facilitate the powder processing of dense heavy alloys at moderate temperatures. Energetic high-current pulses have been used recently for powder consolidation. In this paper, the use of a homopolar generator as a power source to consolidate selected tungsten and tungsten-based alloys is examined. Various materials were consolidated including unalloyed tungsten, W-Nb, W-Ni, and tungsten heavy alloy with boron carbide. The effect of process parameters such as pressure and specific energy input on the consolidation of different alloy systems is described in terms of microstructure and property relationships. (orig.).

  8. Plasma spheroidization of iron powders in a non-transferred DC thermal plasma jet

    International Nuclear Information System (INIS)

    Kumar, S.; Selvarajan, V.

    2008-01-01

    In this paper, the results of plasma spheroidization of iron powders using a DC non-transferred plasma spray torch are presented. The morphology of the processed powders was characterized through scanning electron microscopy (SEM) and optical microscopy (OM). The percentages of spheroidized powders were calculated by the shape factors such as the Irregularity Parameter (IP) and Roundness (RN). A maximum of 83% of spheroidization can be achieved. The spheroidization results are compared with the theoretical estimation and they are found to be in good agreement. The phase composition of the spheroidized powder was analyzed by XRD. The effect of plasma jet temperature and plasma gas flow rate on spheroidization is discussed. At low plasma gas flow rates and at high plasma jet temperatures, the percentage of spheroidization is high

  9. Compact Process for the Preparation of Microfine Spherical High-Niobium-Containing TiAl Alloy Powders

    Science.gov (United States)

    Tong, J. B.; Lu, X.; Liu, C. C.; Wang, L. N.; Qu, X. H.

    2015-03-01

    High-Nb-containing TiAl alloys are a new generation of materials for high-temperature structural applications because of their superior high-temperature mechanical properties. The alloy powders can be widely used for additive manufacturing, thermal spraying, and powder metallurgy. Because of the difficulty of making microfine spherical alloy powders in quantity by conventional techniques, a compact method was proposed, which consisted of two-step ball milling of elemental powders and subsequent radio frequency (RF) argon plasma spheroidization. In comparison with conventional mechanical alloying techniques, the two-step milling process can be used to prepare alloy powders with uniform scale in a short milling time with no addition of process control agent. This makes the process effective and less contaminating. After RF argon plasma spheroidization, the powders produced exhibit good sphericity, and the number-average diameter is about 8.2 μm with a symmetric unimodal particle size distribution. The powders perform high composition homogeneity and contain predominately supersaturated α 2-Ti3Al phase. The oxygen and carbon contents of the spheroidized powder are 0.47% and 0.050%, respectively.

  10. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    Energy Technology Data Exchange (ETDEWEB)

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  11. Carbon Sequestration in Olivine and Basalt Powder Packed Beds.

    Science.gov (United States)

    Xiong, Wei; Wells, Rachel K; Giammar, Daniel E

    2017-02-21

    Fractures and pores in basalt could provide substantial pore volume and surface area of reactive minerals for carbonate mineral formation in geologic carbon sequestration. In many fractures solute transport will be limited to diffusion, and opposing chemical gradients that form as a result of concentration differences can lead to spatial distribution of silicate mineral dissolution and carbonate mineral precipitation. Glass tubes packed with grains of olivine or basalt with different grain sizes and compositions were used to explore the identity and spatial distribution of carbonate minerals that form in dead-end one-dimensional diffusion-limited zones that are connected to a larger reservoir of water in equilibrium with 100 bar CO 2 at 100 °C. Magnesite formed in experiments with olivine, and Mg- and Ca-bearing siderite formed in experiments with flood basalt. The spatial distribution of carbonates varied between powder packed beds with different powder sizes. Packed beds of basalt powder with large specific surface areas sequestered more carbon per unit basalt mass than powder with low surface area. The spatial location and extent of carbonate mineral formation can influence the overall ability of fractured basalt to sequester carbon.

  12. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  13. Powder processing of high Tc oxide superconductors and their properties

    International Nuclear Information System (INIS)

    Vajpei, A.C.; Upadhyaya, G.S.

    1992-01-01

    Powder processing of ceramics is an established technology and in the area of high T c superconductors, its importance is felt even more significantly. The present monograph is an attempt in this direction to explore the perspectives and practice of powder processing routes towards control and optimization of the microstructure and pertinent properties of high T c oxide superconductors. The monograph consists of 6 chapters. After a very brief introduction (Chapter 1), Chapter 2 describes various classes of high T c oxide superconductors and their phase equilibria. Chapter 3 highlights the preparation of oxide superconductor powders through various routes and details their subtle distinctions. Chapter 4 briefly covers characterisation of the oxide superconductors, laying emphasis on the process-analysis and microstructure. Chapter 5 describes in detail various fabrication techniques for bulk superconductors through the powder routes. The last Chapter (Chapter 6) describing properties of bulk oxide superconductors, discusses the role of subtituents, compositional variations and processing methods on such properties. References are given at the end of each chapter. (orig.)

  14. Extremely fine structured cathode for solid oxide fuel cells using Sr-doped LaMnO3 and Y2O3-stabilized ZrO2 nano-composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Sumi, Hirofumi; Nomura, Katsuhiro; Yamaguchi, Yuki; Fujishiro, Yoshinobu

    2017-02-01

    A solid oxide fuel cell (SOFC) for high power density operation was developed with a microstructure-controlled cathode using a nano-composite powder of Sr-doped LaMnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) synthesized by spray pyrolysis. The individual LSM-YSZ nano-composite particles, formed by crystalline and amorphous nano-size LSM and YSZ particles, showed spherical morphology with uniform particle size. The use of this powder for cathode material led to an extremely fine microstructure, in which all the LSM and YSZ grains (approximately 100-200 nm) were highly dispersed and formed their own network structures. This microstructure was due to the two phase electrode structure control using the powder, namely, nano-order level in each particle and micro-order level between particles. An anode-supported SOFC with the LSM-YSZ cathode using humidified H2 as fuel and ambient air as oxidant exhibited high power densities, such as 1.29 W cm-2 under a voltage of 0.75 V and a maximum power density of 2.65 W cm-2 at 800 °C. Also, the SOFC could be stably operated for 250 h with no degradation, even at a high temperature of 800 °C.

  15. Study of Diffusion Bonding of 45 Steel through the Compacted Nickel Powder Layer

    Science.gov (United States)

    Zeer, G. M.; Zelenkova, E. G.; Temnykh, V. I.; Tokmin, A. M.; Shubin, A. A.; Koroleva, Yu. P.; Mikheev, A. A.

    2018-02-01

    The microstructure of the transition zone and powder spacer, the concentration distribution of chemical elements over the width of the diffusion-bonded joint, and microhardness of 45 steel-compacted Ni powder spacer-45 steel layered composites formed by diffusion bonding have been investigated. It has been shown that the relative spacer thickness χ compacting pressure of 500 MPa. The solid-state diffusion bonding is accompanied by sintering the nickel powder spacer and the formation of the transition zone between the spacer and steel. The transition zone consists of solid solution of nickel in the α-Fe phase and ordered solid solution of iron in nickel (FeNi3).

  16. Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive

    Directory of Open Access Journals (Sweden)

    YUAN Jiang

    2017-09-01

    Full Text Available Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La.The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.

  17. Doped-carbon composites, synthesizing methods and applications of the same

    Science.gov (United States)

    Viswanathan, Tito

    2017-05-09

    A method of synthesizing a doped carbon composite includes preparing a solution having a carbon source material and a heteroatom containing additive, evaporating the solution to yield a plurality of powders, and subjecting the plurality of powders to a heat treatment for a duration of time effective to produce the doped carbon composite.

  18. Quantitative adaptation analytics for assessing dynamic systems of systems: LDRD Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, John H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). System Readiness & Sustainment Technologies (6133, M/S 1188); Miner, Nadine E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military & Energy Systems Analysis (6114, M/S 1188); Wilson, Michael L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Resilience and Regulatory Effects (6921, M/S 1138); Le, Hai D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). System Readiness & Sustainment Technologies (6133, M/S 1188); Kao, Gio K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Networked System Survivability & Assurance (5629, M/S 0671); Melander, Darryl J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Software Systems R& D (9525, M/S 1188); Longsine, Dennis Earl [Sandia National Laboratories, Unknown, Unknown; Vander Meer, Jr., Robert C. [SAIC, Inc., Albuquerque, NM (United States)

    2015-01-01

    Our society is increasingly reliant on systems and interoperating collections of systems, known as systems of systems (SoS). These SoS are often subject to changing missions (e.g., nation- building, arms-control treaties), threats (e.g., asymmetric warfare, terrorism), natural environments (e.g., climate, weather, natural disasters) and budgets. How well can SoS adapt to these types of dynamic conditions? This report details the results of a three year Laboratory Directed Research and Development (LDRD) project aimed at developing metrics and methodologies for quantifying the adaptability of systems and SoS. Work products include: derivation of a set of adaptability metrics, a method for combining the metrics into a system of systems adaptability index (SoSAI) used to compare adaptability of SoS designs, development of a prototype dynamic SoS (proto-dSoS) simulation environment which provides the ability to investigate the validity of the adaptability metric set, and two test cases that evaluate the usefulness of a subset of the adaptability metrics and SoSAI for distinguishing good from poor adaptability in a SoS. Intellectual property results include three patents pending: A Method For Quantifying Relative System Adaptability, Method for Evaluating System Performance, and A Method for Determining Systems Re-Tasking.

  19. Real-time discriminatory sensors for water contamination events :LDRD 52595 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Borek, Theodore Thaddeus III (; ); Carrejo-Simpkins, Kimberly; Wheeler, David Roger; Adkins, Douglas Ray; Robinson, Alex Lockwood; Irwin, Adriane Nadine; Lewis, Patrick Raymond; Goodin, Andrew M.; Shelmidine, Gregory J.; Dirk, Shawn M.; Chambers, William Clayton; Mowry, Curtis Dale (1722 Micro-Total-Analytical Systems); Showalter, Steven Kedrick

    2005-10-01

    The gas-phase {mu}ChemLab{trademark} developed by Sandia can detect volatile organics and semi-volatiles organics via gas phase sampling . The goal of this three year Laboratory Directed Research and Development (LDRD) project was to adapt the components and concepts used by the {mu}ChemLab{trademark} system towards the analysis of water-borne chemicals of current concern. In essence, interfacing the gas-phase {mu}ChemLab{trademark} with water to bring the significant prior investment of Sandia and the advantages of microfabrication and portable analysis to a whole new world of important analytes. These include both chemical weapons agents and their hydrolysis products and disinfection by-products such as Trihalomethanes (THMs) and haloacetic acids (HAAs). THMs and HAAs are currently regulated by EPA due to health issues, yet water utilities do not have rapid on-site methods of detection that would allow them to adjust their processes quickly; protecting consumers, meeting water quality standards, and obeying regulations more easily and with greater confidence. This report documents the results, unique hardware and devices, and methods designed during the project toward the goal stated above. It also presents and discusses the portable field system to measure THMs developed in the course of this project.

  20. RF/microwave properties of nanotubes and nanowires : LDRD Project 105876 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Scrymgeour, David; Lee, Mark; Hsu, Julia W. P.; Highstrete, Clark

    2009-09-01

    LDRD Project 105876 was a research project whose primary goal was to discover the currently unknown science underlying the basic linear and nonlinear electrodynamic response of nanotubes and nanowires in a manner that will support future efforts aimed at converting forefront nanoscience into innovative new high-frequency nanodevices. The project involved experimental and theoretical efforts to discover and understand high frequency (MHz through tens of GHz) electrodynamic response properties of nanomaterials, emphasizing nanowires of silicon, zinc oxide, and carbon nanotubes. While there is much research on DC electrical properties of nanowires, electrodynamic characteristics still represent a major new frontier in nanotechnology. We generated world-leading insight into how the low dimensionality of these nanomaterials yields sometimes desirable and sometimes problematic high-frequency properties that are outside standard model electron dynamics. In the cases of silicon nanowires and carbon nanotubes, evidence of strong disorder or glass-like charge dynamics was measured, indicating that these materials still suffer from serious inhomogeneities that limit there high frequency performance. Zinc oxide nanowires were found to obey conventional Drude dynamics. In all cases, a significant practical problem involving large impedance mismatch between the high intrinsic impedance of all nanowires and nanotubes and high-frequency test equipment had to be overcome.

  1. Plasma spraying of Fe-Cr-Al alloy powder

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Leitner, J.; Kolman, Blahoslav Jan; Písačka, Jan; Schneeweiss, Oldřich

    2008-01-01

    Roč. 46, č. 1 (2008), s. 17-25 ISSN 0023-432X R&D Projects: GA AV ČR IAA1041404 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z20410507 Keywords : Fe-Cr-Al alloy powder * plasma spraying * oxidation * vaporization * composition changes Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.345, year: 2007

  2. Structure and properties of nanocrystalline soft magnetic composite materials with silicon polymer matrix

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Nowosielski, R.; Konieczny, J.; PrzybyI, A.; WysIocki, J.

    2005-01-01

    The paper concerns investigation of nanocrystalline composites technology preparation. The composites in the form of rings with rectangular transverse section, and with polymer matrix and nanocrystalline metallic powders fulfillment were made, for obtaining good ferromagnetic properties. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses strips in an as-quenched state. Generally for investigation, Co matrix alloys with the silicon polymer were used. Magnetic properties in the form of hysteresis loop by rings method were measured. Generally composite cores showed lower soft ferromagnetic properties than winded cores of nanocrystalline strips, but composite cores showed interesting mechanical properties. Furthermore, the structure of strips and powders on properties of composites were investigated

  3. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    International Nuclear Information System (INIS)

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-01-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  4. The Potential of Coconut Shell Powder (CSP) and Coconut Shell Activated Carbon (CSAC) Composites as Electromagnetic Interference (EMI) Absorbing Material

    International Nuclear Information System (INIS)

    Siti Nurbazilah Abdul Jabal; Seok, Y.B.; Hoon, W.F.

    2016-01-01

    Agriculture waste is potentially useful as an alternative material to absorb and attenuate electromagnetic interference (EMI). This research highlights the use of coconut shell powder (CSP) and coconut shell activated carbon (CSAC) as raw materials with epoxy resin and amine hardener composite to absorb microwave signals over frequency of 1 - 8 GHz. In order to investigate the suitability of these raw materials as EMI absorbing material, carbon composition of the raw materials is determined through CHNS Elemental Analysis. The surface morphology of the raw materials in term of porosity is investigated by using TM3000 Scanning Electron Microscope (SEM). The complex permittivity of the composites is determined by using high temperature dielectric probe in conjunction with Network Analyzer. From the result, the Carbon% of CSP and CSAC is 46.70 % and 84.28 % respectively. In term of surface morphology, the surface porosity of CSP and CSAC is in the range of 2 μm and 1 μm respectively. For the dielectric properties, the dielectric constant and the dielectric loss factor for CSP and CSAC is 4.5767 and 64.8307 and 1.2144 and 13.8296 respectively. The materials more potentially useful as substitute materials for electromagnetic interference (EMI) absorbing are discussed. (author)

  5. The incorporation of exhauster powder mass in ceramics atomised

    International Nuclear Information System (INIS)

    Knop, W.R.; Valentina, L. Dalla; Folgueiras, M.V.; Semptikovski, S.C.

    2009-01-01

    Inside the context of alternative search for the use of industrial waste as natural raw for the industrial ceramic, this work had the objective to evaluate the possibility of the use of exhauster powder generated in the foundry process. The characterization was performed by scanning electron microscopy, x-ray diffractometry and thermal analysis, noting that it is a powder with a high content of fine and compatible with the composition of ceramic bodies. Formulations were prepared with different exhauster powder content. The sintered materials at 1000, 1100 and 1200 deg C were characterized according technological properties as water absorption, linear shrinkage, bulk density and apparent density. Microstructural analysis was carried out by scanning electron microscopy and X-ray diffraction. The results showed that it is possible to use the waste. It was observed that the waste increase the density in sintering process, and with high levels of waste occurs an increase of the porosity and intensification in the color of the new material. (author)

  6. Formation and characterization of solid-solution (V,W,Ti)CN composite powder

    CSIR Research Space (South Africa)

    Bolokang, Amogelang S

    2017-04-01

    Full Text Available We report on the synthesis of a mixture of vanadium (V), tungsten (W), titanium (Ti) and carbon (C) mixture using ball milling in argon atmosphere. Thermal analysis of the milled powder showed an exothermic reaction at approximately 700°C...

  7. CNTs Modified and Enhanced Cu Matrix Composites

    Directory of Open Access Journals (Sweden)

    ZHANG Wen-zhong

    2016-12-01

    Full Text Available The composite powders of 2%-CNTs were prepared by wet ball milling and hydrogen annealing treatment-cold pressing sintering was used to consolidate the ball milled composite powders with different modifications of the CNTs. The results show that the length of the CNTs is shortened, ports are open, and amorphous carbon content is increased by ball milling. And after a mixed acid purification, the impurity on the surface of the CNTs is completely removed,and a large number of oxygen-containing reactive groups are introduced; the most of CNTs can be embedded in the Cu matrix and the CNTs have a close bonding with the Cu matrix, forming the lamellar composite structure, then, ultrafine-grained composite powders can be obtained by hydrogen annealing treatment. Shortening and purification of the CNTs are both good for dispersion and bonding of CNTs in the Cu matrix, and the tensile strength and hardness of the composites after shortening and purification reaches the highest, and is 296MPa and 139.8HV respectively, compared to the matrix, up to 123.6% in tensile strength and 42.9% in hardness, attributed to the fine grain strengthening and load transferring.

  8. Method of manufacturing aluminide sheet by thermomechanical processing of aluminide powders

    Science.gov (United States)

    Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

    2000-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr.ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  9. Combined sol–gel and carbothermal synthesis of ZrC–TiC powders for composites

    Energy Technology Data Exchange (ETDEWEB)

    Umalas, Madis [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Estonian Nanotechnology Competence Centre, Riia 142, 51014, Tartu (Estonia); Hussainova, Irina, E-mail: irina.hussainova@ttu.ee [Department of Materials Engineering, Tallinn University of Technology, Ehitajate 5, 19086, Tallinn (Estonia); ITMO University, Kronverksky 49, St. Petersburg, 197101 (Russian Federation); Reedo, Valter [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Young, Der-Liang [Department of Materials Engineering, Tallinn University of Technology, Ehitajate 5, 19086, Tallinn (Estonia); Cura, Erkin; Hannula, Simo-Pekka [Department of Materials Science and Engineering, Aalto University, School of Chemical Technology, POB 16200, Aalto, 00076 (Finland); Lõhmus, Rünno [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Estonian Nanotechnology Competence Centre, Riia 142, 51014, Tartu (Estonia); Lõhmus, Ants [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia)

    2015-03-01

    The TiC–ZrC binary compound of nanostructured powders was synthesised by combination of sol–gel and carbothermal reduction. The polymeric precursor of the blend was produced by sol–gel process from titanium tetrabutoxide, zirconium tetrabutoxide and benzene-1.4-diol; then carbothermally reduced to the TiC–ZrC blend at 1600 °C in an inert environment. The chemical reactions occurring in the system were monitored by infrared spectrometry. Stable alkoxide solution was obtained by adding acetylacetone to avoid premature gelation of the metal alkoxide mixture. A solid solution of ZrTiC{sub 2} was produced by spark plasma sintering at temperature of 2000 °C. - Highlights: • A polymeric precursor of TiC–ZrC blend was synthesised by sol–gel process. • The polymeric precursor synthesis was studied by infrared spectroscopy. • TiC–ZrC powder blend was carbothermally reduced from polymeric precursor. • TiC–ZrC powder blend was sintered to ZrTiC{sub 2} solid solution by spark plasma sintering. • Sintered ZrTiC{sub 2} have good mechanical properties.

  10. Combined sol–gel and carbothermal synthesis of ZrC–TiC powders for composites

    International Nuclear Information System (INIS)

    Umalas, Madis; Hussainova, Irina; Reedo, Valter; Young, Der-Liang; Cura, Erkin; Hannula, Simo-Pekka; Lõhmus, Rünno; Lõhmus, Ants

    2015-01-01

    The TiC–ZrC binary compound of nanostructured powders was synthesised by combination of sol–gel and carbothermal reduction. The polymeric precursor of the blend was produced by sol–gel process from titanium tetrabutoxide, zirconium tetrabutoxide and benzene-1.4-diol; then carbothermally reduced to the TiC–ZrC blend at 1600 °C in an inert environment. The chemical reactions occurring in the system were monitored by infrared spectrometry. Stable alkoxide solution was obtained by adding acetylacetone to avoid premature gelation of the metal alkoxide mixture. A solid solution of ZrTiC 2 was produced by spark plasma sintering at temperature of 2000 °C. - Highlights: • A polymeric precursor of TiC–ZrC blend was synthesised by sol–gel process. • The polymeric precursor synthesis was studied by infrared spectroscopy. • TiC–ZrC powder blend was carbothermally reduced from polymeric precursor. • TiC–ZrC powder blend was sintered to ZrTiC 2 solid solution by spark plasma sintering. • Sintered ZrTiC 2 have good mechanical properties

  11. Sintering behaviour of CeO2-Gd2O3 powders prepared by the oxalate coprecipitation method

    International Nuclear Information System (INIS)

    Duran, P.; Jurado, J.R.; Moure, C.

    1993-01-01

    The powder and compact characteristics as well as the sintering behaviour of two CeO 2 -Gd 2 O 3 compositions prepared by the oxalate coprecipitation method are studied as a function of the powder particle size and the pore-size distribution in the powder compacts. Shrinkage was measured at a constant heating rate and the results are compared with those obtained by isothermal sintering experiments. Grain growth and microstructural development on sintered samples were studied. (orig.)

  12. Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing.

    Science.gov (United States)

    Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

    2015-01-06

    The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer-ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds' critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering.

  13. Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing

    International Nuclear Information System (INIS)

    Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

    2015-01-01

    The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer–ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds’ critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering. (paper)

  14. Antibacterial characteristics of CaCO{sub 3}-MgO composites

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Osamu, E-mail: yamamoto@cges.akita-u.ac.jp [Center for Geo-Environmental Science, Faculty of Engineering and Resource Science, Akita University, 1-1 Tegata Gakuen-machi, Akita 010-8502 (Japan); Ohira, Toshiaki; Alvarez, Kelly [Center for Geo-Environmental Science, Faculty of Engineering and Resource Science, Akita University, 1-1 Tegata Gakuen-machi, Akita 010-8502 (Japan); Fukuda, Masayuki [Division of Dentistry and Oral Surgery, Akita University Hospital, 1-1-1 Hondo, Akita 010-8543 (Japan)

    2010-10-15

    Dentifrices, such as tooth-paste, are pastes containing insoluble abrasives that aid in the removal of plaque from the teeth and help to polish them. Composite powders contributing to oral hygiene application, i.e., nano-scale MgO crystallite dispersed in CaCO{sub 3} grain, were fabricated by the thermal decomposition of dolomite. The composite obtained by heating at 800 deg. C consisted of CaCO{sub 3} grains including 20 nm MgO fine crystallite, being the purpose powder in this study. The antibacterial activity of these powders related to gram-positive and gram-negative bacteria was evaluated in vitro. The thermal decomposition above 800 deg. C resulted in the mixture of CaO and MgO. Antibacterial activity of the composite enhanced with increasing powder concentration. Though antibacterial action toward Staphylococcus aureus was greater than towards Escherichia coli, the death rate constant was identical in both bacteria. It can be concluded that the obtained composite possesses two functions able to improve the oral hygiene: as a tooth abrasive and as an antibacterial agent.

  15. Development of antifriction composites based on polypyromellitimide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Olifirov, L.K., E-mail: M80786@yandex.ru [National University of Science and Technology «MISIS» (Russian Federation); Kaloshkin, S.D.; Tcherdyntsev, V.V. [National University of Science and Technology «MISIS» (Russian Federation); Danilov, V.D. [Blagonravov Institute of Machines Science of Russian Academy of Sciences (Russian Federation)

    2014-02-15

    Highlights: • Polypyromellitimide powder from waste of production polyimide films were obtained. • Structure of polypyromellitimide strongly changes after high energy ball milling. • Addition of commercial polyimide powder improve moldability of polypyromellitimide. • Polypyromellitimide based composites show good tribological properties in dry friction mode. -- Abstract: A method of polypyromellitimide powder production from PM-A film was proposed and a possibility of fabricating bulk composites based on polypyromellitimide matrix was investigated. The powders were prepared by the treatment of PM-A films in a planetary ball mill. The compositions based on polypyromellitimide containing additives of Al{sub 65}Cu{sub 23}Fe{sub 12} quasicrystals, graphite, polytetrafluoroethylene and PI-PR-20 polyimide were prepared by the solid-state mixing in an IKA M20 batch mill. The bulk samples were fabricated by the compression molding technique. Thus produced materials were characterized by using the methods of sieve analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, dynamo-mechanical analysis and tribological tests. It was found that the PM-A polypyromellitimide powder had a low sinterability and, therefore, the bulk samples of unfilled PM-A and also the composites based on PM-A containing additives of Al{sub 65}Cu{sub 23}Fe{sub 12} quasicrystals, graphite and polytetrafluoroethylene exhibited a high brittleness and show unstable behavior in the tribological tests. It was found that an addition of 15 wt.% PI-PR-20 polyimide improved the sinterability of PM-A and also provides excellent antifriction properties.

  16. Fabrication and Mechanical Properties of SiCw(p/SiC-Si Composites by Liquid Si Infiltration using Pyrolysed Rice Husks and SiC Powders as Precursors

    Directory of Open Access Journals (Sweden)

    Dan Zhu

    2014-03-01

    Full Text Available Dense silicon carbide (SiC matrix composites with SiC whiskers and particles as reinforcement were prepared by infiltrating molten Si at 1550 °C into porous preforms composed of pyrolysed rice husks (RHs and extra added SiC powder in different ratios. The Vickers hardness of the composites showed an increase from 18.6 to 21.3 GPa when the amount of SiC added in the preforms was 20% (w/w, and then decreased to 17.3 GPa with the increase of SiC added in the preforms up to 80% (w/w. The values of flexural strength of the composites initially decreased when 20% (w/w SiC was added in the preform and then increased to 587 MPa when the SiC concentration reached 80% (w/w. The refinement of SiC particle sizes and the improvement of the microstructure in particle distribution of the composites due to the addition of external SiC played an effective role in improving the mechanical properties of the composites.

  17. Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

    Energy Technology Data Exchange (ETDEWEB)

    Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.; Wiese-Smith, Deneille

    2007-12-01

    The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includes an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.

  18. Coir fiber reinforced polypropylene composite panel for automotive interior applications

    Science.gov (United States)

    Nadir Ayrilmis; Songklod Jarusombuti; Vallayuth Fueangvivat; Piyawade Bauchongkol; Robert H. White

    2011-01-01

    In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the...

  19. Mechanical and thermal properties of polypropylene (PP) composites filled with modified shell waste

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Z.T., E-mail: sxyzt@126.com [College of Materials Science and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Chen, T. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Li, H.Y. [Zhoushan Ocean Research Institute, Zhejiang University, Zhoushan 316021 (China); Xia, M.S., E-mail: msxia@zju.edu.cn [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Ye, Y.; Zheng, H. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China)

    2013-11-15

    Highlights: • Adding modified shell powder could significantly increase the properties of PP. • The modified shell powder could act as a nucleating agent in PP matrix. • The modified shell powder has a potential to be used as a bio-filler. -- Abstract: Shell waste, with its high content of calcium carbonate (CaCO{sub 3}) plus organic matrix, has a potential to be used as a bio-filler. In this work, shell waste was modified by furfural and then incorporated to reinforce polypropylene (PP). The shell waste and modified powder were characterized by means of X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray photoelectronic spectroscopy (XPS), and Fourier transformed infrared spectroscopy (FTIR). The mechanical and thermal properties of neat PP and PP composites were investigated as well. Thermal gravimetric (TG) analyses confirmed the reinforcing role of modified powder in PP composites. The mechanical properties studied showed that adding modified powder could significantly increase the impact strength, elongation at break point and flexural modulus of composites. The maximum incorporation content could reach 15 wt.% with a good balance between toughness and stiffness of PP composites. Differential scanning calorimetry (DSC) results showed that the modified powder could act as a nucleating agent and thus increase the crystallization temperature of PP. Polarized optical microscopy (POM) observation also indicated that the introduction of modified powder could promote the heterogeneous nucleation of PP matrix.

  20. Antioxidant and antimicrobial activities of squid ink powder

    Directory of Open Access Journals (Sweden)

    Fatimah Zaharah, M.Y.

    2017-10-01

    Full Text Available Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assays named 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and Ferric Reducing Antioxidant Power (FRAP assay, and antimicrobial analysis were done on the powdered squid ink. The proximate results of squid ink powder were 4.43 ± 0.29% moisture, 62.46 ± 0.62% protein, 3.96 ± 0.08% fat, and 9.29 ± 0.05% ash. Results of DPPH assay showed that water extraction of squid ink powder has the highest 94.87 ± 4.87%, followed by ethanol 67.57 ± 7.55%, and hexane extract 2.10 ± 1.18%. FRAP assay result presented the same trend with water extraction had the highest value of 929.67 ± 2.31 μmol Fe (II / g of sample extract, followed by ethanol extract 201.00 ± 26.29 μmol Fe (II per gram sample and hexane 79.67 ± 12.66 μmol Fe (II / g of sample extract. Both water and ethanol extract showed antimicrobial properties with inhibition range of 7 to 15 mm, respectively. Fresh squid ink had 1.254 × 103 colony forming unit per gram of sample of microbial content. Squid ink powder had protein as major compound and microbial content was below from standard value of fisheries products as stated in Food Act 1983 and Regulation 1985.

  1. Powder Materials and Energy Efficiency in Transportation: Opportunities and Challenges

    Science.gov (United States)

    Marquis, Fernand D. S.

    2012-03-01

    The transportation industry accounts for one quarter of global energy use and has by far the largest share of global oil consumption. It used 51.5% of the oil worldwide in 2003. Mobility projections show that it is expected to triple by 2050 with associated energy use. Considerable achievements recently have been obtained in the development of powder and powder-processed metallic alloys, metal matrix composites, intermetallics, and carbon fiber composites. These achievements have resulted in their introduction to the transportation industry in a wide variety of transportation components with significant impact on energy efficiency. A significant number of nano, nanostructured, and nanohybrid materials systems have been deployed. Others, some of them incorporating carbon nanotubes and graphene, are under research and development and exhibit considerable potential. Airplane redesign using a materials and functional systems integration approach was used resulting in considerable system improvements and energy efficiency. It is expected that this materials and functional systems integration soon will be adopted in the design and manufacture of other advanced aircrafts and extended to the automotive industry and then to the marine transportation industry. The opportunities for the development and application of new powder materials in the transportation industry are extensive, with considerable potential to impact energy utilization. However, significant challenges need to be overcome in several critical areas.

  2. [Glass transition of Chinese medicine extract powder and its application].

    Science.gov (United States)

    Luo, Xiao-Jian; Liu, Hui; Liang, Hong-Bo; Xiong, Lei; Rao, Xiao-Yong; Xie, Yin; He, Yan

    2017-01-01

    Glass transition theory is an important theory in polymer science, which is used to characterize the physical properties. It refers to the transition of amorphous polymer from the glassy state to the rubber state due to heating or the transition from rubber state to glassy state due to cooling. In this paper, the glassy state and glass transition of food and the similar relationship between the composition of Chinese medicine extract powder and food ingredients were described; the determination method for glass transition temperature (Tg) of Chinese medicine extract powder was established and its main influencing factors were analyzed. Meanwhile, the problems in drying process, granulation process and Chinese medicine extract powder and solid preparation storage were analyzed and investigated based on Tg, and then the control strategy was put forward to provide guidance for the research and production of Chinese medicine solid preparation. Copyright© by the Chinese Pharmaceutical Association.

  3. Noncontact surface thermometry for microsystems: LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Mark (Georgia Institute of Technology, Atlanta, GA); Beecham, Thomas (Georgia Institute of Technology, Atlanta, GA); Graham, Samuel (Georgia Institute of Technology, Atlanta, GA); Kearney, Sean Patrick; Serrano, Justin Raymond; Phinney, Leslie Mary

    2006-10-01

    We describe a Laboratory Directed Research and Development (LDRD) effort to develop and apply laser-based thermometry diagnostics for obtaining spatially resolved temperature maps on working microelectromechanical systems (MEMS). The goal of the effort was to cultivate diagnostic approaches that could adequately resolve the extremely fine MEMS device features, required no modifications to MEMS device design, and which did not perturb the delicate operation of these extremely small devices. Two optical diagnostics were used in this study: microscale Raman spectroscopy and microscale thermoreflectance. Both methods use a low-energy, nonperturbing probe laser beam, whose arbitrary wavelength can be selected for a diffraction-limited focus that meets the need for micron-scale spatial resolution. Raman is exploited most frequently, as this technique provides a simple and unambiguous measure of the absolute device temperature for most any MEMS semiconductor or insulator material under steady state operation. Temperatures are obtained from the spectral position and width of readily isolated peaks in the measured Raman spectra with a maximum uncertainty near {+-}10 K and a spatial resolution of about 1 micron. Application of the Raman technique is demonstrated for V-shaped and flexure-style polycrystalline silicon electrothermal actuators, and for a GaN high-electron-mobility transistor. The potential of the Raman technique for simultaneous measurement of temperature and in-plane stress in silicon MEMS is also demonstrated and future Raman-variant diagnostics for ultra spatio-temporal resolution probing are discussed. Microscale thermoreflectance has been developed as a complement for the primary Raman diagnostic. Thermoreflectance exploits the small-but-measurable temperature dependence of surface optical reflectivity for diagnostic purposes. The temperature-dependent reflectance behavior of bulk silicon, SUMMiT-V polycrystalline silicon films and metal surfaces is

  4. Early stages of the mechanical alloying of TiC-TiN powder mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mura, Giovanna [Dipartimento di Ingegneria Elettrica ed Elettronica, Universita degli Studi di Cagliari, via Marengo 2, 09123 Cagliari (Italy); Musu, Elodia [Industrial Telemicroscopy Laboratory, Sardegna Ricerche, Polaris, Technology Park of Sardinia, Edificio 3, Loc. Piscinamanna, 09010 Pula (Italy); Delogu, Francesco, E-mail: francesco.delogu@dimcm.unica.it [Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Universita degli Studi di Cagliari, via Marengo 2, I-09123 Cagliari (Italy)

    2013-01-15

    The present work focuses on the alloying behavior of TiC-TiN powder mixtures submitted to mechanical processing by ball milling. Accurate X-ray diffraction analyses indicate a progressive modification of the unit cell parameters of the TiC and TiN phases, suggesting the formation of TiC- and TiN-rich solid solutions with an increasingly larger content of solutes. Once the discrete character of the mechanical treatment is taken into due account, the smooth change of the unit cell parameters can be explained by a sequence of mutual dissolution stages related to individual collisions. At each collision, the average chemical composition of small amounts of TiC- and TiN-rich phases changes discontinuously. The discontinuous changes can be tentatively ascribed to local mass transport processes activated by the mechanical deformation of powders at collisions. -- Highlights: Black-Right-Pointing-Pointer Mechanically processed TiC-TiN powder mixtures form two solid solutions. Black-Right-Pointing-Pointer An analytical model was developed to describe the mechanical alloying kinetics. Black-Right-Pointing-Pointer The amount of powder alloyed at collision was indirectly estimated. Black-Right-Pointing-Pointer A few nanomoles of material participate in the alloying process at each collision. Black-Right-Pointing-Pointer The chemical composition of the solid solutions was shown to change discontinuously.

  5. Microstructure of bonding zones in laser-clad Ni-alloy-based composite coatings reinforced with various ceramic powders

    International Nuclear Information System (INIS)

    Pei, Y.T.; Ouyang, J.H.; Lei, T.C.

    1996-01-01

    Microstructure of the bonding zones (BZs) between laser-clad Ni-alloy-based composite coatings and steel substrates was studied by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. Observations indicate that for pure Ni-alloy coating the laser parameters selected for good interface fusion have no effect on the microstructure of the BZ except for its thickness. However, the addition of ceramic particles (TiN, SiC, or ZrO 2 ) to the Ni alloy varies the compositional or constitutional undercooling of the melt near the solid/liquid interface and consequently leads to the observed changes of microstructure of the BZs. For TiN/Ni-alloy coating the morphology of γ-Ni solid solution in the BZ changes from dendritic to planar form with increasing scanning speed. A colony structure of eutectic is found in the BZ of SiC/Ni-alloy coating in which complete dissolution of SiC particles takes place during laser cladding. The immiscible melting of ZrO 2 and Ni-alloy powders induces the stratification of ZrO 2 /Ni-alloy coating which consists of a pure ZrO 2 layer fin the upper region and a BZ composed mainly of γ-Ni dendrites adjacent to the substrate. All the BZs studied in this investigation have good metallurgical characteristics between the coatings and the substrates

  6. Influence of increasing amount of recycled concrete powder on mechanical properties of cement paste

    Science.gov (United States)

    Topič, Jaroslav; Prošek, Zdeněk; Plachý, Tomáš

    2017-09-01

    This paper deals with using fine recycled concrete powder in cement composites as micro-filler and partial cement replacement. Binder properties of recycled concrete powder are given by exposed non-hydrated cement grains, which can hydrate again and in small amount replace cement or improve some mechanical properties. Concrete powder used in the experiments was obtained from old railway sleepers. Infrastructure offer more sources of old concrete and they can be recycled directly on building site and used again. Experimental part of this paper focuses on influence of increasing amount of concrete powder on mechanical properties of cement paste. Bulk density, shrinkage, dynamic Young’s modulus, compression and flexural strength are observed during research. This will help to determine limiting amount of concrete powder when decrease of mechanical properties outweighs the benefits of cement replacement. The shrinkage, dynamic Young’s modulus and flexural strength of samples with 20 to 30 wt. % of concrete powder are comparable with reference cement paste or even better. Negative effect of concrete powder mainly influenced the compression strength. Only a 10 % cement replacement reduced compression strength by about 25 % and further decrease was almost linear.

  7. Development of an alternative route for recycling AA2050 aluminum alloy by powder metallurgy

    International Nuclear Information System (INIS)

    Guido, V.; Oliveira, A.C. de; Travessa, D.N.; Cardoso, K.R.

    2014-01-01

    This paper presents an alternative solid state route to recycling AA2050 aeronautical aluminium alloy chips. The first stage in the recycling process, reported in this work, is the obtainment of the alloy powder by high energy ball milling to subsequent cold pressing and hot extrusion. The process started with the cleaning of chips with the aim of contaminant removing from machining process and transport, followed by the high energy ball milling to result in the AA2050 alloy powder. The powder obtained was characterized by laser size particle analysis, scanning electron microscopy (SEM), X-Ray diffraction (DRX) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results show the feasibility of obtaining a powder having appropriate particle size and chemical composition in accordance with the specification for alloy. (author)

  8. Laboratory Directed Research and Development (LDRD) on Mono-uranium Nitride Fuel Development for SSTAR and Space Applications

    International Nuclear Information System (INIS)

    Choi, J; Ebbinghaus, B; Meiers, T; Ahn, J

    2006-01-01

    The US National Energy Policy of 2001 advocated the development of advanced fuel and fuel cycle technologies that are cleaner, more efficient, less waste-intensive, and more proliferation resistant. The need for advanced fuel development is emphasized in on-going DOE-supported programs, e.g., Global Nuclear Energy Initiative (GNEI), Advanced Fuel Cycle Initiative (AFCI), and GEN-IV Technology Development. The Directorates of Energy and Environment (E and E) and Chemistry and Material Sciences (C and MS) at Lawrence Livermore National Laboratory (LLNL) are interested in advanced fuel research and manufacturing using its multi-disciplinary capability and facilities to support a design concept of a small, secure, transportable, and autonomous reactor (SSTAR). The E and E and C and MS Directorates co-sponsored this Laboratory Directed Research and Development (LDRD) Project on Mono-Uranium Nitride Fuel Development for SSTAR and Space Applications. In fact, three out of the six GEN-IV reactor concepts consider using the nitride-based fuel, as shown in Table 1. SSTAR is a liquid-metal cooled, fast reactor. It uses nitride fuel in a sealed reactor vessel that could be shipped to the user and returned to the supplier having never been opened in its long operating lifetime. This sealed reactor concept envisions no fuel refueling nor on-site storage of spent fuel, and as a result, can greatly enhance proliferation resistance. However, the requirement for a sealed, long-life core imposes great challenges to research and development of the nitride fuel and its cladding. Cladding is an important interface between the fuel and coolant and a barrier to prevent fission gas release during normal and accidental conditions. In fabricating the nitride fuel rods and assemblies, the cladding material should be selected based on its the coolant-side corrosion properties, the chemical/physical interaction with the nitride fuel, as well as their thermal and neutronic properties. The US

  9. Optimation of particle size and composition in fabrication of granite particle composite floortiles

    International Nuclear Information System (INIS)

    Budiarto; Parikin; Mohammad-Dani

    2004-01-01

    Granite particle composite floortile materials, that have epoxy matrix, may be utilized as water resist and ductile materials. The utility of composite materials for industrial households is, however, very important and very promising indeed. Starting from powdering the granite refuges into particles of 100, 140 and 200 in mesh, the powder was mixed by epoxy containing versamid hardener and stirred till highly homogenized. Specimens were mould in glass frame and dried in ambient temperature for 48 hours. The specimens were prepared into certain dimensions, conformed to testing needs: hardness, density, compression and bending. The hardness and density data show clearly the value change of particulate composition (34, 40, 50 and 70) and matrix (66, 60, 50 and 30) as well. From bending and compression tests, the optimum grain size (μm) and composition (%) of granite particles reveal between the number of 120-123 and 55-61 respectively. The accurate point of the values can be determined by using differential method. As conclusion, for the better mechanical properties of granite particles composite floortiles, the grains should be 121 in μm and 57% composition of granite particles

  10. Evaluation of Sintering Behavior of Premix Al-Zn-Mg-Cu Alloy Powder

    Directory of Open Access Journals (Sweden)

    Haris Rudianto

    2015-01-01

    Full Text Available Sintering of light aluminium alloys powder has been investigated as a way to substitute steels in automotive and aerospace industries. Premix Al-5.5Zn-2.5Mg-0.5Cu composite powder called Alumix 431D was analyzed in this research. Sintering was carried out under ultra high purity nitrogen gas and before reaching sintering temperature, green samples were delubricated at 400°C for 30 min. The powder possesses high sinterability by reaching 96% relative density at 580°C sintering temperature. Formation of liquid phase seems to support achieving high sintering density. Optimum mechanical properties also were obtained under those conditions. T6 heat treatment was done to improve the mechanical properties by formation of precipitation strengthening, and MgZn2 appears to be dominant strengthening precipitate. X-ray diffraction, optical microscopy, and SEM-EDS were used to characterize powder, and sintered and heat treated samples.

  11. Material accountancy measurement techniques in dry-powdered processing of nuclear spent fuels

    International Nuclear Information System (INIS)

    Wolf, S. F.

    1999-01-01

    The paper addresses the development of inductively coupled plasma-mass spectrometry (ICPMS), thermal ionization-mass spectrometry (TIMS), alpha-spectrometry, and gamma spectrometry techniques for in-line analysis of highly irradiated (18 to 64 GWD/T) PWR spent fuels in a dry-powdered processing cycle. The dry-powdered technique for direct elemental and isotopic accountancy assay measurements was implemented without the need for separation of the plutonium, uranium and fission product elements in the bulk powdered process. The analyses allow the determination of fuel burn-up based on the isotopic composition of neodymium and/or cesium. An objective of the program is to develop the ICPMS method for direct fissile nuclear materials accountancy in the dry-powdered processing of spent fuel. The ICPMS measurement system may be applied to the KAERI DUPIC (direct use of spent PWR fuel in CANDU reactors) experiment, and in a near-real-time mode for international safeguards verification and non-proliferation policy concerns

  12. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Energy Technology Data Exchange (ETDEWEB)

    Milly, Hussam [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Andiappan, Manoharan [Unit of Dental Public Health, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Thompson, Ian [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Banerjee, Avijit, E-mail: avijit.banerjee@kcl.ac.uk [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Unit of Conservative Dentistry, King' s College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom)

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  13. Gas-thermal coating of powdered materials. Communication 2

    International Nuclear Information System (INIS)

    Ermakov, S.S.

    1986-01-01

    This paper investigates the microstructure, microhardness, chemical composition of the transition zone, and also the strength characteristics of gas-thermal coatings including their adhesive power to the substrate (iron brand NC 100.24) and the residual stresses in the coatings. The microstructure of the transition zone was investigated; it was established that on the side of the substrate its density is greater than the mean density of both types of coating. It is shown that the porosity of the substrate has a competing effect on the thermal interaction of materials. Discovered regularities lead to the conclusion that the process of gas-thermal coating of powdered materials is more effective than when compact materials are coated; most effective is the combination of gas-thermal coating with processes of heat treatment of powder-metallurgy products

  14. Niobium Carbide-Reinforced Al Matrix Composites Produced by High-Energy Ball Milling

    Science.gov (United States)

    Travessa, Dilermando Nagle; Silva, Marina Judice; Cardoso, Kátia Regina

    2017-06-01

    Aluminum and its alloys are key materials for the transportation industry as they contribute to the development of lightweight structures. The dispersion of hard ceramic particles in the Al soft matrix can lead to a substantial strengthening effect, resulting in composite materials exhibiting interesting mechanical properties and inspiring their technological use in sectors like the automotive and aerospace industries. Powder metallurgy techniques are attractive to design metal matrix composites, achieving a homogeneous distribution of the reinforcement into the metal matrix. In this work, pure aluminum has been reinforced with particles of niobium carbide (NbC), an extremely hard and stable refractory ceramic. Its use as a reinforcing phase in metal matrix composites has not been deeply explored. Composite powders produced after different milling times, with 10 and 20 vol pct of NbC were produced by high-energy ball milling and characterized by scanning electron microscopy and by X-ray diffraction to establish a relationship between the milling time and size, morphology, and distribution of the particles in the composite powder. Subsequently, an Al/10 pct NbC composite powder was hot extruded into cylindrical bars. The strength of the obtained composite bars is comparable to the commercial high-strength, aeronautical-grade aluminum alloys.

  15. Fabrication and characterization of aluminium hybrid composites reinforced with fly ash and silicon carbide through powder metallurgy

    Science.gov (United States)

    Bilal Naim Shaikh, Mohd; Arif, Sajjad; Arif Siddiqui, M.

    2018-04-01

    This paper reports the fabrication and characterization of aluminium hybrid composites (AMCs) reinforced with commonly available and inexpensive fly ash (FA, 0, 5, 10 and 15 wt.%) particles along silicon carbide (SiC) using powder metallurgy process. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were employed for microstructural characterization and phase identification respectively. Wear behaviour were investigated using pin-on-disc wear tester for the different combinations of wear parameters like load (10, 20 and 30 N), sliding speed (1.5, 2 and 2.5 m s‑1) and sliding distance (300, 600 and 900 m). SEM confirms the uniform distribution of FA and SiC in aluminium matrix. The hardness of Al/SiC/FA is increased by 20%–25% while wear rate decreased by 15%–40%. From wear analysis, sliding distance was the least significant parameter influencing the wear loss followed by applied load and sliding speed. To identify the mechanism of wear, worn out surface were also analysed by SEM.

  16. Comparative effects of gamma irradiation and ozone treatment on hygienic quality of Korean red ginseng powder

    International Nuclear Information System (INIS)

    Byun, Myung-Woo; Yook, Hong-Sun; Kang, Il-Jun; Chung, Cha-Kwon; Kwon, Joong-Ho; Choi, Kang-Ju

    1998-01-01

    For the purpose of improving hygienic quality of Korean red ginseng powder, the comparative effects of gamma irradiation and ozone treatment on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of the red ginseng powder. Physicochemical properties including compositions of the red ginseng saponin (ginsenosides) and fatty acids, pH and hydrogen donating activity were not significantly changed by gamma irradiation, whereas, ozone treatment caused significant changes in fatty acid compositions, TBA value, pH, acidity and hydrogen donating activity. The results from this study led us to conclude that gamma irradiation was more effective than ozone treatment both for the improvement of hygienic quality and for the maintenance of physicochemical quality of red ginseng powder

  17. Comparative effects of gamma irradiation and ozone treatment on hygienic quality of Korean red ginseng powder

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Myung-Woo; Yook, Hong-Sun; Kang, Il-Jun; Chung, Cha-Kwon; Kwon, Joong-Ho; Choi, Kang-Ju

    1998-06-01

    For the purpose of improving hygienic quality of Korean red ginseng powder, the comparative effects of gamma irradiation and ozone treatment on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of the red ginseng powder. Physicochemical properties including compositions of the red ginseng saponin (ginsenosides) and fatty acids, pH and hydrogen donating activity were not significantly changed by gamma irradiation, whereas, ozone treatment caused significant changes in fatty acid compositions, TBA value, pH, acidity and hydrogen donating activity. The results from this study led us to conclude that gamma irradiation was more effective than ozone treatment both for the improvement of hygienic quality and for the maintenance of physicochemical quality of red ginseng powder.

  18. [Study on physical properties of titanium alloy sample fabricated with vacuum-sintered powder metallurgy].

    Science.gov (United States)

    Ding, X; Liang, X; Chao, Y; Han, X

    2000-06-01

    To investigate the physical properties of titanium alloy fabricated with vacuum-sintered powder metallurgy. The titanium powders of three different particle sizes(-160mesh, -200 - +300mesh, -300mesh) were selected, and mixed with copper and aluminum powder in different proportions. Two other groups were made up of titanium powder(-200 - +300mesh) plated with copper and tin. The build-up and, condensation method and a double-direction press with a metal mold were used. The green compacts were sintered at 1000 degrees C for 15 minutes in a vacuum furnace at 0.025 Pa. In the double-direction press, the specimens were compacted at the pressure of 100 MPa, 200 MPa and 300 MPa respectively. Then the linear shrinkage ratio and the opening porosity of the sintered compacts were evaluated respectively. 1. The linear shrinkage ratio of specimens decreased with the increased compacted pressure(P powders at the same compacted pressure(P > 0.05), but that of titanium powder plated with copper and tin was higher than those of other specimens without plating(P powder did not affect the opening porosity at the same compacted pressure(P > 0.05). The composition of titanium-based metal powder mixtures and the compacted pressures affect the physical properties of sintered compacts. Titanium powder plated with copper and tin is compacted and sintered easily, and the physical properties of sintered compacts are greatly improved.

  19. Characterisation of Aronia powders obtained by different drying processes.

    Science.gov (United States)

    Horszwald, Anna; Julien, Heritier; Andlauer, Wilfried

    2013-12-01

    Nowadays, food industry is facing challenges connected with the preservation of the highest possible quality of fruit products obtained after processing. Attention has been drawn to Aronia fruits due to numerous health promoting properties of their products. However, processing of Aronia, like other berries, leads to difficulties that stem from the preparation process, as well as changes in the composition of bioactive compounds. Consequently, in this study, Aronia commercial juice was subjected to different drying techniques: spray drying, freeze drying and vacuum drying with the temperature range of 40-80 °C. All powders obtained had a high content of total polyphenols. Powders gained by spray drying had the highest values which corresponded to a high content of total flavonoids, total monomeric anthocyanins, cyaniding-3-glucoside and total proanthocyanidins. Analysis of the results exhibited a correlation between selected bioactive compounds and their antioxidant capacity. In conclusion, drying techniques have an impact on selected quality parameters, and different drying techniques cause changes in the content of bioactives analysed. Spray drying can be recommended for preservation of bioactives in Aronia products. Powder quality depends mainly on the process applied and parameters chosen. Therefore, Aronia powders production should be adapted to the requirements and design of the final product. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Microwave to millimeter-wave electrodynamic response and applications of semiconductor nanostructures: LDRD project 67025 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Shaner, Eric Arthur; Lee, Mark; Averitt, R. D. (Los Alamos National Laboratory); Highstrete, Clark; Taylor, A. J. (Los Alamos National Laboratory); Padilla, W. J. (Los Alamos National Laboratory); Reno, John Louis; Wanke, Michael Clement; Allen, S. James (University of California Santa Barbara)

    2006-11-01

    Solid-state lighting (SSL) technologies, based on semiconductor light emitting devices, have the potential to reduce worldwide electricity consumption by more than 10%, which could significantly reduce U.S. dependence on imported energy and improve energy security. The III-nitride (AlGaInN) materials system forms the foundation for white SSL and could cover a wide spectral range from the deep UV to the infrared. For this LDRD program, we have investigated the synthesis of single-crystalline III-nitride nanowires and heterostructure nanowires, which may possess unique optoelectronic properties. These novel structures could ultimately lead to the development of novel and highly efficient SSL nanodevice applications. GaN and III-nitride core-shell heterostructure nanowires were successfully synthesized by metal organic chemical vapor deposition (MOCVD) on two-inch wafer substrates. The effect of process conditions on nanowire growth was investigated, and characterization of the structural, optical, and electrical properties of the nanowires was also performed.

  1. Spherical rhenium metal powder

    International Nuclear Information System (INIS)

    Leonhardt, T.; Moore, N.; Hamister, M.

    2001-01-01

    The development of a high-density, spherical rhenium powder (SReP) possessing excellent flow characteristics has enabled the use of advanced processing techniques for the manufacture of rhenium components. The techniques that were investigated were vacuum plasma spraying (VPS), direct-hot isostatic pressing (D-HIP), and various other traditional powder metallurgy processing methods of forming rhenium powder into near-net shaped components. The principal disadvantages of standard rhenium metal powder (RMP) for advanced consolidation applications include: poor flow characteristics; high oxygen content; and low and varying packing densities. SReP will lower costs, reduce processing times, and improve yields when manufacturing powder metallurgy rhenium components. The results of the powder characterization of spherical rhenium powder and the consolidation of the SReP are further discussed. (author)

  2. In situ Fabrication of Fe-TiB{sub 2} Nanocomposite Powder by Planetary Ball Milling and Subsequent Heat-treatment of FeB and TiH{sub 2} Powder Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Xuan-Khoa [Hanoi Uneversity of Science and Technology, Hanoi (Viet Nam); Bae, Sun-Woo; Kim, Ji Soon [University of Ulsan, Ulsan (Korea, Republic of)

    2017-01-15

    Fe-TiB{sub 2} powder was synthesized in-situ by the planetary ball milling and subsequent heat-treatment of an iron boride (FeB) and titanium hydride (TiH{sub 2}) powder mixture. Mechanical activation of the (FeB+TiH{sub 2}) powder mixtures was observed after a milling time of 3 hours at 700 rpm of rotation speed, but activation was not the same after 1 hour milling time. The particle size of the (FeB+ TiH{sub 2}) powder mixture was reduced to the nanometer scale, and each constituent was homogeneously distributed. A sharp exothermic peak was observed at a lower temperature (749 ℃) on the DSC curves for the (FeB+TiH{sub 2}) powder mixture milled for 3 hours, compared to the one milled for 1 hour (774 ℃). These peaks were confirmed to have resulted from the formation reaction of the TiB{sub 2} phase, from Ti and B elements in the FeB. The Fe-TiB{sub 2} composite powder fabricated in situ exhibited only two phases of Fe and TiB{sub 2} with homogeneous distribution. The size of the TiB{sub 2} particulates in the Fe matrix was less than 5 nm.

  3. Measurement of loose powder density

    International Nuclear Information System (INIS)

    Akhtar, S.; Ali, A.; Haider, A.; Farooque, M.

    2011-01-01

    Powder metallurgy is a conventional technique for making engineering articles from powders. Main objective is to produce final products with the highest possible uniform density, which depends on the initial loose powder characteristics. Producing, handling, characterizing and compacting materials in loose powder form are part of the manufacturing processes. Density of loose metallic or ceramic powder is an important parameter for die design. Loose powder density is required for calculating the exact mass of powder to fill the die cavity for producing intended green density of the powder compact. To fulfill this requirement of powder metallurgical processing, a loose powder density meter as per ASTM standards is designed and fabricated for measurement of density. The density of free flowing metallic powders can be determined using Hall flow meter funnel and density cup of 25 cm/sup 3/ volume. Density of metal powders like cobalt, manganese, spherical bronze and pure iron is measured and results are obtained with 99.9% accuracy. (author)

  4. Single step synthesis of GdAlO3 powder

    International Nuclear Information System (INIS)

    Sinha, Amit; Nair, S.R.; Sinha, P.K.

    2011-01-01

    Research highlights: → First report on direct formation of GdAlO 3 powder using a novel combustion process. → Study of combustion characteristics of Gd(NO 3 ) 3 and Al(NO 3 ) 3 towards three fuels. → Preparation of highly sinterable GdAlO 3 powders through fuel-mixture approach. → Significant reduction in energy consumption for production of GdAlO 3 sintered body. - Abstract: A novel method for preparation of nano-crystalline gadolinium aluminate (GdAlO 3 ) powder, based on combustion synthesis, is reported. It was observed that aluminium nitrate and gadolinium nitrate exhibit different combustion characteristics with respect to urea, glycine and β-alanine. While urea was proven to be a suitable fuel for direct formation of crystalline α-Al 2 O 3 from its nitrate, glycine and β-alanine are suitable fuels for gadolinium nitrate for preparation of its oxide after combustion reaction. Based on the observed chemical characteristics of gadolinium and aluminium nitrates with respect to above mentioned fuels for the combustion reaction, the fuel mixture composition could be predicted that could lead to phase pure perovskite GdAlO 3 directly after the combustion reaction without any subsequent calcination step. The use of single fuel, on the other hand, leads to formation of amorphous precursor powders that call for subsequent calcination for the formation of crystalline GdAlO 3 . The powders produced directly after combustion reactions using fuel mixtures were found to be highly sinterable. The sintering of the powders at 1550 o C for 4 h resulted in GdAlO 3 with sintered density of more than 95%. T.D.

  5. Effect of incorporation of pumpkin (Cucurbita moshchata) powder and guar gum on the rheological properties of wheat flour.

    Science.gov (United States)

    Kundu, Himani; Grewal, Raj Bala; Goyal, Ankit; Upadhyay, Neelam; Prakash, Saurabh

    2014-10-01

    The present study was carried out to study the effect of incorporation of fibre rich pumpkin powder and guar gum on the farinographic characteristics of wheat flour. The flour and pumpkin powder were assessed for proximate composition, total dietary fibre, minerals and β-carotene. Pumpkin powder contained appreciable amount of fibre, minerals and β-carotene. The effects of incorporation of different levels of pumpkin powder and guar gum along with pumpkin powder on farinographic characteristics were studied. Dough development time, dough stability, time to break down and farinograph quality number increased whereas mixing tolerance index decreased with incorporation of pumpkin powder (> 5 %) and guar gum (1.0 and 1.5 %) along with pumpkin powder in the flour. Resistance to extension as well as extensibility of dough prepared increased significantly by adding pumpkin powder (5-15 %) whereas increase in resistance to extension only was noticed with inclusion of guar gum (0.5-1.5 %) to flour containing 5 % pumpkin powder. Results indicated that pumpkin can be processed to powder that can be utilized with guar gum for value addition.

  6. Magnetostrictive properties of FeAl/polyester and FeAl/silicone composites

    Energy Technology Data Exchange (ETDEWEB)

    Riesgo, G. [Dpto. de Ciencias y Técnicas de la Navegación, Universidad de Oviedo, Campus universitario de Gijón, 33203 Gijón (Spain); Carrizo, J. [Dpto. de Física de la Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Elbaile, L., E-mail: elbaile@uniovi.es [Dpto. de Física de la Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Crespo, R.D. [Dpto. de Física de la Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Sepúlveda, R. [Dpto. de Ingeniería Mecánica y de los Materiales, Universidad de Sevilla, Isla Cartuja, 41092 Sevilla (Spain); García, J.A. [Dpto. de Física de la Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain)

    2017-01-15

    Highlights: • Nanocrystalline powders of FeAl have been obtained from the Fe{sub 81}Al{sub 19} ribbon produced by melt spinning. • The method allows the obtainment of a FeAl solid solution from the starting process. • The microstructure and magnetic properties of the powders were investigated. • Composites with a magnetostriction of 45 ppm have been obtained. - Abstract: Ribbons of composition Fe{sub 81}Al{sub 19} obtained by the melt spinning method have been used to yield powder by mechanical milling. Using this method, a rapid nanocrystallization and a FeAl solid solution phase was obtained from the start of the process. The microstructural and magnetic properties as well as the XRD patterns of the powders were studied in function of the milling time. Grain refinement and an increase of the coercive field were the main transformations resulting from increasing the milling time. Two sets of magnetostrictive composites were produced from the 100 h-milled powder. In one of them polyester was used as matrix and in the other one silicone. In the case of the silicone composites cured in a magnetic field of 140 mT in the longitudinal direction a saturation magnetostriction as high as 45 ppm was obtained.

  7. Specific Adaptation of Gas Atomization Processing for Al-Based Alloy Powder for Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver [Ames Lab., Ames, IA (United States); Siemon, John [Alcoa, Inc, Pittsburgh, PA (United States)

    2017-06-30

    The initial three atomization attempts resulted in “freeze-outs” within the pour tubes in the pilot-scale system and yielded no powder. Re-evaluation of the alloy liquidus temperatures and melting characteristics, in collaboration with Alcoa, showed further superheat to be necessary to allow the liquid metal to flow through the pour tube to the atomization nozzle. A subsequent smaller run on the experimental atomization system verified these parameters and was successful, as were all successive runs on the larger pilot scale system. One alloy composition froze-out part way through the atomization on both pilot scale runs. SEM images showed needle formation and phase segregations within the microstructure. Analysis of the pour tube freeze-out microstructures showed that large needles formed within the pour tube during the atomization experiment, which eventually blocked the melt stream. Alcoa verified the needle formation in this alloy using theoretical modeling of phase solidification. Sufficient powder of this composition was still generated to allow powder characterization and additive manufacturing trials at Alcoa.

  8. Chemical Reduction Synthesis of Iron Aluminum Powders

    Science.gov (United States)

    Zurita-Méndez, N. N.; la Torre, G. Carbajal-De; Ballesteros-Almanza, L.; Villagómez-Galindo, M.; Sánchez-Castillo, A.; Espinosa-Medina, M. A.

    In this study, a chemical reduction synthesis method of iron aluminum (FeAl) nano-dimensional intermetallic powders is described. The process has two stages: a salt reduction and solvent evaporation by a heat treatment at 1100°C. The precursors of the synthesis are ferric chloride, aluminum foil chips, a mix of Toluene/THF in a 75/25 volume relationship, and concentrated hydrochloric acid as initiator of the reaction. The reaction time was 20 days, the product obtained was dried at 60 °C for 2 h and calcined at 400, 800, and 1100 °C for 4 h each. To characterize and confirm the obtained synthesis products, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques were used. The results of morphology and chemical characterization of nano-dimensional powders obtained showed a formation of agglomerated particles of a size range of approximately 150 nm to 1.0 μm. Composition of powders was identified as corundum (Al2O3), iron aluminide (FeAl3), and iron-aluminum oxides (Fe0. 53Al0. 47)2O3 phases. The oxide phases formation were associated with the reaction of atmospheric concentration-free oxygen during synthesis and sintering steps, reducing the concentration of the iron aluminum phase.

  9. Fundamentals of powder metallurgy

    International Nuclear Information System (INIS)

    Khan, I.H.; Qureshi, K.A.; Minhas, J.I.

    1988-01-01

    This book is being presented to introduce the fundamentals of technology of powder metallurgy. An attempt has been made to present an overall view of powder metallurgy technology in the first chapter, whereas chapter 2 to 8 deal with the production of metal powders. The basic commercial methods of powder production are briefly described with illustrations. Chapter 9 to 12 describes briefly metal powder characteristics and principles of testing, mixing, blending, conditioning, compaction and sintering. (orig./A.B.)

  10. Superficial evolution and compacting aptitude of uranium dioxide powders

    International Nuclear Information System (INIS)

    Danroc, J.

    1982-04-01

    Long term storage of UO 2 powder improves slightly shaping and solidity of compacted powder. The aim of this work is the study of material evolution and the increase of this evolution rate for application to industrial fabrication. Aging in wet air at different temperatures is examined. Evolution of texture and superficial composition is followed. Below 80 0 C UO 3 , 2H 2 O is formed at crystal surface and thermal decomposition gives different hydrates. Kinetics of the transformation is studied. Oxidohydratation in liquid phase is rapid with hydrogen peroxide. The aged or treated material is compacted and mechanical behaviour is examined. Improvement is explained by inter-layer water molecule of the superficial hydrate giving lubricant and pseudo-plastic properties [fr

  11. Studies on the structure of zirconium carbide powders subjected to vibration grinding

    International Nuclear Information System (INIS)

    Kravchik, A.E.; Neshpor, V.S.

    1976-01-01

    The present work is a study of zirconium carbide powders subjected to vibratory milling in various media. The powders were comminuted in air (dry milling), benzene, trichloroethylene, and distilled water. The milling time was 10-160 h. The chemical compositions, specific surfaces, and crystal lattice parameters of the powder in the initial condition and after milling for 100 h in the various media are given. Vibratory milling of zirconium carbide powder can be successfully performed in benzene. Comminution in benzene enables a large specific surface to be attained, with practically no chemical reaction between the medium and the milling products. In milling in trichloroethylene the latter decomposes, with the formation of hydrochloric acid which reacts with the milling products. In a study of the fine structure parameters of zirconium carbide in the , , and directions the smallest crystal lattice strains and block sizes were observed in the direction. This may be taken as evidence that under such disintegration conditions the (110) planes constitute cleavage planes. An evaluation of internal and surface energies established that the strained crystal lattice energy reaches values which must be allowed for in any subsequent uses of the powder

  12. Investigation the Al–Fe–Cr–Ti nano composites structures with using ...

    Indian Academy of Sciences (India)

    It shows that Al–Fe–Cr–Ti composites have very low diffusivity and equilibrium solubility in Al (0.05 at.% Fe, >0.02 at.% Cr, and >0.3 at.% Ti). Al–Ti– Fe–Cr composite powders have also been prepared from sol–gel method starting from elemental powders at both ambient and elevated temperatures. The obtained results ...

  13. Effect of Ni content on microwave absorbing properties of MnAl powder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen-zhong; Lin, Pei-hao, E-mail: gllph2002@163.com; Huang, Wei-chao; Pan, Shun-kang; Liu, Ye; Wang, Lei

    2016-09-01

    MnAlNi powder was prepared by the process of vacuum levitation melting and high-energy ball milling, The morphology and phase structure of the powder were analyzed by Scanning Electron Microscope(SEM), X-ray diffraction(XRD) and the effect of the Ni content on microwave absorbing properties of MnAl powder was investigated by an vector network analyzer. The addition of Ni, which improved the microwave absorbing properties of MnAl powder but not changed the composition of Al{sub 8}Mn{sub 5} alloy. The minimum reflectivity of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} powder with a coating thickness (d) of 1.8 mm was about −40.8 dB and has better bandwidth effect, the absorbing mechanism of AlMnNi powders on the electromagnetic was related to the electromagnetic loss within the absorbing coatings and the effect of coating thickness on the interference loss of electromagnetic wave. - Highlights: • The grain size and cell volume of Al{sub 8}Mn{sub 5} alloy phase were decreased with the increasing of Ni. • ε″ and μ″ of powder moves toward low frequency region at the beginning then moves high. • The minimum reflectivity of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} powder was −40.8 dB with 1.8 mm thickness. • The lowest reflection loss peak of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} was −46.3 dB with 2.2 mm thickness.

  14. Direct Iron Coating onto Nd-Fe-B Powder by Thermal Decomposition of Iron Pentacarbonyl

    International Nuclear Information System (INIS)

    Yamamuro, S; Okano, M; Tanaka, T; Sumiyama, K; Nozawa, N; Nishiuchi, T; Hirosawa, S; Ohkubo, T

    2011-01-01

    Iron-coated Nd-Fe-B composite powder was prepared by thermal decomposition of iron pentacarbonyl in an inert organic solvent in the presence of alkylamine. Though this method is based on a modified solution-phase process to synthesize highly size-controlled iron nanoparticles, it is in turn featured by a suppressed formation of iron nanoparticles to achieve an efficient iron coating solely onto the surfaces of rare-earth magnet powder. The Nd-Fe-B magnetic powder was successfully coated by iron shells whose thicknesses were of the order of submicrometer to micrometer, being tuneable by the amount of initially loaded iron pentacarbonyl in a reaction flask. The amount of the coated iron reached to more than 10 wt.% of the initial Nd-Fe-B magnetic powder, which is practically sufficient to fabricate Nd-Fe-B/α-Fe nanocomposite permanent magnets.

  15. Processing of tungsten scrap into powders by electroerosion disintegration

    International Nuclear Information System (INIS)

    Fominskii, L.P.; Leuchuk, M.V.; Myuller, A.S.; Tarabrina, V.P.

    1985-01-01

    Utilization of tungsten and tungsten alloy swarf and other waste and also of rejected and worn parts is a matter of great importance in view of the shortage of this metal. The authors examine the electroerosion (EE) disintegration of tungsten in water as a means of utilizing swarf and other loose waste. Unlike chemical methods, EE disintegration ensures ecological purity since there are no effluent waters or toxic discharges. Swarf and trimmings of rods of diameters up to 20 mm obtained after the lathe-turning of tungsten bars sintered from PVN and PVV tungsten powders were disintegrated in water at room temperature between tungsten electrodes. The phase composition of the powder was studied using FeK /SUB alpha/ radiation, by x-ray diffraction methods in a DRON-2 diffractometer with a graphite monochromator on the secondary beam. When tungsten is heated to boiling during EE disintegration, the impurities present in it can evaporate and burn out. Thus, tungsten powder produced by EE disintegration can be purer than the starting metal

  16. A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Xuezheng Zhang

    2016-05-01

    Full Text Available Microstructural and mechanical characterization of 10 vol% SiC particles (SiCp reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF was investigated in comparison with the PTF and permanent mold cast (PMC 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiCp, which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

  17. A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties.

    Science.gov (United States)

    Zhang, Xuezheng; Chen, Tijun; Qin, He; Wang, Chong

    2016-05-24

    Microstructural and mechanical characterization of 10 vol% SiC particles (SiC p ) reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF) was investigated in comparison with the PTF and permanent mold cast (PMC) 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiC p , which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa) of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

  18. Fabrication Process and Thermoelectric Properties of CNT/Bi2(Se,Te3 Composites

    Directory of Open Access Journals (Sweden)

    Kyung Tae Kim

    2015-01-01

    Full Text Available Carbon nanotube/bismuth-selenium-tellurium composites were fabricated by consolidating CNT/Bi2(Se,Te3 composite powders prepared from a polyol-reduction process. The synthesized composite powders exhibit CNTs homogeneously dispersed among Bi2(Se,Te3 matrix nanopowders of 300 nm in size. The powders were densified into a CNT/Bi2(Se,Te3 composite in which CNTs were randomly dispersed in the matrix through spark plasma sintering process. The effect of an addition of Se on the dimensionless figure-of-merit (ZT of the composite was clearly shown in 3 vol.% CNT/Bi2(Se,Te3 composite as compared to CNT/Bi2Te3 composite throughout the temperature range of 298 to 473 K. These results imply that matrix modifications such as an addition of Se as well as the incorporation of CNTs into bismuth telluride thermoelectric materials is a promising means of achieving synergistic enhancement of the thermoelectric performance levels of these materials.

  19. Two-dimensional distribution of carbon nanotubes in copper flake powders

    Energy Technology Data Exchange (ETDEWEB)

    Tan Zhanqiu; Li Zhiqiang; Fan Genlian; Li Wenhuan; Liu Qinglei; Zhang Wang; Zhang Di, E-mail: lizhq@sjtu.edu.cn, E-mail: zhangdi@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-06-03

    We report an approach of flake powder metallurgy to the uniform, two-dimensional (2D) distribution of carbon nanotubes (CNTs) in Cu flake powders. It consists of the preparation of Cu flakes by ball milling in an imidazoline derivative (IMD) aqueous solution, surface modification of Cu flakes with polyvinyl alcohol (PVA) hydrosol and adsorption of CNTs from a CNT aqueous suspension. During ball milling, a hydrophobic monolayer of IMD is adsorbed on the surface of the Cu flakes, on top of which a hydrophilic PVA film is adsorbed subsequently. This PVA film could further interact with the carboxyl-group functionalized CNTs and act to lock the CNTs onto the surfaces of the Cu flakes. The CNT volume fraction is controlled easily by adjusting the concentration/volume of CNT aqueous suspension and Cu flake thickness. The as-prepared CNT/Cu composite flakes will serve as suitable building blocks for the self-assembly of CNT/Cu laminated composites that enable the full potential of 2D distributed CNTs to achieve high thermal conductivity.

  20. Two-dimensional distribution of carbon nanotubes in copper flake powders

    International Nuclear Information System (INIS)

    Tan Zhanqiu; Li Zhiqiang; Fan Genlian; Li Wenhuan; Liu Qinglei; Zhang Wang; Zhang Di

    2011-01-01

    We report an approach of flake powder metallurgy to the uniform, two-dimensional (2D) distribution of carbon nanotubes (CNTs) in Cu flake powders. It consists of the preparation of Cu flakes by ball milling in an imidazoline derivative (IMD) aqueous solution, surface modification of Cu flakes with polyvinyl alcohol (PVA) hydrosol and adsorption of CNTs from a CNT aqueous suspension. During ball milling, a hydrophobic monolayer of IMD is adsorbed on the surface of the Cu flakes, on top of which a hydrophilic PVA film is adsorbed subsequently. This PVA film could further interact with the carboxyl-group functionalized CNTs and act to lock the CNTs onto the surfaces of the Cu flakes. The CNT volume fraction is controlled easily by adjusting the concentration/volume of CNT aqueous suspension and Cu flake thickness. The as-prepared CNT/Cu composite flakes will serve as suitable building blocks for the self-assembly of CNT/Cu laminated composites that enable the full potential of 2D distributed CNTs to achieve high thermal conductivity.