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Sample records for nanocomposite wc-mgo powders

  1. Fabrication of silicon nitride/boron nitride nanocomposite powder

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Si3N4/BN nanocomposite powders with the microstructure of the micro-sized α-Si3N4 particles coated with nano-sized BN particles were synthesized via the chemical reaction of boric acid, urea, and α-Si3N4 powder in a hydrogen gas. The results of XRD, TEM, and selected area electron diffraction showed that amorphous BN and a little amount of turbostratic BN(t-BN) were coated on Si3N4 particles as the second phase after reaction at 1100℃. After reheating the composite powders at 1450℃ in a nitrogen gas, the amorphous and turbostratic BN is transformed into h-BN. These nanocomposite powders can be used to prepare Si3N4/BN ceramic composites by hot-pressing at 1800℃, which have perfect machinability and can be drilled with normal metal tools.

  2. Nano-Composite Superfine Nickel Powder Double Absorbent Coating Designing

    Institute of Scientific and Technical Information of China (English)

    LU Yan-hong; WANG Zhi-hui; HUANG Dong-zhen; HU Chuan-xin; ZHANG Chen-jia; LI Wan-zhi; LIANG Wen-ting

    2004-01-01

    We adopt a definite procedure to compound traditional absorbing material-superfine powder nickel and nano -SiC powder to obtain the nano-composite nickel powder, then testing the absorbing speciality of the composite powder. In virtue of computer assistant designing, we apply double-deck absorbent structure to improve absorbent effect and widen wave band. The experiment indicated that it is possible to achieve the anticipative object to improve the absorbing capability by adopting nano-composite absorbing material, but each component of the composite material must have matched electromagnetic parameter with another. For matching double-coating structure, it ought to modulate the correlativity of each factor to achieve the most matching in order to optimise the absorbent speciality.

  3. Agarose encapsulated mesoporous carbonated hydroxyapatite nanocomposites powder for drug delivery.

    Science.gov (United States)

    Kolanthai, Elayaraja; Abinaya Sindu, P; Thanigai Arul, K; Sarath Chandra, V; Manikandan, E; Narayana Kalkura, S

    2017-01-01

    The powder composites are predominantly used for filling of voids in bone and as drug delivery carrier to prevent the infection or inflammatory reaction in the damaged tissues. The objective of this work was to study the synthesis of agarose encapsulation on carbonated hydroxyapatite powder and their biological and drug delivery properties. Mesoporous, nanosized carbonated hydroxyapatite/agarose (CHAp/agarose) powder composites were prepared by solvothermal method and subsequently calcined to study the physico-chemical changes, if it subjected to thermal exposure. The phase of the as-synthesized powder was CHAp/agarose whereas the calcinated samples were non-stoichiometric HAp. The CHAp/agarose nanorods were of length 10-80nm and width 40-190nm for the samples synthesized at temperatures 120°C (ST120) and 150°C (ST150). The calcination process produced spheres (10-50nm) and rods with reduced size (40-120nm length and 20-30nm width). Composites were partially dissolved in SBF solution followed by exhibited better bioactivity than non-stoichiometric HAp confirmed by gravimetric method. Hemo and biocompatibility remained unaffected by presence of agarose or carbonate in the HAp. Specific surface area of the composites was high and exhibited an enhanced amoxicillin and 5-fluorouracil release than the calcined samples. The composites demonstrated a strong antimicrobial activity against E. coli, S. aureus and S. epidermidis. The ST120 showed prolonged drug (AMX and 5-Fcil) release and antimicrobial efficacy than ST150 and calcined samples. This technique would be simple and rapid for composites preparation, to produce high quality crystalline, resorbable, mesoporous and bioactive nanocomposite (CHAp/agarose) powders. This work provides new insight into the role of agarose coated on bioceramics by solvothermal technique and suggests that CHAp/agarose composites powders are promising materials for filling of void in bone and drug delivery applications.

  4. A Novel Method for Direct Synthesis of WC-Co Nanocomposite Powder

    Science.gov (United States)

    Zhu, M.; Bao, X. Y.; Yang, X. P.; Gu, N. S.; Wang, H.; Zeng, M. Q.; Dai, L. Y.

    2011-09-01

    In this study, a novel method, termed dielectric-barrier-discharge-plasma (DBDP) assisted ball milling and low-temperature carburization, was used to synthesize WC-Co nanocomposite powder. X-ray diffraction, scanning/transmission electron microscopy, and differential scanning calorimetry were used to characterize the microstructure of powders. Starting from W, Co, and graphite powder mixtures, the DBDP-milled W-C-10Co powder exhibited a flakelike morphology with very fine lamellar structure. The WC-Co composite powder was synthesized at 1273 K (1000 °C), which is much lower than the requisite temperature for the conventional carburizing method. The obtained WC-Co composite powder had a nanocomposite microstructure in which fine WC particles were bounded by homogenously distributed Co phase, and the WC crystals had a slablike morphology with a planar size of about 200 nm and carburization temperature and the nanocomposite structure of WC-Co powder.

  5. Fabrication and characterization of TiN nanocomposite powders fabricated by DC arc-plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, K., E-mail: kaneko@zaiko.kyushu-u.ac.j [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); JST-CREST (Japan); Kitawaki, K. [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Sadayama, S. [FEI Company Japan Ltd., NSS-II Bldg 1F, 13-34 Kohnan 2-chome, Minato-ku, Tokyo 108-0075 (Japan); Razavi, H. [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Hernandez-Garrido, J.C.; Midgley, P.A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Okuyama, H.; Uda, M. [Nano Ceramics Center, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sakka, Y. [Nano Ceramics Center, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); WPI Center for MANA, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2010-03-04

    TiN nanocomposite powders with various morphologies were synthesized by DC arc-plasma method from Ti-Si ingot under N{sub 2}-H{sub 2}-Ar atmosphere. Microstructures of powders were characterized by powder X-ray diffraction method and transmission electron microscopy with compositional analysis, then morphologies by three-dimensional electron tomography. It was found that the powders were consisted of TiN nanoparticles covered by Ti{sub 5}Si{sub 3} nanoparticles, which possibly suppressed the growth of facets and controlled the final morphologies of TiN-Ti{sub 5}Si{sub 3} nanocomposite.

  6. MECHANICAL ALLOYING SYNTHESIS OF FORSTERITE-DIOPSIDE NANOCOMPOSITE POWDER FOR USING IN TISSUE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Sorour Sadeghzade

    2015-03-01

    Full Text Available In present study the pure forsterite-diopside nanocomposite powder was successfully synthesized by the economical method of mechanical alloying and subsequence sintering, for the first time. The starting economical materials were talc (Mg3Si4H2O12, magnesium carbonate (MgCO3 and calcium carbonate (CaCO3 powders. The prepared powder was characterized by thermo gravimetric analysis (TGA, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The results showed preparation of forsterite- diopside nanocomposite powder after 10 h mechanical alloying and sintering at 1200oC for 1 h. The powder crystallite sizes and agglomerated particle sizes were measured about 73 +/- 4 nm and 0.3 - 4 μm, respectively. Absence of enstatite that causes a reduction in mechanical and bioactivity properties of forsterite ceramic, is an important feature of produced powder.

  7. The Preparation of CoWO4/WO3 Nanocomposite Powder

    Institute of Scientific and Technical Information of China (English)

    SHAO Gang-qin; GUO Jing-kun; XIE Ji-ren; DUAN Xing-long; WU Bo-lin; YUAN Run-zhang

    2004-01-01

    Ammonium metatungstate and cobalt nitrate were mixed at the molecular level in distilled water and then spray-decomposed to CoWO4/WO3 nanocomposite powder.The particle morphology,crystalline size,forming course,chemical composition and phase structure of the powder were studied by SEM,TEM,DTA-TG,IR and XRD,respectively.Results show that the powder is homogeneous,spherical and nano-aggregated.

  8. Preparation and biocompatibility evaluation of bioactive glass-forsterite nanocomposite powder for oral bone defects treatment applications.

    Science.gov (United States)

    Saqaei, Mahboobe; Fathi, Mohammadhossein; Edris, Hossein; Mortazavi, Vajihesadat

    2015-11-01

    Bone defects which emerge around dental implants are often seen when implants are placed in areas with insufficient alveolar bone, in extraction sockets, or around failing implants. Bone regeneration in above-mentioned defects using of bone grafts or bone substitutes may cure the long-term prognoses of dental implants. Biocompatibility, bioactivity and osteogenic properties are key factors affecting the applications of a bone substitute. This study was aimed at preparation, characterization, biocompatibility and bioactivity evaluation of the bioactive glass-forsterite nanocomposite powder as a desired candidate for oral bone defect treatments. Nanocomposite powders containing 58S bioactive glass and different amounts of forsterite nanopowder were synthesized in situ by sol-gel technique. Characterization of the prepared nanocomposite powders and their cytotoxicity assessment was performed via MTT test. Bioactivity assessment was done by immersing the prepared powder in the simulated body fluid (SBF). Results showed that nanocomposite powders containing forsterite with crystallite size of 20-50nm were successfully fabricated by calcination at 600°C. The prepared bioactive glass-forsterite nanocomposite powders revealed high in vitro biocompatibility; besides, the nanocomposite containing 20wt.% forsterite showed a substantial increase in the cell viability compared with control groups. During immersion in SBF, the formation of apatite layer confirmed the bioactivity of bioactive glass-forsterite nanocomposite powders. According to the results, the fabricated nanocomposite powders can be introduced as a promising candidate for oral bone imperfection treatments and hard tissue mend.

  9. ZnO-CdS Powder Nanocomposite: Synthesis, Structural and Optical Characterization

    Directory of Open Access Journals (Sweden)

    Dinesh Saini

    2013-07-01

    Full Text Available A simple mechanical alloying technique for the synthesis of ZnO-CdS powder nanocomposite is reported. Structural and optical properties of ZnO-CdS powder nanocomposite have been evaluated by suitable characterization techniques. The X-ray diffraction spectrum contains a series of peaks corresponding to reflections from various sets of lattice planes of hexagonal ZnO as well as hexagonal CdS. In UV-Vis absorption spectra, two different absorption peaks were observed. The room temperature photoluminescence spectrum of the ZnO-CdS powder nanocomposites has two emission bands: an ultraviolet emission peak at 365 nm and a green emission around 510 nm. FTIR spectroscopy confirmed the presence of Zn-O bond and Cd-S bond.

  10. Nanocomposite ceramic powder production by laser-induced gas-phase reactions

    Energy Technology Data Exchange (ETDEWEB)

    Borsella, E. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Botti, S. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Alexandrescu, R. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Morjan, I. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Dikonimos-Makris, T. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Giorgi, R. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy)); Martelli, S. (ENEA, Area INN, Dip. Sviluppo Tecnologie di Punta, Frascati, Rome (Italy))

    1993-08-31

    A comparative study of laser-produced nanocomposite ternary Si-C-N powders, obtained from different SiH[sub 4], amines and NH[sub 3] mixtures, is presented. It is shown that the final composition of powders is correlated with and may be controlled by the experimental parameters. Preliminary results on laser irradiation of SiH[sub 4], NH[sub 3] and (CH[sub 3])[sub 3]Al mixtures demonstrate the possibility of producing nanosized powders composed of a matrix of Si[sub 3]N[sub 4] with a different content of Al. (orig.)

  11. Nanocomposite Thermolectric Materials by High Pressure Powder Consolidation Manufacturing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need to develop advanced nanostructured thermolectric materials, UTRON is proposing an innovative high pressure powder consolidation...

  12. Nanocomposite Thermolectric Materials by High Pressure Powder Consolidation Manufacturing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need to develop advanced nanostructured thermolectric materials, UTRON is proposing an innovative high pressure powder consolidation...

  13. NANOCOMPOSITE POWDERS FOR NEW CONTACT MATERIALS BASED ONCOPPER AND ALUMINA

    OpenAIRE

    Marija Korać; Željko Kamberović; Miloš Tasić; Milorad Gavrilovski

    2008-01-01

    This paper is a contribution to characterization of Cu-Al2O3 powders with nanostructure designed for the production of dispersion strengthened contact materials. New materials with predetermined properties can be successfully synthesized by utilizing the principles of hydrometallurgy and powder metallurgy. The results show a development of a new procedure for the synthesis. The applied characterization methods were differential thermal and thermogravimetric analysis (DTA-TGA), X-ray diffracti...

  14. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E., E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: souzajulio@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2009-07-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  15. Synthesis and electrochemical properties of SnO2-CuO nanocomposite powders

    Institute of Scientific and Technical Information of China (English)

    MA Ming-you; HE Ze-qiang; XIAO Zhuo-bing; HUANG Ke-long; XIONG Li-zhi; WU Xian-ming

    2006-01-01

    SnO2-CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl4·5H2O, NH3·H2O and Cu(NO3)2·3H2O as raw materials. The powders were characterized by thermogravimertric(TG) analysis and differential thermal analysis(DTA), X-ray diffraction(XRD), and scanning electron microscope(SEM). The electrochemical properties of SnO2-CuO and undoped SnO2 powders as anode materials of lithium ion batteries were investigated comparatively by galvanostatic charge-discharge experiments and AC impedance. The results show that SnO2-CuO nanocomposite powders with the average particle size of 87 nm can be obtained by this method. The structure of SnO2 does not change with the introduction of CuO, but the average particle size of nano-SnO2 decreases. SnO2-CuO nanocomposite powders show a reversible capacity of 752 mA·h/g and better cycleability compared with nano-SnO2. The capacity retention rates after 60 cycles of nano-SnO2-CuO and SnO2 are 93.6% and 92.0% at the chargedischarge rate of 0.1 C, respectively, which suggests that the introduction of CuO into SnO2 can improve the cycleability of nanoSnO2.

  16. NANOCOMPOSITE POWDERS FOR NEW CONTACT MATERIALS BASED ONCOPPER AND ALUMINA

    Directory of Open Access Journals (Sweden)

    Marija Korać

    2008-11-01

    Full Text Available This paper is a contribution to characterization of Cu-Al2O3 powders with nanostructure designed for the production of dispersion strengthened contact materials. New materials with predetermined properties can be successfully synthesized by utilizing the principles of hydrometallurgy and powder metallurgy. The results show a development of a new procedure for the synthesis. The applied characterization methods were differential thermal and thermogravimetric analysis (DTA-TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, Transmission Electron Microscopy (TEM: Focused Ion Beam (FIB and Analytical Electron Microscopy (AEM. Nanostructure characteristics, particle size in range 20-50 nm, and uniform distribution of dispersoide in copper matrix were validated.

  17. ZnO-cellulose nanocomposite powder for application in UV sensors

    Science.gov (United States)

    Sahoo, Karunakar; Nayak, J.

    2017-05-01

    Zinc oxide nanorods were grown over cellulose fibers by a double step chemical bath deposition process. In the first step, the formation of ZnO seeds layer on cellulose fiber surfaces was induced by the alkaline hydrolysis of aqueous Zn(II). In the second step, growth of ZnO seeds into larger nanoparticles followed by growth of ZnO nanorods was achieved by controlled hydrolysis of Zn(II)-amine complex. The ZnO-cellulose nanocomposite was obtained in form of a white crystalline powder. The electrical properties of the above powder was studied making pellets with hydraulic press machine. Photoconductivity of the above ZnO-cellulose nanocomposite changed when it was exposed to Ultraviolet (UV) light. A higher UV photoconductivity was observed in ZnO-cellulose nanocomposites compared to that observed in case of ZnO nanorods. The above observations show that our ZnO-cellulose can be used for fabrication of ultra-high ON to OFF ratio UV sensors.

  18. Synthesis of Carbon Nanotube-Reinforced Al2024 Matrix Nanocomposite Using Flake Powder Metallurgy Method

    Science.gov (United States)

    Rikhtegar, F.; Shabestari, S. G.; Saghafian, H.

    2016-12-01

    In current work, the flake powder metallurgy method was applied to achieve the uniform dispersion of carbon nanotubes (CNTs) within the Al2024 powder. For this purpose, the flake morphology of Al2024 powder with suitable diameter-to-thickness ratio ( D/ t = 85) was obtained after ball milling for 4 hours at 250 rpm and ball-to-powder ratio = 10. Then, the surface of matrix was modified by a hydrophilic polymer [polyvinyl alcohol (PVA)] to obtain the sufficient -OH group on its surface. Additionally, the refluxing of CNTs in nitric acid was performed at 393 K (120 °C) for 6 hours to functionalize the reinforcement by -COOH agent. After preparation of initial materials, the Al2024-1.5 wt pct CNTs suspension was stirred in a slurry at pH 3 until the color was changed in steady state from ink-like to transparent at pH 5. The hydrogen bonding was formed between the -OH groups of PVA coated Al2024 and -COOH groups of functionalized MWCNTs during the mixing step. Also, the temporary polarity could be considered between H+ and {{{C}}_{12}}{{{H}}_{25}}{{SO}}_4^ - ions on the surface of constituents, which led to improvement in the CNT distribution due to the changing of suspension pH. Consequently, the homogenous dispersion of CNTs in Al2024 flaky powders resulted in a chemical reaction of constituents without any destructive effects of mechanical forces. The morphological changes of Al2024 powders were studied by scanning electron microscopy (SEM), and surface treatments were evaluated by Fourier transform infrared and Raman spectroscopies. The dispersion of nanocomposite powder was investigated through field emission SEM. Also, X-ray diffraction analysis was used to investigate the initial Al2024 powder and formed phases after the ball milling process.

  19. Preparation and investigation of Al–4 wt% B4C nanocomposite powders using mechanical milling

    Indian Academy of Sciences (India)

    A Alizadeh; E Taheri-Nassaj; H R Baharvandi

    2011-08-01

    Boron carbide nanoparticles were produced using commercially available boron carbide powder (0.8 m).Mechanical milling was used to synthesize Al nanostructured powder in a planetary ball-mill under argon atmosphere up to 20 h. The same process was applied for Al–4 wt% B4C nanocomposite powders to explore the role of nanosize reinforcements on mechanical milling stages. Scanning electron microscopy (SEM) analysis as well as apparent density measurements were used to optimize the milling time needed for completion of the mechanical milling process. The results show that the addition of boron carbide particles accelerate the milling process, leading to a faster work hardening rate and fracture of aluminum matrix. FE-SEM images show that distribution of boron carbide particles in aluminum matrix reaches a full homogeneity when steady state takes place. The better distribution of reinforcement throughout the matrix would increase hardness of the powder. To study the compressibility of milled powder, modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles. For better distribution of reinforcement throughout the matrix, , modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles.

  20. Characterization of NbSi2-Al2O3 nanocomposite coatings prepared with plasma spraying mechanically alloyed powders

    Science.gov (United States)

    Yazdani, Zohreh; Karimzadeh, Fathallah; Abbasi, Mohammad-Hasan; Amini, Abbas

    2015-07-01

    The present study characterized NbSi2-Al2O3 nanocomposite powders plasma-sprayed on Ti-6Al-4V substrates. The powders were agglomerated to obtain suitable particle sizes for spraying. The agglomerated powders were then plasma-sprayed using atmospheric plasma spraying. The structural transformations of the powders along with the morphological and mechanical changes of the coatings were examined by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and hardness testing. The results showed that after plasma spraying, the grain size increased, and the lattice strain decreased. However, the grain size of this compound after spraying was still in the nanometer range. The coating was uniform and exhibited good adhesion to the substrate. The microhardness and fracture toughness of the nanocomposite coating were higher than those of a nanostructured NbSi2 coating.

  1. Synthesis and characterization of polyaniline-Fe@C magnetic nanocomposite powder

    Science.gov (United States)

    Fleaca, C. T.; Dumitrache, F.; Morjan, I.; Niculescu, A.-M.; Sandu, I.; Ilie, A.; Stamatin, I.; Iordache, A.; Vasile, E.; Prodan, G.

    2016-06-01

    We report the synthesis of novel magnetic nanocomposite based on polyaniline (PANI) matrix and Fe-C nanoparticles. These hydrophobic Fe-FexC@C nanoparticles (having diameters under 20 nm) were synthesized by laser pyrolysis from Fe(CO)5 and C2H4/H2 and dispersed in water using sodium carboxymethylcellulose, followed by the PANI coating using ultrasonication-assisted oxidative polymerization of aniline hydrochloride. The structure of the resulted composite was characterized by Transmission Electron Microscopy, X-ray diffraction and also by Raman and Infrared spectroscopy. The composite powder shows ferromagnetic behavior with low coercivity and 6.4 emu/g saturation magnetization, having also electric and electrochemical behavior similar with pure PANI reference.

  2. Surface Coating of Oxide Powders: A New Synthesis Method to Process Biomedical Grade Nano-Composites

    Directory of Open Access Journals (Sweden)

    Paola Palmero

    2014-07-01

    Full Text Available Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering. This review aims at deepening understanding of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on the key role of the synthesis methods to develop homogeneous and tailored microstructures. In this frame, the authors have developed an innovative method, named “surface-coating process”, in which matrix oxide powders are coated with inorganic precursors of the second phase. The method is illustrated into two case studies; the former, on Zirconia Toughened Alumina (ZTA materials for orthopedic applications, and the latter, on Zirconia-based composites for dental implants, discussing the advances and the potential of the method, which can become a valuable alternative to the current synthesis process already used at a clinical and industrial scale.

  3. MECHANISMS CONTROLLING Ca ION RELEASE FROM SOL-GEL DERIVED IN SITU APATITE-SILICA NANOCOMPOSITE POWDER

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Latifi

    2015-03-01

    Full Text Available Ca ion release from bioactive biomaterials could play an important role in their bioactivity and osteoconductivity properties. In order to improve hydroxyapatite (HA dissolution rate, in situ apatite-silica nanocomposite powders with various silica contents were synthesized via sol-gel method and mechanisms controlling the Ca ion release from them were investigated. Obtained powders were characterized by X-ray diffraction (XRD and transmission electron spectroscopy (TEM techniques, acid dissolution test, and spectroscopy by atomic absorption spectrometer (AAS. Results indicated the possible incorporation of (SiO44- into the HA structure and tendency of amorphous silica to cover the surface of HA particles. However, 20 wt. % silica was the lowest amount that fully covered HA particles. All of the nanocomposite powders showed more Ca ion release compared with pure HA, and HA - 10 wt. % silica had the highest Ca ion release. The crystallinity, the crystallite size, and the content of HA, along with the integrity, thickness, and ion diffusion possibility through the amorphous silica layer on the surface of HA, were factors that varied due to changes in the silica content and were affected the Ca ion release from nanocomposite powders.

  4. 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.

  5. Synthesis and characterization of polyaniline–Fe@C magnetic nanocomposite powder

    Energy Technology Data Exchange (ETDEWEB)

    Fleaca, C.T., E-mail: claudiufleaca@yahoo.com [National Institute for Lasers, Plasma and Radiation Physics (NILPRP), Atomistilor 409, R-077125 Magurele (Romania); “Politehnica” University of Bucharest, Faculty of Applied Sciences, Physics Department, Independentei 313, Bucharest (Romania); Dumitrache, F. [National Institute for Lasers, Plasma and Radiation Physics (NILPRP), Atomistilor 409, R-077125 Magurele (Romania); “Politehnica” University of Bucharest, Faculty of Applied Sciences, Physics Department, Independentei 313, Bucharest (Romania); Morjan, I.; Niculescu, A.-M.; Sandu, I. [National Institute for Lasers, Plasma and Radiation Physics (NILPRP), Atomistilor 409, R-077125 Magurele (Romania); Ilie, A. [National Institute for Lasers, Plasma and Radiation Physics (NILPRP), Atomistilor 409, R-077125 Magurele (Romania); University of Bucharest, Physics Faculty, Atomistilor 405, Magurele (Romania); Stamatin, I.; Iordache, A. [3NanoSAE Research Center, University of Bucharest, Atomistilor 405, Magurele (Romania); Vasile, E. [“Politehnica” University of Bucharest, Faculty of Applied Chemistry and Materials Science, Gh. Polizu. 1-7, Bucharest (Romania); Prodan, G. [“Ovidius” University, Nanotechnology and Alternative Energy Sources Institute, Mamaia 124, Constanta (Romania)

    2016-06-30

    Highlights: • Carbon-encapsulated Fe–Fe{sub x}C nanoparticles were synthesized by laser pyrolysis. • Fe–C@PANI was obtained by redox polymerization in aqueous acid suspension. • The composite show low coercivity and 6 emu/g saturation magnetization. • Electric and redox behavior of Fe–C@PANI is similar with those of pure PANI. - Abstract: We report the synthesis of novel magnetic nanocomposite based on polyaniline (PANI) matrix and Fe–C nanoparticles. These hydrophobic Fe–Fe{sub x}C@C nanoparticles (having diameters under 20 nm) were synthesized by laser pyrolysis from Fe(CO){sub 5} and C{sub 2}H{sub 4}/H{sub 2} and dispersed in water using sodium carboxymethylcellulose, followed by the PANI coating using ultrasonication-assisted oxidative polymerization of aniline hydrochloride. The structure of the resulted composite was characterized by Transmission Electron Microscopy, X-ray diffraction and also by Raman and Infrared spectroscopy. The composite powder shows ferromagnetic behavior with low coercivity and 6.4 emu/g saturation magnetization, having also electric and electrochemical behavior similar with pure PANI reference.

  6. Structural investigation of SiSn/(reduced graphene oxide) nanocomposite powder for Li-ion battery anode applications

    Science.gov (United States)

    Kawasaki, Masahiro; Laokawee, Viratchara; Sarakonsri, Thapanee; Hashizume, Takashi; Shiojiri, Makoto

    2016-11-01

    We synthesized SiSn/(reduced graphene oxide (rGO)) nanocomposite powder for a Li-ion battery material and characterized the structure by transmission electron microscopy (TEM) and analytical scanning transmission electron microscopy (STEM). Graphene oxide was prepared by Hummers method. The graphene oxide powder processed by heat treatment was added together with Si powder into a solution of SnCl2 ṡ 2(H2O) dissolved in N2 bubbled ethylene glycol, and the solution was reacted with NaBH4. The product had a nominal atomic ratio of Si: Sn: C = 14: 3.5: 100. High-resolution TEM/STEM analysis revealed that the powder consisted of crystalline particles of Sn, Si, and SiO as well as thin reduced graphene oxide (rGO) lamellae of amorphous-like graphite with distorted lattices that were often found in areas as local as a few nm2. The aggregated Si and SiO particles grew up to several hundred nm across. Sn particles grew as large as a few tens of nm while those as small as a few nm were scattered on the (0001) rGO surface with some epitaxial relations. Si, SiO, and Sn particles were found hanging on at the edges of the rGO lamellae. An electrochemical test was performed for this nanocomposite powder. The result suggested that the SiSn/rGO powder would be a promising anode material for lithium-ion batteries with high capacity.

  7. Zn,Ni ferrite/NiO nanocomposite powder obtained from acetylacetonato complexes

    Science.gov (United States)

    Vucinic-Vasic, M.; Antic, B.; Kremenovic, A.; Nikolic, A. S.; Stoiljkovic, M.; Bibic, N.; Spasojevic, V.; Colomban, Ph

    2006-10-01

    The results on the synthesis, microstructure, structure and DC magnetization studies of nanocomposite Zn,Ni ferrite/NiO powder obtained by thermal decomposition of acetylacetonato complexes are reported in this paper. According to the results obtained by inductively coupled plasma optical emission spectroscopy (ICP-OES) element analysis and multiphase Rietveld refinement, the three samples made are composed of spinel-ferrite (86.7% 96.7%) and NiO (3.3% 13.3%) phases. The compositions of the spinel-ferrite (SP) phase in the investigated samples, S1 S3, are Zn0.72Ni0.24Fe1.98O4, Zn0.56Ni0.29Fe2.07O4 and Zn0.40Ni0.40Fe2.10O4, respectively. Due to the cation deficiency in spinels, created vacancies induce a partial change in the cation valence, \\mathrm {Ni^{2+}} \\to \\mathrm {Ni^{3+}} . The vacancy distribution is found to be random at 8a and 16d cation sites, except in sample S3, where all vacancies are over octahedral sites. The x-ray line broadening due to crystallite size effect is found to be isotropic for all spinels, while the x-ray line broadening due to the strain effect is anisotropic. A correlation between the Zn2+ occupancy of the tetrahedral site and the 650 cm-1 Raman peak intensities is shown. The observed coercivity decrease and shift in hysteresis loop in the samples are caused by the interaction between spinel and NiO phase. The results of M(H) measurements point to the properties of an ensemble of interacting nanoparticles. High saturation magnetization values and superparamagnetic behaviour at room temperature point to the technological significance of the title compounds.

  8. Synthesis of Cu or Cu2O-polyimide nanocomposites using Cu powders and their optical properties

    Science.gov (United States)

    Choi, Dong Joo; Maeng, Ju Sung; Ahn, Key-one; Jung, Myoung Jin; Song, Seok Ho; Kim, Young-Ho

    2014-09-01

    Nanocomposites consisting of Cu or Cu2O nanoparticles in various polyimide (PI) films were successfully prepared using polyamic acid (PAA) and Cu powders. Cu powders were dissolved into PAA solutions, and the solutions were spin-coated onto the substrates. Cu or Cu2O nanoparticles were formed in PI film by curing in a reducing or inert atmosphere, respectively. The Cu nanoparticles were transformed to Cu2O nanoparticles by post-heat treatment in an oxidizing atmosphere after curing in a reducing atmosphere. Transmission electron microscopy showed that uniform, round Cu2O nanoparticles 6.0 nm in diameter were dispersed in the PI film by post-heat treatment. The addition of Cu2O nanoparticles in the 4,4‧-(hexafluoroisopropylidene)diphthalic anhydride-4,4‧-oxydianiline (6FDA-ODA) PI film enhanced the refractive index of the 6FDA-ODA PI film from 1.60 to 1.72 at 633 nm, and the transparency of the nanocomposite film was about 70-90% in the visible region and remained around 90% beyond 550 nm.

  9. Investigation of possibility to fabricate Si3N4-TiN ceramic nanocomposite powder by azide SHS method

    Science.gov (United States)

    Kondratieva, L. A.; Kerson, I. A.; Illarionov, A. Yu; Amosov, A. P.; Bichurov, G. V.

    2016-11-01

    The process of self-propagating high-temperature synthesis with use of a powder of sodium azide NaN3 as a nitriding agent (the SHS-Az method) was applied to fabricate a nanocomposite powder Si3N4-TiN. Combustion of the initial mixtures of NaN3 only with precursors that are halides of silicon and titanium: Na2SiF6, (NH4)2SiF6, Na2TiF6, (NH4)2TiF6 did not allow us to synthesize the composite powder of Si3N4-TiN, as the phases of silicon nitride Si3N4 were not formed. After water washing, the ultrafine powdered product of combustion consisted of one target phase of titanium nitride only and a large amount of impurity of side phases. Replacement of the halide salt of one of the elements (Si or Ti) by the powder of this element in the initial mixture of SHS-Az system resulted in formation of silicon nitride together with the titanium nitride and impurities. The least amount of impurities was obtained by burning the initial mixtures of xSi + y(NH4)2TiF6 + zNaN3 system. Only the initial mixture of 9Si + (NH4)2TiF6 + 6NaN3 allowed us to obtain as a result of the SHS-Az process the nanostructured composite powder of Si3N4-TiN without impurities.

  10. Magnetic properties of TCr2O4 (T = Co, Ni) fine powders and TCr2O4/SiO2 nanocomposites

    Science.gov (United States)

    Mantlikova, Alice; Poltierova Vejpravova, Jana; Holec, Petr; Plocek, Jiri; Niznansky, Daniel

    2011-10-01

    We have studied magnetic properties of TCr2O4 (T = Co, Ni) fine powders, obtained by the citric acid method, and TCr2O4/SiO2 nanocomposites, constituted of spinel nanoparticles embedded in silica matrix fabricated by a modified sol gel method. All samples were characterized by powder X-ray diffraction, scanning electron microscopy and microprobe analysis. The profile analysis of the powder X-ray diffraction revealed that the particle size is larger for the fine powder samples, as expected. Detailed measurements of magnetization, hysteresis loops and a.c. susceptibility demonstrate significant differences in magnetic properties of the fine powders in comparison to the nanocomposite samples. The values of the coercitivity at 10 K ranges from ≈ 2T for NiCr2O4 fine powders to ≈ 0.6 T for CoCr2O4/SiO2 nanocomposites. Moreover, the hysteresis loops of the NiCr2O4/SiO2 samples are brightly asymmetric. The phenomenon will be discussed in context of the exchange-bias originated by presence of a tiny amount of the antiferromagnetic phase, Cr2O3 in the samples.

  11. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis.

    Science.gov (United States)

    Habibi, Neda

    2015-02-05

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the NCH3 functional group about 2850cm(-1) is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  12. Processing and Characterization of Multi-Walled Carbon Nanotubes Containing Alumina-Carbon Refractories Prepared by Nanocomposite Powder Technology

    Science.gov (United States)

    Liang, Feng; Li, Nan; Liu, Baikuan; He, Zhongyang

    2016-06-01

    Carbon nanotubes (CNTs) have often been used as additives to improve the properties of refractories containing carbon. However, it is very difficult to evenly distribute CNTs in the matrix. In order to solve this difficulty, an alumina/multi-walled carbon nanotube (MWCNT) (AM) composite powder in which MWCNTs had grown on the surfaces of Al2O3 particles was developed and used in alumina-carbon (Al2O3-C) refractories. The effects of the AM composite powders on the microstructure and properties of the Al2O3-C refractories were studied and compared with the commercial MWCNTs. The nanocomposite powders significantly improved the distribution uniformity of MWCNTs in the Al2O3-C matrix. The densification, fracture properties, thermal shock resistance, and slag corrosion resistance were enhanced due to the well-dispersed MWCNTs. On the contrary, no improvement of the densification, fracture properties, and thermal shock resistance of the refractories was achieved by addition of commercial MWCNTs due to the agglomeration of MWCNTs.

  13. Effect of starting composition on formation of MoSi2–SiC nanocomposite powder via ball milling

    Indian Academy of Sciences (India)

    M Zakeri; M Ahmadi

    2012-08-01

    MoSi2–SiC nanocomposite powders were successfully synthesized by ball milling Mo, Si and graphite elemental powders. Effects of milling time and annealing temperature were also investigated. The composite formation and phase transformation were monitored by X-ray diffraction. The microstructure of milled powders was studied by SEM, TEM and XRD peak profile analysis. Formation of this composite was completed after 10 and 20 h of milling for 25%SiC and 50%SiC, respectively. High temperature polymorph (HTP) of MoSi2 was obtained at the end of milling (20 h). On the other hand, annealing led to transformation of HTP to low temperature polymorph (LTP) of MoSi2. Mo5Si3 was formed during annealing as a product of a reaction between MoSi2 and excess graphite. Mean grain size <50 nm was obtained for 20 h milled sample on the basis of peak profile analysis and TEM images.

  14. Strong and Stable Nanocomposites Prepared by High-Pressure Torsion of Cu-Coated Fe Powders

    Directory of Open Access Journals (Sweden)

    Timo Müller

    2016-09-01

    Full Text Available Segregation and chemical inhomogeneity are well-known problems in powder metallurgy and are also an issue for new applications of powder mixtures, for example as starting materials for severe plastic deformation. In this study, Cu-coated Fe powder was prepared via immersion deposition, inductively hot-pressed and subsequently deformed using high-pressure torsion. The homogeneity of the pressed material was found to be much better than that of powder mixtures that were prepared for comparison. During severe plastic deformation, higher hardness was observed for the coated powder as compared to powder mixtures even after low strains. In the saturation state, the coated powder was found to result in a hardness of about 600 HV, which is significantly harder than for the powder mixtures. This is attributed to the greater amount of impurities introduced by the coating process. It is shown that coated powders are promising starting materials for severe plastic deformation in order to reduce the amount of strain necessary to reach the saturation state and to obtain high strength and more homogeneous mechanical alloying.

  15. cs of abrasive-reactive nanocomposite powder synthesis in the SiO2 − C/S system

    Directory of Open Access Journals (Sweden)

    Faryt Urakaev

    2015-03-01

    Full Text Available In this study, the syntheses of cementite (Fe3C and pyrite (FeS2 have been performed by mechanical activation of a mixture of graphite or sulfur with amorphous or crystalline silica in a planetary ball mill AGO-2 with steel fittings. XRD analysis was used to record products and changes of systems components after mechanical activation of the studied systems. The formation of nanocomposites based on cementite (or pyrite has been recorded and the quantitative characteristics of abrasive-reactive wear of steel milling tools have been evaluated. It has been demonstrated the possibility of steel material reaction of milling tools for direct mechanochemical preparation of composite based on cementite using abrasive properties of silica modifications. It has obtained nanocomposites based on pyrite and glass matrix during mechanical activation of quartz glass and sulfur in a time of 1-2 orders of magnitude lower than traditional mechanical alloying powders of iron and sulfur. It can be noted that any scrap metal and ceramic products can be used as milling tools. This significantly enhances the ability of the proposed method of abrasive-reactive nanowear of milling tools materials of mechanochemical reactors and processed materials.

  16. Supercritical CO2-Assisted Spray Drying of Strawberry-Like Gold-Coated Magnetite Nanocomposites in Chitosan Powders for Inhalation

    Directory of Open Access Journals (Sweden)

    Marta C. Silva

    2017-01-01

    Full Text Available Lung cancer is one of the leading causes of death worldwide. Therefore, it is of extreme importance to develop new systems that can deliver anticancer drugs into the site of action when initiating a treatment. Recently, the use of nanotechnology and particle engineering has enabled the development of new drug delivery platforms for pulmonary delivery. In this work, POXylated strawberry-like gold-coated magnetite nanocomposites and ibuprofen (IBP were encapsulated into a chitosan matrix using Supercritical Assisted Spray Drying (SASD. The dry powder formulations showed adequate morphology and aerodynamic performances (fine particle fraction 48%–55% and aerodynamic diameter of 2.6–2.8 µm for deep lung deposition through the pulmonary route. Moreover, the release kinetics of IBP was also investigated showing a faster release of the drug at pH 6.8, the pH of lung cancer. POXylated strawberry-like gold-coated magnetite nanocomposites proved to have suitable sizes for cellular internalization and their fluorescent capabilities enable their future use in in vitro cell based assays. As a proof-of-concept, the reported results show that these nano-in-micro formulations could be potential drug vehicles for pulmonary administration.

  17. Manufacturing conductive polyaniline/graphite nanocomposites with spent battery powder (SBP) for energy storage: A potential approach for sustainable waste management

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xiaojuan; Deng, Jinxing; Wang, Xue; Guo, Jinshan [State Key Laboratory of Applied Organic Chemistry and Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Liu, Peng, E-mail: pliu@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry and Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Joint Research Center of Urban Resource Recycling Technology of Graduate School at Shenzhen, Tsinghua University and Shenzhen Green Eco-Manufacturer High-Tech, Shenzhen 518055 (China)

    2016-07-15

    Highlights: • Potential approach to sustainable waste management was established. • Spent battery material was used for manufacturing conductive polymer. • The obtained nanocomposites possessed better electrochemical performance. - Abstract: A potential approach for sustainable waste management of the spent battery material (SBM) is established for manufacturing conductive polyaniline (PANI) nanocomposites as electrode materials for supercapacitors, following the principle of “What comes from the power should be used for the power”. The ternary nanocomposites (G/MnO{sub 2}/PANI) containing PANI, graphite powder (G) and remanent MnO{sub 2} nanoparticles and the binary nanocomposites of polyaniline and graphite powder (G/PANI) are synthesized by the chemical oxidative polymerization of aniline in hydrochloric aqueous solution with the MnO{sub 2} nanoparticles in the spent battery powder (SBP) as oxidant. The G/PANI sample, which was prepared with MnO{sub 2}/aniline mole ratio of 1:1 with 1.0 mL aniline in 50 mL of 1.0 mol L{sup −1} HCl, exhibits the electrical conductivity of 22.22 S cm{sup −1}, the highest specific capacitance up to 317 F g{sup −1} and the highest energy density of 31.0 Wh kg{sup −1}, with retention of as high as 84.6% of its initial capacitance after 1000 cycles, indicating good cyclic stability.

  18. Synthesis and characterization of high volume fraction Al-Al{sub 2}O{sub 3} nanocomposite powders by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, B. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Suryanarayana, C. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States)]. E-mail: csuryana@mail.ucf.edu; An, L. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816-2455 (United States); Vaidyanathan, R. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816-2455 (United States)

    2006-06-15

    Al-Al{sub 2}O{sub 3} metal matrix composite (MMC) powders with volume fractions of 20, 30, and 50% Al{sub 2}O{sub 3} were synthesized by high-energy milling of the blended component powders. The particle sizes of Al{sub 2}O{sub 3} studied were 50 nm, 150 nm, and 5 {mu}m. A uniform distribution of the Al{sub 2}O{sub 3} reinforcement in the Al matrix was successfully obtained after milling the powders for a period of 20 h at a ball-to-powder ratio of 10:1 in a SPEX mill. The uniform distribution of Al{sub 2}O{sub 3} in the Al matrix was confirmed by characterizing these nanocomposite powders by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray mapping, and X-ray diffraction (XRD) techniques.

  19. Synthesis and characteristics of W-Ni-Fe nano-composite powders prepared by mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mixture of 90W-7Ni-3Fe(mass fraction, %) powders was milled in a planetary ball mill. Its structurechanged during milling, the surface characteristics and thermal stability of the milled powders were studied with X-raydiffraction(XRD), Brunaure-Emmett-Teller (BET) nitrogen adsorption technique and differential thermal analysis(DTA). The results show that high-energy ball milling leads to the formation of composite powders with amorphousbinder phase and supersaturated W(Ni, Fe) nano-crystalline grains in which great lattice distortion exists. The crystallization temperature of the amorphous binder phase during heating decreases with milling time. The specific surface area andthe pore size of the powder mixtures decreases with milling time due to agglomeration and welding hetween particles

  20. Study on the Carbonyl Iron Powder Based Nano-Composite Radar Wave Absorbing Coatings

    Institute of Scientific and Technical Information of China (English)

    HUANG Dong-zhen; WANG Zhi-hui; LV Yan-hong; HU Chuan-xin; LI Wan-zhi; LIANG wen-ting; YAO Jun-min

    2004-01-01

    With the rapid development of stealth technique, carbonyl iron powder is regarded as an ideal radar absorbing material. In this paper, radar absorbing properties of carbonyl iron powder was investigated by using nano composite and macroscopic multi- layer composite approach. The machine- chemistry composite methods were employed during the experiment to produce nano composite absorbent. Two carbonyl iron powders named HP1, HP2 and nano powder named HP3 were employed. Absorbents were obtained by adding 10% HP3 powder with average size of 28 nm to the HP1 and HP2 carbonyl iron powders by weight respectively. By a series of composite techniques, sample plate with the radar absorbing coating was prepared. Compared with the single coating, the wave absorbing properties were significantly improved. The working band in which the wave reflectivity was less than 5 db was 4.8 ~ 18 GHz with the coating thickness of 1.0 mm. The lowest reflectivity was found to be 12.34 db at 8 GHz. The wave absorbing coating with thin thickness,broadband and strong absorbing properties was obtained.

  1. Optimizing Powder Distribution in Production of Surface Nano-Composite via Friction Stir Processing

    Science.gov (United States)

    Heydarian, Arash; Dehghani, Kamran; Slamkish, Taymor

    2014-06-01

    Notwithstanding the extensive interest in using friction stir processing (FSP) for producing metal matrix composite (MMC), more uniform powder distribution along the composite zone is still needed. In most studies, one groove is machined out of the specimen, filled with powder, and then processed by identical passes. In this investigation, an innovative technique was used that involved machining out of three gradient grooves with increasing depth from the advancing side to the retreating side instead of using a conventional sample with just a groove. Macro, optical, and scanning electron microscopy (SEM) images and microhardness test were used to evaluate the powder distribution. The images indicated that the most uniform distribution of SiC particles in the whole composite zone was related to a three-gradient grooves sample. Microohardness measurement of a three-gradient grooves sample, carried out along the cross section and perpendicular to the traverse direction of FSP, experiences less fluctuation in hardness compared with other techniques.

  2. Production of copper-niobium carbide nanocomposite powders via mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Marques, M.T. [INETI-DMTP, Estrada do Paco do Lumiar, 22, 1649-038 Lisbon (Portugal)]. E-mail: tmarques@ineti.pt; Livramento, V. [INETI-DMTP, Estrada do Paco do Lumiar, 22, 1649-038 Lisbon (Portugal); Correia, J.B. [INETI-DMTP, Estrada do Paco do Lumiar, 22, 1649-038 Lisbon (Portugal); Almeida, A. [IST-Dep. Eng. de Materiais, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Vilar, R. [IST-Dep. Eng. de Materiais, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

    2005-06-15

    Nanocrystalline niobium carbide was synthesed in situ in a copper matrix during high-energy milling of elemental powders. Three powder batches were produced with nominal compositions of 5, 10 and 20 vol.% NbC. Characterisation by X-ray diffraction and scanning electron microscopy indicates that early during the milling process a carbide dispersion is formed within a nanostructured copper matrix. After annealing at 873 K, the carbide structure and particle size are maintained, reflecting the ability of the microstructure to resist to coarsening. The hardness levels attained are more than twice those of nanostructured copper.

  3. Si3N4/SiC nanocomposite powder from a preceramic polymeric network based on poly(methylsilane as the SiC precursor

    Directory of Open Access Journals (Sweden)

    Maurício F. Gozzi

    2001-01-01

    Full Text Available Si3N4/SiC nanocomposite powders were obtained from a preceramic polymeric network based on poly(methylsilane as the in situ quasi-stoichiometric SiC source. These powders were constituted of nanosized SiC particles homogeneously distributed in the Si3N4 particulate matrix. beta-SiC whiskers were grown at 1400 °C in the pores of the matrix. At 1600 °C, the alpha -> beta Si3N4 phase transition took place, but no elemental silicon from Si3N4 decomposition was detected, evidencing the protective effect of the SiC phase.

  4. Processing of Ceramic Based Nanocomposite Using α-Al2O3 Powder and FeCl2 Solution as Starting Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Alumina-iron nanocomposite powders were prepared by a two-step process. In the first step, α-Al2O3-FeCl2 powder mixture was formed by mixing α-Al2O3 powders with FeCl2 solution followed by drying. In the second step, the FeCl2 in the dry power mixture was selectively reduced to iron particles. A reduction temperature of 750℃ for 15 min in dry H2 was chosen based on the thermodynamic calculations. The concentration of iron in FeCl2 solution was calculated to be 20 vol. pct in the final composite. Two techniques were used to produce composite bulk materials. The Al2O3 nanocomposite powders were divided to two batches. The first batch of the produced mixture was hot pressed at 1400℃ and 27 MPa for 30 min in a graphite die. To study the effect of oxygen on the Al2O3/Fe interface bonding and mechanical properties of the composite,the second batch was heat treated in air at 700℃ for 20 min to partially oxidize the iron particles before hot pressing. Characterization of the composites was undertaken by conventional density measurements, X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe micro analysis (EPMA). The suggested processing route (mixing, reduction and hot pressing)produces ceramic-metal nanocomposite much tougher than the pure Al2O3. The fracture strength of the produced Al2O3/Fe nanocomposite is nearly twice that of the pure Al2O3. The presence of spinel phase,FeAl2O4, as thick layer around the Fe particles in the Al2O3 matrix has a detrimental effect on interfacial bonding between Fe and Al2O3 and the fracture properties of the composite.

  5. Manufacturing conductive polyaniline/graphite nanocomposites with spent battery powder (SBP) for energy storage: A potential approach for sustainable waste management.

    Science.gov (United States)

    Duan, Xiaojuan; Deng, Jinxing; Wang, Xue; Guo, Jinshan; Liu, Peng

    2016-07-15

    A potential approach for sustainable waste management of the spent battery material (SBM) is established for manufacturing conductive polyaniline (PANI) nanocomposites as electrode materials for supercapacitors, following the principle of "What comes from the power should be used for the power". The ternary nanocomposites (G/MnO2/PANI) containing PANI, graphite powder (G) and remanent MnO2 nanoparticles and the binary nanocomposites of polyaniline and graphite powder (G/PANI) are synthesized by the chemical oxidative polymerization of aniline in hydrochloric aqueous solution with the MnO2 nanoparticles in the spent battery powder (SBP) as oxidant. The G/PANI sample, which was prepared with MnO2/aniline mole ratio of 1:1 with 1.0mL aniline in 50mL of 1.0molL(-1) HCl, exhibits the electrical conductivity of 22.22Scm(-1), the highest specific capacitance up to 317Fg(-1) and the highest energy density of 31.0 Wh kg(-1), with retention of as high as 84.6% of its initial capacitance after 1000 cycles, indicating good cyclic stability.

  6. Plasma Sprayed Dense MgO-Y2O3 Nanocomposite Coatings Using Sol-Gel Combustion Synthesized Powder

    Science.gov (United States)

    Wang, Jiwen; Jordan, Eric H.; Gell, Maurice

    2010-09-01

    MgO-Y2O3 nanostructured composite powder (volume ratio of 50:50) was synthesized by a sol-gel combustion process which generated crystal sizes in the 10-20 nm range. The MgO-Y2O3 nanopowder was plasma sprayed using a conventional, DC arc plasma spray system. X-ray diffraction analysis shows that the as-sprayed MgO-Y2O3 coating is composed of cubic MgO and Y2O3 phases and has ~95% density. Microstructure characterization by SEM reveals that the as-sprayed coating has fine grain sizes of 100-300 nm as a result of rapid solidification. The hardness of the coating, 7.5 ± 0.6 GPa, is higher than that of coarse-grained, dense MgO, and Y2O3 ceramics. This approach demonstrates the potential of plasma spray processes for making thick, dense MgO-Y2O3 nanocomposite performs for applications as durable, infrared windows.

  7. Structural and magnetic properties of turmeric functionalized CoFe2O4 nanocomposite powder

    Science.gov (United States)

    Mehran, E.; Farjami Shayesteh, S.; Sheykhan, M.

    2016-10-01

    The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4 magnetic nanoparticles (NPs) are studied by analyzing the results from the x-ray diffraction (XRD), transmission electron microscopy (TEM), FT-IR spectroscopy, thermogravimetry (TG), and vibrating sample magnetometer (VSM). To extract the structure and lattice parameters from the XRD analysis results, we first apply the pseudo-Voigt model function to the experimental data obtained from XRD analysis and then the Rietveld algorithm is used in order to optimize the model function to estimate the true intensity values. Our simulated intensities are in good agreement with the experimental peaks, therefore, all structural parameters such as crystallite size and lattice constant are achieved through this simulation. Magnetic analysis reveals that the synthesized functionalized NPs have a saturation magnetization almost equal to that of pure nanoparticles (PNPs). It is also found that the presence of the turmeric causes a small reduction in coercivity of the functionalized NPs in comparison with PNP. Our TGA and FTIR results show that the turmeric is bonded very well to the surface of the NPs. So it can be inferred that a nancomposite (NC) powder of turmeric and nanoparticles is produced. As an application, the anti-arsenic characteristic of turmeric makes the synthesized functionalized NPs or NC powder a good candidate for arsenic removal from polluted industrial waste water. Project supported by the University of Guilan and the Iran Nanotechnology Initiative Council.

  8. Chitosan/banana peel powder nanocomposites for wound dressing application: Preparation and characterization.

    Science.gov (United States)

    Kamel, Nagwa A; Abd El-Messieh, Salwa L; Saleh, Neveen M

    2017-03-01

    Wound infection is a serious infection has been spread worldwide. In order to provide fast aid treatments for such infection, banana peels have been incorporated within chitosan as wound dressing. Banana was collected from Egyptian markets peeled and the dried peels were grounded to powder, Incorporated as nano fillers within chitosan matrix with different concentrations (0, 2, 5 and 10wt%). Glycerol was added as plasticizer and crosslinker to the membranes. The banana peel powder (BPP) particle shape and size were determined using Transmission Electron Microscope (TEM), The homogeneity and distribution of BPP in the membranes were investigated through Scanning Electron Microscope (SEM). The interaction between BPP and chitosan was characterized by Fourier Transform Infrared (FTIR). The dielectric properties of chitosan and BPP-chitosan membranes studied via dielectric constant, dielectric loss and conductivity measurements over a frequency range 100Hz up to 100kHz. The curves relating ε″ and the applied frequency are broad enough reflecting more than one relaxation process. These processes may be attributed to the relaxation processes of the main chain and its related motions. The higher values of ε″ at low frequency range may be a combination of the losses due to the electrical conductivity and the interfacial polarization process called "Maxwell Wagner Sillers" effect. By increasing BPP content in the sample a pronounced shift towards lower frequency was noticed. This shift may be due to some sort of polymer/filler interaction which causes an increase in the relaxed units and consequently the relaxation time. The addition of BPP decreases the swelling degree of chitosan matrix. The antimicrobial properties of the membranes were done against Gram positive, Gram negative bacteria and yeast. The results showed that chitosan/BPP membranes have a synergistic action with the highest activity at 10wt%. Moreover, Candida albicans was the most sensitive strain

  9. CuO· SnO2 Nanocomposite Powders: Synthesis and Characterization%纳米复合氧化物CuO·SnO2的制备与结构表征

    Institute of Scientific and Technical Information of China (English)

    高红旭; 赵凤起; 罗阳; 郝海霞; 高茵; 王晗; 李上文

    2005-01-01

    CuO·SnO2 Nanocomposite powders were prepared by solid state reaction from Cu(NO3)2·3H2O, SnCl4·5H2O with NaOH at low temperature. The crystal form, particle size and morphology of the material were characterized by XRD, TEM, FTIR, SEM-EDS and XPS. The results showed that CuO·SnO2 nanocomposite was composed of CuO with monoclinic crystalline structure and SnO2 with tetragonal crystalline structure. The average particle size of the CuO·SnO2 nanocomposite was about 10 nm.

  10. Low-temperature exothermic reactions in fully-dense Al/MoO{sub 3} nanocomposite powders

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Rayon A.; Schoenitz, Mirko; Ermoline, Alexandre; Dreizin, Edward L., E-mail: dreizin@njit.edu

    2014-10-20

    Highlights: • Low temperature exothermic reactions in 8Al·MoO{sub 3} nano-thermites are described by Cabrera–Mott model. • Ignition in the nano-thermites is caused by subsolidus low-temperature exothermic reactions. • Cabrera–Mott model combined with multistage model of Al oxidation describes reactions in thermites. • Al·MoO{sub 3} composite prepared by milling are readily hydrated; dehydration must be accounted for in reaction models. • Interface separating Al from MoO{sub 3} in the prepared thermites is discontinuous. - Abstract: Low-temperature redox reactions in nano-thermites prepared by arrested reactive milling (ARM) were described by Cabrera–Mott (CM) mechanism, in which the growth of very thin oxide layers is accelerated by an electric field induced across such layers. A reaction mechanism combining the initial CM step with following oxidation steps identified earlier for oxidation of Al and representing growth of and phase transitions in various polymorphs of alumina was proposed and shown to be valid for different Al/CuO nanocomposite powders prepared by ARM. This work explores whether a similar multi-step reaction mechanism can be applied to describe thermal initiation in another ARM-prepared thermite system, Al/MoO{sub 3}. The powder particles comprise a fully dense Al matrix with nano-sized MoO{sub 3} inclusions. The structure, morphology, and compositions of the prepared powder with composition 8Al·MoO{sub 3} were characterized using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetry (TG) data were collected at varied heating rates, in addition to micro-calorimetry data collected both isothermally and at several very low heating rates. The shapes of the recorded DSC and TG traces at low temperatures were substantially different compared to those obtained earlier for Al/CuO. A weight loss representing dehydration of the composite

  11. Preparation and properties of β-SiAlON/ZrN nano-composites from ZrO2-coated Si3N4 powder

    Directory of Open Access Journals (Sweden)

    Aljoša Maglica

    2007-12-01

    Full Text Available In this study we report on the preparation and properties ofβ-SiAlON/ZrN electro-conductive nano-composites from ZrO2-coated Si3N4 powder. The silicon nitride powder was coated with nano-sized zirconia particles by the precipitation of ZrO2 from a zirconium acetate solution using urea as the precipitating agent. For the preparation of sintered β-SiAlON/ZrN composites two different approaches were used. In the first one the ZrO2-coated Si3N4 powder was mixed with the appropriate sintering additives (Al2O3, Y2O3 and AlN and reaction sintered, while in the second approach the coated powder was first calcined at 1600°C to prepare ZrNcoated Si3N4 powder that was subsequently mixed with the sintering additives and sintered. For comparison, composites with the same composition were also prepared by mixing Si3N4 and ZrO2 powders with sintering additives and sintered. During the thermal treatment and/or sintering of the Si3N4/ZrO2/AlN powder mixtures zirconia reacts with silicon nitride and aluminium nitride to form zirconium nitride. However, during sintering the agglomeration and grain growth of small, nanometric ZrN particles occurs. Despite the fact that the samples were sintered at atmospheric pressure they are dense, have relatively good flexural strengths and are electrically conductive.

  12. Synthesis and characterization of the NiFe{sub 2}O{sub 4}/Ni{sub 3}Fe nanocomposite powder and compacts obtained by mechanical milling and spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Marinca, T.F.; Neamţu, B.V.; Popa, F.; Tarţa, V.F. [Materials Sciences and Engineering Department, Technical University of Cluj-Napoca, 103-105, Muncii Avenue, 400641 Cluj-Napoca (Romania); Pascuta, P. [Physics and Chemistry Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Takacs, A.F. [Faculty of Physics, Babeş-Bolyai University, 1 Mihail Kogălniceanu, 400084 Cluj-Napoca (Romania); Chicinaş, I., E-mail: Ionel.Chicinas@stm.utcluj.ro [Materials Sciences and Engineering Department, Technical University of Cluj-Napoca, 103-105, Muncii Avenue, 400641 Cluj-Napoca (Romania)

    2013-11-15

    Nanocomposite powder and compacts of NiFe{sub 2}O{sub 4}/Ni{sub 3}Fe type were synthesized using mechanical milling and spark plasma sintering (SPS) techniques. The samples have been investigated by X-ray diffraction (XRD), laser particles size analysis, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX). The nanocomposite powder was obtained by mechanical milling in a high planetary ball mill of nanocrystalline NiFe{sub 2}O{sub 4} and nanocrystalline Ni{sub 3}Fe powders. The nanocomposite powder consists from Ni{sub 3}Fe particles covered at the surface with a layer of NiFe{sub 2}O{sub 4} fine particles and NiFe{sub 2}O{sub 4} particles. The nanocomposite particles have the median diameter d{sub 50} of 1.6 μm. The sintering in 400–600 °C temperature range preserve the nanocomposite phases but lead to a high porosity. The nanocomposite compacts consist in Ni{sub 3}Fe clusters surrounded by NiFe{sub 2}O{sub 4}. A sintering temperature of 800 °C leads to a good density for the nanocomposite compacts and to the new phase formation. The new phase is a wustite type (Fe{sub 1−x}Ni{sub x}O) and is formed at the metal/ceramic interface. A change in the Ni/Fe ratio, in the spinel structure, was evidenced during sintering. Sintering at a temperature of 800 °C, leads to the formation of a mixed iron–nickel ferrite with a very small amount of nickel, Ni{sub 1−x}Fe{sub x}Fe{sub 2}O{sub 4}.

  13. High throughput production of nanocomposite SiO x powders by plasma spray physical vapor deposition for negative electrode of lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Keiichiro Homma

    2014-04-01

    Full Text Available Nanocomposite Si/SiO x powders were produced by plasma spray physical vapor deposition (PS-PVD at a material throughput of 480 g h−1. The powders are fundamentally an aggregate of primary ~20 nm particles, which are composed of a crystalline Si core and SiO x shell structure. This is made possible by complete evaporation of raw SiO powders and subsequent rapid condensation of high temperature SiO x vapors, followed by disproportionation reaction of nucleated SiO x nanoparticles. When CH4 was additionally introduced to the PS-PVD, the volume of the core Si increases while reducing potentially the SiO x shell thickness as a result of the enhanced SiO reduction, although an unfavorable SiC phase emerges when the C/Si molar ratio is greater than 1. As a result of the increased amount of Si active material and reduced source for irreversible capacity, half-cell batteries made of PS-PVD powders with C/Si = 0.25 have exhibited improved initial efficiency and maintenance of capacity as high as 1000 mAh g−1 after 100 cycles at the same time.

  14. EFFECTS OF PH ON AGGLOMERATION STATE OF Al2O3 – ZrO2 (ZTA NANOCOMPOSITE POWDERS SYNTHESIZED BY TARTARIC GEL METHOD

    Directory of Open Access Journals (Sweden)

    Mustafa Tuncer

    2012-07-01

    Full Text Available Alumina – 20 vol% zirconia (ZTA nanocomposites were synthesized by the tartaric acid sol-gel method. The precursors gelled from solutions at different pH were prepared and then calcined from 1000 to 1500°C. Surface area measurement (BET, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to characterize the synthesized powders. Control of agglomeration state was carried out by changing the pH of the solution. Weakly agglomerated powders were obtained at pH=6, whereas the solution at pH=1 revealed hard agglomerated powders, (agglomeration degrees, N, were found to be 16425 at pH=1 and 102 at pH=6, respectively. The pH dependence of agglomeration was explained by the dissociation behavior of tartaric acid at various pH environments. XRD results showed that the powders have been fully tetragonal phase at 1000°C, while they exhibited tetragonal zirconia with minor monoclinic phase as well as a-Al2O3 at 1500°C. The presence of a-Al2O3 in the nanocrystalline composite contributes the wide range of temperature stability for t-ZrO2 up to 1500°C. TEM micrograph confirmed that alumina and zirconia were dispersed homogenously. Mechanical properties (hardness and indentation fracture toughness of sintered samples were also determined.

  15. Magnetic properties of TCr{sub 2}O{sub 4} (T = Co, Ni) fine powders and TCr{sub 2}O{sub 4}/SiO{sub 2} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Mantlikova, Alice; Vejpravova, Jana Poltierova [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles university, Prague (Czech Republic); Holec, Petr; Niznansky, Daniel [Department of Inorganic Chemistry, Faculty of Nature Science, Charles university, Prague (Czech Republic); Plocek, Jiri, E-mail: AliceMantlikova@seznam.cz [Institute of Inorganic Chemistry, Academy of science of the CR, Husinec-Rez (Czech Republic)

    2011-10-29

    We have studied magnetic properties of TCr{sub 2}O{sub 4} (T = Co, Ni) fine powders, obtained by the citric acid method, and TCr{sub 2}O{sub 4}/SiO{sub 2} nanocomposites, constituted of spinel nanoparticles embedded in silica matrix fabricated by a modified sol gel method. All samples were characterized by powder X-ray diffraction, scanning electron microscopy and microprobe analysis. The profile analysis of the powder X-ray diffraction revealed that the particle size is larger for the fine powder samples, as expected. Detailed measurements of magnetization, hysteresis loops and a.c. susceptibility demonstrate significant differences in magnetic properties of the fine powders in comparison to the nanocomposite samples. The values of the coercitivity at 10 K ranges from {approx} 2T for NiCr{sub 2}O{sub 4} fine powders to {approx} 0.6 T for CoCr{sub 2}O{sub 4}/SiO{sub 2} nanocomposites. Moreover, the hysteresis loops of the NiCr{sub 2}O{sub 4}/SiO{sub 2} samples are brightly asymmetric. The phenomenon will be discussed in context of the exchange-bias originated by presence of a tiny amount of the antiferromagnetic phase, Cr{sub 2}O{sub 3} in the samples.

  16. Synthesis and characterization of nanocomposite powders of calcium phosphate/silica-gel; Sintese e caracterizacao de pos nanoestruturados de fosfato de calcio/silica-gel

    Energy Technology Data Exchange (ETDEWEB)

    Muller, D.T.; Delima, S.A. [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Dept. de Engenharia Mecanica; Santos, R.B.M.; Camargo, N.H.A., E-mail: dem2nhac@joinville.udesc.b [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais

    2009-07-01

    In the recent years ceramics of calcium phosphate are pointed out as an outstanding material in substitution and regeneration in defects from osseous tissue, in reason of their similar mineralogical characteristics of apatite of bone structure. However, the challenge with phosphate calcium ceramics find out about the mechanical properties and the development of biomaterials similar of the bone structure, what sometimes is not so easy, about fragile materials. The aim of this work focused in synthesis and characterization nanocomposites powders of calcium phosphate/silica-gel with percentages 1, 2, 3 e 5% of nanometric silica. The method synthesis used for the compositions elaboration was dissolution-precipitation. The presented results are related with the optimization to method elaboration of nanostructured powders, the mineralogical characterization with X-ray diffraction, thermal behavior with thermal differential analysis, differential scanning calorimetry here is ADT and dilatometer. The scanning electronic microscopy was used to help of morphological characterization the nanostructured powders and the surfaces from body test recovered from the mechanical test. (author)

  17. EFFECT OF CUP AND BALL TYPES ON MECHANO-CHEMICAL SYNTHES IS OF Al2O3–TiC NANOCOMPOSITE POWDER

    Directory of Open Access Journals (Sweden)

    M. Zakeri

    2012-07-01

    Full Text Available Al2O3–TiC nanocomposite powder was successfully synthesized by ball milling TiO2, Al and graphite powders. Effects of cup and ball type, milling time and annealing were investigated. XRD was used to characterize milled and annealed powders. The morphological and microstructural evolutions were studied by SEM and TEM. Results showed that the formation of this composite begins after 20 h and completes after 35 h of milling with stainless steel cup and balls. In contrast, there is no reaction during milling (up to 80 h with ZrO2 cup and balls. Fe and ZrO2 were the major impurities introduced during milling with stainless steel and ZrO2 cups, respectively. The Fe impurity was removed by leaching in 3HCl·HNO3 solution for 4 days. Mean grain size less than 7 nm was achieved at the end of milling. In spite of grain growth, this composite maintained its nanocrystalline nature after annealing at 1000°C.

  18. Obtention of polyester-montmorillonite (MMT) nanocomposites applied to powder coating - part 1: nanocomposites characterization;Obtencao de nanocompositos de poliester-montmorilonita (MMT) aplicados em tinta em po - parte 1: caracterizacao dos nanocompositos

    Energy Technology Data Exchange (ETDEWEB)

    Piazza, Diego; Zattera, Ademir J., E-mail: piazza@nol.com.b [Universidade de Caxias do Sul (UCS), RS (Brazil). Lab. de Polimeros; Silveira, Debora S.; Lorandi, Natalia P.; Birriel, Eliena J.; Scienza, Lisete C., E-mail: ajzattera@terra.com.b [Universidade de Caxias do Sul (UCS), RS (Brazil). Lab. de Corrosao

    2009-07-01

    The development and obtention of polymeric nanocomposites in the nanotechnology and nanoscience field have attracted great attention due to diversity of potential applications and significant property improvement when compared to conventional composites. In this work, commercial formulations of polyester-based powder coating with 0, 2 and 4% (w/w) of montmorillonite (MMT) were obtained by incorporation in the melting state and characterized by TEM, SEM, DSC, TGA and XRD. The nanocoatings were applied on the mild carbon steel panels by electrostatic paint. The microscopy analysis showed MMT in the coating film, predominantly in the exfoliated form, corroborated by XRD results. Some tactoid structures and a surface film with some defects and porous were also revealed. Progressive reduction of crosslinking temperature and thermal stability was observed in thermal analysis. The best clay dispersion in the coating and a higher quality film were achieved at 2% MMT concentration. (author)

  19. Rapid synthesis of MoSi2-Si3N4 nanocomposite via reaction milling of Si and Mo powder mixture

    Institute of Scientific and Technical Information of China (English)

    Majid Abdellahi; Alireza Amereh; Hamed Bahmanpou; and Behzad Sharafati

    2013-01-01

    The nanocomposite of MoSi2-Si3N4 (molybdenum disilicide-silicon nitride) was synthesized by reaction milling of the Mo and Si powder mixture. Changing the processing parameters led to the formation of diff erent products such asα-andβ-MoSi2, Si3N4, Mo2N, and Mo5Si3 at various milling times. A thermodynamic appraisal showed that the milling of Mo32Si68 powder mixture was associated with highly exothermic mechanically induced self-sustaining reaction (MSR) between Mo and Si. The MSR took place around 5 h of milling led to the formation ofα-MoSi2 and the reaction between Si and N2 to produce Si3N4 under a nitrogen pressure of 1 MPa. By increasing the nitrogen pressure to 5 MPa, more heat is released, resulting in the dissociation of Si3N4 and the transformation ofα-MoSi2 toβ-MoSi2. Heat treatment was also performed on the milled samples and led to the formation of Mo2N and the transformation ofα-MoSi2 toβ-MoSi2 at the milling times of 10 and 40 h, respectively.

  20. Mechanochemical Synthesis of Mo-Cu Nanocomposites Powders at Low Temperature%低温机械化学法制备Mo-Cu纳米复合粉末

    Institute of Scientific and Technical Information of China (English)

    孙翱魁; 王德志; 李翼

    2012-01-01

    Low temperature synthesis of Mo-Cu composite powders was conducted by mechanochemical treatment (hall-milling) of CuMoO4 and MoO3 mixtures followed by subsequent coreduction process. The preparation temperature of the precursors (CuMoO4-MoO3 mixtures), phases and microstructures of the Mo-Cu composites were investigated by differential scanning calorimeter (DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. The thermodynamical conditions at different stages of hydrogen reduction of Mo-Cu nanocotnposite powders were analyzed. Results show that the mechanochemical treatment (ball-milling) can significantly enhance the reduction activity by rbducing the particle sizes of powders and hence increasing the reaction surface area, therefore giving rise to the synthesis of Mo-Cu composite powders at relatively low temperature (680 ℃). By optimizing the experimental parameters, Mo-25 wt% Cu nanocomposite powders with superfine particles ranging from 50 to 100 nmcanbe obtained by ball-milling for 15 h followed by reduction in hydrogen at 680 ℃.%以CuMoO4-MoO3粉末为前驱体,采用机械化学-氢气共还原的方法制备出Mo-Cu纳米复合粉末.通过DSC对前躯体的制备温度进行研究,通过XRD、SEM及TEM分别对粉末的相组成、形貌和粒度进行表征,从热力学的角度对粉末的还原过程进行分析.结果表明,机械球磨可以有效地降低粉末的颗粒尺寸,增大反应面积,提高粉末还原活性,从而在低温下制备出Mo-Cu复合粉末.通过优化工艺参数,对机械球磨15h的CuMoO4-MoO3混合粉末在680℃下还原,可以得到颗粒尺寸为50~100 nm的Mo-25%Cu (质量分数)纳米复合粉末.

  1. 纳米ZnO/TiO2复合粉体的制备及其抗菌性能研究%Preparation and Antibacterial Properties of ZnO/TiO 2 Nanocomposite Powders

    Institute of Scientific and Technical Information of China (English)

    刘佳妮; 郝晗; 高尚; 孙彤; 励建荣

    2013-01-01

    ZnO/TiO2 nanocomposite powders were synthesized by hydrothermal method with titanium tetrachloride and zinc chloride as raw materials. With the antibacterial circle size as the evaluation pointer , the antibacterial properties of ZnO/TiO2 nanocomposite powders on Escherichia coli and Staphylococcus aureus were studied which prepared in different process conditions. Meanwhile , the powders were characterized by XRD, SEM, UV and FT-IR. The results showed that the crystal structure , granularities and microstructure of the composite powders were affected by the molar ratio of Ti to Zn and calcined treatment. The antibacterial properties of the ZnO/TiO2 nanocomposite powders was better than the others when the molar ratio of Ti to Zn was 1︰2, and the samples were calcined.%以TiCl4和ZnCl2为主要原料,采用水热法制备ZnO/TiO2复合粉体。以抑菌圈大小为评价指标,研究了不同工艺条件下制得的ZnO/TiO2复合粉体对大肠杆菌和金黄色葡萄球菌的抗菌性能的影响。同时,对制备的粉体进行了XRD、SEM、UV-vis和FT-IR表征。研究结果表明,Ti︰Zn摩尔比和煅烧处理影响ZnO/TiO2纳米复合粉体的晶体结构、粒度和微观形貌。Ti︰Zn摩尔比为1︰2的纳米复合粉体经煅烧后具有较好的抗菌性能。

  2. Study of Oxidation Behaviour of Bond Coating Nanocomposites Ni-20Cr-6Al Powder Synthesized by Mechanical Alloying

    OpenAIRE

    Akbar Salarvand; Vahid Shafi pour

    2011-01-01

    In this study, nano crystalline Ni-20Cr-6Al composite powder was produced using a high energy planetary ball milling and a two-stage process. Then the oxidation behavior of coating of that superalloy at different temperatures considered. Nanostructured Ni-20Cr-6Al coating was deposited by cold spray for application as a bond coat to thermal barrier coating on industrial gas turbine components. The paper samples synthesized were characterized by scanning electron microscopy (SEM) and transmiss...

  3. CNTs/TiC Reinforced Titanium Matrix Nanocomposites via Powder Metallurgy and Its Microstructural and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Katsuyoshi Kondoh

    2008-01-01

    Full Text Available By using pure titanium powder coated with unbundled multiwall carbon nanotubes (MWCNTs via wet process, powder metallurgy (P/M titanium matrix composite (TMC reinforced with the CNTs was prepared by spark plasma sintering (SPS and subsequently hot extrusion process. The microstructure and mechanical properties of P/M pure titanium and reinforced with CNTs were evaluated. The distribution of CNTs and in situ formed titanium carbide (TiC compounds during sintering was investigated by optical and scanning electron microscopy (SEM equipped with EDS analyzer. The mechanical properties of TMC were significantly improved by the additive of CNTs. For example, when employing the pure titanium composite powder coated with CNTs of 0.35 mass%, the increase of tensile strength and yield stress of the extruded TMC was 157 MPa and 169 MPa, respectively, compared to those of extruded titanium materials with no CNT additive. Fractured surfaces of tensile specimens were analyzed by SEM, and the uniform distribution of CNTs and TiC particles, being effective for the dispersion strengthening, at the surface of the TMC were obviously observed.

  4. Photocatalytic and Escherichia antibacterial activities of Ag-TiO2-SiO2 nanocomposite powder under simulated solar light irradiation

    Science.gov (United States)

    Van Dang, Han; Le, Vien Minh; Hoang, Hoang Anh

    2017-09-01

    The photocatalytic nanocomposite powder TiO2, TiO2-SiO2 and Ag-TiO2-SiO2 (ATS) were synthesized by sol-gel method assisted with hydrothermal treatment and characterized by X-ray diffraction (XRD), Raman spectroscopy (RAMAN), Fourier transformed infrared spectroscopy (FT-IR), Energy dispersive X-ray (EDX), Transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) surface area and UV-Vis absorption spectra analysis. The Escherichia coli (E. coli) antibacterial activity of synthesized photo-catalysts under simulated solar light have been also investigated. The heterogeneous A4TS10 with the 4 wt.% Ag and 10 wt.% SiO2 had anatase and rutile phase, spherical in shape with the particle size about 20 - 30 nm, specific surface area (SSA) of 218.4 m2/g, the band gap of 3.06 eV. The E. coli antibacterial activities of the synthesized samples under simulated solar light were also investigated under simulated solar light with 25 W of light intensity. The E. coli antibacterial ability of A4TS10 performed the highest photo-activity. E. coli bacteria was entirely killed after 30-minute irradiation and no bacterial regrowth was observed after 24 hours. The research results demonstrated that the photocatalytic A4TS10 is a promising green material to treatment wastewater infected bacteria application.

  5. Synthesis of MgO-CaO-Al2O3-SiO2 nanocomposite powder by polymeric complex method as a novel sintering additive of AlN ceramics

    Science.gov (United States)

    Lee, Hwa-Jun; Cho, Woo-Seok; Kim, Hyeong Jun; Pan, Wei; Shahid, Mohammad; Ryu, Sung-Soo

    2016-09-01

    A MgO-CaO-Al2O3-SiO2 (MCAS) nanocomposite powder with a particle size of 50 nm and a specific surface area of 40.6 m2/g was successfully synthesized via heat-treatment of polymeric precursors containing Mg, Ca, Al and Si in air at 700 °C for 5 h. It was characterized as a novel sintering additive for the densification AlN ceramics at a low temperature below 1600 °C. It was found that the nanosized MCAS powder was suitable for the densification of AlN ceramics. In particular, full densification could be achieved when only 1.0 wt% MCAS additive-doped AlN powder compact was sintered for 1 h at 1600 °C, and a thermal conductivity of 84 W/m·K was attained.

  6. Study of Oxidation Behaviour of Bond Coating Nanocomposites Ni-20Cr-6Al Powder Synthesized by Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Akbar Salarvand

    2011-08-01

    Full Text Available In this study, nano crystalline Ni-20Cr-6Al composite powder was produced using a high energy planetary ball milling and a two-stage process. Then the oxidation behavior of coating of that superalloy at different temperatures considered. Nanostructured Ni-20Cr-6Al coating was deposited by cold spray for application as a bond coat to thermal barrier coating on industrial gas turbine components. The paper samples synthesized were characterized by scanning electron microscopy (SEM and transmission microscope (TEM. The crystallite size was found to be less than 18 nm. XRD pattern of the nanostructured Ni-20Cr-6Al milled powder consisted of two phases (Ni,Cr rich and (Ni3Al and so pure metals of Ni,Cr and Al that transferred into the coating. XRD pattern of the oxidized coating revealed that α-Al2O3 oxide was the main phase of the oxide and so Ni(Cr,Al 2O4 spinel phases despite the formation of α- Al2O3 oxide.

  7. 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.

  8. Friction stir processing of an aluminum-magnesium alloy with pre-placing elemental titanium powder: In-situ formation of an Al{sub 3}Ti-reinforced nanocomposite and materials characterization

    Energy Technology Data Exchange (ETDEWEB)

    Khodabakhshi, F., E-mail: farzadkhodabakhshi83@gmail.com [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Boulevard, Shiraz (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Kokabi, A.H. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Gerlich, A.P. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON (Canada)

    2015-10-15

    A fine-grained Al–Mg/Al{sub 3}Ti nanocomposite was fabricated by friction stir processing (FSP) of an aluminum-magnesium (AA5052) alloy with pre-placed titanium powder in the stirred zone. Microstructural evolutions and formation of intermetallic phases were analyzed by optical and electron microscopic techniques across the thickness section of the processed sheets. The microstructure of the nanocomposite consisted of a fine-grained aluminum matrix (1.5 µm), un-reacted titanium particles (<40 µm) and reinforcement particles of Al{sub 3}Ti (<100 nm) and Mg{sub 2}Si (<100 nm). Detailed microstructural analysis indicated solid-state interfacial reactions between the aluminum matrix and micro-sized titanium particles to form Al{sub 3}Ti intermetallic phase. The hard inclusions were then fractured and re-distributed in the metal matrix by the severe thermo-mechanical conditions imposed by FSP. Evaluation of mechanical properties by hardness measurement and uniaxial tensile test determined significant enhancement in the mechanical strength (by 2.5 order of magnetite) with a high ductility (~22%). Based on a dislocation-based model analysis, it was suggested that the strength enhancement was governed by grain refinement and the presence of hard inclusions (4 vol%) in the metal matrix. Fractographic studies also showed a ductile-brittle fracture mode for the nanocomposite compared with fully ductile rupture of the annealed alloy as well as the FSPed specimen without pre-placing titanium particles. - Highlights: • FSP was employed to fabricate in situ nanocomposite. • The AA5052 Al alloy with pre-placed micro-sized Ti particles were utilized. • The structural analysis was revealed that the in situ formation of Al{sub 3}Ti nanophase. • The SZ grain structure was refined by PSN and ZHP mechanisms during DRX. • Hardness and tensile strength were improved up to ~2.5 times with a good ductility.

  9. Electrochemical properties of hollow-structured MnS-carbon nanocomposite powders prepared by a one-pot spray pyrolysis process.

    Science.gov (United States)

    Lee, Su Min; Lee, Jung-Kul; Kang, Yun Chan

    2014-02-01

    Spherical, hollow MnS-C composite powders were prepared from a solution of manganese salt, thiourea, and sucrose by one-pot spray pyrolysis. The MnS-C composite powders were generated by direct sulfidation of MnO with hydrogen sulfide gas generated in situ by decomposition of thiourea during spray pyrolysis. Sucrose, which is used as a carbon source material, plays a key role in the formation of the MnS-C composite powders by improving the reducing atmosphere around the powders. Dot-mapping images of the composite powders demonstrated uniform distribution of the manganese, sulfur, and carbon components within the MnS-C composite powder. Fine crystals of MnS were uniformly mixed with carbon derived from polymerization and carbonization of sucrose. The carbon content of the MnS-C composite powders was 26 wt%. The discharge capacities of the MnS-C composite powders in the 2nd and 200th cycles were 863 and 967 mA h g(-1), respectively, at a current density of 1000 mA g(-1). The spherical and hollow morphology of the MnS-C composite powders was completely retained, even after 200 cycles. The enhanced cycling and rate performance of the MnS-C composite powders is ascribed to the structural stability of the composite powders.

  10. Fabrication and characterization of Ti3SiC2–SiC nanocomposite by in situ reaction synthesis of TiC/Si/Al powders

    Indian Academy of Sciences (India)

    Baoyan Liang; Mingzhi Wang; Xiaopu Li; Yunchao Mu

    2011-12-01

    The microstructure and mechanical properties of Ti3SiC2–SiC nanocomposite fabricated by in situ hot pressing (HP) synthesis process were studied. The results show that dense Ti3SiC2–SiC composite contained minor TiSi2 obtained by hot sintering at 1350°C for 1 h. The average grain size of Ti3SiC2 was 4 m in length, and the size of SiC grains is about 100 nm. With its fine microstructure, the Ti3SiC2–SiC nanocomposite shows good mechanical properties.

  11. Facile one-pot synthesis of spherical zinc sulfide-carbon nanocomposite powders with superior electrochemical properties as anode materials for Li-ion batteries.

    Science.gov (United States)

    Jang, Yong Seung; Kang, Yun Chan

    2013-10-21

    A novel and simple one-pot method of systematically synthesizing spherical metal sulfide-carbon composite powders is reported for the first time. The zinc sulfide-carbon composite is selected as the first target material. The prepared composite powders show superior electrochemical properties as anode materials for lithium-ion batteries.

  12. 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.

  13. 层层组装技术制备牙科硅藻土基纳米复相陶瓷粉体%Preparation of diatomite based nano-composite dental ceramic powders by layer-by-layer technique

    Institute of Scientific and Technical Information of China (English)

    陆小丽; 钱蕴珠; 刘梅; 周雪锋; 章非敏; 顾宁

    2011-01-01

    Objective To prepare a novel bioactive and degradable scaffold with mineralized collagenpolyose based composite by biomimetic synthesis for bone tissue engineering and explore the compatibility of osteoblast culturing on the scaffold. Methods Two kinds of polyelectrolyte were assembled on the surface of diatomite particles in order to adsorbe on nano-zirconia through opposite charges. Zeta potential,particle size and size distribution were compared before and after the modification of diatomite; IR was used to analysis molecular structure of functional group changes on the surface of diatomite particles, nano-composite powder morphology was observed by SEM. Results Two kinds of the polyelectrolyte were successfully assembled on the surface of diatomite powders. Particle size and size distribution were significantly reduced, d (0.5) reduce from 16.421 μm to 0.420 μm. SEM showed the dispersion of the modified diatomite was improved and had a good adsorption with nano-zirconia. Conclusion Layer-by-layer technique could enhance the dispersion of diatomite-based dental ceramic powders as well as a good adsorption of nano-composite ceramic powder.%目的 探讨层层组装技术对硅藻土基牙科陶瓷粉体的改性效果及其与纳米氧化锆的吸附能力的影响,减小硅藻土及纳米氧化锆粉体的团聚现象,制备出分散均匀的纳米复相陶瓷粉体.方法 采用层层组装将2种聚电解质分别组装到硅藻土颗粒表面,再将硅藻土与纳米氧化锆通过异种电荷进行吸附.比较改性前后硅藻土Zeta电位、粒径及粒径分布的变化、红外谱图(IR)分析硅藻土颗粒表面官能团和分子结构特征的变化,扫描电子显微镜(SEM)观察纳米复相陶瓷粉体的形貌.结果 聚电解质在硅藻土表面成功组装,且硅藻土粒径和粒径分布明显减小,d(0.5)从16.421μm减小到0.420μm;SEM显示改性后硅藻土的分散性得到提高且与纳米氧化锆吸附良好.结论 层层组装

  14. Preparation of nanocomposite thoriated tungsten cathode by swaging technique

    Institute of Scientific and Technical Information of China (English)

    王发展; 诸葛飞; 张晖; 丁秉钧

    2002-01-01

    By using the high energy ball milling method,the nanosized ThO2 powders were obtained.Through mixing powders,sintering and hot swaging processing,a nanocomposite thoriated tungsten cathode was fabricated.The relative density of the nanocomposite material is near 100%.The microstructure of nanocomposite cathode is quite different from that of conventional thoriated tungsten cathode.Most of thoria particles are less than 100 nm in diameter,and distribute on the boundaries of tungsten grains.The nanocomposite cathode shows a much lower arc starting field than that of conventional cathode,which will improve the performance of the cathode significantly.

  15. Polyolefin nanocomposites

    Science.gov (United States)

    Chaiko, David J.

    2007-01-02

    The present invention relates to methods for the preparation of clay/polymer nanocomposites. The methods include combining an organophilic clay and a polymer to form a nanocomposite, wherein the organophilic clay and the polymer each have a peak recrystallization temperature, and wherein the organophilic clay peak recrystallization temperature sufficiently matches the polymer peak recrystallization temperature such that the nanocomposite formed has less permeability to a gas than the polymer. Such nanocomposites exhibit 2, 5, 10, or even 100 fold or greater reductions in permeability to, e.g., oxygen, carbon dioxide, or both compared to the polymer. The invention also provides a method of preparing a nanocomposite that includes combining an amorphous organophilic clay and an amorphous polymer, each having a glass transition temperature, wherein the organophilic clay glass transition temperature sufficiently matches the polymer glass transition temperature such that the nanocomposite formed has less permeability to a gas than the polymer.

  16. Magnetic properties of YCo{sub 5} (70%wt)+Y{sub 2}Co{sub 17} (30%wt) nanocomposite powders at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Elizalde-Galindo, J.T. [Departamento de Ciencias Basicas, Instituto de Ingenieria y Tecnologia, Universidad Autonoma de Ciudad Juarez, Av. Del Charro 460 norte, Cd. Juarez, Chihuahua 32310 (Mexico); Department of Physics, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Rivera Gomez, F.J.; Matutes-Aquino, J.A. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31120 (Mexico); Botez, C.E. [Department of Physics, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States)], E-mail: cbotez@utep.edu

    2008-07-15

    Nanostructured YCo{sub 5} (70%wt)+Y{sub 2}Co{sub 17} (30%wt) composite powders were prepared by mechanical milling and subsequent annealing at 1073 K for 1.5 min. The average grain size of the YCo{sub 5} and Y{sub 2}Co{sub 17} phases, obtained from XRD data, was 14 and 12 nm, respectively. The temperature dependence of the magnetic properties was studied by DC magnetization measurements at temperatures T ranging from 3 to 300 K. Hysteresis loops (H{sub max}=70 kOe) show that both the coercivity H{sub C} and the squareness {sigma}{sub r}/{sigma}{sub max} are temperature-dependent. The coercivity increases from 12 kOe at room temperature to 18 kOe at T=3 K. The observed enhanced remanence ({sigma}{sub r}/{sigma}{sub max}>0.5) indicates that a strong exchange coupling is present at all temperatures used in this study. The maximum magnetization {sigma}{sub max} changes little with temperature and has a value of about 70% of the effective saturation magnetization of the title compound.

  17. An Investigation into W or Nb or ZnFe2O4 Doped Titania Nanocomposites Deposited from Blended Powder Targets for UV/Visible Photocatalysis

    Directory of Open Access Journals (Sweden)

    Vladimir Vishnyakov

    2013-08-01

    Full Text Available The photocatalytic behavior of titania coatings is largely determined by their crystalline structure. Depending on deposition conditions, though, titania may form amorphous, brookite, anatase or rutile structures, with anatase or anatase/rutile mixed phase structures showing the highest levels of activity. Anatase is activated by UV light and, consequently, there is a great deal of interest in doping titania films to both increase activity and extend it into the visible range. In this study, titania and doped titania coatings have been deposited from blended oxide powder targets. This highly versatile and economical technique allows dopant levels to be readily varied. Using this technique, titania coatings doped with W, Nb and ZnFe2O4 have been deposited onto glass substrates by pulsed magnetron sputtering. The as-deposited coatings were analyzed by scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDX and micro-Raman spectroscopy. Selected coatings were then annealed at temperatures in the range of 400–700 °C and re-analyzed. Structural transformation of the titania coatings was initiated in the 500–600 °C range, with the coatings annealed at 700 °C having predominantly anatase structures. The photocatalytic activity of the coatings was assessed through measurements of the degradation of organic dyes, such as methyl orange, under the influence of UV and fluorescent light sources. It was found that, after annealing, coatings with photo-active surfaces were produced and that activity varied with dopant content. Activity levels under fluorescent light irradiation were up to 60% of the activity measured under UV irradiation.

  18. Optical properties of polymer nanocomposites

    Indian Academy of Sciences (India)

    S Srivastava; M Haridas; J K Basu

    2008-06-01

    Nanomaterials have emerged as an area of interest motivated by potential applications of these materials in light emitting diodes, solar cells, polarizers, light – stable colour filters, optical sensors, optical data communication and optical data storage. Nanomaterials are of particular interest as they combine the properties of two or more different materials with the possibility of possessing novel mechanical, electronic or chemical behaviour. Understanding and tuning such effects could lead to hybrid devices based on these nanocomposites with improved optical properties. We have prepared polymer nanocomposites of well-defined compositions and studied the optical properties of powders and their thin films. UV-vis absorption spectroscopy on nanocomposite powders and spectroscopic ellipsometry measurements on thin films was used to study the effect of interfacial morphology, interparticle spacing and finite size effects on optical properties of nanocomposites. Systematic shift in the imaginary part of the dielectric function can be seen with variation in size and fraction of the gold nanoparticle. The thickness of the film also plays a significant role in the tunability of the optical spectra.

  19. Metal Nanocomposites

    DEFF Research Database (Denmark)

    Fischer, Søren Vang; Uthuppu, Basil; Jakobsen, Mogens Havsteen

    2014-01-01

    We have made SU-8 gold nanoparticle composites in two ways, ex situ and in situ, and found that in both methods nanoparticles embedded in the polymer retained their plasmonic properties. The in situ method has also been used to fabricate a silver nanocomposite which is electrically conductive....... The silver composite was structured using UV lithography, and initial results are very promising with regards to obtained resolution....

  20. Based Adaptive Nanocomposite Coatings

    Science.gov (United States)

    Ramazani, M.; Ashrafizadeh, F.; Mozaffarinia, R.

    2014-08-01

    A promising Ni(Al)-Cr2O3-Ag-CNT-WS2 self-lubricating wear-resistant coating was deposited via atmospheric plasma spray of Ni(Al), nano Cr2O3, nano silver and nano WS2 powders, and CNTs. Feedstock powders with various compositions prepared by spray drying were plasma sprayed onto carbon steel substrates. The tribological properties of coatings were tested by a high temperature tribometer in a dry environment from room temperature to 400 °C, and in a natural humid environment at room temperature. It was found that all nanocomposite coatings have better frictional behavior compared with pure Ni(Al) and Ni(Al)-Cr2O3 coatings; the specimen containing aproximately 7 vol.% Ag, CNT, and WS2 had the best frictional performance. The average room temperature friction coefficient of this coating was 0.36 in humid atmosphere, 0.32 in dry atmosphere, and about 0.3 at high temperature.

  1. Investigation on the effects of milling atmosphere on synthesis of barium ferrite/magnetite nanocomposite

    NARCIS (Netherlands)

    Molaei, M.J.; Ataie, A.; Raygan, S.; Picken,n S.J.

    2011-01-01

    In this research, barium ferrite /magnetite nanocomposites synthesized via a mechano-chemical route. Graphite was used in order to reduce hematite content of barium ferrite to magnetite to produce a magnetic nanocomposite. The effects of processing conditions on the powder characteristics were inves

  2. 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.

  3. Magnetic contribution of Bi0.85La0.15FeO3 in (1-x)Bi0.85La0.15FeO3-(x)CoFe2O4 nanocomposite powders

    Science.gov (United States)

    Han, Ru-shuai; Qi, Li-qian; Hou, Xue; Liu, Li-hu; Liu, Hui-yuan; Xian, Xiao-Ning; Guo, Ge-Xin; Sun, Hui-yuan

    2016-12-01

    In this work, a solid phase reaction method was used to fabricate (1-x)Bi0.85La0.15FeO3-xCoFe2O4 (x=0.1, 0.2, 0.3, 0.4) composite powders. X-ray diffraction patterns showed that no chemical reaction occurred between the separate Bi0.85La0.15FeO3 and CoFe2O4 phases and indicated that the powder samples had two distinct phases with a CoFe2O4 spinel phase and a Bi0.85La0.15FeO3 perovskite phase. The average crystallite sizes of the Bi0.85La0.15FeO3 in the composite powder were almost unchanged as the CoFe2O4 content was increased. By comparing the experimental and theoretical values for the magnetization, we found that the Bi0.85La0.15FeO3 phase contributed to the magnetization of the composite powders. In addition, it also provides a new way to prove the existence of magnetoelectric coupling in the sample.

  4. Design Wood Nanocomposites from Polymer Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LVWenhua; ZHAOGuangjie

    2004-01-01

    Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect for the development and study of new wood composites with high appending values and multi-properties. This paper reviewed the conventional wood composites, and then discussed the approaches to prepare wood nanocomposites. Based on the achievements of researches on polymer/montmorillonite (MMT) nanocomposites, the design ideas of preparing nanocomposites of wood and inorganic MMT were systematically put forward. Nano compounding of wood and other materials is an effective approach to greatly improve or modify wood.

  5. Preparation and fluorescence properties of 6-carboxyfluorescein/hydrotalcite nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunfang, E-mail: lichunfang@mail.ipc.ac.cn [State Key Laboratory Base of Eco-chemical Engineering, Lab of Colloid and Functional Nanostructures, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Qi, Yanhai; Li, Qianru [State Key Laboratory Base of Eco-chemical Engineering, Lab of Colloid and Functional Nanostructures, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Li, Dongxiang, E-mail: lidx@iccas.ac.cn [State Key Laboratory Base of Eco-chemical Engineering, Lab of Colloid and Functional Nanostructures, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Hou, Wanguo, E-mail: wghou@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China)

    2014-03-15

    The nanocomposites of fluorescent dye/hydrotalcite-like compounds (HTlc) synthesized by intercalation and/or surface adsorption methods have exhibited specific photophysical and photochemical property. In this work, 6-carboxyfluorescein (6CF)/HTlc nanocomposites were synthesized by ammonia coprecipitation and reconstruction-induced surface adsorption methods, and they were characterized by powder X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Thermogravimetric differential thermal measurements (TG-DTA) and fluorescence spectra. The results demonstrate that the dye molecules are primarily adsorbed on HTlc surface. The fluorescence emission of 6CF/Mg–Al HTlc composites is related with 6CF dosage due to the self-quenching mechanism. The 6CF/Zn–Al HTlc nanocomposite reconstructed at high temperature have much strong luminescence than that reconstructed at room temperature and the 6CF/Mg–Al HTlc nanocomposites. -- Highlights: • Fluorescent 6-carboxyfluorescein/HTlc nanocomposites were synthesized. • Fluorescent dye molecules are primarily adsorbed on HTlc surface. • Nanocomposite luminescence is related with the cluster structure of fluorescent dyes.

  6. Structural assessment of nanocomposites.

    Science.gov (United States)

    Gan, Yong X

    2012-07-01

    This paper provides an overview on structural assessment of nanocomposite materials. First of all, a brief description of advanced structure characterization methods such as scanning electron microscopy, X-ray diffraction, transmission electron microscopy, atomic force microscopy, and scanning tunneling microscopy is presented. Secondly, applications of these methods for analysis of structures and compositions of typical nanocomposites are introduced. The nanocomposites are formed by different nanoscale processing technologies. Electrochemically polymerized polyaniline (PANi) nanocomposites, thermomechanically processed metal matrix nanocomposites, nanocast ceramic matrix composites are typical examples discussed in this paper. Case studies on several functional nanocomposites for energy storage/conversion, catalysis and sensing applications are mentioned. After that, assessment of the interface structures of nanocomposite materials using surface characterization techniques and mechanical damage models is discussed. Finally, concluding remarks are provided.

  7. Effect of nanocomposite structure on the thermoelectric properties of 0.7-at% Bi-doped Mg2Si nanocomposite

    Institute of Scientific and Technical Information of China (English)

    Yang Mei-Jun; Shen Qiang; Zhang Lian-Meng

    2011-01-01

    Nanocomposites offer a promising approach to the incorporation of nanostructured constituents into bulk thermoelectric materials.The 0.7-at% Bi-doped Mg2Si nanocomposites are prepared by spark plasma sintering of the mixture of nanoscale and microsized 0.7-at% Bi-doped Mg2Si powders.Microstructure analysis shows that the bulk material is composed of nano- and micrograins.Although the nanograin hinders electrical conduction,the nanocomposite structure is more helpful to reduce thermal conductivity and increase the Seebeck coefficient,hence improving thermoelectric performance.A dimensionless figure of merit of 0.8 is obtained for the 0.7-at% Bi-doped Mg2Si nanocomposite with 50-wt % nanopowder,which is about twice larger than that of the sample without nanopowder.

  8. Preparation of biocompatible magnetite-carboxymethyl cellulose nanocomposite: Characterization of nanocomposite by FTIR, XRD, FESEM and TEM

    Science.gov (United States)

    Habibi, Neda

    2014-10-01

    The preparation and characterization of magnetite-carboxymethyl cellulose nano-composite (M-CMC) material is described. Magnetite nano-particles were synthesized by a modified co-precipitation method using ferrous chloride tetrahydrate and ferric chloride hexahydrate in ammonium hydroxide solution. The M-CMC nano-composite particles were synthesized by embedding the magnetite nanoparticles inside carboxymethyl cellulose (CMC) using a freshly prepared mixture of Fe3O4 with CMC precursor. Morphology, particle size, and structural properties of magnetite-carboxymethyl cellulose nano-composite was accomplished using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. As a result, magnetite nano-particles with an average size of 35 nm were obtained. The biocompatible Fe3O4-carboxymethyl cellulose nano-composite particles obtained from the natural CMC polymers have a potential range of application in biomedical field.

  9. Nonlinear I-V characteristics of nanoparticle compacts and nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Herth, Simone [Rensselaer Polytechnic Institute, Troy, NY (United States); Bielefeld University, Bielefeld (Germany); Wang, Xiaoping; Hugener, Teresa; Schadler, Linda; Siegel, Richard [Rensselaer Polytechnic Institute, Troy, NY (United States); Hillborg, Henrik; Auletta, Tommaso [ABB AB, Corporate Research, Schweden (Sweden)

    2007-07-01

    Materials with nonlinear I-V characteristics are commonly used as field grading materials. In many cases, the non-linearity is achieved through the addition of equiaxed fillers to a polymer matrix. These composite field grading materials are optimized in terms of nonlinearity, conductivity, and breakdown strength. One limitation in designing new field grading materials is a robust understanding of the relationship between powder morphology, composition and electrical characteristics of the powder, as well as a robust understanding of the relationship between powder conductivity and non-linearity and composite non-linearity. In this work, treatment of ZnO powder with a SnF{sub 2} solution resulted in a powder that yielded highly non-linear behavior. The highest non-linearity was achieved for powders with at least two different phases and a rough surface, as indicated by transmission electron micrographs. In contrast, the non-linearity of the nanocomposite conductivity is mainly determined by the conductivity of the nanofiller. The electrical behavior of the non-linear powder can be understood by a polarization of the nanoparticles at the interfaces, whereas the nonlinearity of the nanocomposites can be explained by a tunnelling mechanism between two particles.

  10. Microstructural Characterization of Aluminum-Carbon Nanotube Nanocomposites Produced Using Different Dispersion Methods.

    Science.gov (United States)

    Simões, Sónia; Viana, Filomena; Reis, Marcos A L; Vieira, Manuel F

    2016-06-01

    This research focuses on characterization of the impact of dispersion methods on aluminum-carbon nanotubes (Al-CNTs) nanocomposite structure. Nanocomposites were produced by a conventional powder metallurgy process after the dispersion of the CNTs on the Al powders, using two approaches: (1) the dispersion of CNTs and mixture with Al powders were performed in a single step by ultrasonication; and (2) the CNTs were previously untangled by ultrasonication and then mixed with Al powders by ball milling. Microstructural characterization of Al-CNT nanocomposites was performed by optical microscopy, scanning and transmission electron microscopy, electron backscatter diffraction, and high-resolution transmission electron microscopy (HRTEM). Microstructural characterization revealed that the use of ball milling for mixing CNTs with Al powders promoted the formation of CNT clusters of reduced size, more uniformly dispersed in the matrix, and a nanocomposite of smaller grain size. However, the results of HRTEM and Raman spectroscopy show that ball milling causes higher damage to the CNT structure. The strengthening effect of the CNT is attested by the increase in hardness and tensile strength of the nanocomposites.

  11. Magnetic nanocomposite sensor

    KAUST Repository

    Alfadhel, Ahmed

    2016-05-06

    A magnetic nanocomposite device is described herein for a wide range of sensing applications. The device utilizes the permanent magnetic behavior of the nanowires to allow operation without the application of an additional magnetic field to magnetize the nanowires, which simplifies miniaturization and integration into microsystems. In5 addition, the nanocomposite benefits from the high elasticity and easy patterning of the polymer-based material, leading to a corrosion-resistant, flexible material that can be used to realize extreme sensitivity. In combination with magnetic sensor elements patterned underneath the nanocomposite, the nanocomposite device realizes highly sensitive and power efficient flexible artificial cilia sensors for flow measurement or tactile sensing.

  12. Superhard Nanocomposite Coatings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The recent development in the field of nanocomposite coatings with good mechanical properties is critically reviewed in this paper. The design principle and materials selection for the nanocomposite coatings are introduced. Different methods for the preparation of superhard nanocomposite coatings are described with emphasis on the magnetron sputtering. Based on recent theoretical and experimental results regarding the appearance of superhardness in nanocomposite coating, lattice parameter changes, crystallite size, microstructure and morphology are reviewed in detail. Also emphasized are the mechanical properties (especially on hardness) and the ways by which the properties are derived.

  13. Synthesis of bio-inspired Ag–Au nanocomposite and its anti-biofilm efficacy

    Indian Academy of Sciences (India)

    S NEWASE; A V BANKAR

    2017-02-01

    In the present study, bio-inspired Ag–Au nanocomposite was synthesized using banana peel extract (BPE) powder. The Ag–Au nanocomposite was characterized using various techniques such as UV–vis spectrophotometry,transmission electron microscopy (TEM) attached with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Efficiency of AuNPs, AgNPs and Ag–Au nanocomposite was tested for their antibacterial activity against Pseudomonas aeruginosa NCIM 2948. The Ag–Au nanocomposite exhibits enhanced antimicrobial activity over its monometallic counterparts. Anti-biofilm activity of AgNPs, AuNPs and Ag–Au nanocomposite against P. aeruginosa was evaluated on glass surfaces. The Ag–Au nanocomposite exhibited the highest biofilm reduction (70–80%) when compared with individual AgNPs and AuNPs. Effect of AuNPs, AgNPs and Ag–Au nanocomposite on biofilm formation was evaluated in 96 wells microtiter plates. The percentage of biofilm inhibition was sharply increased with increasing concentration of AuNPs, AgNPs and Ag–Au composite. However, Au–Ag nanocomposite showed the highest biofilm inhibition when compared with individual AuNPs and AgNPs. This synergistic anti-biofilm activity of Ag–Au nanocomposite has an importance in the development of novel therapeutics against multidrug-resistant bacterial biofilm.

  14. Hard and superhard nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Musil, J. [Univ. of West Bohemia, Plzen (Czech Republic). Dept. of Phys.

    2000-03-01

    This article reviews the development of hard coatings from a titanium nitride film through superlattice coatings to nanocomposite coatings. Significant attention is devoted to hard and superhard single layer nanocomposite coatings. A strong correlation between the hardness and structure of nanocomposite coatings is discussed in detail. Trends in development of hard nanocomposite coatings are also outlined. (orig.)

  15. Solution combustion synthesis of Fe-Ni-Y2O3 nanocomposites for magnetic application

    Institute of Scientific and Technical Information of China (English)

    刘烨; 秦明礼; 章林; 贾宝瑞; 陈鹏起; 张德志; 曲选辉

    2015-01-01

    Fe−Ni−Y2O3 nanocomposites with uniform distribution of fine oxide particles in the gamma FeNi matrix were successfully fabricated via solution combustion followed by hydrogen reduction. The morphological characteristics and phase transformation of the combusted powder and the Fe−Ni−Y2O3 nanocomposites were characterized by XRD, FESEM and TEM. Porous Fe−Ni−Y2O3 nanocomposites with crystallite size below 100 nm were obtained after reduction. The morphology, phases and magnetic property of Fe−Ni−Y2O3 nanocomposites reduced at different temperatures were investigated. The Fe−Ni−Y2O3 nanocomposite reduced at 900 °C has the maximum saturation magnetization and the minimum coercivity values of 167.41 A/(m2·kg) and 3.11 kA/m, respectively.

  16. Preparation and Characterization of Polymer-Grafted Montmorillonite-Lignocellulose Nanocomposites by In Situ Intercalative Polymerization

    Directory of Open Access Journals (Sweden)

    Tavengwa Bunhu

    2016-01-01

    Full Text Available Lignocellulose-clay nanocomposites were synthesized using an in situ intercalative polymerization method at 60°C and a pressure of 1 atm. The ratio of the montmorillonite clay to the lignocellulose ranged from 1 : 9 to 1 : 1 (MMT clay to lignocelluloses, wt%. The adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, transmission electron microscopy (TEM, and X-ray powder diffraction (XRD. FTIR results showed that the polymers were covalently attached to the nanoclay and the lignocellulose in the nanocomposites. Both TEM and XRD analysis showed that the morphology of the materials ranged from phase-separated to intercalated nanocomposite adsorbents. Improved thermal stability, attributable to the presence of nanoclay, was observed for all the nanocomposites. The nanocomposite materials prepared can potentially be used as adsorbents for the removal of pollutants in water treatment and purification.

  17. Improved photoluminescence property of CTAB assisted polyaniline-AlZnO nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Mousumi; Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah (India); Kargupta, Kajari [Department of Chemical Engineering, Jadavpur University, Kolkata (India); Ganguly, Saibal [Chemical Engineering department, Universiti Teknology Petronas, Tronoh (Malaysia)

    2015-06-24

    Polyaniline-Al doped ZnO ((PANI-AlZnO:: 70:30) nanocomposite was prepared via in situ chemical oxidative polymerization, while the hexagonal powder of AlZnO was synthesized via sol-gel technique, using Hexadecyltrimethylammonium bromide (CTAB) as a capping agent. The prepared nanocomposite was characterized by High resolution transmission electron microscopy (HRTEM), EDAX, X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectra. The optical property of the nanomaterials is examined by photoluminescence (PL) spectra analysis. The XRD pattern confirms the formation of Al doped ZnO as well as PANI. The HRTEM images of the composite showed the formation of hexagonal AlZnO embedded in polyaniline matrix. EDAX spectrum shows the compositional analysis of the nanocomposite. FTIR spectra confirm the formation of nanocomposite of PANI and hexagonal AlZnO. The PL intensity of the nanocomposite is improved as compared to pure AlZnO.

  18. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    Detailed characterisation of the properties of composite materials with nanoscale fibres is central for the further progress in optimization of their manufacturing and properties. In the present study, a methodology for the determination and analysis of the volumetric composition of nanocomposites...... is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  19. Hydrogen storage properties of nano-composites of Mg and Zr-Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.; Ciureanu, M.; Roberge, R. [H Power Enterprises of Canada, 1069 Begin Street, St. Laurent, Quebec (Canada)

    2000-05-01

    Mg and Zr-Ni-Cr alloy nano-composite hydrogen storage materials have been prepared by high energy mechanical milling (MM) of Mg powders with either crystalline ZrNiCr and ZrNi{sub 1.6}Cr{sub 0.4} powders or mechanically milled amorphous ZrNiCr and ZrNi{sub 1.6}Cr{sub 0.4} powders. Nano-composites of amorphous Zr-Ni-Cr alloy and Mg have better desorption kinetics compared to crystalline Zr-Ni-Cr alloy and Mg nano-composites. Amorphous ZrNi{sub 1.6}Cr{sub 0.4} and Mg nano-composites desorb larger amount of H{sub 2} much faster than amorphous ZrNiCr and Mg nano-composites. The nano-composite of 35 wt.% amorphous ZrNi{sub 1.6}Cr{sub 0.4} and Mg releases 4.3 wt.% H{sub 2} at 300C in 30 min. X-ray diffraction revealed that there are no reactions between Mg and Zr-Ni-Cr alloys in the milling, activation, and subsequent cycling processes, proving that amorphous ZrNi{sub 1.6}Cr{sub 0.4} is an effective hydrogen absorption and desorption catalyst.

  20. Study of nanocomposites based on iron oxides and pectin

    Energy Technology Data Exchange (ETDEWEB)

    Chistyakova, Nataliya I., E-mail: nchistyakova@yandex.ru; Shapkin, Alexey A., E-mail: nchistyakova@yandex.ru; Sirazhdinov, Ruslan R., E-mail: nchistyakova@yandex.ru; Gubaidulina, Tatiana V., E-mail: nchistyakova@yandex.ru; Kiseleva, Tatiana Yu., E-mail: nchistyakova@yandex.ru; Kazakov, Alexander P., E-mail: nchistyakova@yandex.ru; Rusakov, Vyacheslav S., E-mail: nchistyakova@yandex.ru [M. V. Lomonosov Moscow State University, Faculty of Physics, Leninskie gory, 119991 Moscow (Russian Federation)

    2014-10-27

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the 'iron-polymer' interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  1. Study of nanocomposites based on iron oxides and pectin

    Science.gov (United States)

    Chistyakova, Nataliya I.; Shapkin, Alexey A.; Sirazhdinov, Ruslan R.; Gubaidulina, Tatiana V.; Kiseleva, Tatiana Yu.; Kazakov, Alexander P.; Rusakov, Vyacheslav S.

    2014-10-01

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the "iron-polymer" interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  2. Phase change induced by polypyrrole in iron-oxide polypyrrole nanocomposite

    Indian Academy of Sciences (India)

    Komilla Suri; S Annapoorni; R P Tandon

    2001-12-01

    Nanocomposites of polypyrrole and iron oxide were prepared using simultaneous gelation and polymerization processes. Varied amounts of pyrrole monomer were added to a solution containing iron nitrate as precursor and 2-methoxy ethanol as solvent. The presence of oxide and polypyrrole was confirmed by using X-ray and FTIR techniques. Some of these nanocomposites exhibited magnetic behaviour. SEM studies of powders indicated presence of nanosized particles. Electrical conductivity studies of powders showed a slight variation in conductivity for lower concentration of pyrrole, with a sudden increase in conductivity at 15% of pyrrole concentration. A transition from a nonmagnetic to magnetic phase was also observed at the same concentration.

  3. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

    2000-01-27

    Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

  4. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Siegal, M. P. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Tallant, D. R. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Provencio, P. N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Simpson, R. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Martinez-Miranda, L. J. [Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2000-05-22

    Modest thermal annealing to 600 degree sign C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5%-10%. We report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approx}15% due to the development of the nanocomposite structure. (c) 2000 American Institute of Physics.

  5. Aqueous combustion synthesis and characterization of zirconia-alumina nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kishan, J.; Mangam, Venu; Reddy, B.S.B.; Das, Siddhartha [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India); Das, Karabi, E-mail: karabi@metal.iitkgp.ernet.i [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)

    2010-02-04

    The zirconia-alumina nanocomposite powders with 3-48 mol% of alumina are prepared by aqueous combustion synthesis technique using stoichiometric amounts of aluminium nitrate, zirconyl nitrate and glycine. The nanopowders are compacted uniaxially and sintered at 1000 {sup o}C temperature in a muffle furnace. Thermodynamic modeling of the combustion reaction shows that, as the alumina content increases, the amount of gases produced increases with a decrease in the adiabatic flame temperature. The green and sintered densities of cold press composite powders decrease with an increase in the mol% of alumina.

  6. Antimicrobial and Controlled Release Studies of a Novel Nystatin Conjugated Iron Oxide Nanocomposite

    Directory of Open Access Journals (Sweden)

    Samer Hasan Hussein-Al-Ali

    2014-01-01

    Full Text Available Nystatin is a tetraene diene polyene antibiotic showing a broad spectrum of antifungal activity. In the present study, we prepared a nystatin nanocomposite (Nyst-CS-MNP by loading nystatin (Nyst on chitosan (CS coated magnetic nanoparticles (MNPs. The magnetic nanocomposites were characterized by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, thermogravimetry analysis (TGA, vibrating sample magnetometer (VSM, and scanning electron microscopy (SEM. The XRD results showed that the MNPs and nanocomposite are pure magnetite. The FTIR analysis confirmed the binding of CS on the surface of the MNPs and also the loading of Nyst in the nanocomposite. The Nyst drug loading was estimated using UV-Vis instrumentation and showing a 14.9% loading in the nanocomposite. The TEM size image of the MNPs, CS-MNP, and Nyst-CS-MNP was 13, 11, and 8 nm, respectively. The release profile of the Nyst drug from the nanocomposite followed a pseudo-second-order kinetic model. The antimicrobial activity of the as-synthesized Nyst and Nyst-CS-MNP nanocomposite was evaluated using an agar diffusion method and showed enhanced antifungal activity against Candida albicans. In this manner, this study introduces a novel nanocomposite that can decrease fungus activity on-demand for numerous medical applications.

  7. Crystallization of Nanocomposite Glasses Made by the SSG Process

    Science.gov (United States)

    1989-08-31

    Silica Glass. Structurally diphasic gels of SiO 2 were prepared using cabosil (ultrafine "glassy" SiO2 powder) and crystalline seeds of cristobalite ...The triphasic gel was prepared by combining colloidal suspensions and proceeded by the formation of spinel and cristobalite followed by reaction to a... Preparation and Densification of Forsterite (MgISiO 4) 8v Nanocomposite Sol-Gel Processing------------------------ ---------- 49 Manuscript #4: Sol/Gel

  8. Tribology of Nanocomposites

    CERN Document Server

    2013-01-01

    This book provides recent information on nanocomposites tribology. Chapter 1 provides information on tribology of bulk polymer nanocomposites and nanocomposite coatings. Chapter 2 is dedicated to nano and micro PTFE for surface lubrication of carbon fabric reinforced polyethersulphone composites. Chapter 3 describes Tribology of MoS2 -based nanocomposites. Chapter 4 contains information on friction and wear of Al2O2 -based composites with dispersed and agglomerated nanoparticles. Finally, chapter 5 is dedicated to wear of multi-scale phase reinforced composites. It is a useful reference for academics, materials and physics researchers, materials, mechanical and manufacturing engineers, both as final undergraduate and postgraduate levels. It is a useful reference for academics, materials and physics researchers, materials, mechanical and manufacturing engineers, both as final undergraduate and postgraduate levels.

  9. Nano-composite materials

    Science.gov (United States)

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  10. 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.

  11. Synthesis, Characterization and Catalytic Properties of Attapulgite/CeO2 Nanocomposite Films for Decomposition of Rhodamine B.

    Science.gov (United States)

    Lu, Xiaowang; Li, Xiazhang; Qian, Junchao; Chen, Feng; Chen, Zhigang

    2015-08-01

    ATP(attapulgite)/CeO2 nanocomposite films were prepared on the glass substrates via a sol-gel and dip-coating route. The ATP/CeO2 nanocomposite films were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and fourier transform infrared spectroscopy (FT-IR). The results showed that the ATP/CeO2 nanocomposite films were free from cracks and the nanoparticles were attached onto the surface of attapulgite. The ATP/CeO2 nanocomposite films displayed excellent catalytic activity for decomposition of Rhodamine B. The COD (chemical oxygen demand) removal rate of rhodamine B using ATP/CeO2 nanocomposite films as catalyst reached as high as 94% when the weight ratio of ATP to CeO2 was 2:1.

  12. On the electrical arc interruption by using PMMA/iron oxide nanocomposites

    Science.gov (United States)

    Doddapaneni, Venkatesh; Saleemi, Mohsin; Ye, Fei; Gati, Rudolf; Toprak, Muhammet S.

    2016-10-01

    An experimental study is undertaken on the fabrication of poly (methyl methacrylate) (PMMA)/iron oxide nanocomposites to determine their potential use for electrical arc interruption in the electrical switching applications such as circuit breakers. Monodisperse iron oxide nanoparticles of average size ∼11 nm are synthesized via thermal decomposition method and then homogeneously dispersed in the PMMA matrix by in situ polymerization. PMMA/iron oxide nanocomposites with different nanoparticle loading have been fabricated to study the effect of loading content on the thermal energy absorption. Detailed physicochemical characterizations on synthesized material are performed using x-ray powder diffraction, scanning electron microscopy, TEM, thermogravimetric analysis and differential scanning calorimetry at different processing stages. A test-setup was designed to evaluate the quality of the nanocomposites for electric arc interruption capability. The results showed that PMMA/iron oxide nanocomposites have a clear impact on the electric arc interruption and therefore should be considered as promising candidates for electrical switching applications.

  13. Structure–property relationships of iron–hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, Jamillah Amer [Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Prajitno, Djoko Hadi [Nuclear Technology Center for Materials and Radiometry, National Nuclear Energy, Bandung 40132 (Indonesia); Saidin, Syafiqah [Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Nur, Hadi, E-mail: hadi@kimia.fs.utm.my [Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Department of Physics, Institut Sains dan Teknologi Nasional, Jl. Moh. Kahfi II, Jagakarsa, Jakarta Selatan 12640 (Indonesia); Hermawan, Hendra, E-mail: hendra.hermawan@gmn.ulaval.ca [Department of Mining, Metallurgical and Materials Engineering & CHU de Québec Research Center, Laval University, Québec City G1V 0A6 (Canada)

    2015-06-01

    Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone–implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12 h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12 h milling in the presence of HPO{sub 4}{sup 2−} ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12 h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesis - Highlights: • Improvement of mechanical properties of HAp bioceramics by mechanosynthesis method • Structure–property relationship of iron–hydroxyapatite ceramic matrix nanocomposite • Milling time influenced the properties of iron–hydroxyapatite ceramic matrix nanocomposite.

  14. Green synthesis of Pd@graphene nanocomposite: Catalyst for the selective oxidation of alco

    Directory of Open Access Journals (Sweden)

    Abdulhadi H. Al-Marri

    2016-11-01

    Full Text Available Due to their excellent physicochemical properties and synergistic effect, graphene metallic NPs based nanocomposites have gained significant attention in various technological fields including catalysis. Here we demonstrate a single pot, facile and environmental friendly synthesis of catalytically active palladium(Pd@graphene nanocomposites (SP-HRG-Pd by the simultaneous reduction of graphene oxide (GRO and PdCl2 using Salvadora persica L. (miswak root extract (RE as bioreductant. The synthesis of SP-HRG-Pd was confirmed by various spectroscopic and microscopic techniques, including ultraviolet–visible (UV–vis, Fourier-transform infrared (FT-IR, Raman and X-ray photoelectron (XPS spectroscopy, X-ray powder diffraction (XRD and transmission electron microscopy (TEM. The polyphenolic (flavonoids and terpenoids rich contents of the miswak RE not only facilitated the reduction of graphene oxide and PdCl2 but also ensured the homogeneous binding of the Pd NPs on graphene, and through stabilization of the surface of SP-HRG-Pd nanocomposites. This also led to the enhanced dispersibility of as synthesized nanocomposites in aqueous solutions. The as-prepared SP-HRG-Pd nanocomposites also demonstrated excellent catalytic activity toward the selective oxidation of aromatic alcohols. Furthermore, in order to study the effect of calcination temperature and concentration of Pd NPs on the catalytic activities of nanocomposites, different samples of SP-HRG-Pd nanocomposites containing different amounts of Pd using various concentrations of Pd precursor were prepared and calcined at various temperatures.

  15. Dynamic mechanical analysis of single walled carbon nanotubes/polymethyl methacrylate nanocomposite films

    Institute of Scientific and Technical Information of China (English)

    Ali Badawi; N. Al-Hosiny

    2015-01-01

    Dynamic mechanical properties of nanocomposite films with different ratios of single walled carbon nan-otubes/polymethyl methacrylate (SWCNTs/PMMA) are studied. Nanocomposite films of different ratios (0, 0.5, 1.0, and 2.0 weight percent (wt%)) of SWCNTs/PMMA are fabricated by using a casting technique. The morphological and struc-tural properties of both SWCNT powder and SWCNTs/PMMA nanocomposite films are investigated by using a high resolution transmission electron microscope and x-ray diffractometer respectively. The mechanical properties including the storage modulus, loss modulus, loss factor (tanδ) and stiffness of the nanocomposite film as a function of tempera-ture are recorded by using a dynamic mechanical analyzer at a frequency of 1 Hz. Compared with pure PMMA film, the nanocomposite films with different ratios of SWCNTs/PMMA are observed to have enhanced storage moduli, loss moduli and high stiffness, each of which is a function of temperature. The intensity of the tanδ peak for pure PMMA film is larger than those of the nanocomposite films. The glass transition temperature (Tg) of SWCNTs/PMMA nanocomposite film shifts towards the higher temperature side with respect to pure PMMA film from 91.2 ◦C to 99.5 ◦C as the ratio of SWCNTs/PMMA increases from 0 to 2.0 wt%.

  16. Ionic liquid-assisted synthesis of carbon nanotube/platinum nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Zou Hua [Shandong University, Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, School of Materials Science and Engineering (China); Luan Yuxia [Shandong University, School of Pharmaceutical Sciences (China); Wang Xiaojun; Xie Zhiyun; Liu Jijuan; Sun Junchao; Wang Yana; Li Zhonghao, E-mail: zhonghaoli@sdu.edu.cn [Shandong University, Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, School of Materials Science and Engineering (China)

    2012-03-15

    The carbon nanotubes (CNTs) without modification for any functional group are used for the formation of CNTs/Pt nanocomposites in the presence of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid (IL) at a mild condition. The effects of platinum salt and [BMIM]Cl concentrations on the morphologies of final products are investigated. The as-prepared products are characterized by transmission electron microscopy, powder X-ray diffraction, and cyclic voltammetry. It shows that the as-prepared CNTs/Pt nanocomposites have a good dispersion of Pt particles with tunable size by controlling the concentration of [BMIM]Cl. The Pt particle size of the synthesized CNTs/Pt nanocomposites could be as small as 7 {+-} 2 nm. The possible formation mechanism of the as-prepared nanocomposites is proposed based on the {pi}-{pi} interaction between the IL and the CNT. The electrochemical response of the synthesized CNTs/Pt nanocomposites to K{sub 3}(FeCN){sub 6} is studied by cyclic voltammetry measurements, which demonstrates the response increases with the decrease of the Pt particle size. Moreover, the electroactivity for methanol oxidation using the synthesized CNTs/Pt nanocomposites with Pt particle size of 7 {+-} 2 nm shows that the as-prepared CNTs/Pt nanocomposites have an improved catalytic performance.

  17. Interfacial Synthesis of Gold-Polyaniline Nanocomposite and Its Electrocatalytic Application.

    Science.gov (United States)

    Bogdanović, Una; Pašti, Igor; Ćirić-Marjanović, Gordana; Mitrić, Miodrag; Ahrenkiel, Scott P; Vodnik, Vesna

    2015-12-30

    Gold-polyaniline (Au-PANI) nanocomposite was prepared using a simple interfacial polymerization method, performed in an immiscible water/toluene biphasic system using tetrachloroaurate, AuCl4(-) as an oxidant. The formation of Au nanoparticles (AuNPs) or Au-PANI nanocomposite can be controlled to a certain degree by varying the ratio of initial Au(+) and aniline concentrations. Under optimal condition (HAuCl4/aniline ratio is 1:2), green dispersion of Au-PANI nanocomposite is produced in aqueous phase, whose morphology, structure and physicochemical properties are investigated in details. The nanocomposite shows granular morphology with mostly rodlike AuNPs embedded in polymer. It was found that polyaniline in the composite is in the conducting emeraldine salt form, containing high amount of Au (28.85 wt %). Furthermore, the electrical conductivity of the nanocomposite was found to be four-fold higher than that of the polymer itself. In addition, the nanocomposite powder, isolated from the as-prepared aqueous dispersion, can later be easily redispersed in water and further used for various applications. Moreover, the obtained Au-PANI nanocomposite showed excellent electrocatalytic performance toward the electrochemical oxygen reduction reaction (ORR), with high ORR onset potential and good selectivity. This makes it a promising candidate for a new class of Pt-free ORR catalyst.

  18. Tribology of nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Davim, J. Paulo (ed.) [Aveiro Univ. (Portugal). Dept. of Mechanical Engineering

    2013-02-01

    This book provides a comprehensive review of the latest developments in nanotribology. It contains the following five chapters: 1. Tribology of bulk polymer nanocomposites and nanocomposite coatings (M. D. Bermudez, F. J. Carrion, C. Espejo, J. Sanes); 2. Nano and micro PTFE for surface lubrication of carbon fabric reinforced polyethersulphone composites (Jayashree Bijwe, Mohit Sharma); 3. Tribology of MoS{sub 2}-based nanocomposites (Kunhong Hu, Xianguo Hu, Yufu Xu, Xiaojun Sun, Yang Jiang); 4. Friction and wear of Al{sub 2}O{sub 3}-based composites with dispersed and agglomerated nanoparticles (Jinjun Lu, Jian Shang, Junhu Meng, Tao Wang); and 5. Wear of multi-scale phase reinforced composites (Zhenyu Jiang, Zhong Zhang).

  19. Chitosan-based nanocomposites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-08-01

    Full Text Available , and hygiene devices. They thus represent a strong and emerging answer for improved and eco-friendly materials. This chapter reviews the recent developments in the area of chitosan-based nanocomposites, with a special emphasis on clay-containing nanocomposites...-sized mineral fillers like silica, talc, and clay are added to reduce the cost and improve chitosan’s performance in some way. However, the mechanical properties such as elongation at break and tensile strength of these composites decrease with the incorporation...

  20. Study of early stages of Cu-NbC nanocomposite synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Marques, M.T. [INETI-DMTP, Estrada do Paco do Lumiar 22, 1649-038 Lisboa (Portugal)]. E-mail: tmarques@ineti.pt; Livramento, V. [INETI-DMTP, Estrada do Paco do Lumiar 22, 1649-038 Lisboa (Portugal); Correia, J.B. [INETI-DMTP, Estrada do Paco do Lumiar 22, 1649-038 Lisboa (Portugal); Almeida, A. [IST, Department of Materials Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Vilar, R. [IST, Department of Materials Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2007-05-31

    Cu-NbC nanocomposites with nominal compositions of 5, 10 and 20 vol.% of NbC were produced in situ via MA from elemental powders. The powders were milled for 1, 2, 4, 8, 16 and 32 h. The as-milled powders were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction results showed that the niobium carbide phase is formed in the early stages of milling and that the time necessary to complete the reaction ranges from 1 to about 8 h of milling.

  1. Bulk Al/SiC nanocomposite prepared by ball milling and hot pressing method

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li

    2006-01-01

    Nano-sized Al/SiC powders were prepared by mechanical alloying method. Two sorts of SiC particle,i.e.,nano-sized and popular micron-sized SiC were utilized. The particle size and microstructure of the milled powder were characterised. Effects of the particle size and agglomerate state of SiC,as well as the microstructure of Al/SiC nanocomposite were studied by SEM and TEM. The results show that nano-sized SiC particles is dispersed in aluminium uniformly after ball milled for only 2 h,whereas the similar process need about 10 h for popular micron-sized SiC particle. The bulk Al/SiC nanocomposite can be fabricated by hot pressing the nano-sized Al/SiC powders at temperature about 723 K under pressure of 100 MPa.

  2. Fibre reinforced polymer nanocomposites

    NARCIS (Netherlands)

    Vlasveld, D.P.N.

    2005-01-01

    In this thesis the results are described of the research on a combination of two types of composites: thermoplastic nanocomposites and continuous fibre composites. In this three-phase composite the main reinforcing phase are continuous glass or carbon fibres, and the matrix consists of a polyamide 6

  3. Granulation of fine powder

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  4. Polyacrolein/mesoporous silica nanocomposite: Synthesis, thermal stability and covalent lipase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Motevalizadeh, Seyed Farshad; Khoobi, Mehdi; Shabanian, Meisam [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Asadgol, Zahra; Faramarzi, Mohammad Ali [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 14176 (Iran, Islamic Republic of); Shafiee, Abbas, E-mail: ashafiee@ams.ac.ir [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Center of Excellence in Biothermodynamics, University of Tehran, Tehran (Iran, Islamic Republic of)

    2013-12-16

    In this work, new polyacrolein/MCM-41 nanocomposites with good phase mixing behavior were prepared through an emulsion polymerization technique. Mesoporous silica was synthesized by in situ assembly of tetraethyl orthosilicate (TEOS) and cetyl trimethyl ammonium bromide (CTAB). The structure and properties of polyacrolein containing nanosized MCM-41 particle (5 and 10 wt%), were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, Dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N{sub 2} adsorption techniques, and thermogravimetric (TGA) analyses. The SEM images from the final powder have revealed good dispersion of the MCM-41 nanoparticles throughout polymeric matrix with no distinct voids between two phases. The results indicated that the thermal properties of the nanocomposite were enhanced by addition of MCM-41. Thermomyces lanuginosa lipase (TLL) was used as a model biocatalyst and successfully immobilized with polyacrolein and the nanocomposite via covalent bonds with the aldehyde groups. The activity between free enzyme, polyacrolein, and MCM-41 nanocomposite (10 wt%)-immobilized TLL was compared. The immobilized lipase with the nanocomposite shows better operational stability such as pH tolerance, thermal and storage stability. In addition, the immobilized lipase with the nanocomposite can be easily recovered and retained at 74% of its initial activity after 15 time reuses. - Graphical abstract: The influence of incorporation of mesoporous MCM-41 nanoparticle with polyacrolein on the thermal properties and enzyme immobilization was investigated. - Highlights: • Polyacrolein/MCM-41 nanocomposites were prepared by emulsion polymerization method. • Thermal stability and char residues in nanocomposites were improved. • Nanocomposites significant effects on immobilization of lipase.

  5. Cow dung powder poisoning

    Directory of Open Access Journals (Sweden)

    Khaja Mohideen Sherfudeen

    2015-01-01

    Full Text Available Cow dung, which has germicidal property, was used in ancient days to clean living premises in South India. Nowadays, people are using commercially available synthetic cow dung powder. It is locally known as "saani powder" in Tamil Nadu. It is freely available in homes and is sometimes accidentally consumed by children. It is available in two colors - yellow and green. Cow dung powder poisoning is common in districts of Tamil Nadu such as Coimbatore, Tirupur, and Erode. We report two cases of yellow cow dung powder poisoning from our hospital.

  6. Cow dung powder poisoning.

    Science.gov (United States)

    Sherfudeen, Khaja Mohideen; Kaliannan, Senthil Kumar; Dammalapati, Pavan Kumar

    2015-11-01

    Cow dung, which has germicidal property, was used in ancient days to clean living premises in South India. Nowadays, people are using commercially available synthetic cow dung powder. It is locally known as "saani powder" in Tamil Nadu. It is freely available in homes and is sometimes accidentally consumed by children. It is available in two colors - yellow and green. Cow dung powder poisoning is common in districts of Tamil Nadu such as Coimbatore, Tirupur, and Erode. We report two cases of yellow cow dung powder poisoning from our hospital.

  7. Direct laser sintered WC-10Co/Cu nanocomposites

    Science.gov (United States)

    Gu, Dongdong; Shen, Yifu

    2008-04-01

    In the present work, the direct metal laser sintering (DMLS) process was used to prepare the WC-Co/Cu nanocomposites in bulk form. The WC reinforcing nanoparticles were added in the form of WC-10 wt.% Co composite powder. The microstructural features and mechanical properties of the laser-sintered sample were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX), and nanoindentation tester. It showed that the original nanometric nature of the WC reinforcing particulates was well retained without appreciable grain growth after laser processing. A homogeneous distribution of the WC reinforcing nanoparticles with a coherent particulate/matrix interfacial bonding was obtained in the laser-sintered structure. The 94.3% dense nanocomposites have a dynamic nanohardness of 3.47 GPa and a reduced elastic modulus of 613.42 GPa.

  8. Multifunctional zirconium oxide doped chitosan based hybrid nanocomposites as bone tissue engineering materials.

    Science.gov (United States)

    Bhowmick, Arundhati; Jana, Piyali; Pramanik, Nilkamal; Mitra, Tapas; Banerjee, Sovan Lal; Gnanamani, Arumugam; Das, Manas; Kundu, Patit Paban

    2016-10-20

    This paper reports the development of multifunctional zirconium oxide (ZrO2) doped nancomposites having chitosan (CTS), organically modified montmorillonite (OMMT) and nano-hydroxyapatite (HAP). Formation of these nanocomposites was confirmed by various characterization techniques such as Fourier transform infrared spectroscopy and powder X-ray diffraction. Scanning electron microscopy images revealed uniform distribution of OMMT and nano-HAP-ZrO2 into CTS matrix. Powder XRD study and TEM study revealed that OMMT has partially exfoliated into the polymer matrix. Enhanced mechanical properties in comparison to the reported literature were obtained after the addition of ZrO2 nanoparticle into the nanocomposites. In rheological measurements, CMZH I-III exhibited greater storage modulus (G') than loss modulus (G″). TGA results showed that these nanocomposites are thermally more stable compare to pure CTS film. Strong antibacterial zone of inhibition and the lowest minimum inhibition concentration (MIC) value of these nanocomposites against bacterial strains proved that these materials have the ability to prevent bacterial infection in orthopedic implants. Compatibility of these nanocomposites with pH and blood of human body was established. It was observed from the swelling study that the swelling percentage was increased with decreasing the hydrophobic OMMT content. Human osteoblastic MG-63 cell proliferations were observed on the nanocomposites and cytocompatibility of these nanocomposites was also established. Moreover, addition of 5wt% OMMT and 5wt% nano-HAP-ZrO2 into 90wt% CTS matrix provides maximum tensile strength, storage modulus, aqueous swelling and cytocompatibility along with strong antibacterial effect, pH and erythrocyte compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Synthesis of electrospun ZnO/CuO nanocomposite fibers and their dielectric and non-linear optic studies

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, G. Nixon Samuel [Department of Physics, R.M.K. Engineering College, R.S.M. Nagar, Kavaraipettai 601206 (India); Materials Research Centre, Department of Physics, Velammal Engineering College, Chennai 600066, TN (India); Devashankar, S.; Rathnakumari, M. [Materials Research Centre, Department of Physics, Velammal Engineering College, Chennai 600066, TN (India); Sureshkumar, P., E-mail: suresrath@yahoo.co [Department of Physics, Saveetha School of Engineering, Saveetha University, Thandalam, Chennai 602105 (India)

    2010-09-24

    Research highlights: {yields} The PVA/Zn acetate/Cu acetate nanocomposite fibers were synthesized for the first time by using the sol-gel and electro spinning techniques. {yields} The nanocomposite was characterized by powder X-ray diffraction, Fourier transform infra red spectroscopy, energy dispersive X-ray analysis and scanning electron microscopy. {yields} The band gap energy of the nanocomposite was calculated from UV spectroscopy. {yields} The dielectric and non-linear optical properties of the nanocomposite were studied for the first time. - Abstract: The blend of sol-gel processing and electrospinning technique, yields composite nanofibers of poly(vinyl alcohol) (PVA)/zinc acetate/copper acetate. Calcining these fibers resulted in nanocomposite fibers of ZnO/CuO with diameters of 50-100 nm which was revealed by the scanning electron microscope images. Energy dispersive X-ray analysis (EDX) confirmed the presence of the ZnO/CuO composite. The synthesized materials have been also characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible-near-infrared spectroscopy (UV-vis-NIR) and powder X-ray diffraction (XRD). From the UV spectra, the band gap of the nanocomposite was calculated to be 3.1 eV. Dielectric properties of these samples at different temperatures were studied with respect to frequency. The second harmonic generation efficiency of the material was found to be 11.1 times that of potassium dihydrogen orthophosphate (KDP).

  10. Inhibition of Recrystallization of Amorphous Lactose in Nanocomposites Formed by Spray-Drying.

    Science.gov (United States)

    Hellrup, Joel; Alderborn, Göran; Mahlin, Denny

    2015-11-01

    This study aims at investigating the recrystallization of amorphous lactose in nanocomposites. In particular, the focus is on the influence of the nano- to micrometer length scale nanofiller arrangement on the amorphous to crystalline transition. Further, the relative significance of formulation composition and manufacturing process parameters for the properties of the nanocomposite was investigated. Nanocomposites of amorphous lactose and fumed silica were produced by co-spray-drying. Solid-state transformation of the lactose was studied at 43%, 84%, and 94% relative humidity using X-ray powder diffraction and microcalorimetry. Design of experiments was used to analyze spray-drying process parameters and nanocomposite composition as factors influencing the time to 50% recrystallization. The spray-drying process parameters showed no significant influence. However, the recrystallization of the lactose in the nanocomposites was affected by the composition (fraction silica). The recrystallization rate constant decreased as a function of silica content. The lowered recrystallization rate of the lactose in the nanocomposites could be explained by three mechanisms: (1) separation of the amorphous lactose into discrete compartments on a micrometer length scale (compartmentalization), (2) lowered molecular mobility caused by molecular interactions between the lactose molecules and the surface of the silica (rigidification), and/or (3) intraparticle confinement of the amorphous lactose.

  11. Highly Thermal Conductive Nanocomposites

    Science.gov (United States)

    Sun, Ya-Ping (Inventor); Connell, John W. (Inventor); Veca, Lucia Monica (Inventor)

    2015-01-01

    Disclosed are methods for forming carbon-based fillers as may be utilized in forming highly thermal conductive nanocomposite materials. Formation methods include treatment of an expanded graphite with an alcohol/water mixture followed by further exfoliation of the graphite to form extremely thin carbon nanosheets that are on the order of between about 2 and about 10 nanometers in thickness. Disclosed carbon nanosheets can be functionalized and/or can be incorporated in nanocomposites with extremely high thermal conductivities. Disclosed methods and materials can prove highly valuable in many technological applications including, for instance, in formation of heat management materials for protective clothing and as may be useful in space exploration or in others that require efficient yet light-weight and flexible thermal management solutions.

  12. Chitin-based Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    D.K.Polyakov; S.N.Chvalun

    2007-01-01

    1 Results The one of the promising development of biodegradable nanocomposites is using native polysaccharides which have pronounced fibril structure to provide not only excellent mechanical properties and biodegradability of produced material but also control the barrier properties, for example increasing selectivity of pervaporation membrane. Chitin is the most popular biopolymer in the nature after cellulose. It is the 2-acetoamido-derivative of cellulose and serves as the fibrous component of the sk...

  13. Microstructure and mechanical properties of ZrO2 (Y2O3)-Al2O3 nanocomposites prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Shufeng Li; Hiroshi Izui; Michiharu Okano; Weihua Zhang; Taku Watanabe

    2012-01-01

    Zirconia (yttria)-alumina ceramic nanocomposites were fabricated from different powders by spark plasma sintering (SPS).One powder was a commercially available nanocomposite powder TZP-3Y2OA,consisting of 3 mol% yttria-stabilized zirconia (3-YSZ) reinforced with 20 wt% alumina,and the other,used as a comparison,was a conventional mechanically mixed powder 3YSZ-20A,a blend made of 3 mol% yttria-stabilized zirconia powder ZrO2 (3Y) and 20 wt% α-alumina powder.The effect of the sintering temperature on the densification,the sintering behavior,the mechanical properties and the microstructure of the composites was investigated.The results showed that the density increased with increasing sintering temperature,and thus,the mechanical properties were strengthened because of the increased densification.The nanocomposite powder TZP-3Y20A was easily sintered,and good mechanical properties were achieved as compared with the powder from the conventional mechanically mixed method,the maximum flexural strength and fracture toughness of which were 967 MPa and 5.27 MPa m1/2,respectively.

  14. Multilayer graphene rubber nanocomposites

    Science.gov (United States)

    Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

    2016-05-01

    Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

  15. CuFe2 O4 -CuO Nanocomposites as Promising Materials for Solar Hydrogen Generation

    Science.gov (United States)

    Razavi, Mehdi; Amrollahi, Pouya; Yazdimamaghani, Mostafa; Tayebi, Lobat; Vashaee, Daryoosh

    2014-03-01

    Currently, hydrogen is produced, almost exclusively, by waterelectrolysis. This method can take advantage of economies of scale and most established techniques of producing hydrogen. We developed a nanocomposite material system composed of CuFe2O4 and CuO semiconductor particles to produce hydrogen by electrolysis of water. The nanocomposite powder was prepared using the sol-gel method. Techniques of X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, transmission electron microscopy and UV diffuse reflectance analysis were employed to characterize the synthesized products.The results confirmed the formation of CuFe2O4-CuO nanocomposite powder. The hydrogen evolution was successfully observed over the new hetero-system of CuFe2O4-CuO. The electrolysis activity depended on the concentration of CuO in the system. In order to enhance the hydrogen production, we further optimized the composite material versus the concentration of the compounds.

  16. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  17. Modification of Nanocomposites by Melting Intercalation of Polypropylene in Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The polypropylene was modified by ultraviolet irradiation.The polypropylene-montmorillonite nanocomposites were prepared by direct melting intercalation of polypropylene powders.The structure of polypropylene,the polyproprlene irradiated, montmorillinote and polypropylene-montmorillonite composites were studied by XRD, IR and DSC. The results show that the PP molecules can are oxidized during ultraviolet irradiation,melt polypropylene can intercalate into montmorillonite layer.As a result,the layered distance (d001) of montmorillonite increases, and the melt absorption peak of polypropylene in layer is eliminated.

  18. Ferromagnetic properties of hybrid cementite and diamond nanocomposite

    Directory of Open Access Journals (Sweden)

    Shao-Hui Kang

    2013-12-01

    Full Text Available A nanocomposite of cementite (Fe3C nanoparticles and diamond obtained via powder mixed dielectric-electrical discharge machining (PMD-EDM is investigated. The processed surface morphology exhibits various structures, including a white layer (machined surface and a heat-affected zone (HAZ. The concentration of the Fe element in the white layer is higher than that in the HAZ. The value of magnetization is about 0.1~0.5 mA/m2. Increasing the frequency of the pulse affects the ferromagnetic behavior of magnets fabricated using the PMD-EDM process.

  19. Fluoride release and bioactivity evaluation of glass ionomer: Forsterite nanocomposite

    Directory of Open Access Journals (Sweden)

    Fatemeh Sadat Sayyedan

    2013-01-01

    Full Text Available Background: The most important limitation of glass ionomer cements (GICs is the weak mechanical properties. Our previous research showed that higher mechanical properties could be achieved by addition of forsterite (Mg 2 SiO 4 nanoparticles to ceramic part of GIC. The objective of the present study was to fabricate a glass ionomer- Mg 2 SiO 4 nanocomposite and to evaluate the effect of addition of Mg 2 SiO 4 nanoparticles on bioactivity and fluoride release behavior of prepared nanocomposite. Materials and Methods: Forsterite nanoparticles were made by sol-gel process. X-ray diffraction (XRD technique was used in order to phase structure characterization and determination of grain size of Mg 2 SiO 4 nanopowder. Nanocomposite was fabricated via adding 3wt.% of Mg 2 SiO 4 nanoparticles to ceramic part of commercial GIC (Fuji II GC. Fluoride ion release and bioactivity of nanocomposite were measured using the artificial saliva and simulated body fluid (SBF, respectively. Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR, scanning electronmicroscopy (SEM, Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES and registration of the changes in pH of soaking solution at the soaking period. Statistical analysis was carried out by one Way analysis of variance and differences were considered significant if P < 0.05. Results: The results of XRD analysis confirmed that nanocrystalline and pure Mg 2 SiO 4 powder was obtained. Fluoride ion release evaluation showed that the values of released fluoride ions from nanocomposite are somewhat less than Fuji II GC. SEM images, pH changes of the SBF and results of the ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Statistical analysis showed that the differences between the results of all groups were significant (P < 0.05. Conclusion: Glass ionomer- Mg 2 SiO 4 nanocomposite could be a good candidate for dentistry and orthopedic

  20. Effects of carbon nanotube content and annealing temperature on the hardness of CNT reinforced aluminum nanocomposites processed by the high pressure torsion technique

    Energy Technology Data Exchange (ETDEWEB)

    Phuong, Doan Dinh, E-mail: phuongdd@ims.vast.ac.vn [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay Distr., Hanoi (Viet Nam); Trinh, Pham Van; An, Nguyen Van; Luan, Nguyen Van; Minh, Phan Ngoc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay Distr., Hanoi (Viet Nam); Khisamov, Rinat Kh.; Nazarov, Konstantin S.; Zubairov, Linar R.; Mulyukov, Radik R.; Nazarov, Ayrat A. [Institute for Metals Superplasticity Problems, Russian Academy of Sciences 39, Stepan Khalturin Str., Ufa 450001 (Russian Federation)

    2014-11-15

    Highlights: • CNT/Al nanocomposites were consolidated by HIP and subsequently processed by the high pressure torsion technique. • High pressure torsion processing was unable to break apart or disperse the CNT agglomerates persisted in powder preparation. • HPT-processed CNT/Al nanocomposites exhibited secondary hardening during annealing at temperatures below 150 °C. - Abstract: In this paper, the microstructure and hardness of CNT reinforced aluminium (CNT/Al) nanocomposites prepared by the advanced powder metallurgy method and subsequently processed by the high pressure torsion (HPT) technique are studied. The effects of CNT content and annealing temperature on the hardness of the nanocomposites are investigated. The results show that annealing materials at temperatures below 150 °C leads to secondary hardening, while annealing at higher temperatures soften the nanocomposites. HPT-processed CNT/Al nanocomposites with 1.5 wt.% of CNTs are shown to have the highest hardness in comparison with other composites containing CNTs from 0 up to 2 wt.%. Microstructures, CNT distribution and the phase composition of CNT/Al nanocomposites are investigated by transmission and scanning electron microscopy and X-ray diffraction techniques.

  1. Synthesis of polyaniline/ZrO$_2$ nanocomposites and their performance in AC conductivity and electrochemical supercapacitance

    Indian Academy of Sciences (India)

    B P PRASANNA; D N AVADHANI; H B MURALIDHARA; K CHAITRA; VINNY ROSE THOMAS; M REVANASIDDAPPA; N KATHYAYINI

    2016-06-01

    Polyaniline/zirconium oxide (PANI/ZrO$_2$) nanocomposites have been synthesized by incorporating ZrO$_2$ nanoparticles into the PANI matrix via liquid–liquid interfacial polymerization method. The composite formationand structural changes in PANI/ZrO$_2$ nanocomposites were investigated by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). PXRD pattern of PANI/ZrO$_2$ nanocomposites exhibited sharp and well-defined peaks of monoclinic phase of ZrO$_2$ in PANI matrix. SEMimages of the composites showed that ZrO$_2$ nanoparticles were dispersed in the PANI matrix. The FT-IR analysis revealed thatthere was strong interaction between PANI and ZrO$_2$. AC conductivity and dielectric properties of the nanocomposites were studied in the frequency range, 50–10$^6$ Hz. AC conductivity of the nanocomposites obeyed the power lawindicating the universal behaviour of disordered media. The nanocomposites showed high dielectric constant in the order of 10$^4$, which could be related to dielectric relaxation phenomenon. Further, the materials were checked fortheir supercapacitance performance by using cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). Among the synthesized nanocomposites, PANI/ZrO2-25 wt.% showed a higherspecific capacitance of 341 F g$^{-1}$ at 2 m Vs$^{-1}$ and good cyclic stability with capacitance retention of about 88% even after 500 charge–discharge cycles.

  2. Powder detergents production plant

    OpenAIRE

    Stanković Mirjana S.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for powder detergent production plant, using technology developed in the IGPC laboratories, in 1998. - 2000. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with a capacity of 25,000 t/y was manufactured, at "Delta In", Zrenjanin, in 2000.This technology was an innovation, because new approach in mixing a powder materials was used, as well as introducing ...

  3. Magnetically responsive enzyme powders

    Energy Technology Data Exchange (ETDEWEB)

    Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

    2015-04-15

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

  4. Electrical behaviour of PMN-PT-PVDF nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Shrabanee; Mishra, S K [MST Division, National Metallurgical Laboratory, Jamshedpur 834007 (India)], E-mail: shrabaneesen@yahoo.co.in

    2008-08-21

    Nanocomposites of polyvinyldene fluoride (PVDF) and a solid solution of lead magnesium niobate and lead titanate (0.65PMN-0.35PT) with varying composition ratios were prepared by the hot-press technique. The phase structure and morphology were studied by thermal analysis (DTA), x-ray diffraction and scanning electron microscopy. The PVDF sample showed an exothermic peak due to the crystallization of the PVDF phase, but with the addition of PMN-PT powders an extra peak appeared due to the crystallization of the pyrochlore phase present in the PMN-PT powder. The crystallite size of the prepared samples was found to be between 40 and 60 nm. The value of the relative permittivity increased with the increase in the ceramic concentration. The presence of a single semicircle confirmed the presence of the bulk effect only. The bulk conductivity indicated an Arrhenius type thermally activated process. The ac conductivity spectrum obeyed the Jonscher power law.

  5. Development of biomimetic nanocomposites as bone extracellular matrix for human osteoblastic cells.

    Science.gov (United States)

    Bhowmick, Arundhati; Mitra, Tapas; Gnanamani, Arumugam; Das, Manas; Kundu, Patit Paban

    2016-05-05

    Here, we have developed biomimetic nanocomposites containing chitosan, poly(vinyl alcohol) and nano-hydroxyapatite-zinc oxide as bone extracellular matrix for human osteoblastic cells and characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction. Scanning electron microscopy images revealed interconnected macroporous structures. Moreover, in this study, the problem related to fabricating a porous composite with good mechanical strength has been resolved by incorporating 5wt% of nano-hydroxyapatite-zinc oxide into chitosan-poly(vinyl alcohol) matrix; the present composite showed high tensile strength (20.25MPa) while maintaining appreciable porosity (65.25%). These values are similar to human cancellous bone. These nanocomposites also showed superior water uptake, antimicrobial and biodegradable properties than the previously reported results. Compatibility with human blood and pH was observed, indicating nontoxicity of these materials to the human body. Moreover, proliferation of osteoblastic MG-63 cells onto the nanocomposites was also observed without having any negative effect.

  6. Preparation of magnetic Ni@graphene nanocomposites and efficient removal organic dye under assistance of ultrasound

    Science.gov (United States)

    Zhao, Chuang; Guo, Jianhui; Yang, Qing; Tong, Lei; Zhang, Jingwei; Zhang, Jiwei; Gong, Chunhong; Zhou, Jingfang; Zhang, Zhijun

    2015-12-01

    In this article, we report a facile one-step synthesis of Ni@graphene nanocomposite microspheres (NGs) in hydrazine hydrate solution under ultrasound conditions. During the ultrasonic process, graphene oxide (GO) was reduced effectively under mild conditions and Ni nanoparticles were simultaneously formed and anchored on graphene sheets, which act as spacers to keep the neighboring sheets separated. The target products exhibit excellent performance for fast and efficient removal of dye contaminants, rhodamine B (RhB) in aqueous solution, under assistance of ultrasound. Finally, the nanocomposites can be easily separated from solution by a magnet. Furthermore, higher content of graphene can be produced under sonication, which facilitates faster and more efficient removal of organic contaminates in the solution. The nanocomposites were also characterized by scanning electron microscopy, Raman spectroscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction and thermogravimetric analysis.

  7. Preparation and performance of ZnO/Polyaniline nano-composite for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.P.; Chang, X.C.; Wang, Z.M.; Han, K.F.; Zhu, H. [Beijing Univ. of Chemical Technology, Beijing (China). School of Science

    2010-07-01

    Supercapacitors combine the advantages of traditional capacitors and batteries. In this study, a zinc oxide (ZnO-PANI) nano-composite material was fabricated in order to investigate its behaviour in a supercapacitor application. The ZnO nano-powder was synthesized using the sol-gel method. An inverted emulsion polymerization method was then used to prepare the ZnO/PANI nanocomposite. X-ray diffraction (XRD) analyses demonstrated that the prepared ZnO had a hexagonal structure. The ZnO/PANI composite electrode was prepared. Electrochemical impedance spectroscopy (EIS) analyses indicated that the nano-composite material functioned well as an electrode. The highest capacitance rating achieved by the electrode was 31.82 F per g. 6 refs., 4 figs.

  8. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  9. Nanoquasicrystalline Al-based matrix/γ-Al{sub 2}O{sub 3} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Galano, M., E-mail: marina.galano@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Marsh, A. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Audebert, F. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Advanced Materials Group, INTECIN, Faculty of Engineering, University of Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina); Department of Mechanical Engineering and Mathematical Sciences, Oxford Brookes University, Wheatley Campus, OX33 1HX Oxford (United Kingdom); Xu, W. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Ramundo, M. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Department of Materials Science and Engineering, Massachusetts Institute of Technology (United States)

    2015-09-15

    Highlights: • Nanoquasicrystalline alloy MCs containing 20–50 nm Al{sub 2}O{sub 3} particles were prepared. • The ball milling process effect on the powders, microstructure and microhardness was studied. • Three different steps during the milling process were observed and explained. • Extruded bars from the ball milled alloy and composite powders were produced. • A remarkable increase in hardness in the composite bar was obtained in comparison to the alloy bar. - Abstract: Quasicrystalline aluminium alloys have been studied in the past years achieving higher strength than commercial Al alloys and retaining high strength at high temperature. In this work a quasicrystalline Al alloy matrix nanocomposite containing nanoceramic particles has been manufactured using ball milling and hot extrusion. For that purpose a nanoquasicrystalline Al–Fe–Cr–Ti alloy was manufactured by powder atomisation. Nanocomposites consisting of a quasicrystalline Al–Fe–Cr–Ti alloy matrix and reinforcement of γ-Al{sub 2}O{sub 3} nano particles were manufactured. The effect of ball milling time on the microstructure and microhardness of the nanocomposite powders was investigated. Bulk materials were produced by consolidation and hot extrusion. The microstructure and microhardness of the extruded materials were characterised. The milling regime behaviour is discussed, and shows three different steps that have a significant effect on the rate of change of uniformity of the reinforcement distribution, matrix microstructure, powder size distribution and its microhardness. No significant decomposition of the quasicrystalline phase occurred over 30 h of milling. Strain increased and the crystallite size of the aluminium phase decreased with milling time, with the Al crystallite size reaching a steady state. Although the quasicrystalline phase decomposed during hot extrusion, the microhardness of the nanocomposite produced is significantly harder (227 ± 3 μHV{sub 500}) than

  10. Dielectrical properties of PANI/TiO{sub 2} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chaturmukha, V. S.; Naveen, C. S.; Rajeeva, M. P.; Avinash, B. S.; Jayanna, H. S.; Lamani, Ashok R., E-mail: ashok1571972@gmail.com [Department of PG Studies and Research in Physics, Kuvempu University, Shankaraghatta-577451, Shimoga, Karnataka (India)

    2016-05-23

    Conducting polyaniline/titanium dioxide (PANI/TiO{sub 2}) composites have been succesfully synthesized by insitu polymerization technique. The PANI/TiO{sub 2} nanocomposites of different compositions were prepared by varying weight percentage of TiO{sub 2} nanoparticles such as 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% into the fixed amount of the aniline monomer. The prepared powder samples were characterized by X-ray diffractometer (XRD) and Scanning electron microscope (SEM). The intensity of diffraction peaks for PANI/TiO{sub 2} composites is lower than that for TiO{sub 2}. SEM pictures show that the nanocomposite were prepared in the form of long PANi chains decorated with TiO{sub 2} nanoparticles. The dielectric properties and AC conductivity were studied in the frequency range1K Hz–10M Hz. At higher frequencies, the composites exhibit almost zero dielectric loss and maximum value of σ{sub ac} is found for a concentration of 20 wt% TiO{sub 2} in polyaniline. The interface between polyaniline and TiO{sub 2} plays an important role in yielding a large dielectric constant in nanocomposites.

  11. Fe-Co metal-carbon nanocomposite based on IR pyrolized polyvinyl alcohol

    Science.gov (United States)

    Vasil'ev, A. A.; Dzidziguri, E. L.; Muratov, D. G.; Karpacheva, G. P.

    2017-05-01

    Powders of metal-carbon nanocomposites consisting of nanosized bimetallic Fe-Co particles dispersed in a carbon matrix are obtained via the IR pyrolysis of a precursor based on polyvinyl alcohol and metal-containing compounds. The obtained samples are investigated by X-ray diffraction and transmission and scanning electron microscopy. The morphology and dispersity of FeCo nanoparticles are studied, depending on the intensity of IR annealing.

  12. Mechanical properties and microstructural evolution of alumina-zirconia nanocomposites by microwave sintering

    OpenAIRE

    Benavente Martínez, Rut; Salvador Moya, Mª Dolores; Penaranda-Foix, Felipe L.; Pallone, Eliria; Borrell Tomás, María Amparo

    2014-01-01

    Microwave sintering has emerged in recent years as a novel method for sintering a variety of materials that have shown significant advantages against conventional sintering procedures. This work involved an investigation of microwave hybrid fast firing of alumina–zirconia nanocomposites using commercial alumina powder and monoclinic nanometric zirconia. The suspensions were prepared separately in order to obtain 5, 10 and 15 vol% of ZrO2 in the alumina matrix. The samples were sinter...

  13. Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials

    Science.gov (United States)

    2008-04-15

    Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials Final Performance Report Contract Number...sintered commercially-available powders. Each project is summarized below: Synthesis : Zirconium diboride and a zirconium diboride/tantalum diboride...mixture were synthesized by solution-based processing. Zirconium n-propoxide was refluxed with 2,4-pentanedione to form zirconium diketonate . This compound

  14. Direct Iron Coating onto Nd-Fe-B Powder by Thermal Decomposition of Iron Pentacarbonyl

    Energy Technology Data Exchange (ETDEWEB)

    Yamamuro, S; Okano, M; Tanaka, T [Department of Materials Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Sumiyama, K [Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Nozawa, N; Nishiuchi, T; Hirosawa, S [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals, Ltd., Osaka 618-0013 (Japan); Ohkubo, T, E-mail: yamamuro@eng.ehime-u.ac.jp [Magnetic Materials Center, National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    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/{alpha}-Fe nanocomposite permanent magnets.

  15. Clay nanocomposites for use in Li batteries

    Science.gov (United States)

    Moore, Gregory John

    1999-11-01

    Nanocomposites, materials made of more than one component and combined in an ordered manner on the nanometer scale, were synthesized using clay mineral hosts with various types of guests. The guests include polymers such as polyethylene oxide (PEO) and polyaniline (PANI), large molecules such as ethylmethyl sulfone, tetramethylene sulfone, and various length alkylamines. Vanadyl groups (VO 2+) were also incorporated with the clays. The otherwise non-swellable mica clay, synthetic Na-fluorophlogopite, was expanded by intercalation of acidic ions such as Cu2+ and Fe3+. As aqueous solutions, these ions caused the stable fluoromica to go from its dehydrated interlayer spacing of 9.8 A to over 14 A. This clay became a host for many other reactions including swelling with alkylamines to over 25 A. However, despite hydrated Cu2+ ions swelling fluorophlogopite, polymeric species such as PEO or PANI could not be inserted. Another clay that was used for formation of nanocomposites came from a procedure for the synthesis of Li-taeniolite, Li(Mg2Li)Si 4O10F2. The clay was synthesized following a high temperature method that led to a non-reactive product. Instead, a novel precursor route was employed that gave a clay product with a single hydration layer. Various chemical analyses gave a formula of Li0.8(Mg 2.2Li0.8)Si4O10(F1.6O 0.4)·H2O. For the purpose of forming nanocomposite electrolytes, ethylmethyl sulfone was synthesized and incorporated into the clay. For comparison of different shaped sulfones, tetramethylene sulfone also was inserted into the layers for electrolytic studies. To make a polymer-clay electrolyte, polyethylene oxide was intercalated into the Li-taeniolite. All of these new electrolyte materials were characterized using impedance spectroscopy for measurement of their conductivity. Syntheses and analyses are thoroughly discussed for all of these materials. Special attention is placed on powder x-ray diffraction and thermogravimetric techniques to

  16. Cellulosic fibril–rubber nanocomposites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2010-06-01

    Full Text Available Cellulose is the most abundant polymer on earth- has emerged as an ideal candidate for providing nanoparticles as reinforcing agents. There is a growing interest in cellulose nanocomposites within the research community and especially...

  17. Sonochemical Preparation of Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Hyoung Jin Choi

    2009-06-01

    Full Text Available Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT and organophillic clay, but also as a special initiator to enhance polymerization for fabrication of polymer nanocomposites with CNT and metallic nanoparticles. Recent developments in the preparation of multi-walled carbon nanotube/polymer nanocomposites with polystyrene and PMMA, magnetic particle/CNT composites and polymer/clay nanocomposites along with their physical characteristics and potential engineering applications will be introduced. Physical characterizations include morphological, thermal, and rheological properties under either an applied electric or magnetic field.

  18. Enhancement of thermal neutron attenuation of nano-B{sub 4}C, -BN dispersed neutron shielding polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaewoo, E-mail: kimj@kaeri.re.kr [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); WCI Quantum Beam based Radiation Research Center, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Missouri University Research Reactor, University of Missouri-Columbia, Columbia, MO 65211 (United States); Lee, Byung-Chul [Nuclear Reactor Core Design Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Uhm, Young Rang [Radioisotopes Research Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Miller, William H. [Missouri University Research Reactor, University of Missouri-Columbia, Columbia, MO 65211 (United States)

    2014-10-15

    Highlights: • Preparation of B{sub 4}C and BN nanopowders using a simple ball milling process. • Homogeneous dispersion and strong adhesion of nano-B{sub 4}C and -BN with polymer matrix. • Enhancement of mechanical properties of the nanocomposites compared to their micro counterparts. • Enhancement of thermal neutron attenuation of the nanocomposites. - Abstract: Nano-sized boron carbide (B{sub 4}C) and boron nitride (BN) powder were prepared using ball milling. Micro- and milled nano-powders were melt blended with high density polyethylene (HDPE) using a polymer mixer followed by hot pressing to fabricate sheet composites. The tensile and flexural strengths of HDPE nanocomposites were ∼20% higher than their micro counterparts, while those for latter decreased compared to neat HDPE. Thermal neutrons attenuation of the prepared HDPE nanocomposites was evaluated using a monochromatic ∼0.025 eV neutron beam. Thermal neutron attenuation of the HDPE nanocomposites was greatly enhanced compared to their micro counterparts at the same B-10 areal densities. Monte Carlo n-Particles (MCNP) simulations based on the lattice structure modeling also shows the similar filler size dependent thermal neutron absorption.

  19. Magnetoelectric Nanocomposites for Flexible Electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-09-01

    Flexibility, low cost, versatility, miniaturization and multi-functionality are key aspects driving research and innovation in many branches of the electronics industry. With many anticipated emerging applications, like wearable, transparent and biocompatible devices, interest among the research community in pursuit for novel multifunctional miniaturized materials have been amplified. In this context, multiferroic polymer-based nanocomposites, possessing both ferroelectricity and ferromagnetism, are highly appealing. Most importantly, these nanocomposites possess tunable ferroelectric and ferromagnetic properties based on the parameters of their constituent materials as well as the magnetoelectric effect, which is the coupling between electric and magnetic properties. This tunability and interaction is a fascinating fundamental research field promising tremendous potential applications in sensors, actuators, data storage and energy harvesting. This dissertation work is devoted to the investigation of a new class of multiferroic polymer-based flexible nanocomposites, which exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature, with the goal of understanding and optimizing the origin of their magnetoelectric coupling. The nanocomposites consist of high aspect ratio ferromagnetic nanowires (NWs) embedded inside a ferroelectric co-polymer, poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE) matrix. First, electrochemical deposition of ferromagnetic NWs inside anodic aluminum oxide membranes is discussed. Characterization of electrodeposited iron, nickel and highly magnetostrictive iron-gallium alloy NWs was done using XRD, electron and magnetic force microscopy. Second, different nanocomposite films have been fabricated by means of spin coating and drop casting techniques. The effect of incorporation of NWs inside the ferroelectric polymer on its electroactive phase is discussed. The remanent and saturation polarization as well

  20. Sintering behavior, microstructure and mechanical properties of vacuum sintered SiC/spinel nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guoqiang, E-mail: lguoqi1@lsu.edu [Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Mechanical Engineering, Southern University, Baton Rouge, LA 70813 (United States); Tavangarian, Fariborz [Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2014-12-05

    Highlights: • Bulk SiC/spinel nanocomposite was synthesized from talc, aluminum and graphite powders. • Sintering behavior and mechanical properties of SiC/spinel nanocomposite was studied. • The obtained bulk SiC/spinel nanocomposite had a mean crystallite size of about 34 nm. - Abstract: A mixture of SiC and spinel (MgAl{sub 2}O{sub 4}) nanopowder was prepared through the ball milling of talc, aluminum and graphite powder. The powder was uniaxially pressed into the form of pellets and the prepared specimens were annealed at various temperatures for different holding times. The prepared samples were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), nanoindentation test, cold crushing strength (CCS) test and Archimedes principle test. The obtained results showed that the hardness, CCS and bulk density did not follow the same trend at different temperatures due to the interaction among various parameters. The detailed investigation of microstructure, phase changes and experimental conditions revealed the mechanisms behind these behaviors. The best sample obtained after annealing at 1200 °C for 1 h in vacuum had the mean hardness of 1.6 GPa and the mean CCS of 118 MPa.

  1. Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles.

    Science.gov (United States)

    Han, Xiao; Huang, Shiming; Wang, Yilong; Shi, Donglu

    2016-07-01

    Anisotropic yolk/shell or Janus inorganic/polystyrene nanocomposites were prepared by combining miniemulsion polymerization and sol-gel reaction. The morphologies of the anisotropic composites were found to be greatly influenced by surface modification of zinc oxide (ZnO) nanoparticle seeds. Two different types of the oleic acid modified ZnO nanoparticles (OA-ZnO) were prepared by post-treatment of commercial ZnO powder and homemade OA-ZnO nanoparticles. The morphologies and properties of the nanocomposites were investigated by transmission electron microscope (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDX). It was found that both post-treated OA-ZnO and in-situ prepared OA-ZnO nanoparticles resulted in the yolk-shell and Janus structure nanocomposites, but with varied size and morphology. These nanocomposites showed stable and strong fluorescence by introducing quantum dots as the co-seeds. The fluorescent anisotropic nanocomposites were decorated separately with surface carboxyl and hydroxyl groups. These composites with unique anisotropic properties will have high potential in biomedical applications, particularly in bio-detection.

  2. Palladium-doped-ZrO2-multiwalled carbon nanotubes nanocomposite: an advanced photocatalyst for water treatment

    Science.gov (United States)

    Anku, William Wilson; Oppong, Samuel Osei-Bonsu; Shukla, Sudheesh Kumar; Agorku, Eric Selorm; Govender, Poomani Penny

    2016-06-01

    The photocatalytic degradation of organic pollutants from water using palladium-doped-zirconium oxide-multiwalled carbon nanotubes (Pd-ZrO2-MWCNTs) nanocomposites is presented. A series of Pd doped-ZrO2-MWCNTs nanocomposites with varying percentage compositions of Pd were prepared by the homogenous co-precipitation method. The photocatalytic applicability of the materials was investigated by the degradation of acid blue 40 dye in water under simulated solar light. The optical, morphological and structural properties of the nanocomposites were evaluated using X-ray powder diffraction, Fourier transformer infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, BET surface area analysis and (UV-Vis) spectroscopy. The Pd-ZrO2-MWCNTs nanocomposites showed enhanced photocatalytic activity toward the degradation of the acid blue 40 dye under visible light compared with bare ZrO2 and ZrO2-MWCNTs alone. The remarkable photocatalytic activity of Pd-ZrO2-MWCNTs nanocomposites in the visible light makes it an ideal photocatalyst for the removal of organic pollutants in water. The 0.5 % Pd-ZrO2-MWCNT was the most efficient photocatalyst with 98 % degradation after 3 h with corresponding K a and band gap values of 16.8 × 10-3 m-1 and 2.79 eV, respectively.

  3. Fabrication and Microhardness Analysis of MWCNT/MnO2 Nanocomposite

    Directory of Open Access Journals (Sweden)

    Md. Zakir Hussain

    2016-01-01

    Full Text Available Recent research has shown that carbon nanotube (CNT acts as a model reinforcement material for fabricating nanocomposites. The addition of CNT as a reinforcing material into the matrix improves the mechanical, thermal, tribological, and electrical properties. In this research paper multiwalled carbon nanotube (MWCNT, with different weight percentage (5%, 10%, and 15%, was reinforced into manganese dioxide (MnO2 matrix using solution method. The different weight % of MWCNT/MnO2 nanocomposite powders was compacted and then sintered. The phase analysis, morphology, and chemical composition of the nanocomposites were examined by X-ray diffractometer, Field Emission Scanning Electron Microscope (FESEM, and Energy Dispersive X-Ray (EDX, respectively. The XRD analysis indicates the formation of MWCNT/MnO2 nanocomposites. The FESEM surface morphology analysis shows that MnO2 nanotube is densely grown on the surface of MWCNT. Further, microhardness of MWCNT/MnO2 nanocomposite was measured and it was found that 10 wt% has higher microhardness in comparison to 5 and 15 wt%. The microhardness of the composites is influenced by mass density, nanotube weight fraction, arrangement of tubes, and dispersion of MWCNT in H2SO4(aq solution.

  4. "Green" nanocomposites from cellulose acetate bioplastic and clay: effect of eco-friendly triethyl citrate plasticizer.

    Science.gov (United States)

    Park, Hwan-Man; Misra, Manjusri; Drzal, Lawrence T; Mohanty, Amar K

    2004-01-01

    "Green" nanocomposites have been successfully fabricated from cellulose acetate (CA) powder, eco-friendly triethyl citrate (TEC) plasticizer and organically modified clay. The effect of the amount of plasticizer varying from 15 to 40 wt % on the performance of the nanocomposites has been evaluated. The morphologies of these nanocomposites were evaluated through X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM) studies. The mechanical properties of nanocomposites are correlated with the XRD and TEM observations. Cellulosic plastic-based nanocomposites with 20 wt % TEC plasticizer and 5 wt % organoclay showed better intercalation and an exfoliated structure than the counterpart having 30/40 wt % plasticizers. The tensile strength, modulus and thermal stability of cellulosic plastic reinforced with organoclay showed a decreasing trend with an increase of plasticizer content from 20 to 40 wt %. The nano-reinforcement at the lower volume fractions (phi < or = 0.02) reduced the water vapor permeability of cellulosic plastic by 2 times and the relative permeability better fits with larger platelet aspect ratios (alpha = 150).

  5. Kinetic evaluation study on the bioactivity of silver doped hydroxyapatite-polyvinyl alcohol nanocomposites.

    Science.gov (United States)

    Mostafa, Amany A; Oudadesse, Hassane; El Sayed, Mayyada M H; Kamal, Gehan; Kamel, Mohamed; Foad, Enas

    2014-12-01

    This work investigates the effect of adding silver nanoparticles (NPs) in ppm on the bioactivity of hydroxyapatite/polyvinyl alcohol nanocomposites (HAV). HAV prepared by an in situ biomimetic approach was doped with different concentrations of silver NPs (HAV-Ag), and the formed powder samples were characterized by different techniques such as Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-EOS), X-ray diffraction, transmission electron microscope, and Fourier Transform Infrared Spectroscopy. Bioactivity was evaluated in simulated body fluid through studying the kinetics of Ca and P uptake onto the different HAV-Ag nanocomposites. Uptake profiles of Ca and P were well described by a pseudo-second order kinetic model, and the obtained kinetic parameters confirmed that the highest uptake capacities were achieved by adding less than 0.001 ppm of silver NPs which is an amount not detectable by ICP. Furthermore, HAV-Ag nanocomposites were shown to be non-toxic as well as have a strong antibacterial effect. Silver NPs significantly enhanced the bioactivity of HAV nanocomposites and thus the developed nanocomposites promise to be excellent biomaterials for bone and reconstructive surgery applications.

  6. Polymer-Layer Silicate Nanocomposites

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela

    Nowadays, some of the material challenges arise from a performance point of view as well as from recycling and biodegradability. Concerning these aspects, the development of polymer layered silicate nanocomposites can provide possible solutions. This study investigates how to obtain polymer layered...... silicate nanocomposites and their structure-properties relationship. In the first part of the thesis, thermoplastic layered silicates were obtained by extrusion. Different modification methods were tested to observe the intercalation treatment effect on the silicate-modifier interactions. The silicate...

  7. Cow dung powder poisoning

    OpenAIRE

    Khaja Mohideen Sherfudeen; Senthil Kumar Kaliannan; Pavan Kumar Dammalapati

    2015-01-01

    Cow dung, which has germicidal property, was used in ancient days to clean living premises in South India. Nowadays, people are using commercially available synthetic cow dung powder. It is locally known as “saani powder” in Tamil Nadu. It is freely available in homes and is sometimes accidentally consumed by children. It is available in two colors - yellow and green. Cow dung powder poisoning is common in districts of Tamil Nadu such as Coimbatore, Tirupur, and Erode. We report two cases of ...

  8. Silver-titanium dioxide nanocomposites as effective antimicrobial and antibiofilm agents

    Science.gov (United States)

    Lungu, Magdalena; Gavriliu, Ştefania; Enescu, Elena; Ion, Ioana; Brătulescu, Alexandra; Mihăescu, Grigore; Măruţescu, Luminiţa; Chifiriuc, Mariana Carmen

    2014-01-01

    Ag-TiO2 nanocomposites were successfully developed from colloidal suspensions containing 750 or 1,500 ppm silver nanoparticles (AgNPs) deposited on 5 % (w/v) titanium dioxide nanoparticles (TiO2NPs) by a chemical reduction approach. The nanocomposites were characterized by diffuse reflectance UV-Vis spectroscopy (DRS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS). DRS spectra showed an absorption band in visible region with maximum absorbance peaks at 452 and 444 nm attributed to AgNPs plasmon peaks, indicating the formation of small spherical or quasi-spherical Ag nanocrystals in nanocomposites. TEM and SEM analysis proved a nearly spherical morphology of particles (15-30 ± 5 nm average size in diameter). EDX analysis revealed the presence of Ti, O, and Ag in both nanocomposite powders having 1.37 or 2.34 wt% Ag content. DLS analysis yielded a bimodal particle size distribution in a narrow range (31.3 ± 0.5 or 23.4 ± 0.4 nm average particle diameter) and a good polydispersity (0.247 or 0.293 polydispersity index). The nanocomposites were screened for their in vitro antimicrobial activity against Gram-positive ( Bacillus subtilis and Staphylococcus aureus) and Gram-negative ( Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) bacterial and fungal ( Candida albicans) reference and clinical strains, in planktonic and adherent state, by qualitative and quantitative assays. The antibacterial activity increased with the increasing AgNPs content, being more intensive for Gram-positive bacteria. Both Ag-TiO2 nanocomposites exhibited a high antibiofilm activity. The obtained results recommend the use of the developed nanocomposites as antimicrobial and antibiofilm agents in practical applications without UV irradiation. The most effective agent proved to be the one with 2.34 wt% AgNPs content.

  9. Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

    Science.gov (United States)

    Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

    2017-01-01

    In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

  10. Magnetic Nanocomposite Cilia Sensors

    KAUST Repository

    Alfadhel, Ahmed

    2016-07-19

    Recent progress in the development of artificial skin concepts is a result of the increased demand for providing environment perception such as touch and flow sensing to robots, prosthetics and surgical tools. Tactile sensors are the essential components of artificial skins and attracted considerable attention that led to the development of different technologies for mimicking the complex sense of touch in humans. This dissertation work is devoted to the development of a bioinspired tactile sensing technology that imitates the extremely sensitive hair-like cilia receptors found in nature. The artificial cilia are fabricated from permanent magnetic, biocompatible and highly elastic nanocomposite material, and integrated on a giant magneto-impedance magnetic sensor to measure the stray field. A force that bends the cilia changes the stray field and is therefore detected with the magnetic sensor, providing high performance in terms of sensitivity, power consumption and versatility. The nanocomposite is made of Fe nanowires (NWs) incorporated into polydimethylsiloxane (PDMS). Fe NWs have a high remanent magnetization, due the shape anisotropy; thus, they are acting as permanent nano-magnets. This allows remote device operation and avoids the need for a magnetic field to magnetize the NWs, benefiting miniaturization and the possible range of applications. The magnetic properties of the nanocomposite can be easily tuned by modifying the NWs concentration or by aligning the NWs to define a magnetic anisotropy. Tactile sensors are realized on flexible and rigid substrates that can detect flow, vertical and shear forces statically and dynamically, with a high resolution and wide operating range. The advantage to operate the sensors in liquids and air has been utilized to measure flows in different fluids in a microfluidic channel. Various dynamic studies were conducted with the tactile sensor demonstrating the detection of moving objects or the texture of objects. Overall

  11. Effect of Nanofiller Characteristics on Nanocomposite Properties

    Science.gov (United States)

    Working, Dennis C.; Lillehei, Peter T.; Lowther, Sharon E.; Siochi, Emilie J.; Kim, Jae-Woo; Sauti, Godfrey; Wise, Kristopher E.; Park, Cheol

    2016-01-01

    This report surveys the effect of nanofiller characteristics on nanocomposites fabricated with two polyimide matrices. Mechanical and electrical properties were determined. Microscopy results showed that matrix chemistry, nanofiller characteristics and processing conditions had significant impact on nanocomposite quality.

  12. Magnetoelectric polymer nanocomposite for flexible electronics

    KAUST Repository

    Alnassar, M.

    2015-03-06

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  13. Production of Al nanocomposite reinforced by Fe-Al intermetallic, Al{sub 4}C{sub 3} and nano-Al{sub 2}O{sub 3} particles using wet milling in toluene

    Energy Technology Data Exchange (ETDEWEB)

    Razavi-Tousi, S.S., E-mail: ser105@mail.usask.ca [Islamic Azad University, Shahrood Branch, Shahrood (Iran, Islamic Republic of); Yazdani-Rad, R. [Materials and Energy Research Center, P.O. Box 31787/316, Karaj (Iran, Islamic Republic of); Manafi, S.A. [Islamic Azad University, Shahrood Branch, Shahrood (Iran, Islamic Republic of)

    2011-06-02

    Highlights: > Production of Al nanocomposite reinforced by Fe-Al intermetallic, Al{sub 4}C{sub 3} and nano-Al{sub 2}O{sub 3} particles using wet milling in toluene. > Production of Al{sub 4}C{sub 3} particles from mechanochemical reaction of Al with PCA. > Effect of second phase particles on sintering. - Abstract: Al matrix nanocomposites were produced by wet milling of Al and nano-alumina powders in a toluene media. X-ray diffraction patterns, inductively coupled plasma, carbon measurement analysis and scanning electron microscopy show that impurities introduced by decomposition of toluene and abrasion of balls and vials are uniformly dispersed in the Al matrix as Al{sub 4}C{sub 3} and Fe-Al intermetallic particles. Though producing homogenous nanocomposites, these second phase particles seem to have a retarding effect on densification of nanocomposite powders.

  14. Synthesis and Study of Optical properties of MgO based TM oxide (TM=Cu, Mn and Zn) nanocomposites

    Science.gov (United States)

    Tamizh Selvi, K.; Alamelumangai, K.; Priya, M.; Rathnakumari, M.; Kumar, P. Suresh; Sagadevan, Suresh

    2016-11-01

    A nanocomposite of MgO based transition metal (TM) oxide (TM=Zn, Mn, and Cu) was synthesized using sol-gel method. The powder x-ray diffraction confirmed the phase purity and particle size. The surface morphology and elemental composition were examined by High resolution scanning electron microscopy and energy-dispersive x-ray spectroscopy. The change in optical band gap of the synthesized nanocomposites, by increasing the Mg content was determined using UV-vis spectra and the luminescent properties were analyzed using photoluminescence spectra.

  15. Ferromagnetic Planar Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Carbucicchio, M.; Rateo, M. [University of Parma, and INFM, Department of Physics (Italy)

    2004-12-15

    Modern permanent magnets require a high coercive field on account of a strong magnetocrystalline anisotropy, as well as a high saturation magnetization and high Curie temperature. The achievement of so different characteristics in a unique phase is the present main difficulty. In principle, this problem can be solved combining the high saturation magnetization of a soft phase with the high magnetic anisotropy of a hard phase, via the exchange coupling on a nanometric scale. The first attempts showed the feasibility of planar magnetic nanocomposites, where soft and hard magnetic layers are intercalated, but on the other hand they also stressed the difficulties still existing. The present paper reviews some theoretical aspects and experimental results, pointing out the potentiality of Moessbauer spectroscopy in determining the spin configuration, as well as the nature and thickness of interfaces, which strongly influence the exchange interaction in these systems.

  16. Synthesis and Characterization of Nanoparticles and Nanocomposite of ZnO and MgO by Sonochemical Method and their Application for Zinc Polycarboxylate Dental Cement Preparation

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Karimi

    2011-01-01

    Full Text Available This paper discusses the synthesis of nanoparticles of ZnO and MgO and ZnO/MgO nanocomposite by the sonochemical method. At first, nanoparticles were synthesized by the reaction of Zn(CHCOO32 and Mg(CHCOO32 with tetramethylammonium hydroxide (TMAH in the presence of polyvinyl pyrrolidone (PVP and constant frequency ultrasonic waves (sonochemical method. Then, ZnO/MgO nanocomposite was prepared through reaction of magnesium acetate with TMAH in the presence of ZnO nanoparticles and PVP as structure director using ultrasonic assisted method. After filtration, the synthesized solution was obtained containing magnesium hydroxide in the presence of ZnO nanoparticles. It was calcinated at the temperature of 550 ºC, so that ZnO/MgO nanocomposite could be produced. The effects of different parameters on particle size and morphology of final ZnO and MgO powders and ZnO/MgO nanocomposite were optimized by ‘‘one at a time’’ method. Under optimum conditions, spongy shaped, uniformed and homogeneous nanostructured zinc oxide and magnesium oxide powders were obtained with particle sizes of 25–50 and 30-60 nm, respectively. ZnO/MgO nanocomposite was also obtained with more spongy morphology and particle size about 65 nm. Both synthesized ZnO and MgO nanoparticles and ZnO/MgO nanocomposite were successfully applied to the preparation of zinc polycarboxylate dental cement.

  17. Residual Monomer Content and Its Release into Water from the Denture Base Nanocomposite Using Organic Montmorillonite as Reinforcement

    Institute of Scientific and Technical Information of China (English)

    LI Hongbo; ZHANG Chao; LI Zhian; WANG Yining; XIAO Qun

    2008-01-01

    A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate(PMMA) and cethyltrimethylammonium bromide modified organic montmorillonite (OMMT).The dispersion of montmorillonite in the polymer matrix was characterized by x-ray diffraction (XRD) and transimission electron microscope (TEM).The content of residual MMA in nanocomposites and the amount of MMA released to water from nanocomposites were determined by gas chromatography (GC).The analysis of TEM and XRD showed that exfoliated-intercalated and intercalated nanocomposites were formed when the content of OMMT was 3% and 5% in the PMMA powder respectively.The results of GC showed that the residual MMA increased with the increase of OMMT content in the polymer matrix.After 7 days in water,the amount of MMA released into water from the nanocomposites tended to be stable.The results of one-way ANOVA and t-test showed that OMMT gave a significant increase of residual MMA concentration (p<0.05) in nanocomposites.

  18. Strong bioresorbable Ca phosphate-PLA nanocomposites with uniform phase distribution by attrition milling and high pressure consolidation.

    Science.gov (United States)

    Rakovsky, Artoum; Gotman, Irena; Rabkin, Eugen; Gutmanas, Elazar Y

    2013-02-01

    Highly dense bioresorbable Ca-deficient HA-PLA (CDHA-PLA) and β-TCP-PLA nanocomposite materials with high (up to 80 vol%) contents of the calcium phosphate (CaP) phase and homogeneous phase distribution were prepared via attrition milling followed by high pressure consolidation at ambient temperature. The microstructure and mechanical properties of the materials obtained were studied as a function of milling time and PLA amount. Attrition milling resulted in disintegration of β-TCP powder agglomerates down to 50-150 nm, disintegration of CDHA agglomerates and refinement of 15 × 150 nm(2) CDHA nanoparticles to a size of 8 × 20 nm(2), and in a uniform distribution of the polymer component. Very high compressive strengths up to 400 MPa and high bending strengths up to 70 MPa were obtained. For both β-TCP and CDHA-based nanocomposites, the strength characteristics increased with milling time and decreased with increasing PLA content. For CDHA-based nanocomposites, attrition milling resulted in decrease of ductility while for β-TCP-40 vol% PLA the ductility increased. The observed behavior may be a result of formation of homogeneous, relatively thick (tens of nanometers), ductile PLA layers in β-TCP-PLA nanocomposites, but very thin (several nanometers) PLA layers in attrition milled CDHA-PLA nanocomposites. Degradation of compressive and bending strength in aqueous solutions was observed for all the studied CaP-PLA nanocomposites.

  19. Novel kojic acid-polymer-based magnetic nanocomposites for medical applications

    Directory of Open Access Journals (Sweden)

    Hussein-Al-Ali SH

    2014-01-01

    Full Text Available Samer Hasan Hussein-Al-Ali,1 Mohamed Ezzat El Zowalaty,2,5 Mohd Zobir Hussein,3 Maznah Ismail,1,4 Dena Dorniani,3 Thomas J Webster6,7 1Laboratory of Molecular Biomedicine, 2Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, 3Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology, 4Department of Nutrition and Dietetics, Faculty of Medicine and Health Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 5Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, Saudi Arabia; 6Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USA; 7Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: Iron oxide magnetic nanoparticles (MNPs were synthesized by the coprecipitation of iron salts in sodium hydroxide followed by coating separately with chitosan (CS and polyethylene glycol (PEG to form CS-MNPs and PEG-MNPs nanoparticles, respectively. They were then loaded with kojic acid (KA, a pharmacologically bioactive natural compound, to form KA-CS-MNPs and KA-PEG-MNPs nanocomposites, respectively. The MNPs and their nanocomposites were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. The powder X-ray diffraction data suggest that all formulations consisted of highly crystalline, pure magnetite Fe3O4. The Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed the presence of both polymers and KA in the nanocomposites. Magnetization curves showed that both nanocomposites (KA-CS-MNPs and KA-PEG-MNPs were superparamagnetic with saturation magnetizations of 8.1 emu/g and 26.4 emu/g, respectively. The KA drug loading was estimated using ultraviolet–visible spectroscopy, which gave a loading of 12.2% and 8.3% for the KA

  20. Platelet-containing tantalum powders

    Energy Technology Data Exchange (ETDEWEB)

    Schiele, E.K.

    1988-04-26

    A method of forming platelet tantalum powders is described comprising the steps of: (a) providing an ingot-derived precursor tantalum powder, and (b) ball-milling the precursor powder for a time sufficient to form a platelet powder having an average FSSS of less than about 2 micrometers, a Scott density not greater than about 30 g/in/sup 3/ and a BET surface area of at least about 0.7 in/sup 2//g.

  1. Au-TiO2 Nanocomposites and Efficient Photocatalytic Hydrogen Production under UV-Visible and Visible Light Illuminations: A Comparison of Different Crystalline Forms of TiO2

    OpenAIRE

    Deepa Jose; Christopher M. Sorensen; Rayalu, Sadhana S.; Khadga M. Shrestha; Klabunde, Kenneth J.

    2013-01-01

    nanocomposites were prepared by the solvated metal atom dispersion (SMAD) method, and the as-prepared samples were characterized by diffuse reflectance UV-visible spectroscopy, powder XRD, BET surface analysis measurements, and transmission electron microscopy bright field imaging. The particle size of the embedded Au nanoparticles ranged from 1 to 10 nm. These Au/TiO2 nanocomposites were used for photocatalytic hydrogen production in the presence of a sacrificial electron donor like ethanol ...

  2. Measuring Apparatus for Coal Powder

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The measuring apparatus for coal powder, equipped with radioactive source, is a set of device andcan be used to measure the density in the pipes and cumulative consumed amount of coal powder in apower plant, and to examine and display the status of the coal powder input system. It is sketched asFig. 1.

  3. Synthesis of Uranium nitride powders using metal uranium powders

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    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{sup 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.

  4. Sol–gel synthesis and luminescence of undoped and Mn-doped zinc orthosilicate phosphor nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    El Ghoul, J., E-mail: ghoultn@yahoo.fr [Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l’Environnement, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); El Mir, L. [Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l’Environnement, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Departement of Physics, Riyadh 11623 (Saudi Arabia)

    2014-04-15

    Zn{sub 2}SiO{sub 4} and Zn{sub 2}SiO{sub 4}:Mn particles embedded in SiO{sub 2} host matrix prepared by sol gel method under supercritical conditions of ethyl alcohol in two steps. Were prepared by a simple solid-phase reaction under natural atmosphere at 1200 °C after the incorporation of ZnO and ZnO:Mn nanoparticles, respectively, in silica monolith. In the case of SiO{sub 2}/Zn{sub 2}SiO{sub 4} nanocomposite, the powder with an average particle size of 80 nm shows a strong luminescence band centred at around 760 nm in the visible range. In addition, the PL spectrum for the SiO{sub 2}/Zn{sub 2}SiO{sub 4}:Mn nanocomposite showed that a dominant peak at 525 nm appeared, which originated from the {sup 4}T{sub 1}–{sup 6}A{sub 1} transitions of Mn{sup 2+} ions. The luminescence properties of nanocomposites were characterized by emission and excitation spectra as well their dependencies of upon temperature and power excitation density. -- Highlights: • The Synthesis of Zn{sub 2}SiO{sub 4} nanocomposites. • Structural and optical characterizations of Zn{sub 2}SiO{sub 4} and Zn{sub 2}SiO{sub 4}:Mn nanocomposites. • The willemite α-Zn{sub 2}SiO{sub 4} structure was formed to the heat treatment temperature 1200 °C. • The powder exhibits a nanometric size. • Strong bands of luminescence have appeared.

  5. Studies on Nanocomposite Conducting Coatings

    Directory of Open Access Journals (Sweden)

    Amitava Bhattacharyya

    2013-01-01

    Full Text Available Nanocomposite conducting coatings can impart stable surface electrical conductivity on the substrate. In this paper, carbon nanofiber (CNF and nanographite (NG are dispersed in thermoplastic polyurethane matrix and coated on the surface of glass and polyethylene terephthalate (PET film. The nanoparticles dispersion was studied under TEM. The coating thicknesses were estimated. Further, their resistance and impedance were measured. It has been observed that the 5 wt% CNF dispersed nanocomposite coatings show good conductivity. The use of NG can bring down the amount of CNF; however, NG alone has failed to show significant improvement in conductivity. The nanocomposite coating on PET film using 2.5 wt% of both CNF and NG gives frequency-independent impedance which indicates conducting network formation by the nanoparticles. The study was carried out at different test distances on nanocomposite coated PET films to observe the linearity and continuity of the conducting network, and the result shows reasonable linearity in impedance over total test length (from 0.5 cm to 4.5 cm. The impedance of nanocomposite coatings on glass is not frequency independent and also not following linear increase path with distance. This indicates that the dispersion uniformity is not maintained in the coating solution when it was coated on glass.

  6. Advanced powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Janney, M.A. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    Gelcasting is an advanced powder forming process. It is most commonly used to form ceramic or metal powders into complex, near-net shapes. Turbine rotors, gears, nozzles, and crucibles have been successfully gelcast in silicon nitride, alumina, nickel-based superalloy, and several steels. Gelcasting can also be used to make blanks that can be green machined to near-net shape and then high fired. Green machining has been successfully applied to both ceramic and metal gelcast blanks. Recently, the authors have used gelcasting to make tooling for metal casting applications. Most of the work has centered on H13 tool steel. They have demonstrated an ability to gelcast and sinter H13 to near net shape for metal casting tooling. Also, blanks of H13 have been cast, green machined into complex shape, and fired. Issues associated with forming, binder burnout, and sintering are addressed.

  7. Powder detergents production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for powder detergent production plant, using technology developed in the IGPC laboratories, in 1998. - 2000. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with a capacity of 25,000 t/y was manufactured, at "Delta In", Zrenjanin, in 2000.This technology was an innovation, because new approach in mixing a powder materials was used, as well as introducing a new type of dryer in detergent production. The product meets all quality demands for detergents with high specific weight (1000 g/l, as well as environmental regulations. The detergent production process is fully automatized, and the product has uniform quality. There is no waste material in detergent zeolite production, because all products with unsatisfactory quality are returned to the process. The production process can be controlled manually, which is necessary during start-up, and repairs.

  8. Dispersing powders in liquids

    CERN Document Server

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  9. Polycarbonate based three-phase nanocomposite dielectrics

    Science.gov (United States)

    Sain, P. K.; Goyal, R. K.; Prasad, Y. V. S. S.; Bhargava, A. K.

    2016-08-01

    Three-phase polycarbonate (PC) matrix nanocomposites are prepared using the solution method. One of the nanocomposite fillers is dielectric and the other is conducting. Lead zirconate titanate (PZT) is used as the dielectric filler. The conducting fillers, nano-Cu and multi-walled carbon nanotubes (MWCNTs), are used to make two different nanocomposites, MWCNT-PZT-PC and Cu-PZT-PC. The prepared nanocomposites are characterized using density measurement, x-ray diffractometry, scanning electron microscopy, energy dispersive x-ray spectroscopy, and differential scanning calorimetry. Percolation is absent in both three-phase nanocomposites within the study’s concentration window of conducting fillers. The dielectric properties of the nanocomposites are evaluated using a precision impedance analyser. The dielectric constant of the Cu-PZT-PC nanocomposite increases to 14 (a dissipation factor of 0.17), whereas in the case of the MWCNT-PZT-PC nanocomposite it increases to 8.5 (a dissipation factor of 0.002). The melting point of both nanocomposites decreases with respect to the control PC. The frequency (1 kHz to 1 MHz) and temperature (room temperature to 200 °C) dependence of the dielectric constant and dissipation factor are examined. For the Cu-PZT-PC nanocomposites, the dielectric constant decreases with increasing frequency, whereas in the case of the MWCNT-PZT-PC nanocomposites the dielectric constant is almost constant. The dielectric constant and dissipation factor exhibit a slight temperature dependence.

  10. Experimental analysis of graphene nanocomposite on Kevlar

    Science.gov (United States)

    Manigandan, S.; Gunasekar, P.; Nithya, S.; Durga Revanth, G.; Anudeep, A. V. S. C.

    2017-08-01

    Graphene nanocomposite is a two dimensional structure which has intense role in material science. This paper investigates the topological property of the graphene nanocomposite doped in Kevlar fiber by direct mixing process. The Kevlar fiber by direct mixing process. The Kevlar fiber taken as the specimen which is fabricated by vacuum bag moulding process. Epoxy used as resin and HY951 as hardener. Three different specimens are fabricated based on the percentage of graphene nanocomposite 2%, 5%, 10% and 20% respectively. We witnessed the strength of the Kevlar fiber is increased when it is treated with nanocomposite. The percentage of the nanocomposite increase the strength of the fiber is increased. However as the nanocomposite beyond 5% the strength of fiber is dropped. In addition, we also seen the interfacial property of the fiber is dropped when the nanocomposite is added beyond threshold limit.

  11. Nanocomposite materials for radiation detection

    Science.gov (United States)

    Sahi, Sunil

    2013-03-01

    Colloidal quantum dots (CdTe, CdSe, and ZnO) have attracted tremendous interest in wide range of application from biological imaging, biosensing, solar cells to optoelectronic devices. However very few published reports on the radiation detection based on colloidal quantum dots. Quantum dots based nanocomposite materials could be a promising material for radiation detection because of their short luminescence life time and high quantum efficiencies as a consequence of quantum size confinement. However stopping power of most quantum dots is low and their scintillation luminescence is very weak. The combination of high stopping power of inorganic scintillator (CeF3LaF3: Ce, YAG:Ce) and high efficiency of quantum dot could potentially lead to a new class of scintillator. We have studied the nanocomposite of inorganic scintillator and quantum dot based on energy transfer principle and investigate the scintillation properties of nanocomposite scintillator.

  12. Nanocomposite Sensors for Food Packaging

    Science.gov (United States)

    Avella, Maurizio; Errico, Maria Emanuela; Gentile, Gennaro; Volpe, Maria Grazia

    Nowadays nanotechnologies applied to the food packaging sector find always more applications due to a wide range of benefits that they can offer, such as improved barrier properties, improved mechanical performance, antimicrobial properties and so on. Recently many researches are addressed to the set up of new food packaging materials, in which polymer nanocomposites incorporate nanosensors, developing the so-called "smart" packaging. Some examples of nanocomposite sensors specifically realised for the food packaging industry are reported. The second part of this work deals with the preparation and characterisation of two new polymer-based nanocomposite systems that can be used as food packaging materials. Particularly the results concerning the following systems are illustrated: isotactic polypropylene (iPP) filled with CaCO3 nanoparticles and polycaprolactone (PCL) filled with SiO2 nanoparticles.

  13. Polyamide 66/Brazilian Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    E. M. Araújo

    2009-01-01

    Full Text Available Polyamide 66 (PA66/Brazilian clay nanocomposites were produced via direct melt intercalation. A montmorillonite sample from the Brazilian state of Paraíba was organically modified with esthearildimethylammonium chloride (Praepagen, quaternary ammonium salt and has been tested to be used in polymer nanocomposites. The dispersion analysis and the interlayer spacing of the clay particles in matrix were investigated by X-ray diffraction (XRD and transmission electron microscopy (TEM. Thermal behavior of the obtained systems was investigated by differential scanning calorimetry (DSC, thermogravimetry (TG, and heat deflection temperature (HDT was reported too. The nanocomposites exhibited a partially exfoliated structure, very interesting HDT values which are higher than those of pure PA66, and good thermal stability.

  14. Effect of ball milling process on the microstructure of titanium-nanohydroxyapatite composite powder

    Institute of Scientific and Technical Information of China (English)

    PANG Pengsha; LI Wei; LIU Ying

    2007-01-01

    Titanium-nanohydroxyapatite (Ti-nHA) composite powders, composed of titanium with 10 vol.% and 20 vol.%of nano-hydroxyapatite, were milled in a planetary ball mill using alcohol media to avoid excessive heat. XRD and SEM were performed for characterization of the microstructure, and the homogeneity of Ti/HA nanocomposite powder was evaluated by EPMA with prolonged ball milling time. The results show that under the condition of wet milling, the grain size of Ti-nHA composite powders is decreased with the increase in ball milling time and the amount of the addition of nHA.While for milling of 30 h, the nanocomposite powder with fine structure, which consists of the nano-hydroxyapatite (nHA)particles and titanium (Ti) phase, is obtained. Three stages of milling can be observed from the element mapping of Ti, Ca,and P by EPMA; meanwhile, it is found that the nHA would be more homogenously distributed after milling for 30 h.

  15. Development of Polymer Nanocomposites for Rapid Manufacturing Application

    Directory of Open Access Journals (Sweden)

    M.S. Wahab

    2009-09-01

    Full Text Available This paper presents initial development of polymer nanocomposites (PNC material for rapid manufacturing (RM application. PNC materials containing a polyamide (PA and nano particles (5wt% were produced by solution blending with the aim to improve the mechanical properties. Commercial polyamide 6 (PA6 was dissolved in formic acid (HCO2H together with two different types of nano particle materials: yttrium stabilised zirconia (YSZ and Hectorite clay (Benton 166 and spray-dried to create powder, creating powder with particle sizes in the range of 10-40 μm. The materials were processed on a CO2 selective laser sintering (SLS experimental machine. Mechanical properties of the PNCs were evaluated and the results were compared with the unfilled base polymer. Good dispersion of additives was achieved by solution blending, however the PA6 was degraded during the material preparation and spray drying process which resulted in the formation of porous structure and low strength. However the addition of 5 (wt% nano particles in the PA6 has shown to increase strength by an average of 50-60%. Further work on powder preparation is required in order to fully realise these performance benefits

  16. Stretchable piezoelectric nanocomposite generator

    Science.gov (United States)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-06-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  17. Aerogel nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A.J.; Ayers, M.; Cao, W. [Lawrence Berkeley Laboratory, CA (United States)] [and others

    1995-05-01

    Aerogels are porous, low density, nanostructured solids with many unusual properties including very low thermal conductivity, good transparency, high surface area, catalytic activity, and low sound velocity. This research is directed toward developing new nanocomposite aerogel materials for improved thermal insulation and several other applications. A major focus of the research has been to further increase the thermal resistance of silica aerogel by introducing infrared opacification agents into the aerogel to produce a superinsulating composite material. Opacified superinsulating aerogel permit a number of industrial applications for aerogel-based insulation. The primary benefits from this recently developed superinsulating composite aerogel insulation are: to extend the range of applications to higher temperatures, to provide a more compact insulation for space sensitive-applications, and to lower costs of aerogel by as much as 30%. Superinsulating aerogels can replace existing CFC-containing polyurethane in low temperature applications to reduce heat losses in piping, improve the thermal efficiency of refrigeration systems, and reduce energy losses in a variety of industrial applications. Enhanced aerogel insulation can also replace steam and process pipe insulation in higher temperature applications to substantially reduce energy losses and provide much more compact insulation.

  18. Graphene/Polymer Nanocomposites

    Science.gov (United States)

    Macosko, Chris

    2010-03-01

    Graphite has attracted large attention as a reinforcement for polymers due to its ability to modify electrical conductivity, mechanical and gas barrier properties of host polymers and its potentially lower cost than carbon nanotubes. If graphite can be exfoliated into atomically thin graphene sheets, it is possible to achieve the highest property enhancements at the lowest loading. However, small spacing and strong van der Waals forces between graphene layers make exfoliation of graphite via conventional composite manufacturing strategies challenging. Recently, two different approaches to obtain exfoliated graphite prior to blending were reported: thermal treatment (Schniepp et al., JACS 2006) and chemical modification (Stankovich et al., J Mat Chem 2006). Both start from graphite oxide. We will describe and evaluate these exfoliation approaches and the methods used to produce graphene reinforced thermoplastics, particularly polyester, polycarbonate and polyurethane nanocomposites. Three different dispersion methods - melt blending, solution mixing and in-situ polymerization -- are compared. Characterization of dispersion quality is illustrated with TEM, rheology and in electrical conductivity, tensile modulus and gas barrier property improvement.

  19. Effects of milling and crystallization conditions on microstructure of Nd2Fe14B/α-Fe powder

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; WANG Er-de

    2007-01-01

    Effects of milling and crystallization conditions on microstructure, such as amorphous phase and nanocrystalline phase, were investigated by X-ray diffractometry(XRD), differential scanning calorimetry(DSC), and transmission electron microscopy (TEM), respectively. The results show that nanocomposite Nd2Fe14B/α-Fe powder can be prepared by mechanical milling in argon atmosphere and a subsequent vacuum annealing treatment. The grain sizes of both Nd2Fe14B and α-Fe phase decrease drastically with increasing milling time. After milling for 5 h, the as-milled material consists of α-Fe nanocomposite phases with the grain size of 10 nm, and some amorphous phases, which can be turned into Nd2Fe14B/α-Fe nanocomposite phases by the subsequent annealing treatment. Milling energy of mechanical milling after 5 h by theoretical calculation is 6 154.25 kJ/g.

  20. Burstable nanostructured micro-raspberries: Towards redispersible nanoparticles from dry powders.

    Science.gov (United States)

    Stauch, Claudia; Ballweg, Thomas; Stracke, Werner; Luxenhofer, Robert; Mandel, Karl

    2017-03-15

    Despite immense progress in nanoscience and technology, one of the yet unsolved challenges is the redispersion of nanoparticles from dry powders back to the individual, primary particles. Herein, an easy to handle powder consisting of nanostructured micron sized raspberry-like particles is presented. These nanostructured micro-raspberries are composed of individual nanoparticles which are equipped with molecules that introduce a separating effect or "spring" functionality. Thereby, a powder system is obtained that allows for an easy and complete redispersibility of the agglomerates down to the level of individual nanoparticles in solvents and polymers. The mechanism of redispersibility involves mechanic stimuli/force as well as solvent like disintegration aspects ("like dissolves like" effect). Furthermore, by tailoring the degree of spacer-equipped particles, the bursting behavior can also be tuned, yielding different redispersion degrees. The redispersibility of the nanostructured micro-raspberries is demonstrated in solvents and silicone-based nanocomposites. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Low Temperature Powder Coating

    Science.gov (United States)

    2011-02-09

    of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) • Legacy primers contain hexavalent chrome • Conventional powder coatings...panels • Third panel exhibited a single filament extending slightly beyond allowable tolerance Filiform Corrosion Resistance LTCPC on 2024 T-3 Clad ...LTCPC on 2024 T-3 Clad O G D E N A I R L O G I S T I C S C E N T E R BE AMERICA’S BEST JTP Results • LTCPC performance similar or better than wet

  2. Synthesis, Characterization, and Microwave-Absorbing Properties of Polypyrrole/MnFe2O4 Nanocomposite

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Hosseini

    2012-01-01

    Full Text Available Conductive polypyrrole (PPy-manganese ferrite (MnFe2O4 nanocomposites with core-shell structure were synthesized by in situ polymerization in the presence of dodecyl benzene sulfonic acid (DBSA as the surfactant and dopant and iron chloride (FeCl3 as the oxidant. The structure and magnetic properties of manganese ferrite nanoparticles were measured by using powder X-ray diffraction (XRD and vibrating sample magnetometer (VSM, respectively. Its morphology, microstructure, and DC conductivity of the nanocomposite were characterized by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and four-wire technique, respectively. The microwave-absorbing properties of the nanocomposite powders dispersing in resin acrylic coating with the coating thickness of 1.5 mm were investigated by using vector network analyzers in the frequency range of 8–12 GHz. A minimum reflection loss of −12 dB was observed at 11.3 GHz.

  3. New fluorescent polymeric nanocomposites synthesized by antimony dodecyl-mercaptide thermolysis in polymer

    Directory of Open Access Journals (Sweden)

    2009-04-01

    Full Text Available In this work, the formation of semiconductive Sb2S3 nanoparticles inside amorphous polystyrene has been achieved by thermal degradation of the corresponding antimony dodecyl-mercaptide, Sb(SC12H253. The thermolysis of the dodecyl-mercaptide precursor was studied as both pure phase and mercaptide solution in polystyrene. The thermal decomposition of the antimony mercaptide precursor at 350°C, under vacuum, showed the formation of a mixture of antimony trisulfide (stibnite, Sb2S3 and zero-valent antimony (Sb phase. X-ray Powder Diffraction (XRD and Rietveld analysis carried out on the obtained nanostructured powder confirmed the presence of Sb and Sb2S3 phases in 10.4 wt% and 89.6 wt% amount, respectively. The same pyrolysis reaction was carried out in the polymer and the resulting nanocomposite material was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, UV-VIS spectroscopy, and fluorescence spectroscopy. The nanocomposite structural characterization indicated the presence of well-dispersed nanoclusters of antimony and stibnite (15–30 nm in size inside the amorphous polymeric phase. Optical measurements on the obtained nanocomposite films showed a strong emission at 432 nm upon excitation at 371 nm, probably related to the presence of Sb2S3 nanoclusters.

  4. Structural Ceramic Nanocomposites: A Review of Properties and Powders’ Synthesis Methods

    Science.gov (United States)

    Palmero, Paola

    2015-01-01

    Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional properties, a deep understanding of the materials’ behavior across length scales is necessary. In fact, knowing how the nanoscale structure influences the bulk properties enables the design of increasingly performing composite materials. A further key point is the ability of tailoring the desired nanostructured features in the sintered composites, a challenging issue requiring a careful control of all stages of manufacturing, from powder synthesis to sintering. This review is divided into four parts. In the first, classification and general issues of nanostructured ceramics are reported. The second provides basic structure–property relations, highlighting the grain-size dependence of the materials properties. The third describes the role of nanocrystalline second-phases on the mechanical properties of ordinary grain sized ceramics. Finally, the fourth part revises the mainly used synthesis routes to produce nanocomposite ceramic powders, underlining when possible the critical role of the synthesis method on the control of microstructure and properties of the sintered ceramics. PMID:28347029

  5. Sintering Behavior of CNT Reinforced Al6061 and Al2124 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2014-01-01

    Full Text Available Ball milling and spark plasma sintering were successfully used to produce carbon nanotube reinforced Al6061 and Al2124 nanocomposites which have potential applications in the fields of aerospace, automotive, electronics, and high precision instrumentation. Al2124 and Al6061 nanocomposite powders containing 0.5 to 2 wt.% CNTs prepared through sonication and wet ball milling were spark plasma sintered at 400, 450, and 500°C for 20 minutes under a pressure of 35 MPa. CNTs were better dispersed, and less agglomerated and had good adhesion to the matrix in composites containing 1 wt.% CNTs. The increase of CNT content to 2 wt.% led to the formation of CNT clusters which resulted in less uniform and homogenous composite powders. Almost full densification of Al6061 reinforced with CNTs was achieved at 500°C. Also, CNTs reinforced Al2124 nanocomposites reached very high densities at 500°C. Composites reinforced with 1 wt.% CNTs displayed better densification compared to composites containing 2 wt.% CNTs. The increase of CNTs content from 0.5 to 1 wt.% increased the hardness of the Al6061 and Al2124 alloys to maximum values. Further increase of CNTs content to 2 wt.% decreased the hardness to values lower than that of the monolithic alloys.

  6. An Investigation on the Sinterability and the Compaction Behavior of Aluminum/Graphene Nanoplatelets (GNPs) Prepared by Powder Metallurgy

    Science.gov (United States)

    Saboori, A.; Novara, C.; Pavese, M.; Badini, C.; Giorgis, F.; Fino, P.

    2017-01-01

    In the present study, the densification response of Al matrix reinforced with different weight percentages (0, 0.5, 1.0, 1.5 and 2.0 wt.%) of graphene nanoplatelets (GNPs) was studied. These composites were produced by a wet method followed by a conventional powder metallurgy. The Raman spectrum of graphene indicates that preparation of the composites through the wet mixing method did not affect the disordering and defect density in the GNPs structure. The nanocomposite powder mixture was consolidated via a cold uniaxial compaction. The samples were sintered at different temperatures (540, 580 and 620 °C) under nitrogen flow so as to assess the sinterability of the nanocomposites. X-ray diffraction (XRD) has been carried out to check the possible reaction between GNPs and aluminum. According to the XRD patterns, it seems that Al4C3 did not form during the fabrication process. The relative density, compressibility, sinterability and Vickers hardness of the nanocomposites were also evaluated. The effects of GNPs on the consolidation behavior of the matrix were studied using the Heckel, Panelli and Ambrosio Filho, and Ge equations. The outcomes show that at early stage of consolidation the rearrangement of particles is dominant, while by increasing the compaction pressure, due to the load partitioning effect of GNPs, the densification rate of the powder mixture decreases. Moreover, the fabricated nanocomposites exhibited high Vickers hardness of 67 HV5, which is approximately 50% higher than monolithic aluminum. The effect of graphene addition on the thermal conductivity of Al/GNPs nanocomposites was evaluated by means of thermal diffusivity measurement, and the results showed that the higher thermal conductivity can be only achieved at lower graphene content.

  7. Effect of Processing on Mechanically Alloyed and Spark Plasma Sintered Al-Al2O3 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2015-01-01

    Full Text Available Metal matrix nanocomposites are advanced materials developed using ceramic nanoreinforcements and nanocrystalline metal matrices. These composites have outstanding properties and high potential for large number of functional and structural applications. In this work, nanocrystalline aluminium and Al-Al2O3 nanocomposites were synthesised using mechanical alloying and consolidated through spark plasma sintering technique. Scanning electron microscopy, X-ray diffraction, and mapping were used to characterize the powders and sintered samples. Density and hardness of sintered samples were measured using densimeter and hardness tester, respectively. It was found that milling of pure aluminium for 24 h reduced its crystallite size to less than 100 nm. For Al-Al2O3 nanocomposites, milling for 24 h decreased the crystallite size of the aluminium phase and resulted in uniform dispersion of the reinforcement. Sintering of the synthesised powders led to grain growth. Al2O3 contributed to growth inhibition when samples were sintered for 20 minutes and improved the hardness but reduced densification. The Al-10 vol.%  Al2O3 nanocomposite had the highest Vickers hardness value of 1460 MPa.

  8. Processing and properties of Cu based micro- and nano-composites

    Indian Academy of Sciences (India)

    S Panda; K Dash; B C Ray

    2014-04-01

    Nano-composites of 1, 3, 5 and 7 vol% Al2O3 (average size < 50 nm) and microcomposites having compositions 5, 10, 15, 20 vol% of Al2O3 (average size ∼ 10 m) reinforced in copper matrix were fabricated by powder metallurgy route. All the specimens were sintered at different sintering temperatures (850, 900 and 1000°C) to study the effect of temperature on the process and progress of sinterability of the reinforced micro- and nanoparticles in the matrix. These micro- and nano-composites were characterized using X-ray diffraction and scanning electron microscopy followed by density, microhardness and wear measurements. The compression and flexural tests were also carried out in order to investigate the mechanical behaviour of the micro- and nano-composites for a fixed optimum sintering temperature. Fractography of the 3-point bend specimens was performed to investigate the fracture behaviour of the micro- and nano-composites. The flexural test results showed that the ultimate flexural strength decreases and flexural modulus increases with the increase in reinforcement content.

  9. Synthesis, Characterization, and Microwave Absorption Properties of Reduced Graphene Oxide/Strontium Ferrite/Polyaniline Nanocomposites.

    Science.gov (United States)

    Luo, Juhua; Shen, Pan; Yao, Wei; Jiang, Cuifeng; Xu, Jianguang

    2016-12-01

    Strontium ferrite nanoparticles were prepared by a coprecipitation method, and reduced graphene oxide/strontium ferrite/polyaniline (R-GO/SF/PANI) ternary nanocomposites were prepared by in situ polymerization method. The morphology, structure, and magnetic properties of the ternary nanocomposites were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), TEM, Raman, and VSM. The microwave-absorbing properties of the composites were measured by a vector network analyzer. The XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. TEM photographs reveal that strontium ferrite nanoparticles are uniformly dispersed on the surfaces of R-GO sheets. The R-GO/SF/PANI nanocomposite exhibited the best absorption property with the optimum matching thickness of 1.5 mm in the frequency of 2-18 GHz. The value of the maximum RL was -45.00 dB at 16.08 GHz with the 5.48-GHz bandwidth. The excellent absorption properties of R-GO/SF/PANI nanocomposites indicated their great potential as microwave-absorbing materials.

  10. Biomimetic formation of apatite on the surface of porous gelatin/bioactive glass nanocomposite scaffolds

    Science.gov (United States)

    Mozafari, Masoud; Rabiee, Mohammad; Azami, Mahmoud; Maleknia, Saied

    2010-12-01

    There have been several attempts to combine bioactive glasses (BaGs) with biodegradable polymers to create a scaffold material with excellent biocompatibility, bioactivity, biodegradability and toughness. In the present study, the nanocomposite scaffolds with compositions based on gelatin (Gel) and BaG nanoparticles in the ternary SiO 2-CaO-P 2O 5 system were prepared. In vitro evaluations of the nanocomposite scaffolds were performed, and for investigating their bioactive capacity these scaffolds were soaked in a simulated body fluid (SBF) at different time intervals. The scaffolds showed significant enhancement in bioactivity within few days of immersion in SBF solution. The apatite formation at the surface of the nanocomposite samples confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD) analyses. In vitro experiments with osteoblast cells indicated an appropriate penetration of the cells into the scaffold's pores, and also the continuous increase in cell aggregation on the bioactive scaffolds with increase in the incubation time demonstrated the ability of the scaffolds to support cell growth. The SEM observations revealed that the prepared scaffolds were porous with three dimensional (3D) and interconnected microstructure, pore size was 200-500 μm and the porosity was 72-86%. The nanocomposite scaffold made from Gel and BaG nanoparticles could be considered as a highly bioactive and potential bone tissue engineering implant.

  11. Biomimetic formation of apatite on the surface of porous gelatin/bioactive glass nanocomposite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Mozafari, Masoud, E-mail: mmozafari@aut.ac.ir [Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, PO Box 15875-4413, Tehran (Iran, Islamic Republic of); Rabiee, Mohammad; Azami, Mahmoud; Maleknia, Saied [Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, PO Box 15875-4413, Tehran (Iran, Islamic Republic of)

    2010-12-15

    There have been several attempts to combine bioactive glasses (BaGs) with biodegradable polymers to create a scaffold material with excellent biocompatibility, bioactivity, biodegradability and toughness. In the present study, the nanocomposite scaffolds with compositions based on gelatin (Gel) and BaG nanoparticles in the ternary SiO{sub 2}-CaO-P{sub 2}O{sub 5} system were prepared. In vitro evaluations of the nanocomposite scaffolds were performed, and for investigating their bioactive capacity these scaffolds were soaked in a simulated body fluid (SBF) at different time intervals. The scaffolds showed significant enhancement in bioactivity within few days of immersion in SBF solution. The apatite formation at the surface of the nanocomposite samples confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD) analyses. In vitro experiments with osteoblast cells indicated an appropriate penetration of the cells into the scaffold's pores, and also the continuous increase in cell aggregation on the bioactive scaffolds with increase in the incubation time demonstrated the ability of the scaffolds to support cell growth. The SEM observations revealed that the prepared scaffolds were porous with three dimensional (3D) and interconnected microstructure, pore size was 200-500 {mu}m and the porosity was 72-86%. The nanocomposite scaffold made from Gel and BaG nanoparticles could be considered as a highly bioactive and potential bone tissue engineering implant.

  12. Preparation, characterization and dye adsorption of Au nanoparticles/ZnAl layered double oxides nanocomposites

    Science.gov (United States)

    Zhang, Yu Xin; Hao, Xiao Dong; Kuang, Min; Zhao, Han; Wen, Zhong Quan

    2013-10-01

    In this work, Au/ZnAl-layer double oxides (LDO) nanocomposties were prepared through a facile calcination process of AuCl4- intercalated ZnAl-layered double hydroxides (LDHs) nanocomposites. The morphology and crystal structure of these nanocomposites were characterized by Scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and N2 sorption analysis. By tailoring the process parameter, such as calcination temperature, heating time and the component composition, the adsorption properties of methyl orange (MO) on the Au/ZnAl-LDO nanocomposites were investigated in this work. In a typical adsorption process, it was found that 0.985 mg of MO (0.01 g L-1, 100 mL, 1 mg of MO in total) can be removed in 60 min by utilizing only 2.5 mg of Au/ZnAl-LDO (Au content, 1%) as adsorbents. Our adsorption data obtained from the Langmuir model also gave good values of the determination coefficient, and the saturated adsorption capacity of Au/ZnAl-LDO nanocomposites for MO was found to be 627.51 mg/g under ambient condition (e.g., room temperature, 1 atm). In principle, these hybrid nanostructures with higher adsorption abilities could be very promising adsorbents for wastewater treatment.

  13. Synthesis of Silver-Doped Zinc Oxide Nanocomposite by Pulse Mode Ultrasonication and Its Characterization Studies

    Directory of Open Access Journals (Sweden)

    T. Siva Vijayakumar

    2013-01-01

    Full Text Available The synthesis of silver-doped zinc oxide (Ag:ZnO nanocomposite material was achieved using a simple chemical coprecipitation method, in which 0.2 M zinc chloride and 0.001 M silver nitrate coprecipitated with 25% ammonia solution by pulse mode dispersion using ultrasonicator. The obtained silvery white precipitate was dried overnight at 110°C in hot air oven, and the powder was collected. The resulted Ag:ZnO nanocomposite was structurally and optically characterized using various techniques. The X-ray diffraction (XRD pattern clearly showed the presence of crystalline Ag:ZnO particles. Further, UV-Vis spectrophotometer and fourier transform infrared spectroscopy (FT-IR results showed the presence of Ag:ZnO nanocomposite at specific wavelengths. The scanning electron microscopy (SEM and transmission electron microscopy (TEM analysis confirm that the synthesized Ag:ZnO nanocomposite material was truncated nanorod in shape and has 48 to 226 nm size in diameter.

  14. Enhanced microwave absorption properties in cobalt-zinc ferrite based nanocomposites

    Science.gov (United States)

    Poorbafrani, A.; Kiani, E.

    2016-10-01

    In an attempt to find a solution to the problem of the traditional spinel ferrite used as the microwave absorber, the Co0.6Zn0.4Fe2O4-Paraffin nanocomposites were investigated. Cobalt-zinc ferrite powders, synthesized through PVA sol-gel method, were combined with differing concentrations of Paraffin wax. The nanocomposite samples were characterized employing various experimental techniques including X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Alternating Gradient Force Magnetometer (AGFM), and Vector Network Analyzer (VNA). The saturation magnetization and coercivity were enhanced utilizing appropriate stoichiometry, coordinate agent, and sintering temperature required for the preparation of cobalt-zinc ferrite. The complex permittivity and permeability spectra, and Reflection Loss (RL) of Co0.6Zn0.4Fe2O4-Paraffin nanocomposites were measured in the frequency range of 1-18 GHz. The microwave absorption properties of nanocomposites indicated that the absorbing composite containing 20 wt% of paraffin manifests the strongest microwave attenuation ability. The composite exhibited the reflection loss less than -10 dB in the whole C-band and 30% of the X-band frequencies.

  15. Effect of oxidation degree on the synthesis and adsorption property of magnetite/graphene nanocomposites

    Science.gov (United States)

    Luo, Kun; Mu, Yuanying; Wang, Peng; Liu, Xiaoteng

    2015-12-01

    A facile approach is demonstrated to synthesize a series of magnetite/graphene nanocomposites by solvothermal method, which can be easily collected after removal of pollutants without secondary pollution of graphene powders. Raman and FT-IR analyses show that the reduction of the mixing vapor of ammonia and hydrazine at different reaction periods generates the discrepancy of oxidation degree for reduced graphene oxide (rGO), which can be kept after the solvothermal synthesis of Fe3O4/rGO nanocomposites. Batch adsorption experiments indicate that the nanocomposite with maximum oxidation degree of rGO presents the largest magnetization of 35.4 emu g-1 and adsorption capacity of 59.2 mg g-1 for Cu2+, while the one with minimum oxidation degree exhibits the strongest adsorption of 39.0 mg g-1 for methylene blue accompanied with appropriate magnetization of 9.0 emu g-1, and only 23% of initial capacity was lost after seven recycling use. The adsorption kinetics of the both composites follows the pseudo-second-order model, suggestive of physical and chemical interactions between the pollutants and adsorbent. The results suggest that the oxidation degree of the rGO substrate can apparently influence both the structure and the adsorbing behavior of Fe3O4/rGO nanocomposites, which allows the control over the adsorbent performance according to the pollutant of interest.

  16. A Convenient Ultraviolet Irradiation Technique for Synthesis of Antibacterial Ag-Pal Nanocomposite

    Science.gov (United States)

    Han, Shuai; Zhang, He; Kang, Lianwei; Li, Xiaoliang; Zhang, Chong; Dong, Yongjie; Qin, Shenjun

    2016-09-01

    In the present work, palygorskite (Pal) was initially subjected to an ion-exchange reaction with silver ions (Pal-Ag+). Subsequently, Ag-Pal nanocomposites were assembled by a convenient ultraviolet irradiation technique, using carbon dots (CDs) derived from wool fiber as the reducing agent. The obtained nanocomposites were characterized by powder X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy. The XRD patterns and UV-vis absorption spectra confirmed the formation of the Ag nanoparticles (NPs). Meanwhile, the TEM images showed that the Ag NPs, which exhibited sizes in the range of 3-7 nm, were located on the surface of the Pal nanofiber structures. Furthermore, the antibacterial activity of the nanocomposites was evaluated against Gram-positive ( Staphylococcus aureus) and Gram-negative ( Escherichia coli) bacteria by applying the disc diffusion method and minimum inhibitory concentration test. Owing to their good antibacterial properties, the Ag-Pal nanocomposites are considered to be a promising bactericide with great potential applications.

  17. Fabrication process and electromagnetic wave absorption characterization of a CNT/Ni/epoxy nanocomposite.

    Science.gov (United States)

    Ryu, Seongwoo; Mo, Chan Bin; Lee, Haeshin; Hong, Soon Hyung

    2013-11-01

    Since carbon nanotube (CNT) was first discovered in 1991, it has been considered as a viable type of conductive filler for electromagnetic wave absorption materials in the GHz range. In this paper, pearl-necklace-structure CNT/Ni nano-powders were fabricated by a polyol process as conductive fillers. Compared to synthesized CNT, pearl-necklace Ni-decorated CNT increased the electrical conductivity by an order of 1 due to the enhancement of the Ni-conductive network. Moreover, the decorated Ni particles prevented the agglomeration of CNTs by counterbalancing the Van der Walls interaction between the CNTs. A CNT/Ni nanocomposite showed a homogeneous dispersion in an epoxy-based matrix. This enhanced physical morphology and electrical properties lead to an increase in the loss tangent and reflection loss in the CNT/Ni/Epoxy nanocomposite compared to these characteristics of a CNT/Epoxy nanocomposite in range of 8-12 GHz. The electromagnetic wave absorption properties of CNT/Ni/epoxy nanocomposites will provide enormous opportunities for electronic applications where lightweight EMI shielding or electro-magnetic wave absorption properties are necessary.

  18. Reduced graphene oxide/CeO{sub 2} nanocomposite with enhanced photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jasmeet, E-mail: jasmeet.dayal@gmail.com; Anand, Kanika; Singh, Gurpreet; Hastir, Anita; Virpal,; Singh, Ravi Chand [Laboratory For Sensors and Physics Education, Department of Physics, GND University, Amritsar-143005 (India); Anand, Kanica [Semiconductors Laboratory, Department of Physics, GND University, Amritsar– 143005 (India)

    2015-05-15

    In this work, reduced graphene oxide /cerium oxide (RGO/CeO{sub 2}) nanocomposite was synthesized by in situ reduction of cerium nitrate Ce(NO{sub 3}){sub 3}·6H{sub 2}O in the presence of graphene oxide by hydrazine hydrate (N{sub 2}H{sub 4}.H{sub 2}O). The intrinsic characteristics of as-prepared nanocomposite were studied using powder x-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FESEM). The photocatalytic degradation of methylene blue (MB) was employed as a model reaction to evaluate the photocatalytic activity of the RGO/CeO{sub 2} nanocomposite. The as-obtained RGO/CeO{sub 2} nanocomposite displays a significantly enhanced photocatalytic degradation of MB dye in comparison with bare CeO{sub 2} nanoparticles under sunlight irradiation, which can be attributed to the improved separation of electron-hole pairs and enhanced adsorption performance due to presence of RGO.

  19. Novel synthesis of ZnO/PMMA nanocomposites for photocatalytic applications

    Science.gov (United States)

    Di Mauro, Alessandro; Cantarella, Maria; Nicotra, Giuseppe; Pellegrino, Giovanna; Gulino, Antonino; Brundo, Maria Violetta; Privitera, Vittorio; Impellizzeri, Giuliana

    2017-01-01

    The incorporation of nanostructured photocatalysts in polymers is a strategic way to obtain novel water purification systems. This approach takes the advantages of: (1) the presence of nanostructured photocatalyst; (2) the flexibility of polymer; (3) the immobilization of photocatalyst, that avoids the recovery of the nanoparticles after the water treatment. Here we present ZnO-polymer nanocomposites with high photocatalytic performance and stability. Poly (methyl methacrylate) (PMMA) powders were coated with a thin layer of ZnO (80 nm thick) by atomic layer deposition at low temperature (80 °C). Then the method of sonication and solution casting was performed so to obtain the ZnO/PMMA nanocomposites. A complete morphological, structural, and chemical characterization was made by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The remarkable photocatalytic efficiency of the nanocomposites was demonstrated by the degradation of methylene blue (MB) dye and phenol in aqueous solution under UV light irradiation. The composites also resulted reusable and stable, since they maintained an unmodified photo-activity after several MB discoloration runs. Thus, these results demonstrate that the proposed ZnO/PMMA nanocomposite is a promising candidate for photocatalytic applications and, in particular, for novel water treatment. PMID:28098229

  20. Novel synthesis of ZnO/PMMA nanocomposites for photocatalytic applications

    Science.gov (United States)

    di Mauro, Alessandro; Cantarella, Maria; Nicotra, Giuseppe; Pellegrino, Giovanna; Gulino, Antonino; Brundo, Maria Violetta; Privitera, Vittorio; Impellizzeri, Giuliana

    2017-01-01

    The incorporation of nanostructured photocatalysts in polymers is a strategic way to obtain novel water purification systems. This approach takes the advantages of: (1) the presence of nanostructured photocatalyst; (2) the flexibility of polymer; (3) the immobilization of photocatalyst, that avoids the recovery of the nanoparticles after the water treatment. Here we present ZnO-polymer nanocomposites with high photocatalytic performance and stability. Poly (methyl methacrylate) (PMMA) powders were coated with a thin layer of ZnO (80 nm thick) by atomic layer deposition at low temperature (80 °C). Then the method of sonication and solution casting was performed so to obtain the ZnO/PMMA nanocomposites. A complete morphological, structural, and chemical characterization was made by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The remarkable photocatalytic efficiency of the nanocomposites was demonstrated by the degradation of methylene blue (MB) dye and phenol in aqueous solution under UV light irradiation. The composites also resulted reusable and stable, since they maintained an unmodified photo-activity after several MB discoloration runs. Thus, these results demonstrate that the proposed ZnO/PMMA nanocomposite is a promising candidate for photocatalytic applications and, in particular, for novel water treatment.

  1. Self-healing supramolecular nanocomposites

    NARCIS (Netherlands)

    Liu, Z.

    2015-01-01

    The aim of this thesis is to execute a bottom-up design of the intrinsically self-healing nanocomposites. We briefly introduced the self-healing materials in chapter 1, covering classification and basic self-healing mechanism. In chapter 2, we have synthesized polyborosiloxane (PBS) according to th

  2. Self-healing supramolecular nanocomposites

    NARCIS (Netherlands)

    Liu, Z.

    2015-01-01

    The aim of this thesis is to execute a bottom-up design of the intrinsically self-healing nanocomposites. We briefly introduced the self-healing materials in chapter 1, covering classification and basic self-healing mechanism. In chapter 2, we have synthesized polyborosiloxane (PBS) according to

  3. Dynamic smoothing of nanocomposite films

    NARCIS (Netherlands)

    Pei, Y.T.; Turkin, A; Chen, C.Q.; Shaha, K.P.; Vainshtein, D.; Hosson, J.Th.M. De

    2010-01-01

    In contrast to the commonly observed dynamic roughening in film growth we have observed dynamic smoothing in the growth of diamondlike-carbon nanocomposite (TiC/a-C) films up to 1.5 mu m thickness. Analytical and numerical simulations, based on the Edwards-Wilkinson model and the Mullins model, visu

  4. Magnetic Nanocomposite Cilia Tactile Sensor

    KAUST Repository

    Alfadhel, Ahmed

    2015-10-21

    A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor\\'s high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

  5. Nanocomposites for electromagnetic radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Petrunin, V. F., E-mail: VFPetrunin@mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

    2016-12-15

    Specific features that characterize nanoparticles and which are due to their small size and allow one to enhance the interaction between the electromagnetic radiation and nanostructured materials and to develop the effective protection of man and equipment against harmful uncontrolled radiation are reported. Examples of the development of nanocomposite radar absorbing materials that can be used for protection of man and equipment are presented.

  6. Nanophase and Nanocomposite Materials II. Symposium Held December 2-5, 1996, Boston, Massachusetts, U.S.A. Volume 457.

    Science.gov (United States)

    1996-12-01

    Organic -inorganic Nanocomposites..........519 L. Ukrainczyk, R.A. Bellman, K.A. Smith, and J.E. Boyd; Synthesis of Self-Assembled Functional Molecules in...INTRODUCTION Fine powders of semiconducting oxides with deposited metal and/or metal oxide particles have been widely used as heterogeneous photocatalysts ... synthesis of delaminated MTS/polymer composites has the potential advantage of utilizing unmodified Na- montmorillonite as opposed to organic cation

  7. ZnS/PVA nanocomposites for nonlinear optical applications

    Science.gov (United States)

    Ozga, K.; Michel, J.; Nechyporuk, B. D.; Ebothé, J.; Kityk, I. V.; Albassam, A. A.; El-Naggar, A. M.; Fedorchuk, A. O.

    2016-07-01

    We have found a correlation between ZnS nanocomposite nonlinear optical features and technological processing using electrolytic method. In the earlier researches this factor was neglected. However, it may open a new stage for operation by photovoltaic features of the well known semiconductors within a wide range of magnitudes. The titled nanostructured zinc sulfide (ZnS) was synthesized by electrolytic method. The obtained ZnS nano-crystallites possessed nano-particles sizes varying within 1.6 nm…1.8 nm. The titled samples were analyzed by XRD, HR-TEM, STEM, and nonlinear optical methods such as photo-induced two-photon absorption (TPA) and second harmonic generation (SHG). For this reason the nano-powders were embedded into the photopolymer poly(vinyl) alcohol (PVA) matrices. Role of aggregation in the mentioned properties is discussed. Possible origin of the such correlations are discussed.

  8. HA/UHMWPE Nanocomposite Produced by Twin-screw Extrusion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The HA/UHMWPE nanocomposite is compounded by twin-screw extrusion of the HA and UHMWPE powder mixture in paraffin oil and then compression molded to a sheet form. TGA measurement shows the HA weight loss after processing is about 1%-2% . FTIR spectra indicate the paraffin oil residue is trivial and UHMWPE is not oxidized. SEM reveals the HA nano particles are homogeneously dispersed by twin- screw extrusion and the inter-particle spaces are penetrated with UHMWPE fibrils by swelling treatment. HRTEM image indicates the HA particles and UHMWPE are intimately contacted by mechanical interlocking. Compared with the unfilled UHMWPE, stiffness of the composite with the HA volume fraction 0.23 was significantly enhanced to 9 times without detriment of the yield strength and the ductility.

  9. Nanocrystalline functional materials and nanocomposites synthesis through aerosol routes

    Directory of Open Access Journals (Sweden)

    Milošević Olivera B.

    2003-01-01

    Full Text Available This paper represents the results of the design of functional nanocrystalline powders and nanocomposites using chemical reactions in aerosols. The process involves ultrasonic aerosol formation (mist generators with the resonant frequencies of 800 kHz, 1.7 and 2.5 MHz from precursor salt solutions and control over the aerosol decomposition in a high-temperature tubular flow reactor. During decomposition, the aerosol droplets undergo evaporation/drying, precipitation and thermolysis in a single-step process. Consequently, spherical, solid, agglomerate-free submicronic particles are obtained. The particle morphology, revealed as a composite structure consisting of primary crystallites smaller than 20 nm was analysed by several methods (XRD, DSC/DTA, SEM, TEM and discussed in terms of precursor chemistry and process parameters. Following the initial attempts, a more detailed aspect of nanocrystalline particle synthesis was demonstrated for the case of nanocomposites based on ZnO-MeO (MeO=Bi Cr+, suitable for electronic applications, as well as an yttrium-aluminum base complex system, suitable for phosphorus applications. The results imply that parts of the material structure responsible for different functional behaviour appear through in situ aerosol synthesis by processes of intraparticle agglomeration, reaction and sintering in the last synthesis stage.

  10. h-BN-TiO2 Nanocomposite for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Václav Štengl

    2016-01-01

    Full Text Available h-BN-TiO2 nanocomposites were synthesized by the thermal hydrolysis of titanium peroxo-complexes in the presence of exfoliated h-BN. The bulk h-BN was prepared by annealing mixture of boric acid and urea, and high intensity ultrasound was used for its exfoliation. The prepared samples were characterized by X-ray powder diffraction (XRD, infrared spectroscopy, Raman spectroscopy, electron spin resonance (ESR, high resolution electron microscopy, BET surface area, and BJH porosity measurement. The UV-Vis diffuse reflectance spectroscopy was employed to estimate band-gap energies. The photoinduced charge on the surface of h-BN-TiO2 nanocomposites was visualized using electric force microscopy (EFM. The photocatalytic activity was determined by azo dyes Orange II and Reactive Black 5 photobleaching. The highest rate constant k = 0.0762 min−1 and 0.0164 min−1, under UV and visible light irradiation, respectively, showed sample denoted TiP050BN with moderate concentration of h-BN.

  11. Microwave sintered nanocomposite electrodes for solid oxide fuel cells.

    Science.gov (United States)

    Raza, Rizwan; Zhu, Bin

    2011-06-01

    Microwave sintering is a very interesting subject, which provides an alternative method to overcome problems faced with conventional sintering. This process is very efficient and only requires a few minutes. In this paper, nanocomposite electrodes (Cu0.15Ni0.85-GDC) were sintered at 700 degrees C for 10 mins in a single mode 2.45 GHz microwave oven by the solid state reaction method. The composition influence and the sintering methods on the as-obtained powder were characterized by XRD, SEM and TEM. It was observed that excellent sintering took place. Excellent fuel cell performance was achieved with microwave sintering compared tosamples sintered using conventional sintering. Electrochemical analysis was carried out using AC Impedance technique. This paper reports a new approach to develop a microwave sintered based nanocomposite material, which is more efficient on time and energy. This method can gain significant economical benefits compared to conventional sintered materials for applications in low temperature solid oxide fuel cells (LTSOFC).

  12. Polyamide blend-based nanocomposites: A review

    Directory of Open Access Journals (Sweden)

    W. S. Chow

    2015-03-01

    Full Text Available Polymer blend nanocomposites have been considered as a stimulating route for creating a new type of high performance material that combines the advantages of polymer blends and the merits of polymer nanocomposites. In nanocomposites with multiphase matrices, the concept of using nanofillers to improve select properties (e.g., mechanical, thermal, chemical, etc of a polymer blend, as well as to modify and stabilize the blend morphology has received a great deal of interest. This review reports recent advances in the field of polyamide (PA blend-based nanocomposites. Emphasis is placed on the PA-rich blends produced by blending with other thermoplastics in the presence of nanofillers. The processing and properties of PA blend-based nanocomposites with nanofillers are discussed. In addition, the mechanical properties and morphology changes of PA blends with the incorporation of nanofillers are described. The issues of compatibility and toughening of PA blend nanocomposites are discussed, and current challenges are highlighted.

  13. Mechanical thermal synthesis of in situ Al based hybrid nanocomposites in Al-Ni-Ti-O system

    Energy Technology Data Exchange (ETDEWEB)

    Dilip, J. John Samuel [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Tamil Nadu 600036 (India); Reddy, B.S.B. [Universal College of Engineering and Technology, Guntur, Andhra Pradesh 522438 (India); Das, Siddhartha, E-mail: sdas@metal.iitkgp.ernet.i [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India); Das, Karabi [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)

    2010-02-04

    Al matrix hybrid nanocomposite is synthesized from a powder blend of Al-12% (wt) NiO-15% (wt) TiO{sub 2} by combined mechanical and thermal activation (mechanical thermal synthesis). The powder blends are mechanically activated by high energy ball milling followed by consolidation and thermal treatment. Milled powders are characterized by differential thermal analysis (DTA), X-ray diffraction (XRD) and electron microscopy. DTA results show the onset reaction temperature to decrease with increase in the milling time. Series of thermal treatments in a wide range of temperatures are performed on the green compacts. The thermally treated samples are then characterized by XRD and electron microscopy. The superior microhardness (1.86-2.25 GPa) of the nanocomposite may be attributed to ultra fine grain size of the Al matrix, and Orowan strengthening from the nanosized reinforcements. Aluminothermic reduction reaction between Al, NiO and TiO{sub 2} is successfully exploited for the synthesis of in situ hybrid nanocomposite by combined mechanical-thermal activation.

  14. Synthesis of mesoporous Mn/TiO2 nanocomposites and investigating the photocatalytic properties in aqueous systems.

    Science.gov (United States)

    Oseghe, Ekemena Oghenovoh; Ndungu, Patrick Gathura; Jonnalagadda, Sreekanth Babu

    2015-01-01

    Mesoporous 20 wt% Mn/TiO2 nanocomposites were synthesized adopting modified sol-gel method at different pH (pH = 2, 7 and 11) conditions and calcined at 400 °C. Based on the characteristics of the 20 wt% Mn/TiO2 nanocomposites synthesized at pH 11, same procedure was adopted for the synthesis of different wt% Mn/TiO2. The nanocomposite samples and their surface properties were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), mapping, inductively coupled plasma optical emission spectrometry (ICP-OES), Fourier transform infrared (FTIR), and fluorescence spectrometry. The nanocomposites existed in the anatase phase of TiO2 with no peak assigned to Mn on the diffractogram. The photocatalytic activities of the materials were evaluated by monitoring degradation of a model dye (methylene blue (MB)) in presence of visible light and ozone. The nanocomposite synthesized under neutral condition (pH = 7) exhibited the best photocatalytic activity resulting from its relatively smaller crystal size (5.98 nm) and larger pore volume (0.30 cm(3)/g). One percentage of weight Mn/TiO2 showed 100% decolouration of MB in the presence of O3 after 100 min.

  15. Role of Intensive Milling on Microstructural and Physical Properties of Cu80Fe20/10CNT Nano-Composite

    Directory of Open Access Journals (Sweden)

    Mahsa Barzegar Vishlaghi

    2014-06-01

    Full Text Available Carbon nano-tube (CNT reinforced metal matrix nano-composites have attracted a great deal of attention in recent years due to the outstanding physical and mechanical properties of CNTs. However, utilizing CNT as reinforcement for alloy matrixes has not been studies systematically and is still a challenging issue. In the present study, Cu80Fe20/10CNT nanocomposite was synthesized by mechanical alloying in two different procedures. The effects of CNT addition on microstructural and physical properties of nano-composite, Phase composition, morphology, magnetic and electrical properties of the samples were investigated by X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer, and four point probe techniques, respectively. The results showed that addition of CNT suppressed the solid solubility extension of Fe in Cu matrix. Dispersion and implantation of CNTs in the metal matrix improved, particles size was smaller and their shape was more granular when CNTs were added at the start of milling. Saturation magnetization and coercivity of composite samples increased with addition of CNT probably due to the presence of non-dissolved Fe in nano-composites and inhomogeneity of microstructure, respectively. Electrical resistivity of nano-composites was higher than that of matrix alloy. The increment was more when milling time of CNTs and metal powder was shorter.

  16. Factors Influence the Structural and Magnetic Properties of Ag-Fe3O4 Nanocomposites Synthesized by Reduction Method

    Science.gov (United States)

    Fajaroh, F.; Nazriati

    2017-05-01

    Silver nanoparticles integrated with a magnetic matrix such as Fe3O4 to form Ag-Fe3O4 nanocomposites show some advantages in their applications as an antibacterial agent and heterogeneous catalyst. This material can be synthesized by a combination of electrochemical and reduction methods supported by ultrasonic route. The purposes of this study are to synthesize the nanocomposites by reduction method and to study the effect of synthesis parameters on the structural and magnetic properties of the generated nanocomposites. This research consisted of three main stages. The first step was the electrochemical synthesis of magnetite nanoparticles using electro-oxidation of iron in water. Second, adsorption of Ag+ on the surface of Fe3O4 carried out by sonication of a mixture of AgNO3 solution and powder of Fe3O4 nanoparticles. The third stage was the reduction of Ag+ to Ag0 with glucose as reductant and NaOH as an accelerator, where it was conducted under a variation of AgNO3 mole ratios to glucose and NaOH concentration. The characterizations of Ag-Fe3O4 nanocomposites were performed using XRD and VSM. The results of the characterizations showed that Ag-Fe3O4 nanocomposites have been successfully synthesized. There was an optimum concentration of NaOH at pH (11) and mole ratio of AgNO3 to glucose (1 : 8) in the synthesis process producing the composite with the highest crystallinity.

  17. Polymer-phyllosilicate nanocomposites and their preparation

    Science.gov (United States)

    Chaiko, David J.

    2007-01-09

    Polymer-phyllosilicate nanocomposites that exhibit superior properties compared to the polymer alone, and methods-for producing these polymer-phyllosilicate nanocomposites, are provided. Polymeric surfactant compatabilizers are adsorbed onto the surface of hydrophilic or natural phyllosilicates to facilitate the dispersal and exfoliation of the phyllosilicate in a polymer matrix. Utilizing polymeric glycol based surfactants, polymeric dicarboxylic acids, polymeric diammonium surfactants, and polymeric diamine surfactants as compatabilizers facilitates natural phyllosilicate and hydrophilic organoclay dispersal in a polymer matrix to produce nanocomposites.

  18. Method to produce catalytically active nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  19. Nanocomposite organomineral hybrid materials. Part I

    OpenAIRE

    KUDRYAVTSEV Pavel Gennadievich; FIGOVSKY Oleg Lvovich

    2016-01-01

    The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility t...

  20. Nanocomposite organomineral hybrid materials. Part 2

    OpenAIRE

    KUDRYAVTSEV Pavel Gennadievich; FIGOVSKY Oleg Lvovich

    2016-01-01

    The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility t...

  1. Structural, magnetic and dielectric properties of polyaniline/MnCoFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Jayaprakash, Rajan [Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

    2015-12-15

    Ferromagnetic PANI containing MnCoFe{sub 2}O{sub 4} nanocomposites were synthesized by in-situ chemical polymerization of aniline incorporated MnCoFe{sub 2}O{sub 4} nanoparticles (20%, 10% w/w of fine powders) with and without ultrasonic treatment. The MnCoFe{sub 2}O{sub 4} nanoparticles were synthesized by auto combustion method. The PANI/MnCoFe{sub 2}O{sub 4} nanocomposites were characterized with Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The average particle size of the resulting PANI/MnCoFe{sub 2}O{sub 4} nanocomposites was confirmed from the TEM and XRD analysis. The structure and morphology of the composites were confirmed by FT-IR spectroscopy, XRD and SEM. In addition, the electrical and magnetic properties of the nanocomposites were investigated. The PANI/MnCoFe{sub 2}O{sub 4} nanocomposites under applied magnetic field exhibited the hysteresis loops of ferromagnetic nature at room temperature. The variation of Dielectric constant, Dielectric loss, and AC conductivity of PANI/MnCoFe{sub 2}O{sub 4} nanocomposites at room temperature as a function of frequency in the range 50 Hz–5 MHz has been studied. Effect of ultrasonication on the PANI/MnCoFe{sub 2}O{sub 4} nanocomposites was also investigated. - Highlights: • An auto-combustion method support to prepare less size of particles. • The particle size influences more on dielectric property. • Effect of ultrasonication on the PANI/MnCoFe{sub 2}O{sub 4} was also investigated.

  2. Mechanical and antibacterial properties of recycled carton paper coated by PS/Ag nanocomposites for packaging.

    Science.gov (United States)

    Nassar, Mona A; Youssef, Ahmed M

    2012-06-05

    Polymer nanocomposites and paper constitute a new class of packaging materials. In this study silver nanoparticles were prepared by novel method as antibacterial additive, where, synthetic takes place with aid of a novel, non-toxic, and eco-friendly biological materials namely rice straw (RS) powder. The prepared Ag nanoparticle was examined by transmission electron microscope (TEM), X-ray diffraction pattern (XRD) and UV-spectroscopy. The silver nanoparticles were then embedded into commercial polystyrene solution. The recycled carton paper was coated by the polystyrene nanocomposites containing different concentration of silver nanoparticles, namely 2, 4, 6 and 8% based on polystyrene. The prepared recycled carton sheets were characterized by scanning electron microscope (SEM). The mechanical properties, water vapor permeability and antibacterial effect of recycled carton sheets were also investigated. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Pulicaria glutinosa extract: a toolbox to synthesize highly reduced graphene oxide-silver nanocomposites.

    Science.gov (United States)

    Al-Marri, Abdulhadi H; Khan, Mujeeb; Khan, Merajuddin; Adil, Syed F; Al-Warthan, Abdulrahman; Alkhathlan, Hamad Z; Tremel, Wolfgang; Labis, Joselito P; Siddiqui, Mohammed Rafiq H; Tahir, Muhammad N

    2015-01-05

    A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag) via simultaneous reduction of both graphene oxide (GRO) and silver ions using Pulicaria glutinosa plant extract (PE) as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG) which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs) on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet-visible (UV-Vis) spectroscopy, powder X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS) activity, and significantly increased the intensities of the Raman signal of graphene.

  4. Pulicaria glutinosa Extract: A Toolbox to Synthesize Highly Reduced Graphene Oxide-Silver Nanocomposites

    Directory of Open Access Journals (Sweden)

    Abdulhadi H. Al-Marri

    2015-01-01

    Full Text Available A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag via simultaneous reduction of both graphene oxide (GRO and silver ions using Pulicaria glutinosa plant extract (PE as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet–visible (UV-Vis spectroscopy, powder X-ray diffraction (XRD, and energy dispersive X-ray (EDX. The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS activity, and significantly increased the intensities of the Raman signal of graphene.

  5. Magnetic Properties of Nd8Fe83Co3B6 Nanocomposite Magnets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of quenching technology, annealing temperature and time on the structures and magnetic properties of Nd8Fe83Co3B6 nanocomposite magnets was investigated. The results show that the α-Fe/Nd2Fe14B nanocomposite magnet containing a small amount of B is difficult to form amorphous state. The magnetic properties of 26 m/s quenched Nd8Fe83Co3B6 powders annealed at 640℃×480 s reach iHc=513 kA/m, Br=1.05 T and (BH)max=92.0 kJ/m3. The grain size is Dα-Fe=21.5 nm and DNd2Fe14B=30.2 nm.

  6. Laser micromachining of CNT/Fe/Al2O3 nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Kwang-Ryul KIM; Byoung-Deog CHOI; Jun-Sin YI; Sung-Hak CHO; Yong-Ho CHOA; Dong-Soo SHIN; Dong-Ho BAE; Myung-Chang KANG; Young-Keun JEONG

    2009-01-01

    CNT/Fe/Al2O3 mixed powders were synthesized from Fe/Al2O3 nanopowders using thermal CVD for the homogeneous dispersion of carbon nanotubes CNTs. CNTs consisted of MWNT, and the diameter was approximately 20-30 nm. After sintering, CNTs were homogenously located throughout Al2O3 grain boundary and were buckled. A femto-second laser installed with special optical systems was used for micromachining of the nanocomposites. The relationship between material ablation rate and energy fluence was theoretically investigated and compared with experimental results from cross-sectional SEM analysis. The nanocomposites which have higher content of CNT show a fairly good machining result due to its higher thermal conductivity and smaller grain size as well as lower light transmittance.

  7. Hydrothermal preparation and electrochemical sensing properties of TiO(2)-graphene nanocomposite.

    Science.gov (United States)

    Fan, Yang; Lu, Hai-Ting; Liu, Jin-Hang; Yang, Chun-Peng; Jing, Qiang-Shan; Zhang, Yu-Xia; Yang, Xing-Kun; Huang, Ke-Jing

    2011-03-01

    A facile hydrothermal method has been developed and shown to be effective for the preparation of TiO(2)-graphene nanocomposite. The as-prepared nanocomposite was characterized using FT-IR spectroscopy, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TiO(2)-graphene modified glassy carbon electrode (GCE) exhibited remarkable electron transfer kinetics and electrocatalytic activity toward the oxidation of dopamine (DA). Furthermore, the oxidation of common interfering agent such as ascorbic acid (AA) was significantly suppressed at this modified electrode, which resulted in good selectivity and sensitivity for electrochemical sensing of DA. These results demonstrate that the TiO(2)-graphene hybrid material has promising potential applications in electrochemical sensors and biosensors design.

  8. Optical and electrical properties of electrochemically deposited polyaniline/CeO2 hybrid nanocomposite film

    Institute of Scientific and Technical Information of China (English)

    Anees A. Ansari; M. A. M. Khan; M. Naziruddin Khan; Salman A. Alrokayan; M. Alhoshan; M. S. Alsalhi

    2011-01-01

    This paper reports the optical and electrical properties of electrochemically deposited polyaniline (PANI)/cerium oxide (CeO2) hybrid nano-composite film onto indium-fin-oxide (ITO) glass substrate. UV-visible spectroscopy and I-V characteristic were performed to study the optical and electrical parameters of the electrochemically deposited film. The film exhibited a strong absorption below 400 nm (3.10 eV) with a well defined absorbance peak at around 285 nm (4.35 eV). The estimated band gap of the CeO2 sample was 3.44 eV, higher than bulk CeO2 powder (Eg = 3.19 eV) due to the quantum confinement effect. Optical and electrochemical characteristics indicated that the electrical properties of PANI/CeO2 hybrid nanocomposite film are dominated by PANI doping.

  9. Preparation of Nanosized AlOOH and Its Application in Polymer-inorganic Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LIAO Haida; ZHANG Lianmeng; WU Bolin

    2008-01-01

    With industrial grade Al(OH)3 as raw materials, the self dispersion nanosized AIOOH crystal powder were prepared by the sol-hydrothermal method. The results of XRD and TEM show that the nanosized AIOOH could automatically disperse to a single-dispersing state in water without surface modification, dispersant, additive and accessional conditions (ultrasonic wave dispersing, ball-mill dispersing). The application results of the product indicate that the nanosized AIOOH can be composed into a toughened nanocomposites without surface modification. Accordingly, the self dispersion characteristic and mechanism of hydrothermal crystallization and charging composite dispersion of nanosized AIOOH are found, and a new technique of preparing polymer/inorganic nanocomposites is proposed, which is called blending compositing new techniques of sol even dispersing at quasi-homogeneous phase.

  10. Nanocomposite polymeric electrolytes to record electrophysiological brain signals in prolonged, unconventional or extreme conditions.

    Science.gov (United States)

    Licoccia, Silvia; Luisa Di Vona, M; Romagnoli, Paola; Narici, Livio; Acquaviva, Massimo; Carozzo, Simone; Marco, Stefano Di; Saturno, Moreno; Sannita, Walter G; Traversa, Enrico

    2006-09-01

    Chemically stable nanocomposite iono-conducting polymeric membranes (based on lithium salts and nanocrystalline oxide powders dispersed in a polymethyl methacrylate matrix) performed successfully in the recording of human brain responses to visual stimulation. Impedance was higher than that of conventional electrodes. However, the electrophysiological signals recorded by acid Al(2)O(3) and neutral Al(2)O(3) 5 wt.% and 10 wt.% nanocomposite gel electrolytes were comparable to those obtained with standard electrodes, even without preliminary skin cleaning and in the absence of gel electrolytes allowing better contact with and skin-electrode ionic conductance. The electrochemical and mechanical characteristics of these membranes make them fit for human and animal research, for clinical application (specifically in emergencies, prolonged electrophysiological recordings), or in unconventional or extreme conditions when fluid electrolytes are unsuitable (e.g., biomedical space research).

  11. Preparation, characterization and mechanical properties of rare-earth-based nanocomposites

    Directory of Open Access Journals (Sweden)

    Musbah S.S.

    2012-01-01

    Full Text Available This study reports research related to different preparation methods and characterization of polymer nanocomposites for optical applications. The Eu-ion doped Gd2O3 nanophosphor powder with different nanoparticle content was embedded in the matrix of PMMA. Preparation was carried out by mixing molding (bulk, electrospinning (nanofibers and solution casting (thin films with neat particles and particles coated with AMEO silane. Among the pros and cons for proposed methods, the mixing molding enables to avoid solvent use while the best deagglomeration and nanoparticle distribution is gained using the electrospinning method. The results of dynamic mechanical analysis (DMA and nanoindentation revealed that the storage modulus of the composites was higher than that of pure PMMA and increased with nanophosphor content. Surface modification of particles improved the mechanical properties of nanocomposites.

  12. Barium ferrite/epoxy resin nanocomposite system: Fabrication, dielectric, magnetic and hydration studies

    Directory of Open Access Journals (Sweden)

    A. Kanapitsas

    2016-03-01

    Full Text Available Composite systems of epoxy resin and barium ferrite nanoparticles have been prepared, and studied varying the content of the inclusions. Morphology of prepared samples has been examined via scanning electron microscopy and X-ray diffraction spectra, while electrical and magnetic properties were investigated by means of broadband dielectric spectroscopy, and magnetization tests respectively. Finally, water vapor sorption measurements were conducted in order to study the water sorption dynamics of the system. Electron microscopy images revealed the successful fabrication of nanocomposites. Dielectric permittivity increases with filler content, while three relaxation processes were detected in the relative spectra. These processes are attributed to interfacial polarization, glass to rubber transition of the matrix, and re-orientation of polar side groups of the polymer’s chain. Magnetization and magnetic saturation increase with magnetic nano-powder content. Nanocomposites absorb a small amount of water, not exceeding 1.7 wt%, regardless filler content, indicating their hydrophobic character.

  13. IN SITU Deposition of Fe-TiC Nanocomposite on Steel by Laser Cladding

    Science.gov (United States)

    Razavi, Mansour; Rahimipour, Mohammad Reza; Ganji, Mojdeh; Ganjali, Mansoreh; Gangali, Monireh

    The possibility of deposition of Fe-TiC nanocomposite on the surface of carbon steel substrate with the laser coating method had been investigated. Mechanical milling was used for the preparation of raw materials. The mixture of milled powders was used as a coating material on the substrate steel surface and a CO2 laser was used in continuous mode for coating. Microstructural studies were performed by scanning electron microscopy. Determinations of produced phases, crystallite size and mean strain have been done by X-ray diffraction. The hardness and wear resistance of coated samples were measured. The results showed that the in situ formation of Fe-TiC nanocomposite coating using laser method is possible. This coating has been successfully used to improve the hardness and wear resistance of the substrate so that the hardness increased by about six times. Coated iron and titanium carbide crystallite sizes were in the nanometer scale.

  14. Method of manufacturing powder particles

    NARCIS (Netherlands)

    Borra, J.P.D.

    2002-01-01

    The invention relates to a method of manufacturing a dry powder particle, preferably using electro-hydrodynamic spraying, wherein two oppositely charged aerosol streams are contacted. The invention allows for the manufacture of powders having various, controllable compositions and shapes. In

  15. Method of manufacturing powder particles

    NARCIS (Netherlands)

    Borra, J.P.D.

    2002-01-01

    The invention relates to a method of manufacturing a dry powder particle, preferably using electro-hydrodynamic spraying, wherein two oppositely charged aerosol streams are contacted. The invention allows for the manufacture of powders having various, controllable compositions and shapes. In particu

  16. CHINESE RE POLISHING POWDER INDUSTRY

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Due to its high polishing efficiency, long working life and wide application range, RE polishing powder has become the most popular fine polishing material. In recent years, accompanying the rapid development of electronic information technology, the demand for polishing powder is

  17. Preparation and Characterization of Nanocomposite Polymer Membranes Containing Functionalized SnO2 Additives

    Directory of Open Access Journals (Sweden)

    Roberto Scipioni

    2014-03-01

    Full Text Available In the research of new nanocomposite proton-conducting membranes, SnO2 ceramic powders with surface functionalization have been synthesized and adopted as additives in Nafion-based polymer systems. Different synthetic routes have been explored to obtain suitable, nanometer-sized sulphated tin oxide particles. Structural and morphological characteristics, as well as surface and bulk properties of the obtained oxide powders, have been determined by means of X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier Transform Infrared (FTIR and Raman spectroscopies, N2 adsorption, and thermal gravimetric analysis (TGA. In addition, dynamic mechanical analysis (DMA, atomic force microscopy (AFM, thermal investigations, water uptake (WU measurements, and ionic exchange capacity (IEC tests have been used as characterization tools for the nanocomposite membranes. The nature of the tin oxide precursor, as well as the synthesis procedure, were found to play an important role in determining the morphology and the particle size distribution of the ceramic powder, this affecting the effective functionalization of the oxides. The incorporation of such particles, having sulphate groups on their surface, altered some peculiar properties of the resulting composite membrane, such as water content, thermo-mechanical, and morphological characteristics.

  18. Preparation, characterizations and photocatalytic activity of a ZnO/TiO2 nanocomposite

    Science.gov (United States)

    Lachom, Vichuda; Poolcharuansin, Phitsanu; Laokul, Paveena

    2017-03-01

    Nanoparticles of TiO2, ZnO and nanocomposite ZnO/TiO2 were prepared via a co-precipitation method. The precursor powders were calcined in air at 400 and 500 °C for 2 h. Crystallite sizes of the calcined samples ranged from 11–43 nm. The XRD patterns of ZnO/TiO2 powder showed two phases of anatase and wurtzite, with no ZnTiO3 impurity phase. TEM images showed three types of particles in the ZnO/TiO2 samples: a fine particle type of TiO2 and submicron ellipsoidal and rod-like particles of ZnO. The energy gap (E g) of the calcined powders was evaluated using UV–vis absorption spectra and found to be in the range of 3.15–3.60 eV. Photodegradation efficiencies of the prepared samples in methyl orange aqueous solution were investigated under UVA irradiation. The results showed that nanocomposite ZnO/TiO2 calcined at 400 °C exhibited the highest apparent rate constant (k), and a higher capacity for methyl orange removal than TiO2 and ZnO nanoparticles.

  19. Exfoliated sodium-montmorillonite in nitrile butadiene rubber nanocomposites with good properties

    Institute of Scientific and Technical Information of China (English)

    WANG QingGuo; ZHANG XiaoHong; QIAO JinLiang

    2009-01-01

    We prepared and utilized a novel ultrafine fully-vulcanized powder nitrile butadiene rubber (UFPNBR)/ sodium montmorillonite (Na-MMT) nanocompound powder, in which nanoscale UFPNBR particles and nanoscale platelets of Na-MMT were isolated and stuck each other. When the UFPNBR/Na-MMT nano-compoud powder was mixed with crude nitrile butadiene rubber (NBR), UFPNBR particles could be easily dispersed in NBR matrix because of good compatibility, and nanoscale Na-MMT was also dis-persed well in NBR matrix due to the carrier aidance of UFPNBR particle, thus the NBR/UFPNBPJNa-MMT ternary nanocomposites adapting to industry was fabricated. X-ray diffraction test and scanning electron microscopy (SEM) observation indicated that nanoscale Na-MMT was dispersed well in NBR matrix. Compared with NBR/Na-MMT binary composites, NBR/UFPNBR/Na-MMT ternary nanocompo-sites have shorter vulcanization time and higher flame retardancy due to the exfoliated Na-MMT in NBR matrix.

  20. Effect of milling parameters on sinterability, mechanical and electrical properties of Cu-4 wt.% ZrO{sub 2} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Mohammed A., E-mail: mtahanrc@gmail.com [Solid-State Physics Department, National Research Centre, El-Buhooth St., 12622, Dokki, Cairo (Egypt); Nassar, Amira H. [Solid-State Physics Department, National Research Centre, El-Buhooth St., 12622, Dokki, Cairo (Egypt); Zawrah, M.F. [Ceramics Department, National Research Centre, El-Buhooth St., 12622, Dokki, Cairo (Egypt)

    2016-09-15

    Mechanical alloying was used to produce Cu matrix nanocomposite reinforced by 4 wt.% ZrO{sub 2} nanoparticles with different milling time up to 16 h and ball-to-powder ratios (BPRs) up to 40:1. The milled nanocomposite powders were investigated by X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). To study the sinterability, the milled powders were cold pressed and sintered at 800 °C for 1 h in argon atmosphere. In order to investigate the relative density and microstructures of the sintered nanocomposites, scanning electron microscopy (SEM) as well as energy dispersive spectrometer (EDS) were employed. The electrical and mechanical properties of the sintered nanocomposites were also examined. The results revealed that a uniform distribution of ZrO{sub 2} reinforcement in Cu matrix was successfully obtained and the agglomeration, crystal and particle sizes were decreased after either milling times and/or BPRs. The results also pointed out that the relative density, microhardness, compressive strength and electrical conductivity of the sintered nanocomposite samples were increased with the increasing of milling time and/or BPRs while apparent porosity was decreased. The maximum values of microhardness, compressive strength and electrical conductivity were 872 MPa, 304 MPa and 45.9% IACS, respectively for the milled sample for 16 h and BRP 40:1. - Highlights: • Cu-4 wt.% ZrO{sub 2} nanoparticles with different parameter by mechanical alloying. • The increased milling times and/or BPRs led to a decrease in the particle size. • Microhardness is increased with increasing ball-to-powder weight ratios. • Compressive strength is increased with increasing milling time. • Electrical conductivity of the samples was increasing with increase milling time.

  1. Synthesis of Silicon Nitride and Silicon Carbide Nanocomposites through High Energy Milling of Waste Silica Fume for Structural Applications

    Science.gov (United States)

    Suri, Jyothi

    Nanocomposites have been widely used in a multitude of applications in electronics and structural components because of their improved mechanical, electrical, and magnetic properties. Silicon nitride/Silicon carbide (Si 3N4/SiC) nanocomposites have been studied intensively for low and high temperature structural applications, such as turbine and automobile engine components, ball bearings, turbochargers, as well as energy applications due to their superior wear resistance, high temperature strength, high oxidation resistance and good creep resistance. Silica fume is the waste material produced during the manufacture of silicon and ferro-silicon alloys, and contains 94 to 97 wt.% SiO2. In the present dissertation, the feasibility of using waste silica fume as the raw material was investigated to synthesize (I) advanced nanocomposites of Si3N4/SiC, and (2) porous silicon carbide (SiC) for membrane applications. The processing approach used to convert the waste material to advanced ceramic materials was based on a novel process called, integrated mechanical and thermal activation process (IMTA) process. In the first part of the dissertation, the effect of parameters such as carbothermic nitridation and reduction temperature and the graphite concentration in the starting silica fume plus graphite mixture, were explored to synthesize nanocomposite powders with tailored amounts of Si3N4 and SiC phases. An effective way to synthesize carbon-free Si3N 4/SiC composite powders was studied to provide a clear pathway and fundamental understanding of the reaction mechanisms. Si3N4/SiC nanocomposite powders were then sintered using two different approaches, based on liquid phase sintering and spark plasma sintering processes, with Al 2O3 and Y2O3 as the sintering aids. The nanocomposites were investigated for their densification behavior, microstructure, and mechanical properties. Si3N4/SiC nanocomposites thus obtained were found to possess superior mechanical properties at much

  2. Mechanical and thermal properties and morphological studies of 10 MeV electron beam irradiated LDPE/hydroxyapatite nano-composite

    Science.gov (United States)

    Soltani, Z.; Ziaie, F.; Ghaffari, M.; Afarideh, H.; Ehsani, M.

    2013-02-01

    In this work the nano-composite samples were prepared using the LDPE filled with different weight percentages of hydroxyapatite powder which was synthesized via hydrolysis method. The samples were subjected to irradiation under 10 MeV electron beam in 75-250 kGy doses. Mechanical and thermal properties as well as the morphology of the nano-composite samples were investigated and compared. The hot-set and swelling tests confirmed the radiation crosslinking induced in the polymer matrix especially between the matrix and reinforcement phase. The result indicates that the mechanical and thermal parameters are strongly dependent on the hydroxyapatite content in comparison to radiation.

  3. Powder-Bed Stabilization for Powder-Based Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Andrea Zocca

    2014-06-01

    Full Text Available The most successful additive manufacturing (AM technologies are based on thelayer-by-layer depositionof a flowable powder. Although considered as the third industrial revolution, one factor still limiting these processes to become completely autonomous is the often necessary build-up of support structures. Besides the prevention of lateral shifts of the part during the deposition of layers, the support assures quality and stability to the built process. The loose powder itself surrounding the built object, or so-called powder-bed, does not provide this sustenance in most existent technology available. Here we present a simple but effective and economical method for stabilizing the powder-bed, preventing distortions in the geometry with no need for support structures. This effect, achieved by applying an air flow through the powder-bed, is enabling an entirely autonomous generation of parts and is a major contribution to all powder-based additive manufacturing technologies. Moreover, it makes powder-based AM independent of gravitational forces, which will facilitate crafting items in space from a variety of powdery materials.

  4. Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying, E-mail: caoying1130@sina.com [Henan Normal University, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Chemical Engineering (China)

    2013-11-15

    Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

  5. Development of novel exchange spring magnet by employing nanocomposites of CoFe{sub 2}O{sub 4} and CoFe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Safi, Rohollah; Ghasemi, Ali, E-mail: ali13912001@yahoo.com; Shoja-Razavi, Reza; Tavoosi, Majid

    2016-12-01

    CoFe{sub 2}O{sub 4}−CoFe2 hard–soft nanocomposites were prepared via reduction of the cobalt ferrite CoFe{sub 2}O{sub 4} in hydrogen atmosphere at different temperature. The structure and the room temperature magnetization of the samples were characterized by X-ray diffraction, field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM). It was found that the saturation magnetization of the nanocomposite powders increases by reduction temperature while their coercivity decreases. The highest M{sub r}/M{sub s} ratio of 0.52 was obtained for sample reduced at 550 °C. Single smooth hysteresis loops of nanocomposites show that these nanocomposites behave as the single-phase materials. This result indicates the presence of exchange coupling between two different hard and soft phases. - Highlights: • CoFe{sub 2}O{sub 4}–CoFe{sub 2} was successfully synthesized by reduction diffusion process. • Two phases are effectively exchange coupled in nanocomposite. • Single smooth hysteresis loop was developed in nanocomposites.

  6. Electrospun Borneol-PVP Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2012-01-01

    Full Text Available The present work investigates the validity of electrospun borneol-polyvinylpyrrolidone (PVP nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber-based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w. Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long-time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano-drug delivery systems with high performance.

  7. Magnetic Nanocomposite Cilia Energy Harvester

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-02-11

    An energy harvester capable of converting low frequency vibrations into electrical energy is presented. The operating principle, fabrication process and output characteristics at different frequencies are discussed. The harvester is realized by fabricating an array of polydimethylsiloxane (PDMS) - iron nanowire nanocomposite cilia on a planar coil array. Each coil element consists of 14 turns and occupies an area of 600 μm x 600μm. The cilia are arranged in a 12x5 array and each cilium is 250 μm wide and 2 mm long. The magnetic characteristics of the fabricated cilia indicate that the nanowires are well aligned inside of the nanocomposite, increasing the efficiency of energy harvesting. The energy harvester occupies an area of 66.96 mm2 and produces an output r.m.s voltage of 206.47μV, when excited by a 40 Hz vibration of 1 mm amplitude.

  8. Colloidal QDs-polymer nanocomposites

    Science.gov (United States)

    Gordillo, H.; Suárez, I.; Rodríguez-Cantó, P.; Abargues, R.; García-Calzada, R.; Chyrvony, V.; Albert, S.; Martínez-Pastor, J.

    2012-04-01

    Nanometer-size colloidal semiconductor nanocrystals, or Quantum Dots (NQD), are very prospective active centers because their light emission is highly efficient and temperature-independent. Nanocomposites based on the incorporation of QDs inside a polymer matrix are very promising materials for application in future photonic devices because they combine the properties of QDs with the technological feasibility of polymers. In the present work some basic applications of these new materials have been studied. Firstly, the fabrication of planar and linear waveguides based on the incorporation of CdS, CdSe and CdTe in PMMA and SU-8 are demonstrated. As a result, photoluminescence (PL) of the QDs are coupled to a waveguide mode, being it able to obtain multicolor waveguiding. Secondly, nanocomposite films have been evaluated as photon energy down-shifting converters to improve the efficiency of solar cells.

  9. Multiscale modeling of polymer nanocomposites

    Science.gov (United States)

    Sheidaei, Azadeh

    In recent years, polymer nano-composites (PNCs) have increasingly gained more attention due to their improved mechanical, barrier, thermal, optical, electrical and biodegradable properties in comparison with the conventional micro-composites or pristine polymer. With a modest addition of nanoparticles (usually less than 5wt. %), PNCs offer a wide range of improvements in moduli, strength, heat resistance, biodegradability, as well as decrease in gas permeability and flammability. Although PNCs offer enormous opportunities to design novel material systems, development of an effective numerical modeling approach to predict their properties based on their complex multi-phase and multiscale structure is still at an early stage. Developing a computational framework to predict the mechanical properties of PNC is the focus of this dissertation. A computational framework has been developed to predict mechanical properties of polymer nano-composites. In chapter 1, a microstructure inspired material model has been developed based on statistical technique and this technique has been used to reconstruct the microstructure of Halloysite nanotube (HNT) polypropylene composite. This technique also has been used to reconstruct exfoliated Graphene nanoplatelet (xGnP) polymer composite. The model was able to successfully predict the material behavior obtained from experiment. Chapter 2 is the summary of the experimental work to support the numerical work. First, different processing techniques to make the polymer nanocomposites have been reviewed. Among them, melt extrusion followed by injection molding was used to manufacture high density polyethylene (HDPE)---xGnP nanocomposties. Scanning electron microscopy (SEM) also was performed to determine particle size and distribution and to examine fracture surfaces. Particle size was measured from these images and has been used for calculating the probability density function for GNPs in chapter 1. A series of nanoindentation tests have

  10. Non-conductive ferromagnetic carbon-coated (Co, Ni) metal/polystyrene nanocomposites films

    Science.gov (United States)

    Takacs, H.; Viala, B.; Tortai, J.-H.; Hermán, V.; Duclairoir, F.

    2016-03-01

    This article reports non-conductive ferromagnetic properties of metal/polymer nanocomposite films intended to be used for RF applications. The nanocomposite arrangement is unique showing a core double-shell structure of metal-carbon-polystyrene: M/C//P1/P2, where M = Co, Ni is the core material, C = graphene or carbon is the first shell acting as a protective layer against oxidation, P1 = pyrene-terminated polystyrene is the second shell for electrical insulation, and P2 = polystyrene is a supporting matrix (// indicates actual grafting). The nanocomposite formulation is briefly described, and the film deposition by spin-coating is detailed. Original spin-curves are reported and analyzed. One key outcome is the achievement of uniform and cohesive films at the wafer scale. Structural properties of films are thoroughly detailed, and weight and volume fractions of M/C are considered. Then, a comprehensive overview of DC magnetic and electrical properties is reported. A discussion follows on the magnetic softness of the nanocomposites vs. that of a single particle (theoretical) and the raw powder (experimental). Finally, unprecedented achievement of high magnetization (˜0.6 T) and ultra-high resistivity (˜1010 μΩ cm) is shown. High magnetization comes from the preservation of the existing protective shell C, with no significant degradation on the particle net-moment, and high electrical insulation is ensured by adequate grafting of the secondary shell P1. To conclude, the metal/polymer nanocomposites are situated in the landscape of soft ferromagnetic materials for RF applications (i.e., inductors and antennas), by means of two phase-diagrams, where they play a crucial role.

  11. Enhanced microwave absorption properties in cobalt–zinc ferrite based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Poorbafrani, A., E-mail: a.poorbafrani@gmail.com; Kiani, E.

    2016-10-15

    In an attempt to find a solution to the problem of the traditional spinel ferrite used as the microwave absorber, the Co{sub 0.6}Zn{sub 0.4}Fe{sub 2}O{sub 4}–Paraffin nanocomposites were investigated. Cobalt–zinc ferrite powders, synthesized through PVA sol–gel method, were combined with differing concentrations of Paraffin wax. The nanocomposite samples were characterized employing various experimental techniques including X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Alternating Gradient Force Magnetometer (AGFM), and Vector Network Analyzer (VNA). The saturation magnetization and coercivity were enhanced utilizing appropriate stoichiometry, coordinate agent, and sintering temperature required for the preparation of cobalt–zinc ferrite. The complex permittivity and permeability spectra, and Reflection Loss (RL) of Co{sub 0.6}Zn{sub 0.4}Fe{sub 2}O{sub 4}–Paraffin nanocomposites were measured in the frequency range of 1–18 GHz. The microwave absorption properties of nanocomposites indicated that the absorbing composite containing 20 wt% of paraffin manifests the strongest microwave attenuation ability. The composite exhibited the reflection loss less than –10 dB in the whole C-band and 30% of the X-band frequencies. - Highlights: • We enhanced the magnetic properties of cobalt–zinc Ferrite nanocomposites. • The samples showed absorption in the whole C-band and 30% of the X-band frequencies. • We tried to solve the problem of the spinel ferrite utilized as efficient absorber. • We enhanced the microwave reflection loss over extended frequency ranges.

  12. Sol-Gel Derived Nanocomposites

    OpenAIRE

    2007-01-01

    Phase distribution in nanocomposite hybrid materials can be analyzed by Force modulation Atomic Force Microscopy (AFM). The combination of this method with conventional analytical methods, e.g. IR spectroscopy and Scanning Electron Microscopy (SEM), leads to a new insight in the formation of these new materials and contributes to tailor their properties. Thin films of such materials were investigated, in order to understand the interactions between the components and their application as natu...

  13. Composite and Nanocomposite Metal Foams

    Directory of Open Access Journals (Sweden)

    Isabel Duarte

    2016-01-01

    Full Text Available Open-cell and closed-cell metal foams have been reinforced with different kinds of micro- and nano-sized reinforcements to enhance their mechanical properties of the metallic matrix. The idea behind this is that the reinforcement will strengthen the matrix of the cell edges and cell walls and provide high strength and stiffness. This manuscript provides an updated overview of the different manufacturing processes of composite and nanocomposite metal foams.

  14. NANOCOMPOSITE COATINGS WITH ENHANCED HARDNESS

    Institute of Scientific and Technical Information of China (English)

    J. Musil

    2005-01-01

    The article reviews the present state of the art in the magnetron sputtering of hart and superhard nanocomposite coatings. It is shown that there are (1) two groups of hard and superhard nanocomposites: (i) nc-MN/hard phase and (ii) nc-MN/soft phase, (2) three possible origins of the enhanced hardness: (i) dislocation-dominated plastic deformation, (ii) cohesive forces between atoms and (iii) nanostructure of materials, and (3) huge differences in the microstructure of single- and two-phase films. A main attention is devoted to the formation of nanocrystalline and/or X-ray amorphous films. Such films are created in a vicinity of transitions between (i)crystalline and amorphous phases, (ii) two crystalline phases of different chemical composition or (iii) two different preferred orientations of grains of the sane material from which the coating is composed. The existence of the last transition makes it possible to explain the enhanced hardness in single-phase films. The thermal stability and oxidation resistance of hard nanocomposite films is also shortly discussed.

  15. 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)

  16. Study the effect of mechanical alloying parameters on synthesis of Cr{sub 2}Nb–Al{sub 2}O{sub 3} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Shayesteh, Payam, E-mail: shayesteh.payam@gmail.com; Mirdamadi, Shamseddin; Razavi, Hossein

    2014-01-01

    Graphical abstract: - Highlights: • Cr{sub 2}Nb–Al{sub 2}O{sub 3} nanocomposite synthesized through MA. • Effect of BPR, rotating speed, milling time and PCA concentration investigated. • After annealing at 1100 °C crystalline phase were appeared. • Williamson–Hall analysis was used in order to study the grain size of nano composite. - Abstract: In this study, Cr{sub 2}Nb–20 vol.% Al{sub 2}O{sub 3} nanocomposite was prepared successfully by mechanochemical reaction between Al, Nb and Cr{sub 2}O{sub 3} powders. Amorphization of powder occurred during mechanical alloying because of high energy collisions between powders and steel balls in milling container which transfer high degree of energy to powders. Therefore, annealing was needed to form crystalline phases. The influence of different mechanical alloying parameters such as BPR, rotating speed, milling time and PCA concentration on synthesis of composite material were investigated. After mechanical alloying, the powder was encapsulated in quartz and then annealed at 1100 °C for 3 h. After annealing, 3 different phases were appeared (Cr{sub 2}Nb (cubic), Cr{sub 2}Nb (hexagonal) and α-Al{sub 2}O{sub 3}). The structural changes of powder particles during mechanical alloying were studied by X-ray diffractometry (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM)

  17. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  18. Nanocrystal-polymer nanocomposite electrochromic device

    Science.gov (United States)

    Milliron, Delia; Runnerstrom, Evan; Helms, Brett; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2015-12-08

    Described is an electrochromic nanocomposite film comprising a solid matrix of an oxide based material, the solid matrix comprising a plurality of transparent conducting oxide (TCO) nanostructures dispersed in the solid matrix and a lithium salt dispersed in the solid matrix. Also described is a near infrared nanostructured electrochromic device having a functional layer comprising the electrochromic nanocomposite film.

  19. Superhard nano-multilayers and nanocomposite coatings

    Institute of Scientific and Technical Information of China (English)

    BAI Xiaoming; ZHENG Weitao; AN Tao

    2005-01-01

    This paper reviews the recent development of nano-multilayers and nanocomposite coatings. The hardening mechanisms and design of hard coating are discussed in details. Recent research on Ti/TiN and nitride/nitride multilayer, Ti-Si-N and Ti-Al-Si-N nanocomposite coatings is described, and the perspectives of the related research are proposed.

  20. Highly Conductive Multifunctional Graphene Polycarbonate Nanocomposites

    Science.gov (United States)

    Yoonessi, Mitra; Gaier, James R.

    2010-01-01

    Graphene nanosheet bisphenol A polycarbonate nanocomposites (0.027 2.2 vol %) prepared by both emulsion mixing and solution blending methods, followed by compression molding at 287 C, exhibited dc electrical percolation threshold of approx.0.14 and approx.0.38 vol %, respectively. The conductivities of 2.2 vol % graphene nanocomposites were 0.512 and 0.226 S/cm for emulsion and solution mixing. The 1.1 and 2.2 vol % graphene nanocomposites exhibited frequency-independent behavior. Inherent conductivity, extremely high aspect ratio, and nanostructure directed assembly of the graphene using PC nanospheres are the main factors for excellent electrical properties of the nanocomposites. Dynamic tensile moduli of nanocomposites increased with increasing graphene in the nanocomposite. The glass transition temperatures were decreased with increasing graphene for the emulsion series. High-resolution electron microscopy (HR-TEM) and small-angle neutron scattering (SANS) showed isolated graphene with no connectivity path for insulating nanocomposites and connected nanoparticles for the conductive nanocomposites. A stacked disk model was used to obtain the average particle radius, average number of graphene layers per stack, and stack spacing by simulation of the experimental SANS data. Morphology studies indicated the presence of well-dispersed graphene and small graphene stacking with infusion of polycarbonate within the stacks.

  1. Organic/inorganic nanocomposite polymer electrolyte

    Institute of Scientific and Technical Information of China (English)

    Li Qi; Shao Jun Dong

    2007-01-01

    The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocom posites membrane materials and their lithium salt complexes have been found thermally stable below 200 ℃. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10-6 S/cm.

  2. Low pressure powder injection moulding of stainless steel powders

    Energy Technology Data Exchange (ETDEWEB)

    Zampieron, J.V.; Soares, J.P.; Mathias, F.; Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Filho, F.A. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

    2001-07-01

    Low-pressure powder injection moulding was used to obtain AISI 316L stainless steel parts. A rheological study was undertaken using gas-atomised powders and binders. The binders used were based on carnauba wax, paraffin, low density polyethylene and microcrystalline wax. The metal powders were characterised in terms of morphology, particle size distribution and specific surface area. These results were correlated to the rheological behaviour. The mixture was injected in the shape of square bar specimens to evaluate the performance of the injection process in the green state, and after sintering. The parameters such as injection pressure, viscosity and temperature were analysed for process optimisation. The binders were thermally removed in low vacuum with the assistance of alumina powders. Debinding and sintering were performed in a single step. This procedure shortened considerably the debinding and sintering time. (orig.)

  3. Preparation and magnetic properties of Cu0.4Zn0.6Cr0.5Sm0.06Fe1.44O4/polyaniline nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LI Liangchao; QIU Haizhen; WANG Yuping; JIANG Jing; XU Feng

    2008-01-01

    A self-propagating combustion synthesis (SPCS) method, citrate SPCS method, was used to synthesize Cu0.4Zn0.6Cr0.5SmxFe1.5-xO4 (x=0-0.1) nanosized powders at relatively low temperature. Polyaniline/Cu0.4Zn0.6Cr0.5Sm0.06Fe1.44O4 (CZCS0.06FO) nanocomposites were prepared by in situ polymerization of aniline in the presence of CZCS0.06FO ferrites. The structures, morphologies, and ferromagnetic properties of ferrite powders and nanocomposites were characterized by powder X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM). The results indicated that ferrite powders were coated effectively by polyaniline, which reduced the agglomeration of ferrite particles to certain extent, and was helpful to the decentralization and stabilization of nanoparticles. The nanocomposites with core-shell structure under applied field exhibited hysteresis loops of the ferromagnetic nature. The nanocomposites were fit for being used as soft magnetic material because of their lower coercivity than that of pure ferrites.

  4. Experimental and mechanical analysis of cement–nanotube nanocomposites

    Indian Academy of Sciences (India)

    J H LEE; B G LEE

    2017-08-01

    Composites of multi-walled carbon nanotubes (MWCNTs) and cement layers were manufactured by grindingcarbon nanotubes and cement powder in a planetary ball mill. Tiny cement nanoparticles were fabricated using anethylene-glycol-assisted synthesis procedure with successive hydrolysis and condensation reactions. Cement–nanotubenanocomposites were then produced by adding functionalized nanotube powder to the colloidal cement nanoparticles suspendedin ethylene glycol (weight ratio of nanotubes to cement = 1:1). Modal analysis of five-walled carbon nanotubenanocomposites with 1–5 cement layers was performed via the finite-element method. The five-walled carbon nanotubenanocomposites with different shapes were modelled using three-dimensional elastic beams of carbon bonds, nodal carbonpoint masses and cement layer shell elements. The natural frequency, vonMises stress and strain energy of the elements werecalculated by considering the Van derWaals forces between the carbon atoms in the hexagonal lattice. In the modal analysis,the greatest variation in displacement was observed along the x-axis, and the maximum values of the total displacementappeared to be larger at the cement layers than at the MWCNTs. The cement–nanotube nanocomposites exhibited a gradualdecrease in deformation and vibration as the number of cement layers was increased.

  5. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  6. A novel aluminum based nanocomposite with high strength and good ductility

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanalizadeh, Hossein, E-mail: hralizadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Emamy, Masoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Shokouhimehr, Mohammadreza [School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul (Korea, Republic of)

    2015-11-15

    Aluminum based nanocomposite containing nano-sized Al{sub 3}Mg{sub 2} reinforcing was fabricated via mechanical milling followed by hot extrusion techniques. For this, Al and Al{sub 3}Mg{sub 2} powders were mixed mechanically and milled at different times (0, 2, 5, 7, 10, 15 and 20 h) to achieve Al–10 wt.% Al{sub 3}Mg{sub 2} composite powders. Hot extrusion of cold pressed powders was done at 400 °C with extrusion ratio of 6:1. Microstructures of the powders and consolidated materials were studied using transmission electron microscopy, scanning electron microscope and X-ray diffraction. Fracture surfaces were also investigated by scanning electron microscopy equipped with EDS analyzer. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. In addition, the fabricated composites exhibited homogeneous distribution and less agglomerations of the n-Al{sub 3}Mg{sub 2} with increasing milling time. The mechanical behavior of these nanocomposites was investigated by hardness and tensile tests, which revealed it has four times the strength of a conventional Al along with good ductility. It was found that the ultimate tensile strength (UTS) and elongation of the nanocomposites were significantly improved with increases in milling time up to 15 h. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-Al{sub 3}Mg{sub 2}. Fracture surfaces showed that the interfacial bonding between Al and Al{sub 3}Mg{sub 2} could be improved with increasing in milling time. Also HRTEM results from interface showed that a metallurgical clean interface and intimate contact between matrix and second phase. By extending the milling process up to 20 h, there was no significant improvement in mechanical behavior of materials, due to the completion of milling process and dynamic and static recovery of composite at higher milling times. - Highlights: • A novel aluminum

  7. Nanocomposite organomineral hybrid materials. Part 3

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-06-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  8. Nanocomposite organomineral hybrid materials. Part I

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-02-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  9. Nanocomposite organomineral hybrid materials. Part 2

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-04-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  10. Parylene nanocomposites using modified magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Ignacio, E-mail: iggarcia@cidetec.es [New Materials Department, CIDETEC - Centre for Electrochemical Technologies, Parque Tecnologico de San Sebastian, Paseo Miramon 196, Donostia-San Sebastian E 20009 (Spain); Luzuriaga, A. Ruiz de; Grande, H. [New Materials Department, CIDETEC - Centre for Electrochemical Technologies, Parque Tecnologico de San Sebastian, Paseo Miramon 196, Donostia-San Sebastian E 20009 (Spain); Jeandupeux, L.; Charmet, J.; Laux, E.; Keppner, H. [HES-SO Arc, Institut des Microtechnologies Appliquees, Eplatures- Grises 17, 2300 La Chaux-de Fonds (Switzerland); Mecerreyes, D.; Cabanero, German [New Materials Department, CIDETEC - Centre for Electrochemical Technologies, Parque Tecnologico de San Sebastian, Paseo Miramon 196, Donostia-San Sebastian E 20009 (Spain)

    2010-11-01

    Parylene/Fe{sub 3}O{sub 4} nanocomposites were synthesized and characterized. The nanocomposites were obtained by chemical vapour deposition polymerization of Parylene onto functionalized Fe{sub 3}O{sub 4} nanoparticles. For this purpose, allyltrichlorosilane was used to modify the surface of 7 nm size Fe{sub 3}O{sub 4} nanoparticles obtained by the coprecipitation method. The magnetic nanoparticles and obtained nanocomposite were characterized with X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and magnetic measurements (SQUID). The successful incorporation of different amounts of nanoparticles into Parylene was confirmed by FTIR and TGA. Interestingly, increments in saturation magnetization of the nanocomposites were observed ranging from 0 emu/g of neat Parylene to 16.94 emu/g in the case of nanocomposite films that contained 27.5 wt% of nanoparticles.

  11. Fabrication and properties of multiferroic nanocomposite films

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-01-01

    A new type of multiferroic polymer nanocomposite is presented, which exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of a ferroelectric copolymer poly(vinylindene fluoride-trifluoroethylene) [P(VDF-TrFE)] and high aspect ratio ferromagnetic nickel (Ni) nanowires (NWs), which were grown inside anodic aluminum oxide membranes. The fabrication of nanocomposite films with Ni NWs embedded in P(VDF-TrFE) has been successfully carried out via a simple low-temperature spin-coating technique. Structural, ferromagnetic, and ferroelectric properties of the developed nanocomposite have been investigated. The remanent and saturation polarization as well as the coercive field of the ferroelectric phase are slightly affected by the incorporation of the NWs as well as the thickness of the films. While the former two decrease, the last increases by adding the NWs or increasing the thickness. The ferromagnetic properties of the nanocomposite films are found to be isotropic.

  12. Description of Extrudate Swell for Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Kejian Wang

    2010-01-01

    Full Text Available Extrudate swell is often observed to be weakened in nanocomposites compared to the pure polymer matrix. A theory quantifying this would be significant either for optimum processing or for understanding their viscoelasticity. A unified extrudate swell correlation with material properties and capillary parameters was suggested for polymer melt and their nanocomposites when considering the reservoir entry effect. More importantly, it was the first to find that the composite swell ratio can be the matrix swell ratio multiplied by the concentration shift factor, which is similar to the dynamic moduli expression for composites. The factor is a function of the shear field (stress or shear rate, filler content, filler internal structure and the surface state as well as the matrix properties. Several sets of swell data for nanocomposites were chosen from publications to test the new theories. The proposed quantitative model displayed good fit for the five kinds of nanocomposites, which verified the rationality of the swell theory for nanocomposites.

  13. Advances in rubber/halloysite nanotubes nanocomposites.

    Science.gov (United States)

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

    The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

  14. Synthesis of (Mo{sub 1-x}-Cr{sub x})Si{sub 2} nanostructured powders via mechanical alloying and following heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani-rad, R.; Mirvakili, S.A. [Materials and Energy Research Center, Tehran (Iran, Islamic Republic of); Zakeri, M., E-mail: M_zakeri@iau-saveh.ac.i [Islamic Azad University (Saveh Branch), P.O. Box: 39187/366, Saveh (Iran, Islamic Republic of)

    2010-01-21

    MoSi{sub 2}-CrSi{sub 2} nanocomposite powder was successfully synthesized by ball milling of Mo, Si and Cr elemental powders. Effects of the Cr content, milling time and annealing temperature were studied. X-ray diffraction (XRD) was used to characterize the milled and annealed powders. The morphological and microstructural evolutions were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). High temperature polymorph (HTP) of MoSi{sub 2} begins to form after 50 h of milling and completes after 70 h of milling. MoSi{sub 2}-CrSi{sub 2} composite powder was also prepared with a combination of short milling time (50 h) and low temperature annealing (850 {sup o}C). Annealing led to the HTP to low temperature polymorph (LTP) transformation of MoSi{sub 2}. MoSi{sub 2}-CrSi{sub 2} nanocomposite powder with the mean grain size less than 50 nm was obtained at the end of milling. This composite maintained its nanocrystalline nature after annealing. A spherical morphology was procured for 50 h milled powder with 0.25 mole Cr.

  15. Structure of composites consolidated from ball milled 7475 aluminum alloy and ZrO{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Dutkiewicz, Jan; Litynska-Dobrzynska, Lidia [Polish Academy of Sciences, Krakow (Poland). Inst. of Metallurgy and Materials Science; Matsuda, Kenji [Toyama Univ., Gofuku (Japan). Graduate School of Science and Engineering

    2013-02-15

    Nanocomposites were prepared from 7475 alloy powder ball milled for 40h with additions of 2% Zr and 10 or 20wt.% of ZrO{sub 2}, Y{sub 2}O{sub 3} stabilized powders. Two types of ZrO{sub 2} powder additions of size near 30nm and 0.3-0.5 {mu}m were used. Transmission electron microscopy studies confirmed the refinement of the aluminum solid solution grain size after milling, down to about 40nm. The milled powders were consolidated using uniaxial hot pressing in vacuum at 380 C and at a pressure of 600 MPa. The hardness of consolidated samples was higher for the 20% ZrO{sub 2} nanocrystalline ceramic powder addition than for 20% ZrO{sub 2} coarser powder, at 320 and 280 HV, respectively. Transmission electron microscopy studies allowed the determination of the grain size of aluminum solid solution to be near 100nm after hot pressing and homogeneous distribution of ZrO{sub 2} particles. The fractions of monoclinic ZrO{sub 2} were similar in the milled powder and in the hot pressed samples. ZrO{sub 2} nanoparticles did not retard the grain growth, contrary to 2% of Zr which prevented grain growth during hot pressing. The compression tests showed 1000 MPa of ultimate compression strength of samples with ZrO{sub 2} nanoparticles, slightly higher than those with ZrO{sub 2} larger particle additions. (orig.)

  16. Synthesis of nanosized tungsten powder

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Nanosized tungsten powder was synthesized by means of different methods and under different conditions with nanosized WO3 powder. The powder and the intermediate products were characterized using XRD, SEM, TEM, BET (Brunauer Emmett Teller Procedure) and SAXS (X-ray diffracto-spectrometer/Kratky small angle scattering goniometer). The results show that nanosized WO3 can be completely reduced to WO2 at 600℃ after 40 min, and WO2 can be reduced to W at 700℃ after 90 min, moreover, the mean size of W particles is less than 40 nm. Furthermore, the process of WO3→WO2→W excelled that of WO3→W in getting stable nanosized tungsten powder with less grain size.

  17. Microstructural characterisation of sintered soft magnetic nanocomposite materials

    Directory of Open Access Journals (Sweden)

    J. Konieczny

    2013-11-01

    Full Text Available Purpose: The main aim of this work is to investigate microstructure of of sintered soft magnetic nanocomposite materials produced by sintering axially on one side in the ambient atmosphere. Design/methodology/approach: Microstructure observations of 20 mm diameter sintered roller by light microscopy OLYMPUS, scanning electron microscopy OPTON DSM-940 and ZEISS SUPRA 35, and transmission electron microscopy JEOL 3010. The X-ray tests were realized with the use of the XRD 7 SEIFERT-FPM diffractometer equipped with the lamp of the cobalt anode of 35 kV voltage and 30 mA filament current was used. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling (8000 SPEX CertiPrep Mixer/Mill of metallic glasses ribbons in as state. The hot pressing process was made on machine “Degussa”. Findings: The analysis of the results enabled determination of the hot pressing parameters on structure of obtained stampings. This is typical of an dispersion strengthened case. Research limitations/implications: For the sintered roller obtained from metallic Co-based amorphous ribbons, further mechanical and magnetic examinations are planed. Practical implications: Conducted research shows that applied technology of sintered roller production allows to obtain good microstructural characteristics. Structure analysis of die stampings of powdered amorphous metallic ribbons is helpful to prepare this material by laboratory methods. Feature an alternative to commercial alloys and composite materials are the amorphous and nanocrystalline metal amorphous ribbons obtained by melt spinning technique and make it possible to obtain the new composite materials with best magnetic properties, which dimensions and shape can be freely formed. Originality/value: The paper presents influence of hot pressing parameters process of metallic powdered ribbons Co77Si11.5B11.5 on structure of obtained die stampings.

  18. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  19. In situ synthesis of calcium phosphate-polycaprolactone nanocomposites with high ceramic volume fractions.

    Science.gov (United States)

    Makarov, C; Gotman, I; Jiang, X; Fuchs, S; Kirkpatrick, C J; Gutmanas, E Y

    2010-06-01

    Biodegradable calcium phosphate-PCL nanocomposite powders with unusually high ceramic volume fractions (80-95%) and uniform PCL distribution were synthesized by a non-aqueous chemical reaction in the presence of the dissolved polymer. No visible polymer separation occurred during processing. Depending on the reagents combination, either dicalcium phosphate (DCP) or Ca-deficient HA (CDHA) was obtained. CDHA-PCL composite powders were high pressure consolidated at room temperature yielding dense materials with high compressive strengths. Such densification route provides the possibility of incorporating drug and proteins without damaging their biological activity. The CDHA-PCL composites were tested in osteoblastic and endothelial cell line cultures and were found to support the attachment and proliferation of both cell types.

  20. Syntheses of Fe–TiC nanocomposite from ilmenite concentrate via microwave heating

    Indian Academy of Sciences (India)

    Mansour Razavi; Mohammad Reza Rahimipour; Tooraj Ebadzadeh; Seyed Salman Razavi Tousi

    2009-04-01

    In this paper, the possibility of production of Fe–TiC nanocomposite as a useful ceramic, from ilmenite concentrate, aluminum powder and carbon black has been investigated. Different amounts of FeTiO3, carbon black and Al powder were activated by a high-energy ball mill. Then the mixtures were synthesized by microwave heating at various times. The results of XRD investigation indicated that TiC has been synthesized within 5–10 min treatment microwave time. Moreover, it was found that by increasing the aluminum content, the Fe2O3 phase was replaced by SiC and Al2O3. In addition, from the broadening of the diffraction lines in the XRD patterns analysis, it was concluded that the TiC crystallites are nano-sized. Also, it was found that the existence of Al lead to increased grain size and decrease of the strain in the process.

  1. Organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides with intercalated phacolysin as ocular delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhiguo; Zhang, Jie; Chi, Huibo; Cao, Feng, E-mail: cpufengc@163.com [China Pharmaceutical University, Department of Pharmaceutics, School of Pharmacy (China)

    2015-12-15

    This study was mainly aimed to evaluate the potential use of a novel ocular drug delivery system, organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides (LDH). Organic polymers of chitosan–glutathione (CG) and pre-activated chitosan–glutathione (CG-2MNA) were successfully synthesized and characterized. LDH with intercalated phacolysin (PCL), including larger hexagonal LDH–PCL (Lh-LDH–PCL), larger spherical LDH–PCL (Ls-LDH–PCL), smaller hexagonal LDH–PCL (Sh-LDH–PCL), CG hybrid LDH–PCL (LDH–PCL-CG), and CG-2MNA hybrid LDH–PCL (LDH–PCL-CG-2MNA), were prepared. The nanocomposites with particle size of 107.2–274.9 nm were characterized by powder X-ray diffraction, Fourier transform infrared, transmission electron micrographs, etc. In vivo precorneal retention studies showed that the detectable time of all nanocomposites was prolonged from 2 to 6 h in comparison to PCL saline. Accordingly, the AUC{sub 0–6h} values of Lh-LDH–PCL, Ls-LDH–PCL, Sh-LDH–PCL, LDH–PCL-CG, and LDH–PCL-CG-2MNA nanocomposites were increased by 2.27-, 2.08-, 3.08-, 4.67-, and 3.36-fold, respectively. The Draize test and hematoxylin and eosin staining demonstrated that modified LDH had no eye irritation after single and repeated administration. These results indicated that chitosan derivatives-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs.Graphical AbstractThiolated chitosan-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs and may facilitate penetration of drugs into tissues of the eyes.

  2. Silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles as antibacterial/antifungal coatings for monumental stones

    Energy Technology Data Exchange (ETDEWEB)

    Aflori, Magdalena [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); Simionescu, Bogdana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); “Costin D. Nenitescu” Centre of Organic Chemistry, 202B Splaiul Independentei, 7114 Bucharest (Romania); Bordianu, Irina-Elena; Sacarescu, Liviu; Varganici, Cristian-Dragos; Doroftei, Florica; Nicolescu, Alina [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); Olaru, Mihaela, E-mail: olaruma@icmpp.ro [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2013-11-20

    Highlights: • Synthesis of nanocomposites with noble metals having high antibacterial efficiency. • Silver nanoparticles antibacterial activity for monumental stone conservation. • A high antibacterial activity while assuring good stone protection. -- Abstract: The present paper reports on the evaluation of two silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles aimed as antibacterial coatings for monumental stones. Sol–gel reaction of titanium isopropoxide and/or 3-(trimethoxysilyl)propyl methacrylate, in the presence of silver nitrate and a primary amine surfactant, yielded new types of hybrid nanocomposites with high antibacterial/antifungal efficacy. Different polymer behaviours regarding a frequently used monumental stone originating from Romania were evidenced through Fourier-transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) technique. Conclusions regarding the stones acid-resistant character and lower influence of salt weathering on its durability, as well as a better protective coating containing titania units were revealed.

  3. Reusable nanocomposite of CoFe2O4/chitosan-graft-poly(acrylic acid) for removal of Ni(II) from aqueous solution

    Science.gov (United States)

    Nguyen, Van Cuong; Huynh, Thi Kim Ngoc

    2014-06-01

    In this paper, CoFe2O4/chitosan-graft-poly(acrylic acid) (CoFe2O4/CS-graft-PAA) nanocomposites were prepared successfully by coprecipitation of the compounds in alkaline solution and were used for removal of nickel (II) ions from aqueous solution. The sorption rate was affected significantly by the initial concentration of the solution, sorbent amount, and pH value of the solution. Batch experiments were conducted to investigate the adsorption capacity under different initial concentration (ranging from 25 to 150 mg L-1), solution pH (4.1, 5.3, 6.4 and 7.6), and contact time. These nanocomposites can be recycled conveniently from water with the assistance of an external magnet because of their exceptional properties. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray powder diffraction (XRD), and thermogravimetric analysis (TGA).

  4. 21 CFR 73.1646 - Bronze powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  5. Effective Optical Properties of Plasmonic Nanocomposites

    Directory of Open Access Journals (Sweden)

    Christoph Etrich

    2014-01-01

    Full Text Available Plasmonic nanocomposites find many applications, such as nanometric coatings in emerging fields, such as optotronics, photovoltaics or integrated optics. To make use of their ability to affect light propagation in an unprecedented manner, plasmonic nanocomposites should consist of densely packed metallic nanoparticles. This causes a major challenge for their theoretical description, since the reliable assignment of effective optical properties with established effective medium theories is no longer possible. Established theories, e.g., the Maxwell-Garnett formalism, are only applicable for strongly diluted nanocomposites. This effective description, however, is a prerequisite to consider plasmonic nanocomposites in the design of optical devices. Here, we mitigate this problem and use full wave optical simulations to assign effective properties to plasmonic nanocomposites with filling fractions close to the percolation threshold. We show that these effective properties can be used to properly predict the optical action of functional devices that contain nanocomposites in their design. With this contribution we pave the way to consider plasmonic nanocomposites comparably to ordinary materials in the design of optical elements.

  6. Flake tantalum powder for manufacturing electrolytic capacitors

    Institute of Scientific and Technical Information of China (English)

    HE Jilin; YANG Guoqi; PAN Luntao; LIU Hongdong; BAO Xifang

    2008-01-01

    The FTP200 flake tantalum powder was introduced.The microstructures of the powder with leaf-like primary particles having an average flakiness of 2 to 20 and porous agglomerated particles were observed.The chemical composition,physical properties,and electrical properties of the FTP200 powder were compared with those of the FTW300 nodular powder.The FTP200 powder is more sinter-resistant,and the surface area of the flake tantalum powder under sintering at high temperature has less loss than that of the nodular tantalum powder.The specific capacitance of the flake tantalum powder is higher than that of the nodular tantalum powder with the same surface area when anodized at high voltage,Thus,the flake tantalum powder is suitable for manufacturing tantalum solid electrolytic capacitors in the range of median and high (20-63 V) voltages.

  7. Designing CAF-adjuvanted dry powder vaccines: Spray drying preserves the adjuvant activity of CAF01

    DEFF Research Database (Denmark)

    Ingvarsson, Pall Thor; Schmidt, Signe Tandrup; Christensen, Dennis

    2013-01-01

    spray drying. The optimal excipient to stabilize CAF01 during spray drying and for the design of nanocomposite microparticles was identified among mannitol, lactose and trehalose. Trehalose and lactose were promising stabilizers with respect to preserving liposome size, as compared to mannitol......Dry powder vaccine formulations are highly attractive due to improved storage stability and the possibility for particle engineering, as compared to liquid formulations. However, a prerequisite for formulating vaccines into dry formulations is that their physicochemical and adjuvant properties...... remain unchanged upon rehydration. Thus, we have identified and optimized the parameters of importance for the design of a spray dried powder formulation of the cationic liposomal adjuvant formulation 01 (CAF01) composed of dimethyldioctadecylammonium (DDA) bromide and trehalose 6,6′-dibehenate (TDB) via...

  8. Nanocomposite of CeO{sub 2} and ZnO: An active material for the treatment of contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Japinder; Bhukal, Santosh; Gupta, Kanu [Department of Chemistry, Panjab University, Chandigarh, 160014 (India); Tripathy, Mukesh [Icon Analytical Equipment (P) Ltd., New Delhi (India); Bansal, Sandeep [Department of Science and Technology, New Delhi (India); Singhal, Sonal, E-mail: sonal1174@gmail.com [Department of Chemistry, Panjab University, Chandigarh, 160014 (India)

    2016-07-01

    A series of catalytically active CeO{sub 2}/ZnO nanocomposites with different molar ratio (CeO{sub 2}: 1, 2, 3, 4, 5 and 6 mol%) were successfully synthesized by hydrothermal method. The synthesized nanocomposites were critically investigated using Powder X-ray diffraction technique, Transmission electron microscopy, Selected area electron diffraction and UV–vis diffused reflectance spectra analysis. Powder X-ray diffraction spectra revealed the presence of diffraction peaks of face-centered cubic phase of CeO{sub 2} and hexagonal wurtzite phase of ZnO. Transmission electron microscopic analysis revealed that nanocomposites consist of ZnO nanorods and CeO{sub 2} nanoparticles; where, CeO{sub 2} nanoparticles were clinging on the surface of ZnO nanorods. UV–vis diffused reflectance spectra analysis revealed the good absorption of all the samples towards UV light. The photocatalytic efficiency of CeO{sub 2}, ZnO and CeO{sub 2}/ZnO was compared by using methylene blue dye as probe molecule. CeO{sub 2}/ZnO nanocomposites were found to possess superior photocatalytic activity as compared to their monocomponent counterparts. Furthermore, CeO{sub 2}/ZnO with 5 mol% CeO{sub 2} presented best photocatalytic performance. Additionally, influence of different process variables on the rate of degradation of methylene blue was investigated using CeO{sub 2}/ZnO with 5 mol% CeO{sub 2} as catalyst. Maximum degradation of methylene blue was observed in alkaline region at a catalyst dosage of 1.00 g/L. - Highlights: • CeO{sub 2}/ZnO nanocomposites were fabricated using hydrothermal method. • Photocatalytic efficiency of CeO{sub 2}/ZnO nanocomposites was compared with their monocomponent counterparts. • Experimental conditions were optimized for the degradation of methylene blue dye. • CeO{sub 2}/ZnO nanocomposite proved to be a better candidate for the photocatalytic degradation of dye.

  9. Applications of nano-composite materials for improving the performance of anode-supported electrolytes of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Jin; Moon, Hwan; Park, Hae-Gu; Yoon, Dae Il; Hyun, Sang-Hoon [School of Advanced Materials Science and Engineering, Yonsei Univ., Seoul 120-749 (Korea)

    2010-01-15

    In order to improve the performance of the anode-supported electrolyte of solid oxide fuel cells (SOFCs), the anode electrode is modified by inserting an anode functional layer of nano-composite powders between a Ni-YSZ electrode and YSZ electrolyte. The NiO-YSZ nano-composite powders are fabricated by coating nano-sized Ni and YSZ particles on the YSZ core particle by the Pechini process. The reduction of the polarization resistance of a single cell that is applied to the anode functional layer is attributed to the increasing reaction of three-phase boundaries (TPBs) within the layer and the micro-structured uniformity in the electrode. Two methods were used, namely tape-casting/dip-coating and tape-casting/co-firing, for studying the performance. It can be concluded that the cell with an anode functional layer thickness (15-20 {mu}m) and a microstructure of NiO-YSZ nano-composite materials which was fabricated by the tape-casting/dip-coating method improved the output power (to 1.3 W cm{sup -2}) at 800 C using hydrogen as fuel and air as an oxidant. (author)

  10. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed

    2015-11-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  11. A novel shape transformation of Fe MgO nanocomposites: microstructural, magnetic and hyperfine investigations

    Science.gov (United States)

    Mukherjee, S.; Kumar, S.; Das, D.

    2007-08-01

    Fe-MgO nanocomposites synthesized by the mechanical high-energy transfer technique were characterized by x-ray diffraction (XRD), transmission electron microscopy, Mössbauer spectroscopy and dc magnetization studies. By varying the duration of milling, powder with different grain sizes in the range 17-40 nm was produced. XRD and Mössbauer measurements could not detect the presence of any form of iron oxide in the nanocomposites. Transmission electron micrographs showed a shape transformation from spherical to acicular-like geometry in the samples ball milled for more than 36 h. Dc magnetization measurements show an increase in the coercive field with decrease in average grain size, with a sharp increase at the point of shape transformation. A marked decrease from the expected values of saturation magnetization and magnetic moment per formula unit was observed. This decrease was ascribed to the magnetic dead layer formed at the surface of the nanoparticles, which increased with the increase in milling time. The nanocomposites ball milled for more than 36 h exhibit a two-component Mössbauer spectra due to the presence of two phases: a crystalline phase and an additional phase corresponding to the atoms residing at the grain boundaries between the crystallites. The grain boundaries give rise to a distribution of hyperfine magnetic fields, typical of an amorphous-like compound.

  12. A novel shape transformation of Fe-MgO nanocomposites: microstructural, magnetic and hyperfine investigations

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700 098 (India); Kumar, S [Department of Physics, Jadavpur University, Kolkata 700 032 (India); Das, D [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700 098 (India)

    2007-08-07

    Fe-MgO nanocomposites synthesized by the mechanical high-energy transfer technique were characterized by x-ray diffraction (XRD), transmission electron microscopy, Moessbauer spectroscopy and dc magnetization studies. By varying the duration of milling, powder with different grain sizes in the range 17-40 nm was produced. XRD and Moessbauer measurements could not detect the presence of any form of iron oxide in the nanocomposites. Transmission electron micrographs showed a shape transformation from spherical to acicular-like geometry in the samples ball milled for more than 36 h. Dc magnetization measurements show an increase in the coercive field with decrease in average grain size, with a sharp increase at the point of shape transformation. A marked decrease from the expected values of saturation magnetization and magnetic moment per formula unit was observed. This decrease was ascribed to the magnetic dead layer formed at the surface of the nanoparticles, which increased with the increase in milling time. The nanocomposites ball milled for more than 36 h exhibit a two-component Moessbauer spectra due to the presence of two phases: a crystalline phase and an additional phase corresponding to the atoms residing at the grain boundaries between the crystallites. The grain boundaries give rise to a distribution of hyperfine magnetic fields, typical of an amorphous-like compound.

  13. Nanoindentation studies of ex situ AlN/Al metal matrix nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fale, Sandeep; Likhite, Ajay; Bhatt, Jatin, E-mail: jatinbhatt@mme.vnit.ac.in

    2014-12-05

    Highlights: • Formation of in-situ phases nucleated on AlN particles strengthens the matrix. • Formation of in-situ phases increases with AlN content in nanocomposites. • Stronger in-situ phases results in increased hardness and modulus of elasticity. - Abstract: Nanocrystalline Aluminium nitride (AlN) powder is dispersed in different weight ratio in Aluminum matrix to fabricate metal matrix nanocomposite (MMNC) using ex situ melt metallurgy process. The synthesized Al–AlN nanocomposites are studied for phase analysis using high resolution scanning electron microscopy (FEG-SEM) and for hardness behavior using microindentation and nanoindentation tests. Quantitative analysis of the oxide phases is calculated from thermodynamic data and mass balance equation using elemental data obtained from energy dispersive spectroscopy (EDS) results. Role of oxide phases in association with AlN particles is investigated to understand the mechanical behavior of composites using nanoindentation tester. Load–displacement profile obtained from nanoindentation test reveals distribution of oxide phases along with AlN particle and their effect on indent penetration.

  14. Thermally Sprayable Anti-corrosion Marine Coatings Based on MAH-g-LDPE/UHMWPE Nanocomposites

    Science.gov (United States)

    Jeeva Jothi, K.; Santhoskumar, A. U.; Amanulla, Syed; Palanivelu, K.

    2014-12-01

    Polymer composite coatings based on low-density polyethylene (LDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) blends were prepared for marine coatings. The incorporation of carboxyl moiety in the polymer blends of LDPE/UHMWPE was carried out by grafting with maleic anhydride (MAH) at varying concentrations of 1-8 wt.% using reactive extrusion process. An optimum percentage of grafting of 2.1% was achieved with 5 wt.% of maleic anhydride. Further, the nanocomposites of MAH-grafted-LDPE/UHMWPE blends were prepared by incorporating cloisite 15A nanoclay at varying concentrations of 1-4 wt.%. The polymer nanocomposites were converted into fine powders suitable for thermal spray having ≤200 μ particle size using cryogenic grinding. The effect of the intact coatings applied on grit-blasted mild steel by thermal spray technique was evaluated for abrasion resistance, adhesion strength, and corrosion resistance. The corrosion resistance of the polymer nanocomposites was studied by salt spray technique and Electrochemical Impedance Spectroscopy The abrasion resistance of coatings increases with increasing UHMWPE content in the blends. However, blends with higher concentration of UHMWPE resulted in coarse coatings with poor adhesion. The coatings with 90:10 MAH-grafted-LDPE/UHMWPE having 3 wt.% of nanoclay showed good abrasion resistance, adhesion strength, and better corrosion resistance.

  15. Thermoelectric Properties of Self Assemble TiO2/SnO2 Nanocomposites

    Science.gov (United States)

    Dynys, Fred; Sayir, Ali; Sehirlioglu, Alp

    2008-01-01

    Recent advances in improving efficiency of thermoelectric materials are linked to nanotechnology. Thermodynamically driven spinodal decomposition was utilized to synthesize bulk nanocomposites. TiO2/SnO2 system exhibits a large spinodal region, ranging from 15 to 85 mole % TiO2. The phase separated microstructures are stable up to 1400 C. Semiconducting TiO2/SnO2 powders were synthesized by solid state reaction between TiO2 and SnO2. High density samples were fabricated by pressureless sintering. Self assemble nanocomposites were achieved by annealing at 1000 to 1350 C. X-ray diffraction reveal phase separation of (Ti(x)Sn(1-x))O2 type phases. The TiO2/SnO2 nanocomposites exhibit n-type behavior; a power factor of 70 (mu)W/m sq K at 1000 C has been achieved with penta-valent doping. Seebeck, thermal conductivity, electrical resistivity and microstructure will be discussed in relation to composition and doping.

  16. Influence of compositional variation on electrical properties of PANI/SnO{sub 2} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chaturmukha, V. S.; Avinash, B. S.; Naveen, C. S.; Rajeeva, M. P.; Harish, B. M.; Suresha, S.; Jayanna, H. S.; Lamani, Ashok R., E-mail: ashok1571972@gmail.com [Department of PG Studies and Research in Physics, Kuvempu University, Shankaraghatta-577451, Shimoga, Karnataka (India); Prasanna, G. D. [Department of Engineering Physics, GMIT, Davangere-577006, Karnataka (India)

    2016-05-06

    Conducting polyaniline/tin oxide (PANI/SnO{sub 2}) nanocomposites have been successfully synthesized by in-situ polymerization technique. The PANI/SnO{sub 2} nanocomposites of different compositions were prepared by varying weight percentage of SnO{sub 2} nanoparticles such as 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% into the fixed amount of the aniline monomer. The prepared powder samples were characterized by X-ray diffractometer (XRD), Fourier Transform Infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM). The intensity of diffraction peaks for PANI/SnO{sub 2} composites is increases with increasing SnO{sub 2} wt%. SEM observation showed that the prepared SnO{sub 2} nanoparticles were uniformly dispersed and highly stabilized throughout the macromolecular chain that formed a uniform metal-polymer nanocomposite material. AC electrical conductivity and dielectric properties were studied in the frequency range of 1 KHz -1 MHz. At higher frequencies, the composites exhibit almost zero dielectric loss and maximum value of AC electrical conductivity (σ{sub ac}) of 0.21 S/m is found for a concentration of 30 wt% of SnO{sub 2} in polyaniline.

  17. Thermoelectric Properties of Self Assembled TiO2/SnO2 Nanocomposites

    Science.gov (United States)

    Dynys, Fred; Sayir, Ali; Sehirlioglu, Alp

    2008-01-01

    Recent advances in improving efficiency of thermoelectric materials are linked to nanotechnology. Thermodynamically driven spinodal decomposition was utilized to synthesize bulk nanocomposites. TiO2/SnO2 system exhibits a large spinodal region, ranging from 15 to 85 mole % TiO2. The phase separated microstructures are stable up to 1400 C. Semiconducting TiO2/SnO2 powders were synthesized by solid state reaction between TiO2 and SnO2. High density samples were fabricated by pressureless sintering. Self assemble nanocomposites were achieved by annealing at 1000 to 1350 C. X-ray diffraction reveal phase separation of (Ti(x)Sn(1-x))O2 type phases. The TiO2/SnO2 nanocomposites exhibit n-type behavior; a power factor of 70 W/mK2 at 1000 C has been achieved with penta-valent doping. Seebeck, thermal conductivity, electrical resistivity and microstructure will be discussed in relation to composition and doping.

  18. Highly anisotropic conductivity of tablets pressed from polyaniline-montmorillonite nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Tokarský, Jonáš, E-mail: jonas.tokarsky@vsb.cz [Nanotechnology centre, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); IT4Innovations Centre of Excellence, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Kulhánková, Lenka [Faculty of Metallurgy and Materials Engineering, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Neuwirthová, Lucie; Mamulová Kutláková, Kateřina [Nanotechnology centre, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Vallová, Silvie [Faculty of Metallurgy and Materials Engineering, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Stýskala, Vítězslav [Faculty of Electrical Engineering and Computer Science, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Čapková, Pavla [Faculty of Science, University of J.E. Purkyně, České mládeže 8, 400 96 Ústí nad Labem (Czech Republic)

    2016-03-15

    Highlights: • Montmorillonite (MMT) can be intercalated with polyaniline (PANI) chains. • Tablets pressed from PANI/MMT exhibit high anisotropy in electrical conductivity. • Pressure 28MPa is sufficient to reach the anisotropy. • Tablets pressed from pure PANI also exhibit anisotropy in electrical conductivity. - Abstract: Polyaniline-montmorillonite nanocomposite was prepared from anilinium sulfate (precursor) and ammonium peroxodisulfate (oxidizing agent) using simple one-step method. The resulting nanocomposite obtained in powder form has been pressed into tablets using various compression pressures (28–400 MPa). Electrical conductivities of tablets in two perpendicular directions, i.e. direction parallel with the main surface of tablet (σ=) and in orthogonal direction (σ⊥), and corresponding anisotropy factors (i.e., the ratio σ=/σ⊥) have been studied in dependence on compression pressure used during the preparation. Polyaniline-montmorillonite nanocomposite was characterized using X-ray diffraction analysis, raman spectroscopy, transmission electron microscopy, thermogravimetric analysis and molecular modeling which led to the understanding of the internal structure. Measurement of hardness performed on pressed tablets has been also involved. Taking into account the highest value of anisotropy factor reached (σ=/σ⊥ = 490), present study shows a chance to design conductors with nearly two-dimensional conductivity.

  19. Thermal and mechanical properties of reduced graphene oxide/polyurethane nanocomposite.

    Science.gov (United States)

    Pokharel, Pashupati; Lee, Dai Soo

    2014-08-01

    Reduced graphene oxide (RGO) based polyurethane (PU) nanocomposites have been successfully prepared without using solvent by in-situ polymerization. RGO was derived from microwave (MW) irradiation of graphite oxide (GO) powder prepared by a modified Hummer's method. A minimum amount of poly(tetramethylene glycol) (PTMEG) was added during the dispersion of RGO in a solvent to stabilize the graphene sheets and to prevent RGO from the restacking after the removal of the solvent. After the reaction of RGO with 4,4'-diphenylmethane diisocyanate (MDI), we obtained the concentrate of RGO in MDI with a minimum amount of PTMEG. Our method facilitated the fine dispersion of RGO in PU elastomers and improved the interfacial strength between RGO and PU. With the incorporation of 2.0 wt% of RGO, the tensile strength and Young's modulus of the PU nanocomposites increased by 30% and 50%, respectively without sacrificing the elongation at break. It was found that the crystalline portion of hard segments of the PU was lowered by the RGO in the nanocomposites.

  20. Interphase and magnetotransport of LSMO-PMMA nanocomposites obtained by a sonochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Mariano [Centro NanoMat/Cryssmat Lab/Cátedra de Física – DETEMA – Facultad de Química – Universidad de la República (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales – Universidad de la República (Uruguay); Pardo, Helena, E-mail: hpardo@fq.edu.uy [Centro NanoMat/Cryssmat Lab/Cátedra de Física – DETEMA – Facultad de Química – Universidad de la República (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales – Universidad de la República (Uruguay); Faccio, Ricardo [Centro NanoMat/Cryssmat Lab/Cátedra de Física – DETEMA – Facultad de Química – Universidad de la República (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales – Universidad de la República (Uruguay); Tumelero, Milton A. [Laboratorio de filmes finos e superficies – Departamento de Física – Universidad Federal de Santa Catarina, Florianópolis (Brazil); and others

    2015-05-15

    In this report, we studied the structural, microstructural and compositional trends in a manganite-polymethylmethacrilate (LSMO-PMMA) nanocomposite prepared by a sonochemical method focusing in the study of its interphase and its correlation with magnetotransport. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Raman scattering and X-ray powder diffraction (XRPD) studies showed evidence of PMMA reactivity with partial decomposition at the LSMO nanoparticles interface. Additionally, grazing incidence small angle X-ray scattering (GISAXS) and high resolution transmission electron microscopy (HRTEM) showed information about the microstructure and the separation between nanoparticles in these nanocomposite materials. An enhancement in the low field magnetoresistance (LFMR) respect to pure LSMO was observed for a 20% weight fraction addition of PMMA in the high temperature regime (205–305 K) probably due to the increase in the magnetic disorder at the grain boundaries caused by the ultrasonic treatment. Nevertheless, lower PMMA weight fraction addition showed no enhancement in LFMR respect to pure LSMO, probably in agreement with the higher decomposition rate observed at the interphase. - Highlights: • We report the synthesis of LSMO-PMMA nanocomposites by a sonochemical method. • Compositional and microstructural trends were obtained from the interphase. • This method showed long-range homogeneity and enhancement of grain boundary disorder. • The enhancement on the LFMR respect to pure manganite was obtained at higher temperatures.

  1. Experimental Preparation and Numerical Simulation of High Thermal Conductive Cu/CNTs Nanocomposites

    Directory of Open Access Journals (Sweden)

    Muhsan Ali Samer

    2014-07-01

    Full Text Available Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu reinforced by multi-walled carbon nanotubes (CNTs up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

  2. Low-temperature Magnesiothermic Synthesis of Mesoporous Silicon Carbide from an MCM-48/Polyacrylamide Nanocomposite Precursor

    Institute of Scientific and Technical Information of China (English)

    Zahra Saeedifar; Amir Abbas Nourbakhsh; Roozbeh Javad Kalbasi; Ebrahim Karamian

    2013-01-01

    Mesoporous silicon carbide with high specific surface area was successfully synthesized from an MCM-48/polyacrylamide nanocomposite precursor in the temperature range of 550-600 ℃ (below the melting point of Mg) by means of a magnesiothermic reduction process.The MCM-48/polyacrylamide precursor nanocomposite was prepared by in-situ polymerization of acrylamide monomer in the presence of mesoporous MCM-48 synthesized by sol-gel method.The physicochemical properties and microstructures of the nanocomposite precursor and the low-temperature SiC product were characterized by X-ray diffraction (XRD),differential scanning calorimetry-thermo gravimetric analysis (DSC-TGA),transmission electron microscopy (TEM) and N2 adsorption-desorption.TEM micrographs and Brunauer-Emmett-Teller (BET) gas adsorption studies showed that the SiC powder was nanocrystalline and had a specific surface area of 330 m2/g and a mesoporosity in the range of 2-10 nm.The presence of an exothermic peak in the DSC trace corresponds to the self-combustion process of the SiC magnesiothermic synthesis.The results also show that the carbon in excess to that required to produce SiC plays a role in the reduction of the SiO2.The mechanism of magnesiothermic synthesis of mesoporous SiC is discussed.

  3. Electromagnetic wave absorbing characteristics of synthetized barium strontium titanate/polyaniline nanocomposites

    Science.gov (United States)

    Mulyani, O.; Hafizah, M. A. E.; Manaf, A.

    2017-07-01

    In this paper, electromagnetic wave absorbing characteristics of electrically conductive composites consisted of polyaniline (PANi) and nanoparticles of barium strontium titanate (BST) is described. The BST nanoparticles were synthesized by the mechanical alloying method and successive particle size reduction steps through high frequency ultrasonic irradiation treatments. Whereas polyaniline was produced by oxidative polymerization processes which allows efficient control of the dielectric properties. Mechanical alloying combined with ultrasonic irradiation treatments has resulted in BST powders with a mean particle size of a few nanometers (less than 100 nm). Such ultra-fine particles of BST were then used to synthesize the BST/PANi nanocomposites with 20:80, 50:50 and 80:20 compositions. The physical properties like particle sizes, dielectric constant, electromagnetic absorption characteristics are investigated by X-Ray Diffractometer, Fourier Transform Infrared, and Vector Network Analyzer. It was found that BST/polyaniline nanocomposite can enhance main properties of the electromagnetic absorber. The high dielectric constant of BST and conductivity of polyaniline support nanocomposite BST/polyaniline as electromagnetic absorber materials.

  4. Pilot Study on the Nano-Composites Coats of Radar Wave's Absorption

    Institute of Scientific and Technical Information of China (English)

    HU Chuan-xin; ZhANG Lei; GAN Ai-feng; LI Wan-zhi; LIANG Wen-ting; ZHANG Chen-jia

    2004-01-01

    This thesis mainly introduced the guiding principle and physical model of the research on the nano-composites coats of radar wave's absorption, and then studied the qualitative analysis of the performance ameliorating of radar wave's absorption composite coats. And on the basis of the optimum design of multilayer wave's absorption materials, two new kinds of radar wave's absorption composite coats have been made, which are composed of nano-composites hydroxyl iron powder and hollow micro-sphere. The research indicated that the surface-density of these two new composite coats is less than 3.5 Kg/m2.The coats' thickness is about 1 mm. And the waves absorption capability is above the level of 5 db, in the range of 3 ~ 18GHz. Therefore the wave's absorption performance of these two new coats is better than nano-crystalloid in low frequency area. The pilot study has proved that the nano-composites coat's performance of radar wave's absorption excels the ordinary radar wave's absorption coats, so it needs to be further studied.

  5. Three-Dimensional Printing of Multifunctional Nanocomposites: Manufacturing Techniques and Applications.

    Science.gov (United States)

    Farahani, Rouhollah D; Dubé, Martine; Therriault, Daniel

    2016-07-01

    The integration of nanotechnology into three-dimensional printing (3DP) offers huge potential and opportunities for the manufacturing of 3D engineered materials exhibiting optimized properties and multifunctionality. The literature relating to different 3DP techniques used to fabricate 3D structures at the macro- and microscale made of nanocomposite materials is reviewed here. The current state-of-the-art fabrication methods, their main characteristics (e.g., resolutions, advantages, limitations), the process parameters, and materials requirements are discussed. A comprehensive review is carried out on the use of metal- and carbon-based nanomaterials incorporated into polymers or hydrogels for the manufacturing of 3D structures, mostly at the microscale, using different 3D-printing techniques. Several methods, including but not limited to micro-stereolithography, extrusion-based direct-write technologies, inkjet-printing techniques, and popular powder-bed technology, are discussed. Various examples of 3D nanocomposite macro- and microstructures manufactured using different 3D-printing technologies for a wide range of domains such as microelectromechanical systems (MEMS), lab-on-a-chip, microfluidics, engineered materials and composites, microelectronics, tissue engineering, and biosystems are reviewed. Parallel advances on materials and techniques are still required in order to employ the full potential of 3D printing of multifunctional nanocomposites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Preparation of Pt-Re/Vulcan carbon nanocomposites using a single-source molecular precursor and relative performance as a direct methanol fuel cell electrooxidation catalyst.

    Science.gov (United States)

    Anderson, Angela D; Deluga, Gregg A; Moore, Joshua T; Vergne, Matthew J; Hercules, David M; Kenik, Edward A; Lukehart, C M

    2004-09-01

    Pt-Re/Vulcan carbon powder nanocomposites have been prepared with total metal loadings of 18 wt.% and 40 wt.% using a new non-cluster (1:1)-PtRe bimetallic precursor as the source of metal. Pt-Re nanoparticles having an average diameter of ca. 6 nm and atomic stoichiometry near 1:1 are formed. TEM, on-particle HR-EDS, and powder XRD data are consistent with the formation of Pt-Re alloy nanoparticles having a hexagonal unit cell with cell constants of a = 2.77 A and c = 4.47 A. A nanocomposite prepared at higher total metal loading under more rigorous thermal treatment also contains Pt-Re alloy nanoparticles having a fcc unit cell structure (a = 3.95 A). The precise dependence of Pt-Re nanocrystal structure on the thermal history of the nanocomposite specimen has not been investigated in detail. While these Pt-Re/carbon nanocomposites are active as anode catalysts in operating direct methanol fuel cells, the measured performance is less than that of commercial Pt-Ru/carbon catalysts and has marginal practical importance.

  7. Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Alfredo Márquez-Herrera

    2016-01-01

    Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

  8. Structural and optical properties of CdO/ZnS core/shell nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Joyce Stella, R.; Thirumala Rao, G.; Pushpa Manjari, V.; Babu, B. [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar 522510, A.P. (India); Rama Krishna, Ch. [Division of Advanced Materials Science & Engineering, Chonbuk National University, 567, Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Ravikumar, R.V.S.S.N., E-mail: rvssn@yahoo.co.in [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar 522510, A.P. (India)

    2015-04-15

    Graphical abstract: Powder X-ray diffraction pattern of CdO nanopowder and CdO/ZnS nanocomposites. XRD pattern of prepared samples confirm the predominant phase is CdO and small, broad peaks show the ZnS phase in nanocomposites. This XRD data is indexed to cubic crystal system and lattice parameter is calculated as a = 4.6916 Å. After the deposition of ZnS, small blue diffraction peaks are observed for cubic CdO nanostructures. The corresponding lattice cell parameters are evaluated as a = 4.6910 for CdO and a = 5.3735 Å for ZnS. After formation of the CdO–ZnS nanocomposites, the peak intensities of CdO decrease and new peaks due to ZnS are observed. This supports the fact that ZnS particles are deposited on the surface of CdO. These results shows well agreement with standard diffraction data of JCPDS file No. 05-0640 for face centred cubic CdO and file No. 05-0566 for cubic ZnS. From this diffraction data crystallite size, strain and dislocation density are evaluated from Scherrer’s formula and Williamson and Hall. After the deposition of ZnS, increase in particle size and decrease in strain and dislocation density is observed. - Highlights: • CdO/ZnS core/shell nanocomposites were synthesized by a two step wet chemical method. • Powder XRD pattern confirms the cubic phase of the prepared materials. • Red shift is observed in PL spectrum after the deposition of ZnS. - Abstract: CdO/ZnS core/shell nanocomposites have been synthesised at room temperature by a simple wet chemical method. The prepared materials are characterized by XRD, SEM, EDS, FT-IR, UV–Vis and Photoluminescence studies. X-ray diffraction pattern exhibits peaks correspond to cubic phase of CdO and ZnS, the evaluated average crystallite size of prepared materials are in the range of 20–30 nm. The strain and dislocation density are also calculated from XRD studies. Morphology of the samples and their chemical composition are analysed by SEM with EDS. FT-IR spectrum shows the

  9. Synthesis of Vanadium-Vanadium Carbide in-situ nanocomposites by high energy ball milling and spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Krishnan Vinoadh Kumar

    2016-01-01

    Full Text Available In the present work, Vanadium-Vanadium Carbide (V-V2C in-situ nanocomposites were synthesized by mechanically milling vanadium powders with 0.5 wt.% stearic acid. Milled powders were consolidated using spark plasma sintering at 1150, 1250 and 1350°C for 10 min. Phase and morphology of the milled powders were studied using X-ray diffraction and scanning electron microscopy. X-ray diffraction analysis of 10 h milled powder shows the evolution of amorphous phase. Energy dispersive X-ray spectroscopy studies on milled powder shows the presence of carbon, which could be due to the decomposition of stearic acid during milling. Degree of crystallinity of milled powder was confirmed using the selective area electron diffraction pattern. X-ray diffraction analysis of sintered samples indicate sharp peaks from vanadium and vanadium carbide (V2C, endorsing amorphous to nanocrystalline transformation. Micro-hardness value of sintered samples increases with increasing sintering temperature.

  10. Powder lubrication of faults by powder rolls in gouge zones

    Science.gov (United States)

    Chen, X.; Madden, A. S.; Reches, Z.

    2013-12-01

    Powder-lubrication by fault gouge can be an effective mechanism of dynamic weakening of faults (Reches & Lockner, 2010); however, the physical mechanisms of this lubrication are poorly understood. While the flow of coarse-grained (> 100 μm) materials, e.g. glass beads or quartz sand, was extensively studied, the flow of fine-grained (nano-powders, have remained enigmatic. We report here experimental results of a new efficient mechanism for powder lubrication. We conducted friction tests on high-velocity rotary shear apparatus (Reches & Lockner, 2010). Two types of experimental faults were tested: (1) faults made of solid, igneous rocks (granite, tonalite and diorite); and (2) fault-zones made of 2-3 mm thick layer of granular materials (oolites, calcite or gypsum) sheared in a confined cell. We performed 21 runs with total slip of 0.14-13 m, normal stress of 1.2-14.5 MPa, slip velocity of 0.012-0.97 m/s. The ultra-microscopic (SEM and AFM) analysis of the experimental slip surfaces revealed two outstanding features in 17 out of the 21 experiments: (1) localized fault-slip along Principal Slip Zones (PSZs) that are composed of a dense, shiny, cohesive crust, 0.5-1 micron thick, that overlaid a porous substrate, and (2) elongated rolls composed of gouge-powder into three-dimensional structures of closely-packed powder grains, (20-50 nm in size). The rolls are cylindrical, 0.75-1.4 micron wide, and 1.7-30 micron long, with smooth outer surface, and laminated, concentric layers of compacted grains. The rolls were exclusively found on the PSZs. Many rolls were destroyed fracturing and smearing on the PSZ, suggesting that the rolls underwent a life cycle of formation and destruction. Significant macroscopic friction reduction was measured in experiments with observed rolls, and no (or minor) friction reduction in the four experiments without rolls. The final, reduced friction coefficients have a general reciprocal relation to the rolls surface coverage, suggesting that

  11. Propulsion and PWR Rapid Response Research and Development (R&R) Support: Delivery Order 0030: Study of Hot Deformation of Nanocomposite Rare Earth Magnets

    Science.gov (United States)

    2006-03-01

    date: 26 Apr 2006. 14. ABSTRACT High performance bulk anisotropic nanograin composite Nd2Fe14B /Fe and Nd2Fe14B /Fe-Co magnets were successfully...deformation, hybrid magnets, interface exchange coupling, nanocomposite, nanograin magnets, nanostructure, Nd2Fe14B , permanent magnets, powder coating...1 High-Performance Nanograin Composite Nd2Fe14B /α-Fe and Nd2Fe14B /Fe-Co Magnets 2 1.1 Magnets prepared by using powder blending technique 2

  12. Microstructure, Mechanical Properties, and Two-Body Abrasive Wear Behavior of Cold-Sprayed 20 vol.% Cubic BN-NiCrAl Nanocomposite Coating

    Science.gov (United States)

    Luo, Xiao-Tao; Yang, Er-Juan; Shang, Fu-Lin; Yang, Guan-Jun; Li, Chen-Xin; Li, Chang-Jiu

    2014-10-01

    20 vol.% cubic boron nitride (cBN) dispersoid reinforced NiCrAl matrix nanocomposite coating was prepared by cold spray using mechanically alloyed nanostructured composite powders. The as-sprayed nanocomposite coating was annealed at a temperature of 750 °C to enhance the inter-particle bonding. Microstructure of spray powders and coatings was characterized. Vickers microhardness of the coatings was measured. Two-body abrasive wear behavior of the coatings was examined on a pin-on-disk test. It was found that, in mechanically alloyed composite powders, nano-sized and submicro-sized cBN particles are uniformly distributed in nanocrystalline NiCrAl matrix. Dense coating was deposited by cold spray at a gas temperature of 650 °C with the same phases and grain size as those of the starting powder. Vickers hardness test yielded a hardness of 1063 HV for the as-sprayed 20 vol.% cBN-NiCrAl coating. After annealed at 750 °C for 5 h, unbonded inter-particle boundaries were partially healed and evident grain growth of nanocrystalline NiCrAl was avoided. Wear resistance of the as-sprayed 20 vol.% cBN-NiCrAl nanocomposite coating was comparable to the HVOF-sprayed WC-12Co coating. Annealing of the nanocomposite coating resulted in the improvement of wear resistance by a factor of ~33% owing to the enhanced inter-particle bonding. Main material removal mechanisms during the abrasive wear are also discussed.

  13. Electroactive functional hybrid layered nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Destri, Giovanni Li; Torrisi, Vanna; Marletta, Giovanni [Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN) - University of Catania and CSGI - Catania (Italy)

    2012-07-11

    Two methodologies to build new nanostructured hybrid layered nanocomposites are presented. The first one involves the preparation of hybrid metal/polymer nanolayers (NLs) by combining two monolayer preparation techniques: Horizontal Precipitation Langmuir Blodgett method (HP-ML), for copolymer monolayers and sputter deposition technique, for Au NLs deposition. The second methodology is aimed to prepare regular arrays of nanopores, with diameter ranging between 40-100 nm, in ultra-thin films of electroactive polymers, to obtain embedded regular arrays of nanopores filled by a further electroactive organic component. The produced hybrid MLs have been characterized by means of X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Grazing Incidence X-ray Diffraction (GI-XRD). In the first case, current-voltage (I-V) measurements demonstrate that the multilayers exhibit a bipolar conduction behaviour (electrons and holes carriers), with a peculiar transition in the nature of the majority carriers (from holes to electrons) above a threshold number of bilayers. In the second case, it is found that the degree of pore filling, as well as the polymer crystallinity can be easily modulated, prompting the tuning of the photoresponse of the nanocomposites.

  14. Light-Emitting Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Kyle Gipson

    2011-01-01

    Full Text Available Inorganic nanoparticles doped with optically active rare-earth ions and coated with organic ligands were synthesized in order to create fluorescent polymethyl methacrylate (PMMA nanocomposites. Two different aromatic ligands (acetylsalicylic acid, ASA and 2-picolinic acid, PA were utilized in order to functionalize the surface of Tb3+ : LaF3 nanocrystals. The selected aromatic ligand systems were characterized using infrared spectroscopy, thermal analysis, rheological measurements, and optical spectroscopy. Nanoparticles produced in situ with the PMMA contained on average 10 wt% loading of Tb3+ : LaF3 at a 6 : 1 La : Tb molar ratio and ~7 wt% loading of 4 : 1 La : Tb molar ratio for the PA and ASA systems, respectively. Measured diameters ranged from 457±176 nm to 150±105 nm which is indicative that agglomerates formed during the synthesis process. Both nanocomposites exhibited the characteristic Tb3+ emission peaks upon direct ion excitation (350 nm and ligand excitation (PA : 265 nm and ASA : 275 nm.

  15. Characterization of mechanically milled and spark plasma sintered Al2124-CNT nanocomposites

    Directory of Open Access Journals (Sweden)

    Saheb N.

    2015-01-01

    Full Text Available In the present work, ball milling and spark plasma sintering were used to develop Al2124-CNT nanocomposites. The effect of milling time on the grain size and lattice strain of the ball milled Al2124 alloy powder and the effect of sintering time and temperature on the grain size of the matrix in spark plasma sintered Al2124 alloy and CNT-reinforced Al2124 nanocomposites were investigated. The density and hardness of the developed materials were evaluated as functions of the sintering parameters. It was found that ball milling not only reduced the particle size of the Al2124 powder but also decreased the grain size of the α-aluminum phase to 50 nm and increased its lattice strain. A milling time of 6 hours was found to be the optimum time to reach a nanostructured α-aluminum matrix. The grain size of the α-aluminum phase in the sintered samples increased with increasing sintering temperature and time to reach maximum values at a sintering temperature of 500°C and a sintering time of 20 minutes. Although sintering led to grain growth, the grain size of the α-aluminium matrix remained in the nanometer range and did not exceed 150 nm. The relative density and hardness of the sintered samples increased with increasing sintering temperature and time to reach maximum values at a sintering temperature of 500°C and a sintering time of 20 minutes.

  16. Synthesis and characterization of silver/talc nanocomposites using the wet chemical reduction method

    Directory of Open Access Journals (Sweden)

    Kamyar Shameli

    2010-09-01

    Full Text Available Kamyar Shameli1, Mansor Bin Ahmad1, Wan Zin Wan Yunus1, Nor Azowa Ibrahim1, Majid Darroudi21Department of Chemistry, Faculty of Science, 2Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, Selangor, MalaysiaAbstract: In this study, silver nanoparticles (Ag-NPs were synthesized using the wet chemical reduction method on the external surface layer of talc mineral as a solid support. Silver nitrate and sodium borohydride were used as the silver precursor and reducing agent in talc. The talc was suspended in aqueous AgNO3 solution. After the absorption of Ag+ on the surface, the ions were reduced with NaBH4. The interlamellar space limits were without many changes (ds = 9.34–9.19 Aº; therefore, Ag-NPs formed on the exterior surface of talc, with dave = 7.60–13.11 nm in diameter. The properties of Ag/talc nanocomposites (Ag/talc-NCs and the diameters of the Ag-NPs prepared in this way depended on the primary AgNO3 concentration. The prepared Ag-NPs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared. These Ag/talc-NCs may have potential applications in the chemical and biological industries.Keywords: nanocomposites, silver nanoparticles, talc, powder X-ray diffraction, scanning electron microscopy

  17. Synthesis and characterization of ZnO-TiO2 nanocomposites and their application as photocatalysts

    Science.gov (United States)

    Habib, Md Ahsan; Shahadat, Md Tusan; Bahadur, Newaz Mohammed; Ismail, Iqbal M. I.; Mahmood, Abu Jafar

    2013-01-01

    Nanocomposite ZnO-TiO2 powders of varying ZnO/TiO2 molar ratios have been prepared from their salt/compound by heating at 600°C and 900°C and characterized using scanning electron microscope and X-ray diffraction techniques. The nanosized powders can decolorize/degrade brilliant golden yellow (BGY), an azo dye extensively used in textile industries, in water under solar irradiation. The effects of various parameters such as photocatalyst loading, molar ratio of ZnO/TiO2, pH of the solution, initial dye concentration, and irradiation time on the photodecolorization have been investigated. ZnO-TiO2 nanocomposite (6 g/L) in the molar ratio of 1:1 or 3:1, prepared at 900°C, can efficiently decolorize about 98% of 20 mg/L BGY at pH of about 7 by 2-h illumination in sunlight. The initial dye decolorization follows pseudo-first-order kinetics. Finally, trial experiments were done using real textile wastewater to find out the effectiveness of the photocatalysts to a more complex system.

  18. Preparation and Microstructure of Cu/Ti3SiC2 Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li; SHENG Wen-bin; CHEN Zong-min

    2006-01-01

    Mixed micron-sized Cu/Ti3SiC2 (vol5%) powder was mechanically milled using agate balls and zirconia balls separately. Then followed an examination of it with the FEI-SEM. The experimental results show that, distributed homogenously in Cu matrix, the Ti3SiC2 particles have a size of about 30-50 nm after milled with agate balls for 8 h, while it remains approximately unchanged after milled with zirconia balls. The microstructure of the mixture at different ball-milling stages was also studied. Bulks of Cu/Ti3SiC2 nano-composite were fabricated by hot pressing nano-sized Cu/Ti3SiC2 powder at the temperature of 1 073 K under 100 MPa. Then came an investigation of the effects of the particle size and agglomerate state of Ti3SiC2 as well as the microstructure of Cu/Ti3SiC2 nano-composite. It was found that the nano-sized Ti3SiC2 particles distribute evenly in copper.

  19. A facile synthesis of poly(3-octylthiophene)-titanium dioxide nanocomposite particles in supercritical CO2.

    Science.gov (United States)

    Yuvaraj, Haldorai; Woo, Min Hee; Park, Eun Ju; Gal, Yeong-Soon; Lim, Kwon Taek

    2008-09-01

    Poly(3-octylthiophene) (P3OT)-titanium dioxide (TiO2) nanocomposite powder where TiO2 was embedded with homogeneous dispersion was synthesized by in-situ chemical oxidative polymerization of 3-octylthiophene in the presence of TiO2 nanoparticles in supercritical carbon dioxide (scCO2), using ferric chloride as the oxidant. The synthesized materials could be obtained as dry powder upon venting of CO2 after the polymerization. The composites were subsequently characterized by FT-IR spectroscopy, transmission electron microscopy (TEM), X-ray diffraction studies (XRD), thermogravimetric analysis (TGA) and photoluminescence (PL). The incorporation of TiO2 in the composite was endorsed by FT-IR studies. TGA revealed enhanced thermal stability of P3OT/TiO2 nanocomposite compared to 3-octylthiophene. TEM analysis showed that well dispersed TiO2 nanoparticles in the polymer matrix. Photoluminescence quenching increased with increasing TiO2 concentration in the composite.

  20. Synthesis of silicon nanocomposite for printable photovoltaic devices on flexible substrate

    Science.gov (United States)

    Odo, E. A.; Faremi, A. A.

    2017-06-01

    Renewed interest has been established in the preparation of silicon nanoparticles for electronic device applications. In this work, we report on the production of silicon powders using a simple ball mill and of silicon nanocomposite ink for screen-printable photovoltaic device on a flexible substrate. Bulk single crystalline silicon was milled for 25 h in the ball mill. The structural properties of the produced silicon nanoparticles were investigated using X-ray diffraction (XRD) and transmission electron microscopy. The results show that the particles remained highly crystalline, though transformed from their original single crystalline state to polycrystalline. The elemental composition using energy dispersive X-ray florescence spectroscopy (EDXRF) revealed that contamination from iron (Fe) and chromium (Cr) of the milling media and oxygen from the atmosphere were insignificant. The size distribution of the nanoparticles follows a lognormal pattern that ranges from 60 nm to about 1.2 μm and a mean particle size of about 103 nm. Electrical characterization of screen-printed PN structures of the nanocomposite formed by embedding the powder into a suitable water-soluble polymer on Kapton sheet reveals an enhanced photocurrent transport resulting from photo-induced carrier generation in the depletion region with energy greater that the Schottky barrier height at the metal-composite interface.

  1. Fabrication and Characterization of AL-AL4C3 Nanocomposite by Mechanical Alloying

    Science.gov (United States)

    Mohammad Sharifi, E.; Enayati, M. H.; Karimzadeh, F.

    Aluminum carbide (Al4C3) seems to be an ideal reinforcement for producing aluminum matrix composites. Al4C3 has high hardness and shear strength as well as a high melting point. The dispersion of Al4C3 particles in the matrix produces a pinning effect that reduces aluminum grain growth, which improves the mechanical properties. In this study, aluminum powders were mixed with 4.5 wt.% graphite and mechanically alloyed using a high-energy ball mill in order to produce Al-Al4C3 nanocomposite. The structural evaluation of powder particles after different milling times was studied by X-ray diffractometry, scanning electron microscopy and microhardness measurements. The aluminum crystallite size estimated with broadening of XRD peaks by Williamson-Hall formula. XRD results suggested that the grain size of aluminum decreased to nanometer range (30 nm) during ball milling. No Al4C3 formed during the mechanical alloying process. Milled powders were then annealed at 300-600 °C for 1 h under argon atmosphere. Annealing at temperatures higher than 300 °C led to formation of Al4C3 phase which increased as annealing temperature increased. Aluminum grain size remained in nanometer range after annealing process. The microhardness of powder particles increased after annealing. Both effects are due to the formation of nanosized Al4C3 particles.

  2. Large-Strain Transparent Magnetoactive Polymer Nanocomposites

    Science.gov (United States)

    Meador, Michael A.

    2012-01-01

    A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer (TPU) matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films (0.1-2 wt%) were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.

  3. Electrical conduction of a XLPE nanocomposite

    Science.gov (United States)

    Park, Yong-Jun; Sim, Jae-Yong; Lim, Kee-Joe; Nam, Jin-Ho; Park, Wan-Gi

    2014-07-01

    The resistivity, breakdown strength, and formation of space charges are very important factors for insulation design of HVDC cable. It is known that a nano-sized metal-oxide inorganic filler reduces the formation of space charges in the polymer nanocomposite. Electrical conduction of cross-linked polyethylene(XLPE) nanocomposite insulating material is investigated in this paper. The conduction currents of two kinds of XLPE nanocomposites and XLPE without nano-filler were measured at temperature of 303 ~ 363 K under the applied electric fields of 10 ~ 50 kV/mm. The current of the nanocomposite specimen is smaller than that of XLPE specimen without nano-filler. The conduction mechanism may be explained in terms of Schottky emission and multi-core model.

  4. Polymer matrix nanocomposites for automotive structural components

    Science.gov (United States)

    Naskar, Amit K.; Keum, Jong K.; Boeman, Raymond G.

    2016-12-01

    Over the past several decades, the automotive industry has expended significant effort to develop lightweight parts from new easy-to-process polymeric nanocomposites. These materials have been particularly attractive because they can increase fuel efficiency and reduce greenhouse gas emissions. However, attempts to reinforce soft matrices by nanoscale reinforcing agents at commercially deployable scales have been only sporadically successful to date. This situation is due primarily to the lack of fundamental understanding of how multiscale interfacial interactions and the resultant structures affect the properties of polymer nanocomposites. In this Perspective, we critically evaluate the state of the art in the field and propose a possible path that may help to overcome these barriers. Only once we achieve a deeper understanding of the structure-properties relationship of polymer matrix nanocomposites will we be able to develop novel structural nanocomposites with enhanced mechanical properties for automotive applications.

  5. Mullins' effect in polymer/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Klitkou, Rasmus

    2012-01-01

    Abstract. Experimental data are reported on polypropylene/clay nanocomposites in uniaxial cyclic tensile tests at room temperature (oscillations between maximum strains and the zero minimum stress with maximum strains increasing monotonically with number of cycles). Observations reveal fading...

  6. A Multimodal Nanocomposite for Biomedical Imaging

    Science.gov (United States)

    Wu, Aiguo; Paunesku, Tatjana; Zhang, Zhuoli; Vogt, Stefan; Lai, Barry; Maser, Jörg; Yaghmai, Vahid; Li, Debiao; Omary, Reed A.; Woloschak, Gayle E.

    2013-01-01

    A multimodal nanocomposite was designed, synthesized with super-paramagnetic core (CoFe2O4), noble metal corona (Au), and semiconductor shell (TiO2). The sizes of core, core-corona, and core-corona-shell particles were determined by TEM. This multimodal nanocrystal showed promise as a contrast agent for two of the most widely used biomedical imaging techniques: magnetic resonance imaging (MRI) and X-ray computed tomography (CT). Finally, these nanocomposites were coated with a peptide SN-50. This led to their ready uptake by the cultured cells and targeted the nanocomposites to the pores of nuclear membrane. Inside cells, this nanocomposite retained its integrity as shown by X-ray fluorescence microscopy (XFM). Inside cells imaged by XFM we found the complex elemental signature of nanoconjugates (Ti-Co-Fe-Au) always co-registered in the 2D elemental map of the cell. PMID:24817775

  7. Nanocomposite polymer electrolyte for rechargeable magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yuyan; Rajput, Nav Nidhi; Hu, Jian Z.; Hu, Mary Y.; Liu, Tianbiao L.; Wei, Zhehao; Gu, Meng; Deng, Xuchu; Xu, Suochang; Han, Kee Sung; Wang, Jiulin; Nie, Zimin; Li, Guosheng; Zavadil, K.; Xiao, Jie; Wang, Chong M.; Henderson, Wesley A.; Zhang, Jiguang; Wang, Yong; Mueller, Karl T.; Persson, Kristin A.; Liu, Jun

    2014-12-28

    Nanocomposite polymer electrolytes present new opportunities for rechargeable magnesium batteries. However, few polymer electrolytes have demonstrated reversible Mg deposition/dissolution and those that have still contain volatile liquids such as tetrahydrofuran (THF). In this work, we report a nanocomposite polymer electrolyte based on poly(ethylene oxide) (PEO), Mg(BH4)2 and MgO nanoparticles for rechargeable Mg batteries. Cells with this electrolyte have a high coulombic efficiency of 98% for Mg plating/stripping and a high cycling stability. Through combined experiment-modeling investigations, a correlation between improved solvation of the salt and solvent chain length, chelation and oxygen denticity is established. Following the same trend, the nanocomposite polymer electrolyte is inferred to enhance the dissociation of the salt Mg(BH4)2 and thus improve the electrochemical performance. The insights and design metrics thus obtained may be used in nanocomposite electrolytes for other multivalent systems.

  8. Mullins' effect in polymer/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Klitkou, Rasmus

    2012-01-01

    Abstract. Experimental data are reported on polypropylene/clay nanocomposites in uniaxial cyclic tensile tests at room temperature (oscillations between maximum strains and the zero minimum stress with maximum strains increasing monotonically with number of cycles). Observations reveal fading of ...

  9. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-05

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption.

  10. Polymer-noble metal nanocomposites: Review

    CSIR Research Space (South Africa)

    Folarin, OM

    2011-09-01

    Full Text Available Polymer-noble metal nanocomposites have been extensively investigated due to their potential ability to provide materials with novel mechanical, electronic or chemical behaviour for technological applications. Many preparative procedures have been...

  11. Polymer matrix nanocomposites for automotive structural components.

    Science.gov (United States)

    Naskar, Amit K; Keum, Jong K; Boeman, Raymond G

    2016-12-06

    Over the past several decades, the automotive industry has expended significant effort to develop lightweight parts from new easy-to-process polymeric nanocomposites. These materials have been particularly attractive because they can increase fuel efficiency and reduce greenhouse gas emissions. However, attempts to reinforce soft matrices by nanoscale reinforcing agents at commercially deployable scales have been only sporadically successful to date. This situation is due primarily to the lack of fundamental understanding of how multiscale interfacial interactions and the resultant structures affect the properties of polymer nanocomposites. In this Perspective, we critically evaluate the state of the art in the field and propose a possible path that may help to overcome these barriers. Only once we achieve a deeper understanding of the structure-properties relationship of polymer matrix nanocomposites will we be able to develop novel structural nanocomposites with enhanced mechanical properties for automotive applications.

  12. Novel bioactive Co-based alloy/FA nanocomposite for dental applications

    Directory of Open Access Journals (Sweden)

    Mohammadhossein Fathi

    2012-01-01

    Full Text Available Background: Dental cobalt base alloys are biocompatible dental materials and have been widely used in dentistry. However, metals are bioinert and may not present bioactivity in human body. Bioactivity is the especial ability to interact with human body and make a bonding to soft and hard tissues. The aim of the present research was fabrication and bioactivity evaluation of novel cobalt alloy/Fluorapatite nanocomposite (CoA/FaNC with different amounts of Fluorapatite (FA nanopowder. Materials and Methods: Co-Cr-Mo alloy (ASTM F75 powder was prepared and mixed in a planetary ball mill with different amounts of FA nanopowders (10, 15, 20% wt. Prepared composite powders were cold pressed and sintered at 1100°C for 4 h. X-ray diffraction (XRD, scanning electron microscopy and transition electron microscopy techniques were used for phase analysis, crystallite size determination of FA and also for phase analysis and evaluation of particle distribution of composites. Bioactivity behavior of prepared nanocomposites was evaluated in simulated body fluid (SBF for 1 up to 28 days. Results: Results showed that nucleus of apatite were formed on the surface of the prepared CoA/FaNC during 1 up to 28 days immersion in the SBF solution. On the other hand, CoA/FaNC unlike Co-base alloy possessed bone-like apatite-formation ability. Conclusion: It was concluded that bioinert Co-Cr-Mo alloy could be successfully converted into bioactive nanocomposite by adding 10, 15, 20 wt% of FA nano particles.

  13. To study the effect of calcinations durations and temperature on optical and structural properties of MgO-CuO nanocomposites

    Science.gov (United States)

    Kumar, Rajesh; Praveen, Sharma, Ashwani; Parmar, R.; Dahiya, S.; Kishor, N.

    2016-05-01

    The MgO-CuO nanocomposites has been synthesized by a sol-gel techniques based on precursor polyvinyl alcohol (PVA). In this work appropriate concentration of cupric nitrate, Magnisium nitrate and PVA are mixed with 50:50 ethanol water followed by heated to 80°C to form a homogeneous gel solution. The obtained gel was slowly heated at 100°C to evaporate the solvent to form a hard homogeneous gel. The hard gel was calcinated at temperature 600°C for 4 hrs and 6 hrs thereafter, crushed the material in agate-motar so that it is converted into fine powder form. The prepared nanocomposites have been characterized using X-Ray Diffraction (XRD), FTIR, UV-VIS spectroscopy, SEM etc. The size of MgO-CuO nanocomposites heated at 600°C for 4 hours and 6 hours evaluated by Debye Scherrer formula are 17.1 nm and 21.2 nm respectively and results show that Size of MgO-CuO nanocomposites increases with increase of calcinations durations. IR spectra is also used to determine purity of samples. Absorption spectra confirm the synthesis of nanomaterials. SEM images give the indication of morphology of the nanocomposites.

  14. A novel high-performance supercapacitor based on high-quality CeO2/nitrogen-doped reduced graphene oxide nanocomposite

    Science.gov (United States)

    Heydari, Hamid; Gholivand, Mohammad Bagher

    2017-03-01

    In this work, we have developed a novel nanocomposite via deposition of ceria (CeO2) on nitrogen-doped reduced graphene (CeO2/NRGO). NRGO was synthesized through a facile, safe, and scalable method to achieve simultaneous thermal reduction along with nitrogen doping of graphene oxide (GO) in air at much lower reaction temperature. CeO2/NRGO was prepared via a sonochemical method in which ceria nanoparticles were uniformly distributed on NRGO sheets. The structure and morphology of CeO2/NRGO nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and Raman spectroscopy. Electrochemical properties of the proposed nanocomposite electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, continuous cyclic voltammetry (CCV), and electrochemical impedance spectroscopy (EIS) measurements. CeO2-NRGO nanocomposite electrodes showed excellent supercapacitive behavior, including much higher specific capacitance (230 F g-1 at 2 mV s-1) and higher rate capability compared to pure N-graphene. The cycling stability of the electrodes was measured by continues cyclic voltammetry (CCV) technique. The CCV showed that the specific capacitance of the CeO2/NRGO and NRGO nanocomposite maintained at 94.1 and 93.2% after 4000 cycles. The results suggest its promising potential as efficient electrode material for supercapacitors.

  15. Characterization of nanocomposites for OPL applications

    OpenAIRE

    Van Gelderen López, Roberto

    2013-01-01

    This project concerns the characterization of nanocomposites of ferrite oxide (NiFe2O4) and carbon black in poly-metal methacrylate (PMMA) for optical power limiting (OPL) applications. This is due to their non-linear optical properties and behavior at nanosize. Polymers show an improvement in properties when they are alloyed with nano-fillers. The polymer-based nanocomposites which are used for OPL applications need to be characterized for particle distribution in relation ...

  16. Mesoporous metal oxide graphene nanocomposite materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Kou, Rong; Wang, Donghai

    2016-05-24

    A nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. A method for making these nanocomposite materials by first forming a mixture of graphene, a surfactant, and a metal oxide precursor, precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.

  17. Synthesis and structural characterization of magnetic cadmium sulfide-cobalt ferrite nanocomposite, and study of its activity for dyes degradation under ultrasound

    Science.gov (United States)

    Farhadi, Saeed; Siadatnasab, Firouzeh

    2016-11-01

    Cadmium sulfide-cobalt ferrite (CdS/CFO) nanocomposite was easily synthesized by one-step hydrothermal decomposition of cadmium diethyldithiocarbamate complex on the CoFe2O4 nanoparticles at 200 °C. Spectroscopic techniques of powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), and magnetic measurements were applied for characterizing the structure and morphology of the product. The results of FT-IR, XRD and EDX indicated that the CdS/CFO was highly pure. SEM and TEM results revealed that the CdS/CFO nanocomposite was formed from nearly uniform and sphere-like nanoparticles with the size of approximately 20 nm. The UV-vis absorption spectrum of the CdS/CFO nanocomposite showed the band gap of 2.21 eV, which made it suitable for sono-/photo catalytic purposes. By using the obtained CdS/CFO nanocomposite, an ultrasound-assisted advanced oxidation process (AOP) has been developed for catalytic degradation of methylene blue (MB), Rhodamine B (RhB), and methyl orange (MO)) in the presence of H2O2 as a green oxidant. CdS/CFO nanocomposite exhibited excellent sonocatalytic activity, so that, dyes were completely degraded in less than 10 min. The influences of crucial factors such as the H2O2 amount and catalyst dosage on the degradation efficiency were evaluated. The as-prepared CdS/CFO nanocomposite exhibited higher catalytic activity than pure CdS nanoparticles. Moreover, the magnetic property of CoFe2O4 made the nanocomposite recyclable.

  18. Preparation of high-quality palladium nanocubes heavily deposited on nitrogen-doped graphene nanocomposites and their application for enhanced electrochemical sensing.

    Science.gov (United States)

    Shen, Yu; Rao, Dejiang; Bai, Wushuang; Sheng, Qinglin; Zheng, Jianbin

    2017-04-01

    A nanocomposite of high-quality palladium nanocubes (PdNCs) decorated nitrogen-doped graphene (NGE/PdNC) was successfully prepared by using bromide ion as a capping agent and polyvinyl pyrrolidone as a stabilizer. The morphology and composition of NGE/PdNC nanocomposites were characterized by field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD) and Raman spectra. To explore the application of NGE/PdNC nanocomposites in electrochemistry, the electrocatalytic response to nitrite at a NGE/PdNC-based electrode was investigated. Thus, a highly sensitive and selective electrochemical sensor for the detection of nitrite was constructed based on a glassy carbon electrode modified with the NGE/PdNC nanocomposites. The electrochemical behavior of this nanocomposites was studied by electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical investigations proved that the NGE/PdNC nanocomposites exhibited good electrocatalytic performance for the oxidation of nitrite, including a wide linear range from 5.0×10(-7) to 1.51×10(-3)molL(-1), a high sensitivity of 342.4μAmM(-1)cm(-2) and a low detection limit of 0.11μmolL(-1) at the signal-to-noise ratio of 3 (S/N=3). This non-enzymatic sensor also showed a good reproducibility and stability. The obtained NGE/PdNC nanocomposites may be a potential composite for applying in the field of other electrochemical sensing, catalysis and optics.

  19. Ultrasonic-assisted synthesis and magnetic studies of iron oxide/MCM-41 nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Ursachi, Irina [Department of Physics ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania); Vasile, Aurelia [Department of Chemistry, ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania); Ianculescu, Adelina [Department of Oxide Materials and Engineering, Polytechnics University of Bucharest, 1-7 Gh. Polizu, 011061 Bucharest (Romania); Vasile, Eugeniu [METAV S.A., Research and Development, 31 C.A. Rosetti, 020011, Bucharest (Romania); Stancu, Alexandru, E-mail: alstancu@uaic.ro [Department of Physics ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania)

    2011-11-01

    Highlights: {yields} A quick and facile route for the synthesis of iron oxide/MCM-41 nanocomposite. {yields} Magnetic nanoparticles were stabilized inside the pores of mesoporous silica MCM-41. {yields} The pore size of MCM-41 dictates the properties of iron oxide nanoparticles. {yields} The procedure provides a narrow size distribution of magnetic nanoparticles. - Abstract: Iron oxide nanoparticles were stabilized within the pores of mesoporous silica MCM-41 amino-functionalized by a sonochemical method. Formation of iron oxide nanoparticles inside the mesoporous channels of amino-functionalized MCM-41 was realized by wet impregnation using iron nitrate, followed by calcinations at 550 deg. C in air. The effect of functionalization level on structural and magnetic properties of obtained nanocomposites was studied. The resulting materials were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy and selected area electron diffraction (HRTEM and SAED), vibrating sample and superconducting quantum interface magnetometers (VSM and SQUID) and nitrogen adsorption-desorption isotherms measurements. The HRTEM images reveal that the most of the iron oxide nanoparticles were dispersed inside the mesopores of silica matrix and the pore diameter of the amino-functionalized MCM-41 matrix dictates the particle size of iron oxide nanoparticles. The obtained material possesses mesoporous structure and interesting magnetic properties. Saturation magnetization value of magnetic iron oxide nanopatricles stabilized in MCM-41 amino-functionalized by in situ sonochemical synthesis was 1.84 emu g{sup -1}. An important finding is that obtained magnetic nanocomposite materials exhibit enhanced magnetic properties than those of iron oxide/MCM-41 nanocomposite obtained by conventional method. The described method is providing a rather short preparation time and a narrow size distribution of iron oxide nanoparticles.

  20. Synthesis and Characterization of Silver/Clay Nanocomposites by Chemical Reduction Method

    Directory of Open Access Journals (Sweden)

    Mansor B. Ahmad

    2009-01-01

    Full Text Available Problem statement: Silver Nanoparticles (Ag-NPs have been synthesized by using chemical reduction method into the interlayer space of a Montmorillonite (MMT as a solid support which is used to antibacterial application and polymer nanocomposites for fabrication of medical devices. Approach: AgNO3 and NaBH4 were used as a silver precursor and reducing agent, respectively. The properties of Ag/MMT nanocomposites were studied as a function of the AgNO3 concentration. The crystalline structure, d-spacing of interlayer of MMT, the size distributions and surface plasmon resonance of synthesized Ag-NPs were characterized using Powder X-Ray Diffraction (PXRD, Transmission Electron Microscopy (TEM and UV-vis spectroscopy. Results: The results obtained from UV-vis spectroscopy of synthesized Ag-NPs showed that the intensity of the maximum wavelength of the plasmon peaks were increased with the increasing in the AgNO3 concentration. The obtained information from UV-vis spectra of Ag-NPs was in an excellent agreement with the obtained microstructures studies performed by Transmission Electron Microscopy (TEM and their size distributions. The prepared Ag/MMT nanocomposites are very stable over a long period of time in aqueous solution. Conclusion: The synthesized Ag/MMT nanocomposites are very stable in aqueous solution over a long period of time without any sign of precipitation. Silver nanoparticles in MMT suspension could be suitable to use antibacterial applications, since MMT is viewed as ecologically and environmentally inert material and used for biological application such as cosmetics and pharmaceutical usage.

  1. Processing, characterization and properties of oxide based nanocomposites

    Science.gov (United States)

    Bhaduri, Sutapa

    The synthesis, characterization and mechanical properties of oxide based nanocomposites are reported in this dissertation. Two binary systems are studied: Alsb2Osb3-MgO and Alsb2Osb3-ZrOsb2. Alsb2Osb3-MgO was chosen because of its relatively large field of solid solubilities at a moderate temperature. On the other hand, Alsb2Osb3-ZrOsb2 was chosen because it shows minimal solid solubility of the constituents. A novel "Auto Ignition" process using suitable fuels and oxidizers was utilized in the synthesis of nanocomposites and solid solutions. Thermodynamic calculations were carried out in predicting end point adiabatic temperatures (Tsbad) for each composition in both systems. Combustion temperatures were experimentally measured by means of a data acquisition system. Characterizations of the powders were carried out by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive analysis (EDAX) and differential thermal analysis (DTA). Heat treatment experiments were carried out to study the grain growth behavior. A hot isostatic pressing (HIP) model was developed for the present nanoceramics. Input parameters were carefully chosen for such nanomaterials. The as-synthesized nanocrystalline powders were consolidated to near theoretical density by hot isostatic pressing (HIPing) while retaining fine grain size. The experimental results were compared with the predictions of the model. Mechanical properties, such as room temperature toughness, low temperatures well as high temperature hardness, were determined for both systems. Room temperature hardness values were (2.89-7.79) GPa and fracture toughness was between 2.7 and 5.82 MPa.msp{1/2} for various compositions in the Alsb2Osb3-MgO system. Room temperature hardness values were between 5.33 and 8.71 GPa and fracture toughness values ranged from (5.3-9.62) MPa.msp{1/2} for various compositions in the Alsb2Osb3-ZrOsb2 system. Nanoindentation experiments were carried out to further explore the room

  2. Excellent photocatalytic performance under visible-light irradiation of ZnS/rGO nanocomposites synthesized by a green method

    Science.gov (United States)

    Azimi, Hassan Rayat; Ghoranneviss, Mahmood; Elahi, Seyed Mohammad; Mahmoudian, Mohammad Reza; Jamali-Sheini, Farid; Yousefi, Ramin

    2016-11-01

    ZnS/graphene nanocomposites with different graphene concentrations (5, 10 and 15 wt.%) were synthesized using L-cysteine as surfactant and graphene oxide (GO) powders as graphene source. Excellent performance for nanocomposites to remove methylene blue (MB) dye and hexavalent chromium (Cr(VI)) under visible-light illumination was revealed. TEM images showed that ZnS NPs were decorated on GO sheets and the GO caused a significant decrease in the ZnS diameter size. XRD patterns, XPS and FTIR spectroscopy results indicated that GO sheets changed into reduced graphene oxide (rGO) during the synthesis process. Photocurrent measurements under a visiblelight source indicated a good chemical reaction between ZnS NPs and rGO sheets.

  3. Synthesis and characterization of Fe{sub 3}O{sub 4}: Porous carbon nanocomposites for biosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Manju, E-mail: marora@nplindia.org [CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi-110012 (India); Zargar, R. A., E-mail: rayeesphy12@gmail.com [Department of Physics, Jamia Millia Islamia, New Delhi-110025 (India)

    2015-08-28

    Fe{sub 3}O{sub 4}:Porous carbon (Fe{sub 3}O{sub 4}:PC) nano-magnetic composites were prepared by using different weight fractions of acid treated PC by the chemical co-precipitation route and annealed at 573 K, 773 K and 973 K temperatures in inert N{sub 2} gas atmosphere for 2 hrs to obtain desired stoichiometry of nanocomposites. The structural, morphological and magnetic properties of these composites were characterized by powder XRD, TEM, EPR and VSM analytical techniques. The crystallinity of the composites, g-value and spin concentration increases with increasing annealing temperature. TEM images confirmed the formation of nanosized ferrite nanoprticles whose size increases from 23 nm to 54 nm on increasing annealing temperature. Porous carbon increases porosity, coercivity and reduces saturation magnetization of these prepared nanocomposites.

  4. Advanced Nanocomposite Coatings of Fusion Bonded Epoxy Reinforced with Amino-Functionalized Nanoparticles for Applications in Underwater Oil Pipelines

    Directory of Open Access Journals (Sweden)

    Patricia A. Saliba

    2016-01-01

    Full Text Available The performance of fusion-bonded epoxy coatings can be improved through advanced composite coatings reinforced with nanomaterials. Hence, in this study a novel organic-inorganic nanocomposite finish was designed, synthesized, and characterized, achieved by adding γ-aminopropyltriethoxysilane modified silica nanoparticles produced via sol-gel process in epoxy-based powder. After the curing process of the coating reinforced with nanoparticles, the formation of a homogenous novel nanocomposite with the development of interfacial reactions between organic-inorganic and inorganic-inorganic components was observed. These hybrid nanostructures produced better integration between nanoparticles and epoxy matrix and improved mechanical properties that are expected to enhance the overall performance of the system against underwater corrosion.

  5. Development and characterization of nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Eschbach, J. [Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Laboratoire Europeen de Recherche Universitaire, Saarland-Lorraine (Germany); Rouxel, D. [Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Laboratoire Europeen de Recherche Universitaire, Saarland-Lorraine (Germany)], E-mail: didier.rouxel@lpmi.uhp-nancy.fr; Vincent, B. [Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Laboratoire Europeen de Recherche Universitaire, Saarland-Lorraine (Germany); Mugnier, Y.; Galez, C.; Le Dantec, R. [Laboratoire Systemes et Materiaux pour la Mecatronique, Polytech' Savoie, Annecy (France); Bourson, P. [Laboratoire Materiaux Optiques, Photoniques et Systemes, CNRS-UMR 7132, Universite Paul Verlaine, Metz (France); Krueger, J.K. [Laboratoire Europeen de Recherche Universitaire, Saarland-Lorraine (Germany); Fachrichtung 7.2, Experimentalphysik, Universitaet des Saarlandes, Bau 38, D-66041 Saarbruecken (Germany); Elmazria, O.; Alnot, P. [Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Laboratoire Europeen de Recherche Universitaire, Saarland-Lorraine (Germany)

    2007-09-15

    In this paper we present the fabrication and characterization of nanocomposite materials based on crystalline nanoparticles dispersed in an oligomer matrix (DGEBA, used in epoxy resin). Two types of nanoparticles are used. Al{sub 2}O{sub 3} nanoparticles, commercially available, allow us to carry out the fabrication process of the nanocomposites. This system (DGEBA + Al{sub 2}O{sub 3}) is considered as a reference for the second one based on iron iodate nanoparticles fabricated by co-precipitation. The nanocomposite fabrication process is described. The dispersion step and the problems inherent to clusters destruction are underlined. Iron iodate nanoparticles are characterized by TEM, SEM, X-ray diffraction, Raman spectroscopy and EDX. Results point out that the nanoparticles have dimensions between 20 and 30 nm and present two different morphologies (ball and needle). Mechanical properties of the nanocomposite based on Al{sub 2}O{sub 3} are explored by Brillouin spectroscopy. An enhancement of the Young's modulus is observed with a very weak mass percentage of nanoparticles (3%), the glass transition is also shifted from 247 K to 251 K. X-ray diffraction measurement on iron iodate nanocomposite demonstrates that nanoparticles remain in the same phase (P6{sub 3}) after the nanocomposite preparation process. This result is of great importance in order to achieve piezoelectric and ferroelectric applications.

  6. Electrodeposition of Fe powder from acid electrolytes

    Directory of Open Access Journals (Sweden)

    VESNA M. MAKSIMOVIC

    2008-08-01

    Full Text Available Polarization characteristics of the electrodeposition processes of Fe powders from sulfate and chloride electrolytes and the morphology of the obtained powders were investigated. The morphology depended on the anion presence in the electrolyte but not on the current density in the investigated range. A characteristic feature of the dendritic powder with cauliflower endings obtained from sulfate electrolyte is the presence of cone-like cavities and the crystallite morphology of the powders surface. On the other hand, Fe powders electrodeposited from chloride electrolyte appear in the form of agglomerates. A soap solution treatment applied as a method of washing and drying provides good protection from oxidation of the powders.

  7. Handbook of polymer nanocomposites processing, performance and application

    CERN Document Server

    Mohanty, Amar; Misra, Manjusri; Kar, Kamal K; Pandey, Jitendra; Rana, Sravendra; Takagi, Hitoshi; Nakagaito, Antonio; Kim, Hyun-Joong

    Volume A forms one volume of a Handbook about Polymer Nanocomposites. In some 20 chapters the preparation, architecture, characterisation, properties and application of polymer nanocomposites are discussed by experts in their respective fields.

  8. Preparation, Properties and Application of Polymeric Organic-Inorganic Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    任杰; 刘艳; 唐小真

    2003-01-01

    Six preparation methods for polymeric organic-inorganic nanocomposites and their respective mechanisms and features are reviewed. The extraordinary properties of polymeric organic-inorganic nanocomposites are discussed,and their potential applications are evaluated.

  9. Structure and property of Cu-based thermosensitive nanocomposite

    Institute of Scientific and Technical Information of China (English)

    LOU Bai-yang; XU Bin; MA Xiao-chun; LI Le-guo

    2006-01-01

    The Cu-based thermosensitive nanocomposites are made by high energy ball milling. The microstructures and properties of Cu-based thermosensitive nanocomposites are studied by transmission electron microscopy(TEM) and themosensitivity test. The effects of milling time on the microstructures and the thermosensitivity of Cu-based nanocomposite material are researched. The results show that the Cu-based nanocomposite can be made by high energy ball milling. As the milling time increases, the copper particle size decreases in the nanocomposite, then the thermoexpansivity of nanocomposite increases. The nanocomposite is of best thermoexpansivity when the milling time is up to 100 h. At 35-45 ℃, the nanocomposite shows good thermosensitivity.

  10. Unique morphology of dispersed clay particles in a polymer nanocomposite

    CSIR Research Space (South Africa)

    Malwela, T

    2011-02-01

    Full Text Available This communication reports a unique morphology of dispersed clay particles in a polymer nanocomposite. A nanocomposite of poly[butylene succinate)-co-adipate] (PBSA) with 3 wt% of organically modified montmorillonite was prepared by melt...

  11. Cyclic viscoelasticity and viscoplasticity of polypropylene/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Hog Lejre, Anne-Lise

    2012-01-01

    Observations are reported in tensile relaxation tests under stretching and retraction on poly-propylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of hybrid nanocomposites. Adjustable parameters...

  12. Spark Plasma Sintered Si3N4/TiN Nanocomposites Obtained by a Colloidal Processing Route

    Directory of Open Access Journals (Sweden)

    L. A. Díaz

    2016-01-01

    Full Text Available Ceramic Si3N4/TiN (22 vol% nanocomposites have been obtained by Spark Plasma Sintering (SPS. Our colloidal processing route allows obtaining dispersed nanoparticles of TiN smaller than 50 nm avoiding the presence of agglomerates. The nanostructured starting powders were obtained by using a colloidal method where commercial Si3N4 submicrometer particles were coated with anatase TiO2 nanocrystals. A later nitridation process led to the formation of TiN nanoparticles on the surface of Si3N4. A second set of powders was prepared by doping the above defined powders with yttrium and aluminium precursors using also a colloidal method as sources of alumina and yttria. After thermal nitridation and SPS treatment, it has been found that the addition of oxides dopants improves the mechanical performance (KIC, σf but increases the electrical resistivity and significantly reduces the hardness. This is due to the formation of a continuous insulating glassy phase that totally envelops the conductive TiN nanoparticles, avoiding the percolative contact between them. The combination of colloidal processing route and SPS allows the designing of tailor-made free glassy phase Si3N4/TiN nanocomposites with controlled microstructure. The microstructural features and the thermoelectrical and mechanical properties of both kinds of dense SPSed compacts are discussed in this work.

  13. POWDER COATINGS: A TECHNOLOGY REVIEW

    Science.gov (United States)

    In 1995, surface coatings accounted for nearly 2.55 million Mg of volatile organic compound (VOC) emissions nationally, which is more than 12% of VOC emissions from all sources. In recent years, powder coatings have been steadily gaining popularity as an alternative to solvent-bo...

  14. Mask materials for powder blasting

    NARCIS (Netherlands)

    Wensink, Henk; Jansen, Henri V.; Berenschot, J.W.; Elwenspoek, Miko C.

    2001-01-01

    Powder blasting, or abrasive jet machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials such as glass, silicon and ceramics. The particle jet (which expand

  15. Advanced composites take a powder

    Energy Technology Data Exchange (ETDEWEB)

    Holty, D.W. (Custom Composite Materials, Inc., Atlanta, GA (United States))

    1993-06-01

    To a professional chemist with more than 25 years of industrial experience, the world of advanced composites is a fascinating new venue. Here resins and fibers come together in a completely synergistic partnership, achieving marvels of strength and light weight that make advanced composite materials virtually the only solution for challenging applications. In the late 1980s, Professor John Muzzy of the Georgia Institute of Technology, was intrigued by the physical properties of thermoplastics, and he developed a new way to bring the thermoplastic resins together with high-performance fibers. As part of the work Muzzy did with Lockheed and NASA he demonstrated that electrostatic powder coating was an attractive new method for combining thermoplastic resins with reinforcing fibers. Presentation of this work by Lockheed at a government-industry conference led to a new project for Muzzy, sponsored by NASA Langley. Powder prepregging proved to be the attractive alternative that NASA was looking for. While working on powder prepregging with LaRC-TPI, Muzzy and his colleagues developed methods for exposing all of the fibers to the powder to improve the distribution of the resin on the tow, a continuous bundle of filaments. Optimal resin distribution was achieved by spreading the moving tow. A very flexible towpreg was produced by maintaining the spread tow through the powder coating chamber and into the oven, where the resin particles were fused to the individual filaments. Muzzy's invention has enabled Custom Composite Materials, Inc. to offer resin/fiber combinations based on thermoplastic resins such as nylon and polypropylene. Beyond the expected advantages over epoxy thermoset systems, they are beginning to exploit a fundamental property of thermoplastic resins: viscoelasticity, which can be defined as the resistance to flow as a function of applied stress. Thermoplastics have a much higher viscoelasticity than thermosets.

  16. Nanocomposites: The End of Compromise

    Science.gov (United States)

    van Damme, H.

    Increase the Young's modulus of a glassy resin by a factor of ten without making it heavier, for a new ski design, for example? Triple the rupture strength of an elastomer? Improve the thermal behaviour of an object made from a thermoplastic polymer by 100 degrees, to make a car dashboard, for example, or a part for the engine? Double the fire resistance time for the sheath around an electricity cable? Reduce the oxygen permeability of a film by a factor of ten, to make long conservation food packaging? All these things have been made possible by incorporating a few percent of inorganic nanoparticles in a polymer matrix. Figures 14.1 and 14.2 illustrate two such nanocomposites: the first was obtained by incorporating lamellar clay particles, and the second by incorporating fibrous nanoparticles, in fact, carbon nanotubes.

  17. Shape-Morphing Nanocomposite Origami

    Science.gov (United States)

    2015-01-01

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

  18. High performance polyethylene nanocomposite fibers

    Directory of Open Access Journals (Sweden)

    A. Dorigato

    2012-12-01

    Full Text Available A high density polyethylene (HDPE matrix was melt compounded with 2 vol% of dimethyldichlorosilane treated fumed silica nanoparticles. Nanocomposite fibers were prepared by melt spinning through a co-rotating twin screw extruder and drawing at 125°C in air. Thermo-mechanical and morphological properties of the resulting fibers were then investigated. The introduction of nanosilica improved the drawability of the fibers, allowing the achievement of higher draw ratios with respect to the neat matrix. The elastic modulus and creep stability of the fibers were remarkably improved upon nanofiller addition, with a retention of the pristine tensile properties at break. Transmission electronic microscope (TEM images evidenced that the original morphology of the silica aggregates was disrupted by the applied drawing.

  19. Laser ablation studies of nanocomposites

    Directory of Open Access Journals (Sweden)

    Oleg V. Mkrtychev

    2015-03-01

    Full Text Available The first experimental measurements of the threshold energy density values for the laser ablation of glass nanocomposites with nanodimensional coatings have been carried out under the action of the YAG–Nd laser power pulse radiation. The coatings in question were of different compositions and had been created by the sol–gel technology. The procedure for determining the laser ablation threshold energy density values was worked out on the base of the breakdown probability level of 0.5. The statistical processing of the measurement data over all the samples allowed obtaining the dependence of the ablation destruction threshold energy parameters on the coating physical and chemical properties such as the sample transmission in the visible region of the spectrum, coating thickness, the chemical composition of the film-forming solution, and on the pulse duration of laser radiation.

  20. Graphite nanoreinforcements in polymer nanocomposites

    Science.gov (United States)

    Fukushima, Hiroyuki

    Nanocomposites composed of polymer matrices with clay reinforcements of less than 100 nm in size, are being considered for applications such as interior and exterior accessories for automobiles, structural components for portable electronic devices, and films for food packaging. While most nanocomposite research has focused on exfoliated clay platelets, the same nanoreinforcement concept can be applied to another layered material, graphite, to produce nanoplatelets and nanocomposites. Graphite is the stiffest material found in nature (Young's Modulus = 1060 GPa), having a modulus several times that of clay, but also with excellent electrical and thermal conductivity. The key to utilizing graphite as a platelet nanoreinforcement is in the ability to exfoliate this material. Also, if the appropriate surface treatment can be found for graphite, its exfoliation and dispersion in a polymer matrix will result in a composite with not only excellent mechanical properties but electrical properties as well, opening up many new structural applications as well as non-structural ones where electromagnetic shielding and high thermal conductivity are requirements. In this research, a new process to fabricate exfoliated nano-scale graphite platelets was established (Patent pending). The size of the resulted graphite platelets was less than 1 um in diameter and 10 nm in thickness, and the surface area of the material was around 100 m2/g. The reduction of size showed positive effect on mechanical properties of composites because of the increased edge area and more functional groups attached with it. Also various surface treatment techniques were applied to the graphite nanoplatelets to improve the surface condition. As a result, acrylamide grafting treatment was found to enhance the dispersion and adhesion of graphite flakes in epoxy matrices. The resulted composites showed better mechanical properties than those with commercially available carbon fibers, vapor grown carbon fibers

  1. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.

  2. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    Nebera; A.; Markusbkin; Yu.; Azarov; V.; Ermolaev; N.

    2005-01-01

    Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.……

  3. Influence of Grain Refinement on Microstructure and Mechanical Properties of Tungsten Carbide/Zirconia Nanocomposites

    Science.gov (United States)

    Nasser, Ali; Kassem, Mohamed A.; Elsayed, Ayman; Gepreel, Mohamed A.; Moniem, Ahmed A.

    2016-11-01

    WC-W2C/ZrO2 nanocomposites were synthesized by pressure-less sintering (PS) and spark plasma sintering (SPS) of tungsten carbide/yttria-stabilized tetragonal zirconia, WC/TZ-3Y. Prior to sintering, WC/TZ-3Y powders were totally ball-milled for 20 and 120 h to obtain targeted nano (N) and nano-nano (N-N) structures, indicated by transmission electron microscopy and powder x-ray diffraction (PXRD). The milled powders were processed via PS at temperatures of 1773 and 1973 K for 70 min and SPS at 1773 K for 10 min. PXRD as well as SEM-EDS indicated the formation of WC-W2C/ZrO2 composites after sintering. The mechanical properties were characterized via Vicker microhardness and nanoindentation techniques indicating enhancements for sufficiently consolidated composites with high W2C content. The effects of reducing particle sizes on phase transformation, microstructure and mechanical properties are reported. In general, the composites based on the N structure showed higher microhardness than those for N-N structure, except for the samples PS-sintered at 1773 K. For instance, after SPS at 1773 K, the N structure showed a microhardness of 18.24 GPa. Nanoindentation measurements revealed that nanoscale hardness up to 22.33 and 25.34 GPa and modulus of elasticity up to 340 and 560 GPa can be obtained for WC-W2C/ZrO2 nanocomposites synthesized by the low-cost PS at 1973 K and by SPS at 1773 K, respectively.

  4. Influence of Grain Refinement on Microstructure and Mechanical Properties of Tungsten Carbide/Zirconia Nanocomposites

    Science.gov (United States)

    Nasser, Ali; Kassem, Mohamed A.; Elsayed, Ayman; Gepreel, Mohamed A.; Moniem, Ahmed A.

    2016-09-01

    WC-W2C/ZrO2 nanocomposites were synthesized by pressure-less sintering (PS) and spark plasma sintering (SPS) of tungsten carbide/yttria-stabilized tetragonal zirconia, WC/TZ-3Y. Prior to sintering, WC/TZ-3Y powders were totally ball-milled for 20 and 120 h to obtain targeted nano (N) and nano-nano (N-N) structures, indicated by transmission electron microscopy and powder x-ray diffraction (PXRD). The milled powders were processed via PS at temperatures of 1773 and 1973 K for 70 min and SPS at 1773 K for 10 min. PXRD as well as SEM-EDS indicated the formation of WC-W2C/ZrO2 composites after sintering. The mechanical properties were characterized via Vicker microhardness and nanoindentation techniques indicating enhancements for sufficiently consolidated composites with high W2C content. The effects of reducing particle sizes on phase transformation, microstructure and mechanical properties are reported. In general, the composites based on the N structure showed higher microhardness than those for N-N structure, except for the samples PS-sintered at 1773 K. For instance, after SPS at 1773 K, the N structure showed a microhardness of 18.24 GPa. Nanoindentation measurements revealed that nanoscale hardness up to 22.33 and 25.34 GPa and modulus of elasticity up to 340 and 560 GPa can be obtained for WC-W2C/ZrO2 nanocomposites synthesized by the low-cost PS at 1973 K and by SPS at 1773 K, respectively.

  5. Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility.

    Science.gov (United States)

    Swain, S K; Gotman, I; Unger, R; Gutmanas, E Y

    2017-09-01

    In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The degradation behavior of the developed composite materials was studied by immersion in Ringer's and saline solutions for up to 1month. The mechanical properties, before and after immersion, were tested in compression and bending. All the compositions exhibited high mechanical strength, the strength in bending being several fold higher than that of polymer toughened β-TCP-30PLA nanocomposites prepared by the similar procedure of attrition milling and cold sintering, and of pure high-temperature sintered β-TCP. Partial substitution of iron with silver led to an increase in both strength and ductility. Furthermore, the galvanic action of silver particles dispersed in the iron phase significantly accelerated in vitro degradation of β-TCP-30(Fe-Ag) nanocomposites. After 1month immersion, the composites retained about 50% of their initial bending strength. In cell culture experiments, β-TCP-27Fe3Ag nanocomposites exhibited no signs of cytotoxicity towards human osteoblasts suggesting that they can be used as an implant material. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 21 CFR 73.2646 - Bronze powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Bronze powder. 73.2646 Section 73.2646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The color additive bronze powder shall conform in identity and specifications to the requirements of §...

  7. Development of a Reproducible Powder Characterization Method using a Powder Rheometer

    DEFF Research Database (Denmark)

    Søgaard, Søren Vinter; Allesø, Morten; Garnæs, Jørgen;

    2012-01-01

    In this study, a powder rheometer was used to measure flow characteristics of two pharmaceutical model powders. Precise measurements were obtained for one of the model powders whereas the results were less precise for the second powder. In conclusion, further work is needed to increase the mechan...

  8. 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

  9. Nanocomposite YSZ-NiO Particles with Tailored Structure Synthesized in a Two-Stage Continuous Hydrothermal Flow Reactor

    DEFF Research Database (Denmark)

    Zielke, Philipp; Xu, Yu; Kiebach, Wolff-Ragnar

    2016-01-01

    the performance of energy storage and conversion devices such as fuel cells, electrolyzers and batteries is important. One promising approach to further improve these devices is the use of carefully structured nanosized materials. Nano-composite particles combining different materials in advanced geometries like......-of-the-art solid oxide fuel and electrolysis cells. The prepared particles were characterized by X-ray powder diffraction, (high resolution) transmission electron microscopy, scanning tunnel transmission microscopy and Raman spectroscopy in order to determine crystal structure, particle size, surface morphology...

  10. Microwave-Hydrothermal Synthesis of SnO2-CNTs Hybrid Nanocomposites with Visible Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Shuisheng Wu

    2017-03-01

    Full Text Available SnO2 nanoparticles coated on carbon nanotubes (CNTs were prepared via a simple microwave-hydrothermal route. The as-obtained SnO2-CNTs composites were characterized using X-ray powder diffraction, Raman spectroscopy, and transmission electron microscopy. The photocatalytic activity of as-prepared SnO2-CNTs for degradation of Rhodamine B under visible light irradiation was investigated. The results show that SnO2-CNTs nanocomposites have a higher photocatalytic activity than pure SnO2 due to the rapid transferring of electrons and the effective separation of holes and electrons on SnO2-CNTs.

  11. Microwave-Hydrothermal Synthesis of SnO2-CNTs Hybrid Nanocomposites with Visible Light Photocatalytic Activity

    Science.gov (United States)

    Wu, Shuisheng; Dai, Weili

    2017-01-01

    SnO2 nanoparticles coated on carbon nanotubes (CNTs) were prepared via a simple microwave-hydrothermal route. The as-obtained SnO2-CNTs composites were characterized using X-ray powder diffraction, Raman spectroscopy, and transmission electron microscopy. The photocatalytic activity of as-prepared SnO2-CNTs for degradation of Rhodamine B under visible light irradiation was investigated. The results show that SnO2-CNTs nanocomposites have a higher photocatalytic activity than pure SnO2 due to the rapid transferring of electrons and the effective separation of holes and electrons on SnO2-CNTs. PMID:28336888

  12. High-aspect ratio magnetic nanocomposite polymer cilium

    Science.gov (United States)

    Rahbar, M.; Tseng, H. Y.; Gray, B. L.

    2014-03-01

    This paper presents a new fabrication technique to achieve ultra high-aspect ratio artificial cilia micro-patterned from flexible highly magnetic rare earth nanoparticle-doped polymers. We have developed a simple, inexpensive and scalable fabrication method to create cilia structures that can be actuated by miniature electromagnets, that are suitable to be used for lab-on-a chip (LOC) and micro-total-analysis-system (μ-TAS) applications such as mixers and flow-control elements. The magnetic cilia are fabricated and magnetically polarized directly in microfluidic channels or reaction chambers, allowing for easy integration with complex microfluidic systems. These cilia structures can be combined on a single chip with other microfluidic components employing the same permanently magnetic nano-composite polymer (MNCP), such as valves or pumps. Rare earth permanent magnetic powder, (Nd0.7Ce0.3)10.5Fe83.9B5.6, is used to dope polydimethylsiloxane (PDMS), resulting in a highly flexible M-NCP of much higher magnetization and remanence [1] than ferromagnetic polymers typically employed in magnetic microfluidics. Sacrificial poly(ethylene-glycol) (PEG) is used to mold the highly magnetic polymer into ultra high-aspect ratio artificial cilia. Cilia structures with aspect ratio exceeding 8:0.13 can be easily fabricated using this technique and are actuated using miniature electromagnets to achieve a high range of motion/vibration.

  13. Nanocomposites for advanced fuel cell technology.

    Science.gov (United States)

    Zhu, Bin

    2011-10-01

    NANOCOFC (Nanocomposites for advanced fuel cell technology) is a research platform/network established based on the FP6 EC-China project www.nanocofc.org. This paper reviews major achievements on two-phase nanocomposites for advanced low temperature (300-600 degrees C) solid oxide fuel cells (SOFCs), where the ceria-salt and ceria-oxide composites are common. A typical functional nanocomposite structure is a core-shell type, in which the ceria forms a core and the salt or another oxide form the shell layer. Both of them are in the nano-scale and the functional components. The high resolution TEM analysis has proven a clear interface in the ceria-based two-phase nanocomposites. Such interface and interfacial function has resulted in superionic conductivity, above 0.1 S/cm at around 300 degrees C, being comparable to that of conventional SOFC YSZ at 1000 degrees C. Against conventional material design from the structure the advanced nanocomposites are designed by non-structure factors, i.e., the interfaces, and by creating interfacial functionalities between the two constituent phases. These new functional materials show indeed a breakthrough in the SOFC materials with great potential.

  14. Polylactide nanocomposites for packaging materials: A review

    Science.gov (United States)

    Widiastuti, Indah

    2016-02-01

    This review aims at highlighting on an attempt for improving the properties of polylactide (PLA) as packaging material by application of nanocomposite technology. PLA is attracting considerable interest because of more eco-friendliness from its origin as contrast to the petrochemical-based polymers and its biodegradability. Despite possessing good mechanical and optical properties, deterioration of the material properties in PLA materials during their service time could occur after prolonged exposure to humidity and high temperature condition. Limited gas barrier is another drawback of PLA material that should be overcome to satisfy the requirement for packaging application. To further extend the range of mechanical and thermal properties achievable, several attempts have been made in modifying the material such as blending with other polymers, use of plasticizing material and development of PLA nanocomposites. Nanocomposite is a fairly new type of composite that has emerged in which the reinforcing filler has nanometer scale dimensions (at least one dimension of the filler is less than 100 nm). In this review, the critical properties of PLA as packaging materials and its degradation mechanism are presented. This paper discusses the current effort and key research challenges in the development of nanocomposites based on biodegradable polymer matrices and nano-fillers. The PLA layered silicate nanocomposites where the filler platelets can be dispersed in the polymer at the nanometer scale owing to the specific filler surface modification, frequently exhibits remarkable improvements of mechanical strength, gas barrier and thermal stability.

  15. Dry PMR-15 Resin Powders

    Science.gov (United States)

    Vannucci, Raymond D.; Roberts, Gary D.

    1988-01-01

    Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

  16. Recent Advances in Hard, Tough, and Low Friction Nanocomposite Coatings

    Institute of Scientific and Technical Information of China (English)

    A.A.Voevodin; J. S. Zabinski; C.Muratore

    2005-01-01

    Nanocomposite coatings demonstrate improved friction and wear responses under severe sliding conditions in extreme environments. This paper provides a review how thin film multilayers and nanocomposites result in hard, tough, low-friction coatings. Approaches to couple multilayered and nanocomposite materials with other surface engineering strategies to achieve higher levels of performance in a variety of tribological applications are also discussed. Encapsulating lubricious phases in hard nanocomposite matrices is one approach that is discussed in detail. Results from state-of-the-art "chameleon" nanocomposites that exhibit reversible adaptability to ambient humidity or temperature are presented.

  17. Cellulose nanofibrils (CNF) filled boron nitride (BN) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Sulaiman, Hanisah Syed; Hua, Chia Chin; Zakaria, Sarani [School of Applied Physic, Faculty of Science and Technology, Universiti Kebangsaan Malaysia.43600 Bangi, Selangor (Malaysia)

    2015-09-25

    In this study, nanocomposite using cellulose nanofibrils filled with different percentage of boron nitride (CNF-BN) were prepared. The objective of this research is to study the effect of different percentage of BN to the thermal conductivity of the nanocomposite produced. The CNF-BN nanocomposite were characterization by FT-IR, SEM and thermal conductivity. The FT-IR analysis of the CNF-BN nanocomposite shows all the characteristic peaks of cellulose and BN present in all samples. The dispersion of BN in CNF were seen through SEM analysis. The effect of different loading percentage of BN to the thermal conductivity of the nanocomposite were also investigated.

  18. Sphericizing metal powders by mechanical means

    Institute of Scientific and Technical Information of China (English)

    WANG Fu-xiang; GAI Guo-sheng; YANG Yu-fen

    2006-01-01

    A dry mechanical surface treatment was described,in which irregularly shaped metal powders were impacted and sphericized by using high speed airflow impact method particles composite system(PCS). The optimum technological parameters for the metal powders processed were determined according to the treatment effect under different conditions. The results show that the irregularly shaped metal powders are impacted into dense spherical particles,the bulk density and tap density of the metal powders increase noticeably. The combination property of metal powders is improved greatly.

  19. Phase diagram of crushed powders

    Science.gov (United States)

    Bodard, Sébastien; Jalbaud, Olivier; Saurel, Richard; Burtschell, Yves; Lapebie, Emmanuel

    2016-12-01

    Compression of monodisperse powder samples in quasistatic conditions is addressed in a pressure range such that particles fragmentation occurs while the solid remains incompressible (typical pressure range of 1-300 MPa for glass powders). For a granular bed made of particles of given size, the existence of three stages is observed during compression and crush up. First, classical compression occurs and the pressure of the granular bed increases along a characteristic curve as the volume decreases. Then, a critical pressure is reached for which fragmentation begins. During the fragmentation process, the granular pressure stays constant in a given volume range. At the end of this second stage, 20%-50% of initial grains are reduced to finer particles, depending on the initial size. Then the compression undergoes the third stage and the pressure increases along another characteristic curve, in the absence of extra fragmentation. The present paper analyses the analogies between the phase transition in liquid-vapour systems and powder compression with crush-up. Fragmentation diagram for a soda lime glass is determined by experimental means. The analogues of the saturation pressure and latent heat of phase change are determined. Two thermodynamic models are then examined to represent the crush-up diagram. The first one uses piecewise functions while the second one is of van der Waals type. Both equations of state relate granular pressure, solid volume fraction, and initial particle diameter. The piecewise functions approach provides reasonable representations of the phase diagram while the van der Waals one fails.

  20. Advances in powder diffraction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Louer, D. [Lab. de Chimie du Solide et Inorganique Moleculaire, Rennes (France). Groupe de Cristallochimie

    1998-11-01

    Powder diffraction offers a wide spectrum of applications to solid-state scientists. The method traditionally used for phase analysis and the study of structural imperfections has benefited, in the last twenty years, from great advances in the instrumentation and computer-based approaches for pattern indexing and modelling. The factors at the origin of the metamorphosis of the method are presented. The major modern applications reported include quantitative analysis and the extraction of three-dimensional structural and microstructural properties. The use of pattern-fitting techniques for the characterization of the microstructure is discussed through applications to nanocrystalline materials. Remarkable results achieved in the solution of crystal structures are presented, as well as the impact in solid-state chemistry of powder crystallography, particularly for elucidating the crystal chemistry of families of compounds for which only powders are available. New strategies for solving the phase problem have been introduced and new classes of solids are being studied, such as drugs, coordination and organic compounds. (orig.) 100 refs.

  1. Synthesis of high magnetic moment soft magnetic nanocomposite powders for RF filters and antennas

    Science.gov (United States)

    Chinnasamy, Chins; Malallah, Yaaqoub; Jasinski, Melania M.; Daryoush, Afshin S.

    2015-04-01

    Fe60Co40 alloy nanoparticles with an average particle size of 30 nm were successfully synthesized in gram scale batches using the modified polyol process. The X-ray diffraction and microstructure studies clearly show the formation of the alloy nanoparticles. The saturation magnetization for the gram scale synthesized Fe60Co40 alloy nanoparticles is in the range of 190-205 emu/g at room temperature. The as-synthesized nanoparticles were used to fabricate transmission lines on FR4 substrate to perform radio frequency (RF) characterization of the nanoparticles at ISM RF bands of interest (all in GHz range). The complex permeability extraction of composite Fe60Co40 nanoparticles were performed using perturbation technique applied to microstrip transmission lines by relative measurement of full two port scattering parameter with respect to a baseline FR4 substrate. The extracted results show attractive characteristics for small size antennas and filters.

  2. Novel Nanocomposite Materials for Advanced Li-Ion Rechargeable Batteries

    Directory of Open Access Journals (Sweden)

    Chuan Cai

    2009-09-01

    Full Text Available Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. Nanocomposite materials will have a further enhancement in properties compared to their constituent phases. This Review describes some recent developments of nanocomposite materials for high-performance Li-ion rechargeable batteries, including carbon-oxide nanocomposites, polymer-oxide nanocomposites, metal-oxide nanocomposites, and silicon-based nanocomposites, etc. The major goal of this Review is to highlight some new progress in using these nanocomposite materials as electrodes to develop Li-ion rechargeable batteries with high energy density, high rate capability, and excellent cycling stability.

  3. Nanocomposites with High Thermoelectric Figures of Merit

    Science.gov (United States)

    Chen, Gang (Inventor); Dresselhaus, Mildred (Inventor); Ren, Zhifeng (Inventor)

    2015-01-01

    The present invention is generally directed to nanocomposite thermoelectric materials that exhibit enhanced thermoelectric properties. The nanocomposite materials include two or more components, with at least one of the components forming nano-sized structures within the composite material. The components are chosen such that thermal conductivity of the composite is decreased without substantially diminishing the composite's electrical conductivity. Suitable component materials exhibit similar electronic band structures. For example, a band-edge gap between at least one of a conduction band or a valence band of one component material and a corresponding band of the other component material at interfaces between the components can be less than about 5k(sub B)T, wherein k(sub B) is the Boltzman constant and T is an average temperature of said nanocomposite composition.

  4. Permeation properties of polymer/clay nanocomposites

    Science.gov (United States)

    Kalendova, A.; Merinska, D.; Gerard, J. F.

    2012-07-01

    The important characteristics of polymer/clay nanocomposites are stability, barrier properties and in the case of polyvinyl chloride also plasticizer migration into other materials. Therefore, the permeation properties of polymer/clay nanocomposites are discussed in this paper. The attention was focused to the polyethylene (PE) and polyvinyl chloride (PVC). Natural type of montmorillonite MMTNa+ and modified types of montmorillonite from Southern Clay Products were used as the inorganic phase. As the compounding machine, one screw Buss KO-kneader was employed. The principal aim is to fully exfoliate the clay into polymer matrix and enhanced the permeation properties. Prepared samples were tested for O2 and CO2 permeability. Polymer/clay nanocomposite structure was determined on the base of X-ray diffraction and electron microscopy (TEM).

  5. Semimetal/Semiconductor Nanocomposites for Thermoelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hong [Univ. of California, Santa Barbara, CA (United States). Materials Dept.; Burke, Peter G. [Univ. of California, Santa Barbara, CA (United States). Materials Dept.; Gossard, Arthur C. [Univ. of California, Santa Barbara, CA (United States). Materials Dept.; Zeng, Gehong [Univ. of California, Santa Barbara, CA (United States). Dept. of Electrical and Computer Engineering; Ramu, Ashok T. [Univ. of California, Santa Barbara, CA (United States). Dept. of Electrical and Computer Engineering; Bahk, Je-Hyeong [Univ. of California, Santa Barbara, CA (United States). Dept. of Electrical and Computer Engineering; Bowers, John E. [Univ. of California, Santa Barbara, CA (United States). Dept. of Electrical and Computer Engineering

    2011-04-15

    In this work, we present research on semimetal-semiconductor nanocomposites grown by molecular beam epitaxy (MBE) for thermoelectric applications. We study several different III-V semiconductors embedded with semimetallic rare earth-group V (RE-V) compounds, but focus is given here to ErSb:InxGa1-xSb as a promising p-type thermoelectric material. Nano­structures of RE-V compounds are formed and embedded within the III-V semiconductor matrix. By codoping the nanocomposites with the appropriate dopants, both n-type and p-type materials have been made for thermoelectric applications. The thermoelectric properties have been engineered for enhanced thermoelectric device performance. Segmented thermoelectric power generator modules using 50 μm thick Er-containing nanocomposites have been fabricated and measured. Research on different rare earth elements for thermoelectrics is discussed.

  6. Block copolymer/ferroelectric nanoparticle nanocomposites

    Science.gov (United States)

    Pang, Xinchang; He, Yanjie; Jiang, Beibei; Iocozzia, James; Zhao, Lei; Guo, Hanzheng; Liu, Jin; Akinc, Mufit; Bowler, Nicola; Tan, Xiaoli; Lin, Zhiqun

    2013-08-01

    Nanocomposites composed of diblock copolymer/ferroelectric nanoparticles were formed by selectively constraining ferroelectric nanoparticles (NPs) within diblock copolymer nanodomains via judicious surface modification of ferroelectric NPs. Ferroelectric barium titanate (BaTiO3) NPs with different sizes that are permanently capped with polystyrene chains (i.e., PS-functionalized BaTiO3NPs) were first synthesized by exploiting amphiphilic unimolecular star-like poly(acrylic acid)-block-polystyrene (PAA-b-PS) diblock copolymers as nanoreactors. Subsequently, PS-functionalized BaTiO3 NPs were preferentially sequestered within PS nanocylinders in the linear cylinder-forming polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer upon mixing the BaTiO3 NPs with PS-b-PMMA. The use of PS-b-PMMA diblock copolymers, rather than traditional homopolymers, offers the opportunity for controlling the spatial organization of PS-functionalized BaTiO3 NPs in the PS-b-PMMA/BaTiO3 NP nanocomposites. Selective solvent vapor annealing was utilized to control the nanodomain orientation in the nanocomposites. Vertically oriented PS nanocylinders containing PS-functionalized BaTiO3 NPs were yielded after exposing the PS-b-PMMA/BaTiO3 NP nanocomposite thin film to acetone vapor, which is a selective solvent for PMMA block. The dielectric properties of nanocomposites in the microwave frequency range were investigated. The molecular weight of PS-b-PMMA and the size of BaTiO3 NPs were found to exert an apparent influence on the dielectric properties of the resulting nanocomposites.Nanocomposites composed of diblock copolymer/ferroelectric nanoparticles were formed by selectively constraining ferroelectric nanoparticles (NPs) within diblock copolymer nanodomains via judicious surface modification of ferroelectric NPs. Ferroelectric barium titanate (BaTiO3) NPs with different sizes that are permanently capped with polystyrene chains (i.e., PS-functionalized BaTiO3NPs) were

  7. Effect of ball milling and heat treatment process on MnBi powders magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wei; Polikarpov, Evgueni; Choi, Jung-Pyung; Bowden, Mark E.; Sun, Kewei; Cui, Jun

    2016-09-01

    The metallic compound MnBi has high intrinsic coercivity with large positive temperature coefficient. The coercivity of MnBi exceeds 12 kOe and 26 kOe at 300 K and 523 K, respectively. Hence MnBi is a good candidate for the hard phase in exchange coupled nanocomposite magnets. In order to maximize the loading of the soft phase, the size of the MnBi particle has to be close to 500 nm, the size of single magnetic domain. Low energy milling is the common method to reduce MnBi particle size. However, only 3-7 mu m size particle can be achieved without significant decomposition. Here, we report our effort on preparing submicron MnBi powders using traditional powder metallurgy methods. Mn55Bi45 magnetic powders were prepared using arc melting method, followed by a series of thermal-mechanical treatment to improve purity, and finished with low energy ball milling at cryogenic temperature to achieve submicron particle size. The Mn55Bi45 powders were decomposed during ball milling process and recovered during 24 h 290 degrees C annealing process. With increasing ball-milling time, the saturation magnetization of MnBi decreases, while the coercivity increases. Annealing after ball milling recovers some of the magnetization, indicating the decomposition occurred during the ball-milling process can be reversed. The coercivity of Mn55Bi45 powders are also improved as a result of the heat treatment at 290 degrees C for 24 h. The world record magnetization 71.2 emu/g measured applying a field of 23 kOe has been achieved via low energy ball mill at room temperature

  8. A Nanocomposite Shield Constructed for Protection Against the Harmful Effects of Dental X-Rays

    Directory of Open Access Journals (Sweden)

    Simel Ayyıldız

    2015-10-01

    Full Text Available Objectives: This study aimed to compare a number of new nanocomposites capable of pro- tecting the jaw from ionizing radiation.Materials and Methods: Four different types of nano-powders [Ti, Zr (IV oxide, Ag and Co] were mixed in a polymer matrix to create nano-composites with doping values of 8% in weight. Small-angle X-ray scattering (SAXS analysis was performed using a HECUS- SAXS system with 50 kV- 50 mA. Co nano-composites (Co-pnm yielded the most prom- ising values of the 4 nanocomposites tested in terms of x-ray absorption. Thus, 4x2 cm Co- pnm samples of different thicknesses (0.20, 0.50, 0.57 and 0.60 cm were prepared, and SAXS analysis was performed in order to assess the effects of material thickness on x-ray absorption. An experimental multi part shield was constructed from Co-pnm around tooth#36 to test the effect of nanomaterial on the image quality under X-ray beam.Results: Logarithmic distributions of the transmitted intensity values (I showed that 0.20 cm Co-pnm had the highest transmission value (16.05 followed by 0.50 cm Co-pnm (15.44, 0.57 cm Co-pnm (15.07 and 0.60 cm Co-pnm (15.06. The 0.2 cm Co-pnm had an effective radius of the nano-aggregation value (77.44 Å lower than that of the other thick- nesses (0.50, 0.57 and 0.60 cm of Co-pnm, which had similar values ranging from 66.22-66.34 Å. The 0.50 cm Co-pnm had the lowest Dmax value of the different thicknesses of Co- pnm tested.Conclusion: Co nanocomposite can be used as a protection shield for the harmful effects of dental X-ray.

  9. Synthesis and Characterization of Polythiophene/Bi2Te3 Nanocomposite Thermoelectric Material

    Science.gov (United States)

    Ao, W. Q.; Wang, L.; Li, J. Q.; Pan, Fred; Wu, C. N.

    2011-09-01

    To achieve low thermal conductivity, polythiophene (PTh)/bismuth telluride (Bi2Te3) nanocomposite has been prepared by spark plasma sintering using a mixture of nanosized Bi2Te3 and PTh powders. Bi2Te3 powder with spherical-shaped particles of 30 nm diameter and PTh nanosheet powder were first prepared by hydrothermal synthesis and chemical oxidation, respectively. X-ray diffraction analysis and scanning electron microscopy observations revealed that the hybrid composite consists of PTh nanosheets and spherical Bi2Te3. The organic PTh acts as an adhesive in the composite. Transport measurements showed that the PTh in the Bi2Te3 matrix can reduce its thermal conductivity significantly, but also dramatically reduces its electrical conductivity. As a result, the figure of merit of the composite is lower than that of pure Bi2Te3 prepared under the same conditions. The maximum value of ZT for the sample with 5% PTh (by weight) was 0.18 at 473 K, which is rather high compared with other polymer/inorganic thermoelectric material composites.

  10. Ammonia detection of 1-D ZnO/polypyrrole nanocomposite: Effect of CSA doping and their structural, chemical, thermal and gas sensing behavior

    Science.gov (United States)

    Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D. C.; Mishra, Satyendra; Shimpi, Navinchandra G.

    2017-02-01

    Nanocomposites of polypyrrole (PPy) with varying concentration of ZnO nanorods (ZnO NRs) were synthesized using in-situ oxidative polymerization technique. The prepared nanocomposites (PPy, PPy-ZnO and CSA doped PPy-ZnO) were studied for various oxidizing and reducing gases at room temperature and found to be more selective towards ammonia gas. Various concentrations of ZnO NRs in Ppy matrix were studied and 15% was found to be optimum in terms of sensor response (66% towards 120 ppm NH3). Further, with 15% doping of camphor sulphonic acid (CSA) in PPy-ZnO nanocomposite for 15% ZnO NRs in Ppy matrix, sensor response increased from 66 to 79% towards 120 ppm of NH3. Structural, Optical and thermal behavior of nanocomposites were studied using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), UV-vis (UV-vis) absorption spectroscopy, room temperature Photoluminescence (PL) Spectroscopy, Thermo-gravimetric analysis (TGA) and Field Emission Scanning Electron Microscopy (FESEM). ZnO has been completely embedded inside the polymeric chains as observed from in SEM. Meanwhile, FT-IR spectra indicate better conjugation and interaction in nanocomposites. With CSA doping interaction grows stronger due to extended delocalization over π electrons leading to higher sensor response and with response time and recovery time of 24 s and 34 s respectively. CSA doped PPy-ZnO (15%) nanocomposites observed to be a potential candidate for ammonia detection at lower ppm level.

  11. Antituberculosis nanodelivery system with controlled-release properties based on para-amino salicylate–zinc aluminum-layered double-hydroxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Saifullah B

    2013-11-01

    Full Text Available Bullo Saifullah,1 Mohd Zobir Hussein,1 Samer Hasan Hussein-Al-Ali,2 Palanisamy Arulselvan,3 Sharida Fakurazi3,41Materials Synthesis and Characterization Laboratory, 2Laboratory of Molecular Biomedicine, 3Laboratory of Vaccines and Immunotherapeutics, 4Department of Human Anatomy, Universiti Putra Malaysia, Serdang, Selangor, MalaysiaAbstract: We report the intercalation and characterization of para-amino salicylic acid (PASA into zinc/aluminum-layered double hydroxides (ZLDHs by two methods, direct and indirect, to form nanocomposites: PASA nanocomposite prepared by a direct method (PASA-D and PASA nanocomposite prepared by an indirect method (PASA-I. Powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis revealed that the PASA drugs were accommodated within the ZLDH interlayers. The anions of the drug were accommodated as an alternate monolayer (along the long-axis orientation between ZLDH interlayers. Drug loading was estimated to be 22.8% and 16.6% for PASA-D and PASA-I, respectively. The in vitro release properties of the drug were investigated in physiological simulated phosphate-buffered saline solution of pH 7.4 and 4.8. The release followed the pseudo-second-order model for both nanocomposites. Cell viability (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assays was assessed against normal human lung fibroblast MRC-5 and 3T3 mouse fibroblast cells at 24, 48, and 72 hours. The results showed that the nanocomposite formulations did not possess any cytotoxicity, at least up to 72 hours.Keywords: drug-delivery system, slow-release nanocarrier, tuberculosis, biocompatible nanocomposites

  12. Engineering Flame Retardant Biodegradable Nanocomposites

    Science.gov (United States)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  13. Thermoelectric Properties of Polyacrylonitrile-Based Nanocomposite

    Science.gov (United States)

    Yusupov, K.; Khovaylo, V.; Muratov, D.; Kozhitov, L.; Arkhipov, D.; Pryadun, V.; Vasiliev, A.

    2016-07-01

    A polyacrylonitrile (PAN)-based nanocomposite with 20 wt.% Fe-Co/C has been prepared by infrared pyrolysis. Morphological and structural studies revealed that the composite consists of polyacrylonitrile as a plastifier, Fe-Co as a filler alloy, and carbon, which was formed during combustion of the polymer. Electrical resistivity and thermal conductivity of the composite are rather low at ambient temperatures and do not exceed 1 Ohm m and 0.5 W/m K, respectively. However, due to a very low Seebeck coefficient, the calculated figure of merit ZT of the nanocomposite does not exceed 2.1 × 10-8.

  14. New polyurethane nanocomposites based on soya oil.

    Science.gov (United States)

    Mohammed, Issam Ahmed; Abd Khadir, Nurul Khizrien; Jaffar Al-Mulla, Emad Abbas

    2014-01-01

    New polyurethane (PU) nanocomposites were prepared from a dispersion of 0 - 5% montmorillonite (MMT) clay with isocyanate and soya oil polyol that was synthesized via transesterification of triglycerides to reduce petroleum dependence. FT-IR spectra indicate the presence of hydrogen bonding between nanoclay and the polymer matrix, whereas the exfoliated structure of clay layers was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Optical microscopy, mechanical and thermal analyses were done to investigate significant improvement of the nanocomposites. The results showed PU-3% nanoclay (NC) showed optimum results in mechanical properties such as tensile and flexural strength but the lowest in impact strength.

  15. Dielectric properties of nanosilica filled epoxy nanocomposites

    Indian Academy of Sciences (India)

    M G VEENA; N M RENUKAPPA; KUNIGAL N SHIVAKUMAR; S SEETHARAMU

    2016-04-01

    This paper presents the development of epoxy-silica nanocomposites and characterized for dielectric properties. The effect of nanosilica loading (0–20 wt%), frequency, temperature and sea water aging on these properties was studied. Transmission electron microscopy (TEM) analysis of the samples showed an excellent dispersion. However, at higher silica loading TEM showed inter-contactity of the particles. The dielectric constant (υ') increased with silica loading and reached an optimum at about 10 wt%. The υ' of the nanocomposites showed linear decrease with frequency whereas AC conductivity (σac) increases. The σac and υ' increased marginally with temperature and sea water aging.

  16. Nanocomposites Derived from Polymers and Inorganic Nanoparticles

    Directory of Open Access Journals (Sweden)

    In-Yup Jeon

    2010-06-01

    Full Text Available Polymers are considered to be good hosting matrices for composite materials because they can easily be tailored to yield a variety of bulk physical properties. Moreover, organic polymers generally have long-term stability and good processability. Inorganic nanoparticles possess outstanding optical, catalytic, electronic and magnetic properties, which are significantly different their bulk states. By combining the attractive functionalities of both components, nanocomposites derived from organic polymers and inorganic nanoparticles are expected to display synergistically improved properties. The potential applications of the resultant nanocomposites are various, e.g. automotive, aerospace, opto-electronics, etc. Here, we review recent progress in polymer-based inorganic nanoparticle composites.

  17. High Temperature Epoxy Nanocomposites for Aerospace Applications

    Science.gov (United States)

    2009-06-10

    epoxy-clay nanocomposites were prepared by dispersing imidazolium- modified clays in diglycidyl ether of bisphenol A ( DGEBA ) mixture by performing...functionalized anionic clay was vigorously mixed for 2h with difunctional epoxy resin ( DGEBA ) that contained small fraction of reactive diluent 1,4...the neat DGEBA resin to increase from ~300°C to ~330°C in the 2 wt% NLDH nanocomposite at 10°C/min heating rate, while it increases from ~305°C in

  18. 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

    2017-06-01

    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.

  19. Improved Workability of the Nanocomposited AgSnO2 Contact Material and Its Microstructure Control During the Arcing Process

    Science.gov (United States)

    Wang, Yaping; Li, Haiyan

    2017-02-01

    There are two major weaknesses for the AgSnO2 contacts used in the low voltage switch devices. One is poor workability, which causes the AgSnO2 materials to hardly deform into the required shape. Another is the increased contact resistance after arcing, which, in turn, causes an unfavorable temperature rise in the switches. In this article, the nanocomposited AgSnO2 materials were developed to overcome the weaknesses. The nanosized SnO2 powders with or without CuO additive were prepared by the chemical precipitation method. The SnO2 powders and Ag powders were high energy milled together to obtain AgSnO2 composite powders, which were then sintered, hot pressed and extruded. It was found that the SnO2 particles mainly distribute in the interior of Ag grains with Ag film on the grain boundary. The hardness of AgSnO2 composites and the wetting angle of Ag melt on SnO2 particles decreased with the addition of a small amount of CuO. By the combining effect of Ag film on grain boundary and the addition of CuO, the elongation and workability of the AgSnO2 materials improved. The experiments of rapid solidification revealed that more SnO2 particles with CuO addition were engulfed in the Ag matrix than those without CuO, which inhibited the redistribution of SnO2 particles on the contact surface during the arcing process. The industrial type test in the 45A contactor suggested that the nanocomposited AgSnO2 materials are suitable to be used as contacts in low voltage switches.

  20. [Identication of pearl powder and conch powder from different origins by differential scanning calorimetry].

    Science.gov (United States)

    Chen, Jia; Li, Ming-hua; Yu, Kun-zi; Dong, Ya-juan; Zhang, Nan-ping; Hu, Xiao-ru; Wei, Feng; Ma, Shuang-cheng

    2015-04-01

    The paper is aimed to establish a methods for identication of pearl powder and conch powder from different origins. Hermetic aluminum pan was used to encapsulate samples. The optimal testing conditions were: heating rate 10 degrees C x min(-1), sample weight 3 mg and nitrogen gas flow rate 40 mL x min(-1). The enthalpy values of pearl powder and conch powder was obvious different. Identication of pearl powder and conch powder by DSC is a practical method for its accuracy, convenience and practificality.

  1. Development of ceramic based nanocomposites with high performance; Koseino ceramic kei nanocomposite no kaihatsu kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Niihara, K.; Sekino, T.; Choa, Y. [Osaka University, Osaka (Japan). The Institute and Industrial Research; Nakahira, A.

    1997-10-15

    Various ceramic-based nanocomposite materials with nano-scale ceramic or metal grains diffused thereinto are introduced. Oxide-based ceramics/ceramics nanocomposite materials such as those based on Al2O3/SiC and on natural mullite/SiC have been successfully produced using the ordinary sintering technology. As intragrain nanocomposite materials of the non-oxide base, those based on Si3N4/granular TiC and on SiC with stacking faults have been developed, and it is disclosed that fracture toughness improves two times in a stacking-fault composite. By the application of the method for manufacturing ceramics/metal-based materials, finer texture control can be exercised than by the application of the ceramics/ceramics-based nanocomposite manufacturing technology. The nanocomposite materials obtained so far include those based on Al2O3/W and on Al2O3/Mo. In the future, various ceramic materials will be manufactured to satisfy versatile requests for different performance, and it is believed that a ceramic material so tough as to withstand the maximum temperature will be realized by combining microcomposite materials and nanocomposite materials. 33 refs., 15 figs., 3 tabs.

  2. Rapidly solidified aluminum alloy powder

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.S.; Chun, B.S.; Won, C.W.; Lee, B.S.; Kim, H.K.; Ryu, M. [Chungnam National Univ., Taejon (Korea, Republic of); Antolovich, S.D. [Washington State Univ., Pullman, WA (United States)

    1997-01-01

    Miniaturization and weight reduction are becoming increasingly important in the fabrication of vehicles. In particular, aluminum-silicon alloys are the logical choice for automotive parts such as pistons and cylinders liners because of their excellent wear resistance and low coefficient of thermal expansion. However, it is difficult to produce aluminum-silicon alloys with silicon contents greater than 20 wt% via ingot metallurgy, because strength is drastically reduced by the coarsening of primary silicon particles. This article describes an investigation of rapid solidification powder metallurgy techniques developed in an effort to prevent coarsening of the primary silicon particles in aluminum-silicon alloys.

  3. Ethylene-Octene Copolymers/Organoclay Nanocomposites: Preparation and Properties

    Directory of Open Access Journals (Sweden)

    Alice Tesarikova

    2016-01-01

    Full Text Available Two ethylene-octene copolymers with 17 and 45 wt.% of octene (EOC-17 and EOC-45 were compared in nanocomposites with Cloisite 93A. EOC-45 nanocomposites have a higher elongation at break. Dynamical mechanical analysis (DMA showed a decrease of tan⁡δ with frequency for EOC-17 nanocomposites, but decrease is followed by an increase for EOC-45 nanocomposites; DMA showed also increased modulus for all nanocomposites compared to pure copolymers over a wide temperature range. Barrier properties were improved about 100% by addition of organoclay; they were better for EOC-17 nanocomposites due to higher crystallinity. X-ray diffraction (XRD together with transmission electron microscopy (TEM showed some intercalation for EOC-17 but much better dispersion for EOC-45 nanocomposites. Differential scanning calorimetry (DSC showed increased crystallization temperature Tc for EOC-17 nanocomposite (aggregates acted as nucleation agents but decrease Tc for EOC-45 nanocomposite together with greatly influenced melting peak. Accelerated UV aging showed smaller C=O peak for EOC-45 nanocomposites.

  4. Structural characterization of SiO2/Zn2SiO4:Ce nanocomposite obtained by sol gel method

    Directory of Open Access Journals (Sweden)

    A. Chelouche

    2014-04-01

    Full Text Available Ce-doped ZnO nanopowder and ZnO:Ce/silica nanocomposite were synthesized by sol–gel process under supercritical drying (temperature and pressure of ethanol. Annealing at 1200 °C under atmospheric pressure has been achieved for the prepared ZnO:Ce/silica nanocomposite. X-ray diffraction (XRD showed good crystallinity and a ZnO hexagonal wurtzite structure of the as-prepared powder. The average crystallite size is of the order of 78 nm. Crystallites agglomerate to form spheres, hexagons and/or hexagons inserted in tori. The introduction of ZnO:Ce in silica leads to the formation of zinc silicate even before annealing. The heat treatment reduces the intensity of the diffraction peaks and enhanced the formation of this new phase. Photoluminescence (PL spectra showed that the introduction of ZnO:Ce in silica before annealing reduces the UV lines and red shifts the entire emission. After annealing the PL intensity of the nanocomposite is significantly reduced.

  5. Si-FeSi2/C nanocomposite anode materials produced by two-stage high-energy mechanical milling

    Science.gov (United States)

    Yang, Yun Mo; Loka, Chadrasekhar; Kim, Dong Phil; Joo, Sin Yong; Moon, Sung Whan; Choi, Yi Sik; Park, Jung Han; Lee, Kee-Sun

    2017-05-01

    High capacity retention Silicon-based nanocomposite anode materials have been extensively explored for use in lithium-ion rechargeable batteries. Here we report the preparation of Si-FeSi2/C nanocomposite through scalable a two-stage high-energy mechanical milling process, in which nano-scale Si-FeSi2 powders are besieged by the carbon (graphite/amorphous phase) layer; and investigation of their structure, morphology and electrochemical performance. Raman analysis revealed that the carbon layer structure comprised of graphitic and amorphous phase rather than a single amorphous phase. Anodes fabricated with the Si-FeSi2/C showed excellent electrochemical behavior such as a first discharge capacity of 1082 mAh g-1 and a high capacity retention until the 30th cycle. A remarkable coulombic efficiency of 99.5% was achieved within a few cycles. Differential capacity plots of the Si-FeSi2/C anodes revealed a stable lithium reaction with Si for lithiation/delithiation. The enhanced electrochemical properties of the Si-FeSi2/C nanocomposite are mainly attributed to the nano-size Si and stable solid electrolyte interface formation and highly conductive path driven by the carbon layer.

  6. Spark plasma sintered Sm(2)Co(17)-FeCo nanocomposite permanent magnets synthesized by high energy ball milling.

    Science.gov (United States)

    Sreenivasulu, G; Gopalan, R; Chandrasekaran, V; Markandeyulu, G; Suresh, K G; Murty, B S

    2008-08-20

    Nanocomposite Sm(2)Co(17)-5 wt% FeCo magnets were synthesized by high energy ball milling followed by consolidation into bulk shape by the spark plasma sintering technique. The evolution of magnetic properties was systematically investigated in milled powders as well as in spark plasma sintered samples. A high energy product of 10.2 MGOe and the other magnetic properties of M(s) = 107 emu g(-1), M(r) = 59 emu g(-1), M(r)/M(s) = 0.55 and H(c) = 6.4 kOe were achieved in a 5 h milled and spark plasma sintered Sm(2)Co(17)-5 wt% FeCo nanocomposite magnet. The spark plasma sintering was carried out at 700 °C for 5 min with a pressure of 70 MPa. The nanocomposite showed a higher Curie temperature of 955 °C for the Sm(2)Co(17) phase in comparison to its bulk Curie temperature for the Sm(2)Co(17) phase (920 °C). This higher Curie temperature can improve the performance of the magnet at higher temperatures.

  7. Characterization and optical properties of TeO2/ZnO nanocomposites synthesized in a narrow temperature range

    Science.gov (United States)

    Lee, Dongjin; Park, Seokhyun; Kim, Hee Jung; Hyun, Soong-Keun; Choe, Kyeonghwan; Jin, Changhyun

    2017-08-01

    Two different TeO2- and ZnO-based nanocomposites were synthesized by a continuous two-step gas phase transport process with a pre-deposited Au catalyst at different synthetic temperatures. The morphology and composition of the TeO2 nanowires showed successive changes with ZnO precursor powder with increasing temperature, going from TeO2 nanowires to TeO2/ZnO nanocomposites. The photoluminescence (PL) spectra of these samples indicated that (1) the as-synthesized TeO2 nanowires have a broad blue emission band at 420 nm as well as green (540 nm), orange (607 nm), and red (723 nm) emissions, and (2) the TeO2/ZnO nanocomposites display not only a narrow violet emission band at 380 nm but also green (510 and 540 nm), orange (607 and 645 nm), and red (723 nm) bands. The optical quality of two different samples, based on the emission intensity ratio (I excitonic/I defect) related to band to band transitions and deep level defects, has a tendency to decrease rapidly with increasing synthesis temperature. Simple control of the synthetic temperature zone between two different oxide composites may cause functional, compositional, and optical changes in the product.

  8. Magnetic α-Fe2O3/MCM-41 nanocomposites: preparation, characterization, and catalytic activity for methylene blue degradation.

    Science.gov (United States)

    Ursachi, Irina; Stancu, Alexandru; Vasile, Aurelia

    2012-07-01

    Catalysts based on nanosized magnetic iron oxide stabilized inside the pore system of ordered mesoporous silica MCM-41 have been prepared. The obtained materials were characterized by powder X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and N(2) adsorption-desorption isotherm. XRD analysis showed that the obtained materials consist from the pure hematite crystalline phase (α-Fe(2)O(3)) dispersed within ordered mesoporous silica MCM-41. Magnetic measurements show that the obtained nanocomposites exhibit at room temperature weak ferromagnetic behavior with slender hysteresis. The catalytic activity of the magnetic α-Fe(2)O(3)/MCM-41 nanocomposites was evaluated by the degradation of methylene blue (MB) aqueous solution. For this purpose, an ultrasound-assisted Fenton-like process was used. The effect of solution pH on degradation of MB was investigated. The results indicated that US-H(2)O(2)-α-Fe(2)O(3)/MCM-41 nanocomposite system is effective for the degradation of MB, suggesting its great potential in removal of dyes from wastewater. It was found that the degradation rate of MB increases with decrease in the pH value of the solution.

  9. Synthesis, characterization and enhanced thermoelectric performance of structurally ordered cable-like novel polyaniline-bismuth telluride nanocomposite

    Science.gov (United States)

    Chatterjee, Krishanu; Mitra, Mousumi; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali

    2013-05-01

    Bismuth telluride (Bi2Te3) nanorods and polyaniline (PANI) nanoparticles have been synthesized by employing solvothermal and chemical oxidative processes, respectively. Nanocomposites, comprising structurally ordered PANI preferentially grown along the surface of a Bi2Te3 nanorods template, are synthesized using in situ polymerization. X-ray powder diffraction, UV-vis and Raman spectral analysis confirm the highly ordered chain structure of PANI on Bi2Te3 nanorods, leading to a higher extent of doping, higher chain mobility and enhancement of the thermoelectric performance. Above 380 K, the PANI-Bi2Te3 nanocomposite with a core-shell/cable-like structure exhibits a higher thermoelectric power factor than either pure PANI or Bi2Te3. At room temperature the thermal conductivity of the composite is lower than that of its pure constituents, due to selective phonon scattering by the nanointerfaces designed in the PANI-Bi2Te3 nanocable structures. The figure of merit of the nanocomposite at room temperature is comparable to the values reported in the literature for bulk polymer-based composite thermoelectric materials.

  10. Fabrication of superparamagnetic magnetite/poly(styrene-co-12-acryloxy-9-octadecenoic acid) nanocomposite microspheres with controllable structure.

    Science.gov (United States)

    Yang, Song; Liu, Huarong; Huang, Haofeng; Zhang, Zhicheng

    2009-10-15

    We herein report a novel and facile approach to the fabrication of the superparamagnetic magnetite/poly(styrene-co-12-acryloxy-9-octadecenoic acid) nanocomposite microspheres with controllable structure via gamma-ray radiation induced inverse emulsion polymerization under room temperature and at ambient pressure. 12-Acryloxy-9-octadecenoic acid (AOA, containing part of sodium salts Na-AOA) as a surfactant can also copolymerize with the styrene. It is interesting that just by changing the added amount of styrene, the magnetic hollow spheres with different wall thickness and various sizes of core, up to the magnetic solid spheres, can be obtained. The final products were thoroughly characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron diffraction (TEM), field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA) which showed the formation of magnetite/poly(styrene-co-AOA) nanocomposite microspheres. Magnetic hysteresis loop measurements showed that the magnetic nanocomposite microspheres exhibited superparamagnetism, which should make them have potential applications in biotechnology and biomedicine. Furthermore, we also proposed a possible formation mechanism of these magnetic microspheres with different morphologies.

  11. Assessment of Powder Mixed EDM: A Review

    Directory of Open Access Journals (Sweden)

    Nanimina Alexis Mouangué

    2014-07-01

    Full Text Available This project research undertakes the assessment of powder added electrical discharge machining (PMDM with focus on effect of additive powders and circulation systems. In PMEDM process, powder can be mixed with dielectric fluid either in the main EDM tank or in a separate tank in order to improve EDM machining performance. Different designs of powder mixed EDM circulating systems such as closed and opened systems with different sizes of tank are described in literature. Various devices such as stirrer, circulating pump etc. are placed in the tank in order to ensure the uniformity of powder mixed dielectric. Each design has its advantages and disadvantages and it might affect the EDM output results. Therefore, there is a need to review the PMEDM with respect to additive powders and circulation systems in order to identify the gap and propose an alternative for improving process.

  12. Adsorption of lignosulfonate compounds using powdered eggshell

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Zulfikar

    2012-07-01

    Full Text Available Batch adsorption of lignosulfonates using untreated powdered eggshell under the influences of mixing time, pH,particle size and dose of powdered eggshell was investigated. Adsorption isotherms of lignosulfonates onto powder eggshellwere also studied. Eggshells were collected from the Balubur traditional market in Bandung, Indonesia, washed with distilledwater, air dried, and then ground into powder of different particle sizes. Kinetic studies found that equilibrium time was ashigh as 90 minutes. From experiments carried out at different pH, it was observed that pH plays an important role in theadsorption of lignosulfonate compounds. It was also observed that particles size has no significant effect on the adsorptionof lignosulfonate compounds. The optimum dosage of powdered eggshell was 30 g/100 mL of 500 mg/L lignosulfonatesolution. Adsorption isotherms studied through the use of graphical methods revealed that the adsorption of lignosulfonatesonto powdered eggshell follows the Langmuir model.

  13. Structural and optical properties of SnO2–Al2O3 nanocomposite synthesized via sol-gel route

    Directory of Open Access Journals (Sweden)

    Mishra Neeraj K.

    2015-12-01

    Full Text Available A nanocomposite of 0.5SnO2–0.5Al2O3 has been synthesized using a sol-gel route. Structural and optical properties of the nanocomposite have been discussed in detail. Powder X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray diffraction spectroscopy confirm the phase purity and the particle size of the 0.5SnO2–0.5Al2O3 nanocomposite (13 to 15 nm. The scanning electron microscopy also confirms the porosity in the sample, useful in sensing applications. The FT-IR analysis confirms the presence of physical interaction between SnO2 and Al2O3 due to the slight shifting and broadening of characteristic bands. The UV-Vis analysis confirms the semiconducting nature because of direct transition of electrons into the 0.5SnO2–0.5Al2O3 nanocomposites.

  14. Manganese-incorporated iron(III) oxide-graphene magnetic nanocomposite: synthesis, characterization, and application for the arsenic(III)-sorption from aqueous solution

    Science.gov (United States)

    Nandi, Debabrata; Gupta, Kaushik; Ghosh, Arup Kumar; De, Amitabha; Banerjee, Sangam; Ghosh, Uday Chand

    2012-12-01

    High specific surface area of graphene (GR) has gained special scientific attention in developing magnetic GR nanocomposite aiming to apply for the remediation of diverse environmental problems like point-of-use water purification and simultaneous separation of contaminants applying low external magnetic field (water. Fabrication of magnetic manganese-incorporated iron(III) oxide (Mn x 2+Fe2- x 3+O4 2-) (IMBO)-GR nanocomposite is reported by exfoliating the GR layers. Latest microscopic, spectroscopic, powder X-ray diffraction, BET surface area, and superconducting quantum interference device characterizations showed that the material is a magnetic nanocomposite with high specific surface area (280 m2 g-1) and pore volume (0.3362 cm3 g-1). Use of this composite for the immobilization of carcinogenic As(III) from water at 300 K and pH 7.0 showed that the nanocomposite has higher binding efficiency with As(III) than the IMBO owing to its high specific surface area. The composite showed almost complete (>99.9 %) As(III) removal (≤10 μg L-1) from water. External magnetic field of 0.3 T efficiently separated the water dispersed composite (0.01 g/10 mL) at room temperature (300 K). Thus, this composite is a promising material which can be used effectively as a potent As(III) immobilizer from the contaminated groundwater (>10 μg L-1) to improve drinking water quality.

  15. Synthesis, Characterization, and Investigation of Visible Light Photocatalytic Activity of C Doped TiO2/CdS Core-Shell Nanocomposite

    Directory of Open Access Journals (Sweden)

    Atul B. Lavand

    2015-01-01

    Full Text Available Carbon (C doped TiO2/CdS core-shell nanocomposite (C/TiO2/CdS was synthesized using microemulsion method. Synthesized powder was characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, energy dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, and UV-visible spectrophotometery. TEM images reveal that C/TiO2/CdS core-shell heterostructure is successfully prepared with CdS as a core and C doped TiO2 as a shell. UV-visible absorption spectra show that CdS nanoparticles act as a sensitizer and effectively enhance the photoabsorption capacity of C/TiO2/CdS nanocomposite in visible region. Visible light photocatalytic activity of synthesized nanocomposite was evaluated for the degradation of methylene blue. C/TiO2/CdS core-shell nanocomposite exhibits better photocatalytic activity as compared to bare TiO2, CdS, CdS/TiO2, and C doped TiO2.

  16. Synthesis and characterization of foldable and magnetic field-sensitive, freestanding poly(vinyl acetate)/poly(vinyl chloride)/polyfuran composite and nanocomposite films

    Science.gov (United States)

    Sarıtaş, Sevilay; Eşsiz, Serpil; Sarı, Bekir

    2017-07-01

    In this study, polyfuran and poly(vinyl acetate)/poly(vinyl chloride)/polyfuran ternary composites were synthesized via the chemical polymerization method. The temperature and magnetic field-sensitive novel composites and the nanocomposite were obtained in the form of powders and films. It was observed that the prepared novel conductive films have superior properties at a certain temperature range (25-50 °C) such as bending and folding. The structural properties, thermal behavior, surface morphology, internal structure, and surface roughness of the prepared samples were investigated by various characterization techniques. The conductivities of the samples were measured at room temperature and different temperatures by the four-point technique. X-ray Diffraction analysis results demonstrated that the PF and composites have an amorphous structure, whereas the nanocomposite is in crystalline form. The saturation magnetization (Ms) values of the magnetite and nanocomposite were found to be 58.9 and 5.3 emu g-1, respectively. It was found that magnetite-doped nanocomposite has superparamagnetic properties at room temperature.

  17. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Nielsen, Ole Faurskov; Ståhl, Kenny

    2010-01-01

    X-ray powder diffraction patterns of lysozyme and insulin were recorded on a standard in-house powder diffractometer. The experimental powder diffraction patterns were compared with patterns calculated from Protein Data Bank coordinate data. Good agreement was obtained by including straightforward...... to include calculated H-atom positions did not improve the overall fit and was abandoned. The method devised was shown to be a quick and convenient tool for distinguishing precipitates and polymorphs of proteins....

  18. Hydrophobic Silsesquioxane Nanoparticles and Nanocomposite Surfaces

    Science.gov (United States)

    2008-09-23

    Nanocomposite Surfaces (Preprint) 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Joseph M. Mabry, Ashwani Vij, Brent D. Viers, Wade W...of FD8T8 or FO8T8 into PCTFE. All samples were blended in a DACA Micro Compounder for 3 minutes at 100 rotations per minute. The DACA Micro

  19. A novel piezoresistive polymer nanocomposite MEMS accelerometer

    Science.gov (United States)

    Seena, V.; Hari, K.; Prajakta, S.; Pratap, Rudra; Ramgopal Rao, V.

    2017-01-01

    A novel polymer MEMS (micro electro mechanical systems) accelerometer with photo-patternable polymer nanocomposite as a piezoresistor is presented in this work. Polymer MEMS Accelerometer with beam thicknesses of 3.3 µm and embedded nanocomposite piezoresistive layer having a gauge factor of 90 were fabricated. The photosensitive nanocomposite samples were prepared and characterized for analyzing the mechanical and electrical properties and thereby ensuring proper process parameters for incorporating the piezoresistive layer into the polymer MEMS accelerometer. The microfabrication process flow and unit processes followed are extremely low cost with process temperatures below 100 °C. This also opens up a new possibility for easy integration of such polymer MEMS with CMOS (complementary metal oxide semiconductor) devices and circuits. The fabricated devices were characterized using laser Doppler vibrometer (LDV) and the devices exhibited a resonant frequency of 10.8 kHz and a response sensitivity of 280 nm g-1 at resonance. The main focus of this paper is on the SU-8/CB nanocomposite piezoresistive MEMS accelerometer technology development which covers the material and the fabrication aspects of these devices. CoventorWare FEA analysis performed using the extracted material properties from the experimental characterization which are in close agreement to performance parameters of the fabricated devices is also discussed. The simulated piezoresistive polymer MEMS devices showed an acceleration sensitivity of 126 nm g-1 and 82 ppm of ΔR/R per 1 g of acceleration.

  20. Polymer nanocomposite processing, characterization, and applications 2013

    CSIR Research Space (South Africa)

    Mago, G

    2014-02-01

    Full Text Available , such as processing technique, interfacial interaction between nanoparticles and host polymers, and state of nanoparticle dispersion. While a number of advances have recently been made in the area of polymer nanocomposites, the studies on understanding of the effects...

  1. In situ SU-8 silver nanocomposites

    Directory of Open Access Journals (Sweden)

    Søren V. Fischer

    2015-07-01

    Full Text Available Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution to this problem, an easy new method of fabricating silver nanocomposites by an in situ reduction of precursors within the epoxy-based photoresist SU-8 has been developed. AgNO3 dissolved in acetonitrile and mixed with the epoxy-based photoresist SU-8 forms silver nanoparticles primarily during the pre- and post-exposure soft bake steps at 95 °C. A further high-temperature treatment at 300 °C resulted in the formation of densely homogeneously distributed silver nanoparticles in the photoresist matrix. No particle growth or agglomeration of nanoparticles is observed at this point. The reported new in situ silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5 µm is achieved in the lithographic process. The UV exposure time is found to be independent of the nanoparticle concentration. The fabricated silver nanocomposites exhibit high plasmonic responses suitable for the development of new optoelectronic and optical sensing devices.

  2. Magnetic graphene based nanocomposite for uranium scavenging

    Energy Technology Data Exchange (ETDEWEB)

    El-Maghrabi, Heba H. [Egyptian Petroleum Research Institute, 11727, Cairo (Egypt); Abdelmaged, Shaimaa M. [Nuclear Materials Authority, 6530 P.O. Box Maadi, Cairo (Egypt); Nada, Amr A. [Egyptian Petroleum Research Institute, 11727, Cairo (Egypt); Zahran, Fouad, E-mail: f.zahran@quim.ucm.es [Faculty of Science, Helwan University, 11795, Cairo (Egypt); El-Wahab, Saad Abd; Yahea, Dena [Faculty of Science, Ain shams University, Cairo (Egypt); Hussein, G.M.; Atrees, M.S. [Nuclear Materials Authority, 6530 P.O. Box Maadi, Cairo (Egypt)

    2017-01-15

    Graphical abstract: Graphical representation of U{sup 6+} adsorption on Magnetic Ferberite-Graphene Nanocomposite. - Highlights: • Synthesis of new magnetic wolframite bimetallic nanostructure on graphene. • A promising adsorption capacity of 455 mg/g was recorded for FG-20 within 60 min at room temperature. • The uranium removal was followed pseudo-second order kinetics and Langmuir isotherm. - Abstract: Magnetic graphene based ferberite nanocomposite was tailored by simple, green, low cost and industrial effective method. The microstructure and morphology of the designed nanomaterials were examined via XRD, Raman, FTIR, TEM, EDX and VSM. The prepared nanocomposites were introduced as a novel adsorbent for uranium ions scavenging from aqueous solution. Different operating conditions of time, pH, initial uranium concentration, adsorbent amount and temperature were investigated. The experimental data shows a promising adsorption capacity. In particular, a maximum value of 455 mg/g was obtained within 60 min at room temperature with adsorption efficiency of 90.5%. The kinetics and isotherms adsorption data were fitted with the pseudo-second order model and Langmuir equation, respectively. Finally, the designed nanocomposites were found to have a great degree of sustainability (above 5 times of profiteering) with a complete maintenance of their parental morphology and adsorption capacity.

  3. montmorillonite nanocomposite containing n,n

    African Journals Online (AJOL)

    Preferred Customer

    After another 24 h soaking period, the films were taken out, dried and weighed for any weight gain. This process was repeated ... type is an exfoliated polymer-clay nanocomposite, in which is there is a loss of ordered structures due to the ...

  4. Durable Nanocomposites for Superhydrophobicity and Superoleophobicity

    Science.gov (United States)

    Steele, Adam

    Anti-wetting surfaces and materials have the potential for dramatic performance improvements such as drag reduction on marine vehicles and fluid power systems as well as anti-fouling on aircraft and wind turbines. Although a wide variety of synthetic superhydrophobic surfaces have been developed and investigated, several critical obstacles remain before industrial application can be realized, including: (1) large surface area application, (2) multi-liquid anti-wetting, (3) environmentally friendly compositions, (4) mechanical durability and adhesion, and (5) long-term performance. In this dissertation, nanocomposite coatings have been investigated to generate high performance anti-wetting surfaces that address these obstacles which may enable application on wind turbine blades. Solution processable materials were used which self-assemble to create anti-wetting nanocomposite surfaces upon spray coating and curing. As a result, the first superoleophobic nanocomposite, the first environmentally friendly superhydrophobic compositions, and the first highly durable superhydrophobic nanocomposite coatings were created. Furthermore, the mechanisms leading to this improved performance were studied.

  5. Nanocomposites in food packaging – A review

    Science.gov (United States)

    A nanocomposite is a multiphase material derived from the combination of two or more components, including a matrix (continuous phase) and a discontinuous nano-dimensional phase with at least one nano-sized dimension (i.e. less than 100 nm). The main types of nanostructures are presented in this ch...

  6. Structure-Property Relationship of Thermoset Nanocomposites

    NARCIS (Netherlands)

    Faraz, M.I.

    2013-01-01

    In this thesis we report the synthesis, characterization and thermo-mechanical properties of a high-temperature resistant themoset nanocomposite system based on an aero-space-grade Bismaleimide resin. Various processing techniques with various fillers are used. The emphasis is on establishing the re

  7. Risk Assessment of Baby Powder Exposure through Inhalation

    OpenAIRE

    Moon, Min Chaul; Park, Jung Duck; Choi, Byung Soon; Park, So Young; Kim, Dong Won; Chung, Yong Hyun; HISANAGA, Naomi; Yu, Il Je

    2011-01-01

    This study was conducted to assess the exposure risk through inhalation to baby powder for babies and adults under simulated conditions. Baby powder was applied to a baby doll and the amount of baby powder consumed per application was estimated. The airborne exposure to baby powder during application was then evaluated by sampling the airborne baby powder near the breathing zones of both the baby doll and the person applying the powder (the applicator). The average amount of baby powder consu...

  8. Electrically Conductive Metal Nanowire Polymer Nanocomposites

    Science.gov (United States)

    Luo, Xiaoxiong

    This thesis investigates electrically conductive polymer nanocomposites formulated with metal nanowires for electrostatic discharge and electromagnetic interference shielding. Copper nanowires (CuNWs) of an average length of 1.98 mum and diameter of 25 +/- 4 nm were synthesized. The oxidation reaction of the CuNWs in air can be divided into two stages at weight of 111.2% on TGA curves. The isoconversional activation energies determined by Starink method were used to fit the different master plots. Johnson-Mehl-Avrami (JMA) equation gave the best fit. The surface atoms of the CuNWs are the sites for the random nucleation and the crystallite strain in the CuNWs is the driving force for the growth of nuclei mechanism during the oxidation process. To improve the anti-oxidation properties of the CuNWs, silver was coated onto the surface of the CuNWs in Ag-amine solution. The prepared silver coated CuNWs (AgCuNWs) with silver content of 66.52 wt. %, diameter of 28--33 nm exhibited improved anti-oxidation behavior. The electrical resistivity of the AgCuNW/low density polyethylene (LDPE) nanocomposites is lower than that of the CuNW/LDPE nanocomposites with the same volume percentage of fillers. The nanocomposites formulated with CuNWs and polyethylenes (PEs) were compared to study the different interaction between the CuNWs and the different types of PE matrices. The electrical conductivity of the different PE matrices filled with the same concentrations of CuNWs correlated well with the level of the CuNW dispersion. The intermolecular force and entanglement resulting from the different macromolecular structures such as molecular weight and branching played an important role in the dispersion, electrical properties and rheological behaviour of the CuNW/PE nanocomposites. Ferromagnetic polycrystalline nickel nanowires (NiNWs) were synthesized with uniform diameter of ca. 38 nm and an average length of 2.68 mum. The NiNW linear low density polyethylene (LLDPE

  9. Graphene based nanocomposite hybrid electrodes for supercapacitors

    Science.gov (United States)

    Aphale, Ashish N.

    There is an unmet need to develop high performance energy storage systems (ESS), capable of storing energy from both renewable and non-renewable sources to meet the current energy crisis and depletion of non-renewable sources. Amongst many available ESS, supercapacitors (ECs) are the most promising because they exhibit a high charge/discharge rate and power density, along with a long cycle life. The possibility of exploring the use of atomically thin carbon allotropes like graphene, carbon nanotubes (CNTs) and electrically conducting polymers (ECPs) such as polypyrrole (PPy) has been studied as a high performance conducting electrodes in supercapacitor application. A novel templated sustainable nanocomposite electrode has been fabricated using cellulose extracted from Cladophora c. aegagropila algae as component of the assembled supercapacitor device which later has been transitioned to a unique template-less freestanding nanocomposite supercapacitor electrode. The specific capacitance of polypyrrole-graphene-cellulose nanocomposite as calculated from cyclic voltammetry curve is 91.5 F g -1 at the scan rate 50 m Vs-1 in the presence of 1M NaCl electrolyte. The open circuit voltage of the device with polypyrrole -graphene-cellulose electrode was found to be around 225 m V and that of the polypyrrole -cellulose device is only 53 m V without the presence of graphene in the nanocomposite electrode. Understanding the fundamentals by fabricating template nanocomposite electrode, it led to fabricate a unique nanocomposite template-less freestanding film which comprises of polypyrrole-graphene-CNT hybrid. Various experiments have been performed using different electrolytes such ascorbic acid, sodium sulfate and sulfuric acid in different scan rates. The specific capacitance of polypyrrole-graphene-CNT nanocomposite with 0.1 wt% of graphene-CNT, as calculated from cyclic voltammetry curve is 450 F g-1 at the scan rate 5 m V s-1. For the first time a nanofibrous membrane has

  10. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    Amit Sinha; B P Sharma

    2005-06-01

    High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The powders were well crystalline and contained oxygen, carbon and hydrogen as impurities. Overall purity was better than 99.9%. The yield of silver powder was better than 99%.

  11. 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.

  12. How to freeze drop oscillations with powders

    Science.gov (United States)

    Marston, Jeremy; Zhu, Ying; Vakarelski, Ivan; Thoroddsen, Sigurdur

    2012-11-01

    We present experiments that show when a water drop impacts onto a bed of fine, hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. For all drop impact speeds, the drop rebounds due to the hydrophobic nature of the powder. However, we observe that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a complete coverage of powder, thus creating a deformed liquid marble. This powder coating acts to freeze the drop oscillations during rebound.

  13. Possibility of Extrusion of Wood Powders

    National Research Council Canada - National Science Library

    MIKI, Tsunehisa; TAKAKURA, Norio; IIZUKA, Takashi; YAMAGUCHI, Katsuhiko; KANAYAMA, Kouzou

    2003-01-01

    .... Effects of extrusion temperature, extrusion ratio, moisture content and particle size of the mixed wood powders on the flow characteristics, bending strength, hardness and bulk density of extruded...

  14. Fine grain tungsten produced with nanoscale powder

    Institute of Scientific and Technical Information of China (English)

    Tao Lin; Fang Zhao; Liying Zhang; Chengyi Wu; Zhimeng Guo

    2005-01-01

    Nanoscale tungsten powder was prepared by reducing nanoscale tungsten trioxide in hydrogen to WO2.90 and further to W powder. After compacted with a rubber die, the nanoscale tungsten powder was sintered in a high-temperature dilatometer to investigate its shrinkage process. The results show that the compact of the nanoscale tungsten powder starts to shrink at 1050℃ and ends at 1500℃. The shrinkage rate reaches the maximum value at 1210℃. The relative density of sintered samples is 96.4%, and its grain size is about 5.8 μm.

  15. New avenues to efficient chemical synthesis of exchange coupled hard/soft nanocomposite magnet.

    Science.gov (United States)

    Lee, Don Keun; Cha, Hyun Gil; Kim, Young Hwan; Kim, Chang Woo; Ji, Eun Sun; Kang, Young Soo

    2009-07-01

    Nd-Fe-B ultrafine amorphous alloy particles were prepared by reaction of metal ions with borohydride in aqueous solution. Monodispersed Fe nanoparticles were synthesized under an argon atmosphere via thermal decomposition of Fe(2+)-oleate2. Exchange coupled Nd2Fe14B/Fe nanocomposite magnets have been prepared by self-assembly using surfactant. The crystal structure of the synthesized nanoparticles was identified by using X-ray powder diffraction (XRD). The size and shape of nanoparticles were obtained by transmission electron microscope (TEM). Thermogravimetry using a microbalance with magnetic field gradient positioned below the sample was used for the measurement of a thermomagnetic analysis (TMA) curve showing the downward magnetic force versus temperature.

  16. Influence of Nanosized Silicon Carbide on Dimensional Stability of Al/SiC Nanocomposite

    Directory of Open Access Journals (Sweden)

    S. M. Zebarjad

    2008-01-01

    Full Text Available This study concentrated on the role of particle size of silicon carbide (SiC on dimensional stability of aluminum. Three kinds of Al/SiC composite reinforced with different SiC particle sizes (25 μm, 5 μm, and 70 nm were produced using a high-energy ball mill. The standard samples were fabricated using powder metallurgy method. The samples were heated from room temperature up to 500∘C in a dilatometer at different heating rates, that is, 10, 30, 40, and 60∘C/min. The results showed that for all materials, there was an increase in length change as temperature increased and the temperature sensitivity of aluminum decreased in the presence of both micro- and nanosized silicon carbide. At the same condition, dimensional stability of Al/SiC nanocomposite was better than conventional Al/SiC composites.

  17. Synthesis and Enhanced Superplasticity of the Zirconia-dispersed Alumina Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    Guoqing CHEN; Kaifeng ZHANG; Wenbo HAN; Junting LUO

    2005-01-01

    A series of alumina-zirconia composites with various grain sizes were prepared from the nano-sized powders with different agglomerations. Microstructural analysis of the sintered compacts indicates that the as-sintered material is a typical intra/inter granular nanocomposite with uniform distribution of the zirconia grains in the alumina matrix.Superplastic deep drawing test under different conditions demonstrates that dense Al2O3/ZrO2 samples with average grain size of 230 nm can be elongated to a dome height of at least 12 mm at the punch rate of 0.6 mm.min-1at 1400℃. Further drawing tests show that for the composites with larger grain size, such elongation cannot be achieved at such a strain rate.

  18. Synthesis, Spectral Characterization, and Antibacterial and Antifungal Studies of PANI/V2O5 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Chakradhar Sridhar

    2016-01-01

    Full Text Available The present study deals with the synthesis and characterization of nanocrystalline vanadium pentoxide (V2O5 nanoparticles and their antibacterial and antifungal activity on Staphylococcus aureus and Aspergillus niger, respectively, by agar diffusion method. The metal oxide has been synthesized by employing the sol-gel method, polyaniline (PANI has been synthesized by chemical oxidation, and PANI/V2O5 composites have been synthesized by in situ polymerization method with different ratios (10, 20, 30, 40, and 50 weight% of V2O5 in PANI. The newly prepared composites were characterized by FTIR and powder X-ray diffraction (P-XRD techniques and are found to be formed of PANI/V2O5 nanocomposites, and also the compounds showed moderate antibacterial and antifungal activity.

  19. Microtron Irradiation Induced Tuning of Dielectric Properties of LDPE-ZnO Nanocomposites

    Directory of Open Access Journals (Sweden)

    Deepu Thomas

    2015-01-01

    Full Text Available Low-density polyethylene (LDPE/ZnO composites were prepared using melt mixing process. ZnO powder with size of 44 nm was used as reinforcing particle. The electron beam irradiation effects on the dielectric behaviour of a polymer nanocomposite dielectric made of low density polyethylene filled with nanoparticles of ZnO were studied. The dielectric constant and dielectric loss values were determined by dielectric spectroscopy over a frequency range of 100 KHz–5 MHz on plane samples of the tested nanodielectrics. The influence of filler concentration, between 2 and 8 wt.%, and the irradiation effects on the dielectric properties are also discussed in the paper.

  20. Preparation, Characterization and Optical Properties of Host-guest Nanocomposite Material Mordenite-silver Iodide

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Silver iodide nanoclusters were successfully prepared in the channels of mordenite by a heat diffusion method. Powder X-ray diffraction, adsorption technique and infrared spectroscopy were used to characterize the prepared materials, which showed that the guest silver iodide had been encapsulated in the channels of mordenite. The optical properties of the solid phase diffuse reflectance absorption of nanocomposite material NaM-AgI were studied, showing that the absorption bands of the diffuse reflectance absorption of the prepared material moved to the region of high energy. The absorption peak of the material prepared shifted to the region of high energy. Namely, blue shift was caused. This has demonstrated the incorporation of silver iodide into the channels of the zeolite. We observed the luminescence and surface photovoltage spectra of NaM-AgI sample, proposing the mechanisms of the photoluminescence and photovoltaic responses.

  1. Facile charge transport in FeNx/Mo₂N/CNT nanocomposites for efficient hydrogen evolution reactions

    Indian Academy of Sciences (India)

    KASINATH OJHA; SHIVALI BANERJEE; ASHOK K GANGULI

    2017-07-01

    Molybdenum based materials are gaining importance as electrocatalysts for hydrogen evolution reaction because of their lowcost and good electrocatalytic efficiency. Introducing iron nitride with molybdenum nitride as a composite results in efficient hydrogen evolution activity with current density of ∼120mA/cm2 at −400 mVvs. RHE. The nanocomposites were characterized using powder XRD, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), ElectronDiffraction, ThermogravimetricAnalysis and FTIRSpectroscopy. The electrochemical investigations suggest that the electrocatalytic activity of the composite increases with iron nitride content. The composite exhibits good electrochemical stability upto 42 hours in acidic medium. The hydrogen evolution reaction (HER) follows Volmer-Heyrovsky mechanism where Volmer reaction is the rate determing step.

  2. ZnO–TiO2 nanocomposite: Characterization and moisture sensing studies

    Indian Academy of Sciences (India)

    N K Pandey; K Tiwari; Akash Roy

    2012-06-01

    This paper reports morphological and relative humidity sensing behaviour of ZnO–TiO2 nanocomposite powder pellets obtained through solid-state reaction route. Resistance of the pellets is observed to decrease with increase in relative humidity in the 10–90% range. Sensing element with 15 wt%of TiO2 in ZnO shows best results with a sensitivity of 9.08 M/%RH in 10–90% relative humidity range. This sensing element manifests crystallite size of 71 nm as measured from XRD and average grain size of 207 nm calculated from SEM micrograph. This sensing element manifests low hysteresis, less effect of ageing and good reproducibility. Response and recovery times of this sensing element are measured to be 84 s and 396 s, respectively.

  3. Preparation,Characterization and Optical Properties of Hostguest Nanocomposite Material Mordenite—silver Iodide

    Institute of Scientific and Technical Information of China (English)

    ZHAIQing-zhou; QIUShi-lun

    2003-01-01

    Silver iodide nanoclusters were successfully prepared in the channels of mordenite by a heat diffusion method.Powder X-ray diffraction.adsorption technique and infrared spectroscopy were used to characterize the prepared materials,which showed that the guest silver iodied had been encapsulated in the channels of mordenite.The optical properties of the solid phase diffuse reflectance absorption of nanocomposite material NaM-AgI were studied,showing that the absorption bands of the diffuse reflectance absorption of the prepared material moved to the region of high energy.The absorption peak of the material prepared shifted to the region of high energy.Namely,blue shift was caused.This has demonstrated the incorporation of silver iodide into the channels of the zeolite.We observed the luminescence and surface photovoltage spectra of NaM-AgI sample,proposing the mechanisms of the photoluminescence and photovoltaic responses.

  4. A Unified Model for the Prediction of Yield Strength in Particulate-Reinforced Metal Matrix Nanocomposites

    Directory of Open Access Journals (Sweden)

    F. A. Mirza

    2015-08-01

    Full Text Available Lightweighting in the transportation industry is today recognized as one of the most important strategies to improve fuel efficiency and reduce anthropogenic climate-changing, environment-damaging, and human death-causing emissions. However, the structural applications of lightweight alloys are often limited by some inherent deficiencies such as low stiffness, high wear rate and inferior strength. These properties could be effectively enhanced by the addition of stronger and stiffer reinforcements, especially nano-sized particles, into metal matrix to form composites. In most cases three common strengthening mechanisms (load-bearing effect, mismatch of coefficients of thermal expansion, and Orowan strengthening have been considered to predict the yield strength of metal matrix nanocomposites (MMNCs. This study was aimed at developing a unified model by taking into account the matrix grain size and porosity (which is unavoidable in the materials processing such as casting and powder metallurgy in the prediction of the yield strength of MMNCs. The Zener pinning effect of grain boundaries by the nano-sized particles has also been integrated. The model was validated using the experimental data of magnesium- and titanium-based nanocomposites containing different types of nano-sized particles (namely, Al2O3, Y2O3, and carbon nanotubes. The predicted results were observed to be in good agreement with the experimental data reported in the literature.

  5. Directed self-assembly in laponite/CdSe/polyaniline nanocomposites.

    Science.gov (United States)

    Kehlbeck, Joanne D; Hagerman, Michael E; Cohen, Brian D; Eliseo, Jennifer; Fox, Melissa; Hoek, William; Karlin, David; Leibner, Evan; Nagle, Emily; Nolan, Michael; Schaefer, Ian; Toney, Alexandra; Topka, Michael; Uluski, Richard; Wood, Charles

    2008-09-02

    Laponite films provide versatile inorganic scaffolds with materials architectures that direct the self-assembly of CdSe quantum dots (QDs or EviTags) and catalytic surfaces that promote the in situ polymerization of polyaniline (PANI) to yield novel nanocomposites for light emitting diodes (LEDs) and solar cell applications. Water-soluble CdSe EviTags with varying, overlapping emission wavelengths in the visible spectrum were incorporated using soft chemistry routes within Na-Laponite host film platforms to achieve broadband emission in the visible spectrum. QD concentrations, composition and synthesis approach were varied to optimize photophysical properties of the films and to mediate self-assembly, optical cascading and energy transfer. In addition, aniline tetramers coupled to CdSe (QD-AT) surfaces using a dithioate linker were embedded within Cu-Laponite nanoscaffolds and electronically coupled to PANI via vapor phase exposure. Nanotethering and specific host-guest and guest-guest interactions that mediate nanocomposite photophysical behavior were probed using electronic absorption and fluorescence spectroscopies, optical microscopy, AFM, SEM, powder XRD, NMR and ATR-FTIR. Morphology studies indicated that Lap/QD-AT films synthesized using mixed solvent, layer by layer (LbL) methods exhibited anisotropic supramolecular structures with unique mesoscopic ordering that affords bifunctional networks to optimize charge transport.

  6. Photocatalytic properties and selective antimicrobial activity of TiO2(Eu)/CuO nanocomposite

    Science.gov (United States)

    Michal, Robert; Dworniczek, Ewa; Caplovicova, Maria; Monfort, Olivier; Lianos, Panagiotis; Caplovic, Lubomir; Plesch, Gustav

    2016-05-01

    TiO2(Eu)/CuO nanocomposites were prepared by precipitation method. The anatase nanocrystallites with a size of 26 nm exhibited well crystallized and characteristical dipyramidal morphology and {1 0 1} and {0 0 1} faceting. Transmission electron microscopy photographs with atomic resolution showed that the Eu(III) dopants were bounded on surface of titania. In the composites, the CuO nanocrystals exhibiting a monoclinic tenorite structure with a size in the range from 2 to 5 nm were grafted to the surface of titania. The influence of copper(II) oxide led to distinct selectivity in the photocatalytic and antimicrobial properties of the investigated TiO2(Eu)/CuO nanocomposites. While the presence of CuO nanocrystals strongly increased the photocatalytic production of hydrogen by ethanol reforming, it decreased the activity in photoinduced total mineralization of phenol comparing with non-modified TiO2(Eu). In investigated TiO2(Eu)/CuO powders, the photoinduced antimicrobial activity against membranes of Enterococcus species was influenced by the selective binding of CuO to the surface of the microorganism leading to distinct selectivity in their action. The activity against Enterococcus faecalis was higher than against Enterococcus faecium.

  7. Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor

    Science.gov (United States)

    Ali, A.; Israr-Qadir, M.; Wazir, Z.; Tufail, M.; Ibupoto, Z. H.; Jamil-Rana, S.; Atif, M.; Khan, S. A.; Willander, M.

    2015-04-01

    In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 µm is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 × 10-4 and 8 × 10-2 M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of 12 s.

  8. Tribological performance of self-lubricating aluminum matrix nanocomposites: Role of graphene nanoplatelets

    Directory of Open Access Journals (Sweden)

    Meysam Tabandeh-Khorshid

    2016-03-01

    Full Text Available In the present investigation, aluminum matrix nanocomposites reinforced by graphene nanoplatelets were synthesized by powder metallurgy method. The microstructure of the Al-Graphene nanoplatelets sample was investigated by TEM. The hardness measurements of these samples were investigated using a Rockwell hardness tester. To investigate the tribological behavior of aluminum matrix composites reinforced by graphene nanoplatelets and pure aluminum, pin-on-disk experiments were conducted on the prepared samples. In the experiments, the influence of reinforcement, volume fraction, normal load, and sliding velocity on the tribological performance was investigated. Results showed that the wear rate of Al-1wt.% GNP is increased with increasing normal loads. However, the coefficient of friction (COF of the Al-1wt.% GNP decreased with increasing normal loads. Formation of graphene film on the worn surface of Al-1wt.% GNP sample and morphology of the worn surfaces of aluminum and composite samples were analyzed by Optical Microscope (OM and Scanning Electron Microscope (SEM. It was found that the graphene nanoplatelets reinforced nano-composites showed superior tribological properties and demonstrated the ability of the self-lubricating nature of the composite during tribological conditions.

  9. Effect of ultrasound irradiation on the production of nHAp/MWCNT nanocomposites.

    Science.gov (United States)

    Lobo, Anderson O; Zanin, Hudson; Siqueira, Idalia A W B; Leite, Nelly C S; Marciano, Fernanda R; Corat, Evaldo J

    2013-10-01

    Large amounts of nanohydroxyapatite (nHAp)-multiwall carbon nanotube (MWCNT) nanocomposites are produced by two different aqueous precipitation methods. The ultrasonic irradiation (UI) and slow-drip addition under continuous magnetic stirring (DMS) methods were used to investigate the precipitation of nHAp acicular crystals. Calcium-nitrate, diammonium hydrogen phosphate, and ammonium hydroxide were used as precursor reagents. Superhydrophilic MWCNT were also employed. XPS analysis evidences that the functionalized MWCNTs are composed of 18 to 20 at.% of oxygen and that this property influences the nHAp formation. The high surface area of the MWCNT decreases the mean free path of ions, favoring the nHAp formation assisted by UI. The crystallinity was evaluated using the Scherrer equation. Semi-qualitative energy dispersive spectroscopy (EDS) analysis showed that the main components of HAp powders were calcium and phosphorus in the ratio Ca/P around of 1.67. Bioactivity properties of the nHAp/MWCNT-UI nanocomposites could be evaluated after 14 days soaking in simulated body fluid medium. Scanning electron microscopy, EDS, Fourier transform infrared attenuated total reflection spectroscopy, and X-ray diffraction techniques proved that the apatites formed on the surface and to points that the nHAp/MWCNT-UI have potential biological applications.

  10. Preparation of hydroxyapatite/zirconia bioceramic nanocomposites for orthopaedic and dental prosthesis applications

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Yun-Mo [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Shin, Young-Keun [Technical Support Division, Korloy Incorporated, Cheongjoo-si, Choongbook 361-290 (Korea, Republic of); Ryu, Jae-Jun [Department of Prosthodontics, Medical School, Korea University, Seoul 136-701 (Korea, Republic of)

    2007-02-14

    Homogeneous mixtures of hydroxyapatite (HAp) and yttria-stabilized zirconia (YSZ) nanoparticles were successfully synthesized using chemical co-precipitation and subsequent calcination. For the synthesis of HAp/YSZ nanopowder, the Ca/P atomic ratio was 1.73 to obtain high-content stoichiometric hydroxyapatite phase and to suppress {beta}-tricalcium phosphate ({beta}-TCP) formation. The agglomerated crystalline powders were milled using YSZ ball media to obtain well-separated nanoparticles. The final particle size of the HAp and YSZ was {approx}50-70 and {approx}15-30 nm, respectively. The crystallinity and morphological feature of the nanopowder was analysed using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses. The ball-milled nanopowder mixture was hot pressed at 1100 deg. C for 1 h under 20 MPa in vacuum atmosphere. The sintered HAp/YSZ nanocomposites exhibited approximately 99% of the theoretical density, due not only to the fine nanoscale of the particles, but also to the homogeneous distribution of the nanoparticle mixture. They also showed fine grain structures of the HAp phase due to the suppressed grain growth by YSZ particles. The nanocomposites showed improved mechanical properties, flexural strength of {approx}155 MPa and fracture toughness of {approx}2.1 MP m{sup 1/2}, due to the YSZ contribution to the HAp matrix.

  11. Preparation of hydroxyapatite/zirconia bioceramic nanocomposites for orthopaedic and dental prosthesis applications

    Science.gov (United States)

    Sung, Yun-Mo; Shin, Young-Keun; Ryu, Jae-Jun

    2007-02-01

    Homogeneous mixtures of hydroxyapatite (HAp) and yttria-stabilized zirconia (YSZ) nanoparticles were successfully synthesized using chemical co-precipitation and subsequent calcination. For the synthesis of HAp/YSZ nanopowder, the Ca/P atomic ratio was 1.73 to obtain high-content stoichiometric hydroxyapatite phase and to suppress β-tricalcium phosphate (β-TCP) formation. The agglomerated crystalline powders were milled using YSZ ball media to obtain well-separated nanoparticles. The final particle size of the HAp and YSZ was ~50-70 and ~15-30 nm, respectively. The crystallinity and morphological feature of the nanopowder was analysed using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses. The ball-milled nanopowder mixture was hot pressed at 1100 °C for 1 h under 20 MPa in vacuum atmosphere. The sintered HAp/YSZ nanocomposites exhibited approximately 99% of the theoretical density, due not only to the fine nanoscale of the particles, but also to the homogeneous distribution of the nanoparticle mixture. They also showed fine grain structures of the HAp phase due to the suppressed grain growth by YSZ particles. The nanocomposites showed improved mechanical properties, flexural strength of ~155 MPa and fracture toughness of ~2.1 MP m1/2, due to the YSZ contribution to the HAp matrix.

  12. Poly(vinyl alcohol) nanocomposite films containing chemically exfoliated molybdenum disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Batista Mancinelli, Ketlin Cristine; Lisboa, Fabio da Silva [Centro de Pesquisa em Quimica Aplicada - CEPESQ, Laboratorio de Quimica de Materiais Avancados, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Soares, Jaisa Fernandes [Laboratorio de Quimica Bioinorganica, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Zawadzki, Sonia Faria [Laboratorio de Polimeros Sinteticos, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Wypych, Fernando, E-mail: wypych@ufpr.br [Centro de Pesquisa em Quimica Aplicada - CEPESQ, Laboratorio de Quimica de Materiais Avancados, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil)

    2013-01-15

    Molybdenum disulfide (2H-MoS{sub 2}) was exfoliated in water after reaction with n-butyl-lithium. Using either alkaline or neutral conditions, different amounts of the resulting single-layer suspension were employed as filler for the production of poly(vinyl alcohol) films containing distinct disulfide contents. These nanocomposite films were obtained by wet casting and were further characterized by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) and Raman spectroscopies. The mechanical properties of the films were also evaluated. Characterization studies revealed the attainment of homogeneous nanocomposite films in both alkaline and neutral conditions, indicating good distribution and interaction of the hydrophilic filler with the polyhydroxylated polymer. Improved Young's (tensile) modulus (+57%) and tensile strength (+9%) as well as reduced elongation (-78%) were achieved only when the neutral suspension of single layers was utilized. Increased MoS{sub 2} content diminished the crystallinity of the polymer, while enhanced mechanical properties were obtained in the presence of intermediate filler content (around 1 wt%). Highlights: Black-Right-Pointing-Pointer Molybdenum disulfide (2H-MoS{sub 2}) was chemically exfoliated in water. Black-Right-Pointing-Pointer MoS{sub 2} single-layer suspension was used as filler for poly(vinyl alcohol) films. Black-Right-Pointing-Pointer Increased MoS{sub 2} content diminished the crystallinity of the polymer. Black-Right-Pointing-Pointer Enhanced mechanical properties were obtained with intermediate filler content.

  13. Bismuth oxyiodide-graphene nanocomposites with high visible light photocatalytic activity.

    Science.gov (United States)

    Liu, Hong; Cao, Wei-Ran; Su, Yun; Chen, Zhen; Wang, Yong

    2013-05-15

    A series of chemically bonded Bismuth oxyiodide (BiOI)-graphene (GR) nanocomposites have been synthesized by a facile one-step hydrothermal method. Both the reduction in graphene oxide (GO) and the formation of BiOI nanocrystals were achieved simultaneously during the hydrothermal reaction. The prepared materials were characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectra, high-resolution transmission electron micrographs (HRTEM), UV-vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activities of these BiOI-GR nanocomposites were evaluated by the degradation of methyl orange. Under visible irradiation (λ>420 nm), the BiOI-GR photocatalysts were found to exhibit higher photocatalytic activities than pure BiOI, and the activity was increased by almost 6 times when loaded with 2.0 wt% graphene. The enhanced photocatalytic activity can be attributed to more effective charge transportations and separations arisen from the strong chemical bonding between BiOI and graphene, the high dye adsorption performance, and the increased light absorption.

  14. Influence of two-step sintering on ceramic nanocomposites microstructure; Influencia da sinterizacao em etapas na microestrutura dos nanocompositos ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, L.; Chinelatto, A.S.A.; Chinelatto, A. L., E-mail: leandro.rodrigues.1991@gmail.com [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Departamento de Engenharia de Materiais

    2012-07-01

    Two-step sintering has been able to produce fully dense bodies and with controlled grain size, without pressure during sintering. In this study, it was studied the sintering behavior of alumina-5% vol zirconia powders submitted to high energy milling. For this, the mixture of 5% vol of Y{sub 2}O{sub 3} partially stabilized zirconia and 95% vol alumina powder was performed by high-energy ball milling (Spex 8000) with a ball ratio: mass of material at 7:1, in a steel vial with balls of steel, in milling times from 0 to 7 hours. The milled powders were characterized by X-ray fluorescence (XRF) and X-ray diffraction (XRD). After milling, the powders were uniaxially pressed and two-step sintered with heating at a temperature of 1500 deg C for 5 minutes, cooling until 1450°C and then sintering at this temperature for 2 hours. The sintered composites were analyzed by X-ray diffraction, apparent density and scanning electron microscopy. The results were compared with the conventional sintering and showed that the microstructure of the nanocomposites appears more refined and homogeneous when they are sintered in steps. (author)

  15. Mg2FeH6-based nanocomposites with high capacity of hydrogen storage processed by reactive milling

    Directory of Open Access Journals (Sweden)

    Alexandre Augusto Cesario Asselli

    2012-04-01

    Full Text Available The compound Mg2FeH6 was synthesized from a 2Mg-Fe mixture in a single process through high-energy ball milling under hydrogen atmosphere at room temperature. The complex hydride was prepared from Mg powder and granulated or powdered Fe using a planetary mill. The phase evolution during different milling times was performed by X-rays diffraction technique. The dehydrogenation behavior of the hydride was investigated through simultaneous thermal analyses of differential scanning calorimetry and thermogravimetry coupled with mass spectrometer. The use of powdered iron as starting material promoted conversion to complex hydride at shorter milling times than when granulated iron was used, nevertheless, after 24 hours of milling the 2Mg-Fe (powdered or granulated mixtures presented similar dehydrogenation behavior. The hydrogen absorption during milling was on average 3.2 wt. (%, however, changing the proportions of the reagents to 3Mg-Fe a Mg2FeH6-MgH2 based nanocomposite with higher density of hydrogen (5.2 wt. (% was obtained.

  16. The effect of powder recycling in direct metal laser deposition on powder and manufactured part characteristics

    OpenAIRE

    Carroll, P A; Pinkerton, A. J.; Allen, J.; Syed, W. U. H.; Sezer, H. K.; Brown, P.; Ng, G; Scudamore, R.; Li, L.

    2006-01-01

    A potential way of improving the material efficiency and cost effectiveness of the Direct Metal Laser Deposition (DMLD) process is to take powder that is not utilised in each deposition attempt and re-use it in subsequent attempts (powder recycling). Currently, this is not widely implemented for fear of a detrimental effect on part quality. This study examines how powder recycling, using simple normalisation techniques, affects the powder and the quality of the deposited part. Work was conduc...

  17. Bonds between metals and nanocomposites created by explosion welding

    Science.gov (United States)

    Bondar', M. P.; Karpov, E. V.; Lukyanov, Ya. L.

    2016-09-01

    This paper describes the study of the influence of a microstructure characterized by directed or chaotic distribution of nanoinclusions and strain rate on the deformability of nanocomposites. It is revealed that, under identical loading conditions, cracks are formed in nanocomposites whose structural elements are mostly directed in the same way at lower strain rates than in nanocomposites with chaotic distribution of the reinforcer. It is shown that, as the strain rate increases, the influence of the structural order on the limiting deformation reduces due to transition from shear strain to rotational strain. No cracks are formed in the creation of bonds between metals and nanocomposites by explosion welding. The experimental results obtained in the study of transverse bending of two-layer welded beams and the structure in the vicinity of the weld reveal that the obtained metal-nanocomposite bond has a uniform structure retained in deformation, with fracture occurring in the nanocomposite.

  18. Bactericidal Influence of Silver Nanocomposites on Clavibacter michiganensis ssp. sepedonicus

    Directory of Open Access Journals (Sweden)

    Perfileva А.I.

    2016-05-01

    Full Text Available The results of studying the effect of silver nanocomposites received by chemical synthesis on the bacterium Clavibacter michiganensis ssp. sepedonicus (Cms are presented. Cms is a Gram-positive bacterium, which causes one of the most dangerous potato diseases, ring rot. The effective alongside ecologically safe methods for combating Cms are lacking. As the agent, possible for application for this purpose, we investigated silver nanocomposites. For definition of nanocomposites influence on Cms we applied seedings to calculation the colony-forming units, after an incubation of bacteria with a nanocomposite in the distilled water (the grown poor environment and on a nutrient medium. Influence of silver nanocomposites on cellular respiration which was estimated on oxygen absorption speed is also investigated. Thus, the obtained results demonstrate the occurrence of bactericidal effects of the substances under study, and favor the supposition on advisability of further research into the silver nanocomposites as the agents for agricultural recovery from the bacterial pathogens.

  19. Enhancement in performance of polycarbazole-graphene nanocomposite Schottky diode

    Directory of Open Access Journals (Sweden)

    Rajiv K. Pandey

    2013-12-01

    Full Text Available We report formation of polycarbazole (PCz–graphene nanocomposite over indium tin oxide (ITO coated glass substrate using electrochemical technique for fabrication of high performance Schottky diodes. The synthesized nanocomposite is characterized before fabrication of devices for confirmation of uniform distribution of graphene nanosheets in the polymer matrix. Pure PCz and PCz-graphene nanocomposites based Schottky diodes are fabricated of configuration Al/PCz/ITO and Al/PCz-graphene nanocomposite/ITO, respectively. The current density–voltage (J-V characteristics and diode performance parameters (such as the ideality factor, barrier height, and reverse saturation current density are compared under ambient condition. Al/PCz-graphene nanocomposite/ITO device exhibits better ideality factor in comparison to the device formed using pure PCz. It is also observed that the Al/PCz-graphene nanocomposite/ITO device shows large forward current density and low turn on voltage in comparison to Al/PCz/ITO device.

  20. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  1. Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method

    Directory of Open Access Journals (Sweden)

    Kalantari K

    2013-05-01

    Full Text Available Katayoon Kalantari,1 Mansor Bin Ahmad,1,* Kamyar Shameli,1,2,* Roshanak Khandanlou11Department of Chemistry, Universiti Putra Malaysia, Serdang, Malaysia; 2Nanotechnology and Advance Materials Department, Materials and Energy Research Center, Karaj, Alborz, Karaj, Iran*These authors contributed equally to this workAbstract: The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4 nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94–0.93 nm; therefore, Fe3O4 nanoparticles formed on the exterior surface of talc, with an average size of 1.95–2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe3O4 nanocomposites may have potential applications in the chemical and biological industries.Keywords: nanocomposites, Fe3O4 nanoparticles, talc, powder X-ray diffraction, scanning electron microscopy

  2. Improvement of electrochemical behavior of Sn{sub 2}Fe/C nanocomposite anode with Al{sub 2}O{sub 3} addition for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Myung; Jung, Heechul; Hwa, Yoon; Sohn, Hun-Joon [Department of Materials Science and Engineering, Research Center for Energy, Conversion and Storage, Seoul National University, Seoul 151-742 (Korea); Kim, Hansu; Im, Dongmin; Doo, Seok-Gwang [Energy and Environment Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics, Giheung Gu, Yongin-Si, Gyeonggi-Gi Do, 446-712 (Korea)

    2010-08-01

    Sn{sub 2}Fe/Al{sub 2}O{sub 3}/C nanocomposites are synthesized using a high-energy, mechanical milling method with thermally synthesized Sn{sub 2}Fe, Al{sub 2}O{sub 3} and carbon (Super P) powders. The effect of Al{sub 2}O{sub 3} addition on the microstructure of the Sn{sub 2}Fe/Al{sub 2}O{sub 3}/C nanocomposites is examined. The electrochemical characteristics of the material as an anode in lithium-ion batteries are also evaluated. High-resolution transmission electron microscopy shows that the crystallite size of active Sn{sub 2}Fe in the Sn{sub 2}Fe/Al{sub 2}O{sub 3}/C nanocomposite is smaller than that of the Sn{sub 2}Fe/C nanocomposite without Al{sub 2}O{sub 3}. A decrease in the initial irreversible capacity and enhanced cycle performance of the Sn{sub 2}Fe/Al{sub 2}O{sub 3}/C nanocomposite electrode are observed. (author)

  3. Preparation of nanocomposites containing nanoclusters of transition metals

    Energy Technology Data Exchange (ETDEWEB)

    Milne, S.B.; Lukehart, C.M., Wittig, J.E. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1996-10-01

    New nanocomposites containing nanoclusters of transition metals have been prepared and characterized by TEM, XRD, and energy dispersive spectroscopy. Organometallic or other coordination compounds functionalized with trialkoxysilyl groups have been synthesized and covalently incorporated into silica xerogels using standard sol-gel techniques. Thermal oxidative treatment of these xerogels in air followed by reduction in hydrogen yielded the desired nanocomposite phases. Using these methods, Mo, Re, Fe, Ru, Os, Pd, Pt, Cu. and Ag nanocomposites have been prepared.

  4. Interfacial Engineering for Low-Density Graphene Nanocomposites

    Science.gov (United States)

    2014-07-23

    AFRL-OSR-VA-TR-2014-0192 Interfacial engineering for low-density graphene nanocomposites Micah Green TEXAS TECH UNIVERSITY SYSTEM Final Report 07/23...98) v Prescribed by ANSI Std. Z39.18 14-07-2014 Final April 2011 - March 2014 Interfacial engineering for low-density graphene nanocomposites and...several new platforms for graphene-based materials. They examined the use of graphene in polymer nanocomposites , including epoxy films and poly vinyl

  5. Structure–property relationship of specialty elastomer–clay nanocomposites

    Indian Academy of Sciences (India)

    Anirban Ganguly; Madhuchhanda Maiti; Anil K Bhowmick

    2008-06-01

    The present work deals with the synthesis of specialty elastomer [fluoroelastomer and poly (styrene--ethylene-co-butylene--styrene (SEBS)]–clay nanocomposites and their structure–property relationship as elucidated from morphology studies by atomic force microscopy, transmission electron microscopy and X-ray diffraction and physico-mechanical properties. Due to polarity match, hydrophilic unmodified montmorillonite clay showed enhanced properties in resulting fluoroelastomer nanocomposites, while hydrophobic organo-clay showed best results in SEBS nanocomposites.

  6. A facile synthesis and spectral characterization of Cu{sup 2+} doped CdO/ZnS nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Joyce Stella, R.; Thirumala Rao, G.; Babu, B.; Pushpa Manjari, V. [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India); Reddy, Ch. Venkata; Shim, Jaesool [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N., E-mail: rvssn@yahoo.co.in [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India)

    2015-06-15

    A facile two-step method is demonstrated for the preparation of Cu{sup 2+} doped CdO/ZnS nanocomposite. Systematic investigations like X-ray diffraction (XRD), Scanning electron microscopy (SEM) with EDS, transmission electron microscopy (TEM), FT-IR, electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and magnetic studies are carried out for the prepared material. From powder XRD, the nanocomposites are comprised for cubic phase of both CdO and ZnS in a close contact with each other. The ground state wave function of dopant ions has been estimated from EPR studies. Optical and EPR data confirm that doped Cu{sup 2+}ions occupy rhombically distorted octahedral sites with the host material. Due to doping, band gap has been changed and blue shifts occurred in PL. Magnetic measurements indicate a possible ferromagnetic response, associated to the exchange interaction between local spin-polarized electrons of Cu{sup 2+} ions and conductive electrons. - Graphical abstract: M–H curve of Cu{sup 2+} doped CdO–ZnS nanocomposites. The magnetic properties of Cu{sup 2+} doped CdO/ZnS nanocomposite has been investigated using vibrating sample magnetometer given as magnetization and hysteresis (M–H) curve. The magnetization curve with noticeable coercivity of M–H loop clearly indicate the existence of ferromagnetic ordering in Cu{sup 2+} doped CdO/ZnS nanocomposite at room temperature. According to the Ruderman–Kittel–Kasuya–Yosida (RKKY) theory, the exchange interaction between local spin-polarized electrons (such as the electrons of Cu{sup 2+} ions) and conductive electrons is the main cause that leads to the ferromagnetism. Coercivity (Hc) of the field is about 98 Oe, saturation magnetization (Ms) and remnant magnetization (Mr) of present sample is estimated to be 15.8×10{sup −3} and 1.43×10{sup −3} emu/g respectively. The ferromagnetism observed in the prepared material is not commencing with other impurities but expected to

  7. Sr hexaferrite/Ni ferrite nanocomposites: Magnetic behavior and microwave absorbing properties in the X-band

    Energy Technology Data Exchange (ETDEWEB)

    Jacobo, Silvia E. [Facultad de Ingeniería, Universidad de Buenos Aires, LAFMACEL-INTECIN, Paseo Colón 850, C1063EHA Buenos Aires (Argentina); Bercoff, Paula G., E-mail: bercoff@famaf.unc.edu.ar [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, IFEG, CONICET, Ciudad Universitaria, X5000HUA Córdoba (Argentina); Herme, Carlos A. [Facultad de Ingeniería, Universidad de Buenos Aires, LAFMACEL-INTECIN, Paseo Colón 850, C1063EHA Buenos Aires (Argentina); Vives, Leandro A. [División Antenas, Instituto de Investigaciones Científicas para la Defensa CITEDEF, Ministerio de Defensa, San Juan Bautista de La Salle 4397, Villa Martelli, B1603ALO Buenos Aires (Argentina)

    2015-05-01

    Nickel ferrite nanoparticles were synthesized by a self-combustion method over nanocrystalline powders of Nd–Co substituted strontium hexaferrite with nominal composition Sr{sub 0.5}Nd{sub 0.5}Co{sub 0.5}Fe{sub 10.5}O{sub 19}, at different mass relations. The samples were structurally characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). The M vs. H loops of the composites were determined with a vibrating sample magnetometer (VSM) and the interaction with the X-band microwave radiation of the nanocomposites dispersed in epoxy resin was measured with a vector network analyzer (VNA). The hysteresis loops showed strong exchange-coupling between the two magnetic phases for the 30:70 and 50:50 Sr{sub 0.5}Co{sub 0.5}Nd{sub 0.5}Fe{sub 10.5}O{sub 19}/NiFe{sub 2}O{sub 4} nanocomposites, while a weak interaction was observed for the 70:30 mass ratio. The nanocomposite with an equal amount of hard and soft phase shows the highest performance both in reflectivity and in bandwidth, reaching a maximum in reflectivity of −34.4 dB at 11.1 GHz while the bandwidth below −10 dB is 3.5 GHz. - Highlights: • Sr{sub 0.5}Co{sub 0.5}Nd{sub 0.5}Fe{sub 10.5}O{sub 19}/NiFe{sub 2}O{sub 4} nanocomposites were synthesized at different mass ratios. • The systems were structurally and magnetically characterized. • The X-band microwave radiation of the composites was evaluated. • Enhancement in reflectivity is related to exchange interaction between hard and soft phases.

  8. The Effect of External Magnetic Field on Microstructure and Magnetic Properties of Melt-Spun Nd-Fe-B/Fe-Co Nanocomposite Ribbons

    Directory of Open Access Journals (Sweden)

    Xuan Truong Nguyen

    2013-01-01

    Full Text Available The ribbons Nd2Fe14B/Fe-Co were prepared with the nominal composition Nd16Fe76B8/40% wt. Fe65Co35 by the conventional and the developed magnetic field-assisted melt-spinning (MFMS techniques. Both ribbons are nanocomposites with the smooth single-phase-like magnetization loops. The 0.32 T magnetic field perpendicular to the wheel surface and assisting the melt-spinning process reduces the grain size inside the ribbon, increases the texture of the ribbon, improves the exchange coupling, and, in sequence, increases the energy product (BHmax of the isotropic powdered samples of MFMS ribbon in ~9% by comparison with that of the ribbon melt-spun conventionally. The grain size reduction effect caused by the assisted magnetic field has also been described quantitatively. The MFMS technique seems to be promising for producing high-performance nanocomposite ribbons.

  9. Sulfur/graphitic hollow carbon sphere nano-composite as a cathode material for high-power lithium-sulfur battery.

    Science.gov (United States)

    Shin, Eon Sung; Kim, Min-Seop; Cho, Won Il; Oh, Si Hyoung

    2013-08-03

    The intrinsic low conductivity of sulfur which leads to a low performance at a high current rate is one of the most limiting factors for the commercialization of lithium-sulfur battery. Here, we present an easy and convenient method to synthesize a mono-dispersed hollow carbon sphere with a thin graphitic wall which can be utilized as a support with a good electrical conductivity for the preparation of sulfur/carbon nano-composite cathode. The hollow carbon sphere was prepared from the pyrolysis of the homogenous mixture of the mono-dispersed spherical silica and Fe-phthalocyanine powder in elevated temperature. The composite cathode was manufactured by infiltrating sulfur melt into the inner side of the graphitic wall. The electrochemical cycling shows a capacity of 425 mAh g-1 at 3 C current rate which is more than five times larger than that for the sulfur/carbon black nano-composite prepared by simple ball milling.

  10. Synthesis of PdO/MCM-41 nanocomposites using trans-[PdCl{sub 2}(PEt{sub 3}){sub 2}] as the source of metal

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Pineda, Jessica [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Rio, Jose Manuel del [Instituto Mexicano del Petroleo, 07730 Mexico D.F. (Mexico); Carreto, Enrique [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Terres, Eduardo; Montoya, J. Asencion [Instituto Mexicano del Petroleo, 07730 Mexico D.F. (Mexico); Zuniga-Gonzalez, Maria de Jesus [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Morgado, Jorge [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Instituto Mexicano del Petroleo, 07730 Mexico D.F. (Mexico)], E-mail: morgadomoreno@yahoo.com.mx

    2009-07-29

    Three PdO/MCM-41 nanocomposites containing PdO species that are dispersed on an MCM-41 support have been prepared using trans-[PdCl{sub 2}(PEt{sub 3}){sub 2}] as the source of metal. Thermal gravimetric analysis of the decomposition of this complex in air reveals a remarkable mass loss of all nonmetallic elements centered at 300 deg. C. The materials were characterized with X-ray powder diffraction (XRPD), nitrogen sorption and TEM, which showed that the PdO nanoparticles were present inside the pores of MCM-41. XRPD analysis confirms formation of PdO (palladinite) nanocrystals, as the sole crystalline phase present in the nanocomposites.

  11. Thermoplastic dry polymer powder prepregging

    Energy Technology Data Exchange (ETDEWEB)

    Bucher, R.A.; Loos, A.C.; Meyer, G. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States)] [and others

    1995-12-01

    Thermoplastic resin systems have shown potential for reducing the manufacturing costs and improving the damage tolerance of composite structures. Current methods for thermoplastic resin impregnation of fiber bundles are limited by various difficulties and thus produce poor quality prepregs. The emerging technology of fiber is one of the most promising options, producing excellent matrix drape, and feasibility for a wide variety of matrix systems. An electrostatic dry polymer powder prepregging system was developed at the NSF Science and Technology Center at Virginia Tech, and has been used to produce high quality thermoplastic towpreg from a wide variety o polymer matrices. Additionally, a modification of the system allows for the production of towpreg from 15 gram polymer samples. This is ideal for the production of composites from resin systems under development, allowing early feedback concerning processing and composite mechanical performance.

  12. Polystyrene/MoS{sub 2}@oleylamine nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Altavilla, Claudia; Ciambelli, Paolo [Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 134 84084 Fisciano (Italy); Centre NANO MATES, University of Salerno, 84084 Fisciano (Italy); Fedi, Filippo; Sorrentino, Andrea; Iannace, Salvatore [Institute for Composite and Biomedical Materials (IMCB), National Research Council (CNR), Piazzale Enrico Fermi 1, 80055 Portici (Italy)

    2014-05-15

    The effects of adding different concentrations of MoS{sub 2}@oleylamine nano particles on the thermal and mechanical properties of polystyrene (PS) nanocomposites have been investigated. X-ray diffraction and optical microscopy were used to characterize the morphology of the resulting nanocomposites. The thermal stability of the nanocomposites has been characterized by thermogravimetric analysis. It has been found that the MoS{sub 2}@oleylamine nanoparticles have a good compatibility with the PS matrix forming homogeneous dispersion even at high concentrations. The PS/MoS{sub 2}@oleylamine nanocomposites showed enhanced thermal stability in comparison with neat polystyrene.

  13. Study on the thermal stability of styrene butadiene rubber nanocomposites

    Science.gov (United States)

    Saeb, M. R.; Chenari, T. N.; Parast, O. Yazdan; Jafari, B.; Asadi, H.; Safari, M. Arfavi; Holisaz, H.

    2012-07-01

    This study aims to investigate the thermal stability of the styrene butadiene rubber (SBR) nanocomposites containig surface modified calcium carbonate (MCC). All nanocomposites were produced at various nanofiller contents, utilizing a laboratory scale two-roll mill. The thermal stability parameters including initial decomposing temperature, temperature at maximum rate of weight loss, and char content of the MCC/SBR nanocomposites were then compared. It was found that by increasing the filler content, the decomposition temperature of MCC/SBR nanocomposites increases. Furthermore, the char content at high temperatures rises by increasing nanofiller content.

  14. Computational modelling for dry-powder inhalers

    NARCIS (Netherlands)

    Kröger, Ralf; Woolhouse, Robert; Becker, Michael; Wachtel, Herbert; de Boer, Anne; Horner, Marc

    2012-01-01

    Computational fluid dynamics (CFD) is a simulation tool used for modelling powder flow through inhalers to allow optimisation both of device design and drug powder. Here, Ralf Kröger, Consulting Senior CFD Engineer, ANSYS Germany GmbH; Marc Horner, Lead Technical Services Engineer, Healthcare, ANSYS

  15. Some features of sintering of tungsten powders

    Directory of Open Access Journals (Sweden)

    Andreiev Igor Viktorovich

    2016-01-01

    Full Text Available A method of activating the sintering process for tungsten powders using a closed reaction space and hydrogen, steam-saturated water was observed. This sintering process is allowed to activate super coarse-grained (1000μm tungsten powder sat relatively low temperatures (1000-1200°C.

  16. CLAY SOIL STABILISATION USING POWDERED GLASS

    Directory of Open Access Journals (Sweden)

    J. OLUFOWOBI

    2014-10-01

    Full Text Available This paper assesses the stabilizing effect of powdered glass on clay soil. Broken waste glass was collected and ground into powder form suitable for addition to the clay soil in varying proportions namely 1%, 2%, 5%, 10% and 15% along with 15% cement (base by weight of the soil sample throughout. Consequently, the moisture content, specific gravity, particle size distribution and Atterberg limits tests were carried out to classify the soil using the ASSHTO classification system. Based on the results, the soil sample obtained corresponded to Group A-6 soils identified as ‘fair to poor’ soil type in terms of use as drainage and subgrade material. This justified stabilisation of the soil. Thereafter, compaction, California bearing ratio (CBR and direct shear tests were carried out on the soil with and without the addition of the powdered glass. The results showed improvement in the maximum dry density values on addition of the powdered glass and with corresponding gradual increase up to 5% glass powder content after which it started to decrease at 10% and 15% powdered glass content. The highest CBR values of 14.90% and 112.91% were obtained at 5% glass powder content and 5mm penetration for both the unsoaked and soaked treated samples respectively. The maximum cohesion and angle of internal friction values of 17.0 and 15.0 respectively were obtained at 10% glass powder content.

  17. Computational modelling for dry-powder inhalers

    NARCIS (Netherlands)

    Kröger, Ralf; Woolhouse, Robert; Becker, Michael; Wachtel, Herbert; de Boer, Anne; Horner, Marc

    2012-01-01

    Computational fluid dynamics (CFD) is a simulation tool used for modelling powder flow through inhalers to allow optimisation both of device design and drug powder. Here, Ralf Kröger, Consulting Senior CFD Engineer, ANSYS Germany GmbH; Marc Horner, Lead Technical Services Engineer, Healthcare,

  18. Fabrication of microstructures by powder blasting

    NARCIS (Netherlands)

    Wensink, H.

    2002-01-01

    This thesis deals with the use of powder blasting as a micromachining technique to create micro systems. Powder blasting is a technology in which small particles, accelerated by an air jet, are directed towards a brittle target for mechanical material removal. It is especially useful for glass

  19. Aerated bunker discharge of fine dilating powders

    NARCIS (Netherlands)

    Ouwerkerk, C.E.D.; Molenaar, H.J.; Frank, M.J.W.

    1992-01-01

    The discharge rate of coarse powders (mean particle size 500 ¿m) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradie

  20. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Harris, Pernille; Ståhl, Kenny

    2011-01-01

    Collecting protein powder diffraction data on standard in-house powder diffractometers requires careful handling of the samples. Specially designed sample holders combined with optimized collimation were found to be the key factors in improving the data quality and reducing the data collection ti...