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Sample records for monoclinic zirconium oxide

  1. Density functional theory analysis of Raman frequency modes of monoclinic zirconium oxide using Gaussian basis sets and isotopic substitution.

    Science.gov (United States)

    Daramola, Damilola A; Muthuvel, Madhivanan; Botte, Gerardine G

    2010-07-29

    Geometry and vibration properties for monoclinic zirconium oxide were studied using Gaussian basis sets and LDA, GGA, and B3LYP functionals. Bond angles, bond lengths, lattice parameters, and Raman frequencies were calculated and compared to experimental values. Bond angles and lengths were found to agree within experimental standard deviations. The B3LYP gave the best performance of all three functionals with a percent error of 1.35% for the lattice parameters while the average difference between experimental and calculated Raman frequency values was -3 cm(-1). The B3LYP functional was then used to assign the atomic vibrations causing each frequency mode using isotopic substitution of (93.40)Zr for (91.22)Zr and (18.00)O for (16.00)O. This resulted in seven modes assigned to the Zr atom, ten modes to the O atom, and one mode being a mixture of both.

  2. ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.

    2008-01-01

    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  3. Method for preparing hydrous zirconium oxide gels and spherules

    Science.gov (United States)

    Collins, Jack L.

    2003-08-05

    Methods for preparing hydrous zirconium oxide spherules, hydrous zirconium oxide gels such as gel slabs, films, capillary and electrophoresis gels, zirconium monohydrogen phosphate spherules, hydrous zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite sorbent, zirconium monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite, hydrous zirconium oxide fiber materials, zirconium oxide fiber materials, hydrous zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite and spherules of barium zirconate. The hydrous zirconium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process are useful as inorganic ion exchangers, catalysts, getters and ceramics.

  4. Investigation of anodic oxide coatings on zirconium after heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1 A, 41-500 Chorzów (Poland); Suchanek, Katarzyna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego Street 152, 31-342 Krakow (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment.

  5. Traps in Zirconium Alloys Oxide Layers

    Directory of Open Access Journals (Sweden)

    Helmar Frank

    2005-01-01

    Full Text Available Oxide films long-time grown on tubes of three types of zirconium alloys in water and in steam were investigated, by analysing I-V characteristic measured at constant voltages with various temperatures. Using theoretical concepts of Rose [3] and Gould [5], ZryNbSn(Fe proved to have an exponential distribution of trapping centers below the conduction band edge, wheras Zr1Nb and IMP Zry-4 proved to have single energy trap levels.

  6. Ellipsometric investigation of anodic zirconium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Patrito, E.M.; Macagno, V.A. (Univ. Nacional de Cordoba, Cordoba (Argentina). Dept. de Fisicoquimica)

    1993-06-01

    The anodic oxidation of zirconium was studied by in situ ellipsometry together with capacity measurements. The oxides were grown under potentiodynamic, galvanostatic, and potentiostatic conditions up to final potentials of 100 V in 0.5M H[sub 2]SO[sub 4] solution. The refractive index of the oxides changes depending on the growth current. The films were slightly absorbing but their absorption coefficient was independent of the oxide growth conditions. Different methods of surface preparation including etching in hydrofluoric acid-based mixtures, electropolishing and mechanical polishing were used. The surfaces and oxides were characterized by SEM examination and XPS measurements. The surface pretreatment affects both the substrate and the oxide optical constants as well as the rate of oxide growth. The density and dielectric constant of the oxides were calculated performing simultaneous ellipsometric, coulometric, and capacity measurements.

  7. Diffusion of insoluble carbon in zirconium oxides

    CERN Document Server

    Vykhodets, V B; Koester, U; Kondrat'ev, V V; Kesarev, A G; Hulsen, C; Kurennykh, T E

    2011-01-01

    The diffusion coefficient of insoluble carbon in zirconium oxides has been obtained for the temperature range of 900-1000A degrees C. There are no published data on the diffusion of insoluble impurities; these data are of current interest for the diffusion theory and nuclear technologies. Tracer atoms 13C have been introduced into oxides by means of ion implantation and the kinetics of their emission from the samples in the process of annealing in air has been analyzed. The measurements have been performed using the methods of nuclear microanalysis and X-ray photoelectron spectroscopy. The diffusion activation energy is 2.7 eV and the carbon diffusion coefficient is about six orders of magnitude smaller than that for oxygen self-diffusion in the same systems. This result indicates the strong anomaly of the diffusion properties of carbon in oxides. As a result, zirconium oxides cannot be used in some nuclear technologies, in particular, as a material of sources for accelerators of short-lived carbon isotopes.

  8. The effect of substrate texture and oxidation temperature on oxide texture development in zirconium alloys

    Science.gov (United States)

    Garner, A.; Frankel, P.; Partezana, J.; Preuss, M.

    2017-02-01

    During corrosion of zirconium alloys a highly textured oxide is formed, the degree of this preferred orientation has previously been shown to be an important factor in determining the corrosion behaviour of these alloys. Two distinct experiments were designed in order to investigate the origin of this oxide texture development on two commercial alloys. Firstly, sheet samples of Zircaloy-4 were oxidised between 500 and 800 °C in air. The resulting monoclinic oxide texture strength was observed to decrease with increasing oxidation temperature. In a second experiment, orthogonal faces of Low Tin ZIRLO™ were oxidised in 360 °C water, providing different substrate textures but identical microstructures. The substrate texture was observed to have a negligible effect on the corrosion performance whilst the major orientation of both oxide phases was found to be independent of substrate orientation. It is concluded that the main driving force for oxide texture development in single-phase zirconium alloys is the compressive stress caused by the Zrsbnd ZrO2 transformation.

  9. Synthesis and characterization of mesoporous and nano-crystalline phosphate zirconium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Enriquez, J.M., E-mail: jmanuelher@hotmail.co [Instituto Tecnologico de Cd. Madero, Division de Estudios de Posgrado e Investigacion, Juventino Rosas y Jesus Urueta S/N, Col. Los Mangos, 89440 Cd. Madero, Tam. (Mexico); Cortez Lajas, L.A.; Garcia Alamilla, R.; Castillo Mares, A.; Sandoval Robles, G. [Instituto Tecnologico de Cd. Madero, Division de Estudios de Posgrado e Investigacion, Juventino Rosas y Jesus Urueta S/N, Col. Los Mangos, 89440 Cd. Madero, Tam. (Mexico); Garcia Serrano, L.A. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Textil, Av. Instituto Politecnico Nacional s/n, Edificio 8, Col. Linda Vista, Delegacion Gustavo A. Madero, 07738 Mexico, D.F. (Mexico)

    2009-08-26

    In this work the preparation and characterization of the materials such as zirconia (ZrO{sub 2}) and zirconia promoted with phosphate ion (ZrO{sub 2}-PO{sub 4}{sup 3-}) is presented. Pure zirconium hydroxide [Zr(OH){sub 4}] was synthesized by the sol-gel method using precursors such as zirconium n-butoxide and 1-butanol maintaining a pH 8 during the synthesis. Zr(OH){sub 4} was impregnated with 15 wt.% of the acid agent. Both were calcined in a dynamic air atmosphere for 3 h at 400, 500 and 600 deg. C. The supports were characterized by thermal analysis, X-ray diffraction, nitrogen physisorption as well as infrared spectroscopy. The results showed a positive effect on the physicochemical properties of the catalytic supports after Zr(OH){sub 4} impregnation with the dopping agent (H{sub 3}PO{sub 4}). Phosphate zirconium oxides remained thermically stable after calcination. It was observed that the dopping agent remained firmly attached to the zirconium oxide surface, inhibiting the particle growth and delaying the syntherization of the material and the apparition of the monoclinic phase, obtaining mesoporous and nano-crystalline materials (crystallite size 1.0-6.5 nm) with high surface areas (210-329 m{sup 2}/g) and tetragonal structure defined for the calcination temperature of 600 deg. C.

  10. Raman spectroscopy analysis of air grown oxide scale developed on pure zirconium substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kurpaska, L., E-mail: lukasz.kurpaska@ncbj.gov.pl [Laboratoire Roberval, UMR 7337, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, CS 60319, 60203 Compiègne Cedex (France); National Center for Nuclear Research, St. A. Soltana 7/23, 05-400 Otwock-Swierk (Poland); Favergeon, J. [Laboratoire Roberval, UMR 7337, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, CS 60319, 60203 Compiègne Cedex (France); Lahoche, L. [Laboratoire Roberval, UMR 7337, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, CS 60319, 60203 Compiègne Cedex (France); Laboratoire des Technologies Innovantes, Université de Picardie Jules-Verne, EA 3899, Avenue des Facultés – Le Bailly, 80025 Amiens Cedex (France); El-Marssi, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules-Verne, 33 rue St. Leu, 80039 Amiens Cedex (France); Grosseau Poussard, J.-L. [LaSIE UMR-CNRS 7356, Pole Sciences et Technologie, Universite de La Rochelle, av. M Crepeau, 17042 La Rochelle, Cedex (France); Moulin, G.; Roelandt, J.-M. [Laboratoire Roberval, UMR 7337, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, CS 60319, 60203 Compiègne Cedex (France)

    2015-11-15

    Using Raman spectroscopy technique, external and internal parts of zirconia oxide films developed at 500 °C and 600 °C on pure zirconium substrate under air at normal atmospheric pressure have been examined. Comparison of Raman peak positions of tetragonal and monoclinic zirconia phases, recorded during the oxide growth at elevated temperature, and after cooling at room temperature have been presented. Subsequently, Raman peak positions (or shifts) were interpreted in relation with the stress evolution in the growing zirconia scale, especially closed to the metal/oxide interface, where the influence of compressive stress in the oxide is the biggest. Reported results, for the first time show the presence of a continuous layer of tetragonal zirconia phase developed in the proximity of pure zirconium substrate. Based on the Raman peak positions we prove that this tetragonal layer is stabilized by the high compressive stress and sub-stoichiometry level. Presence of the tetragonal phase located in the outer part of the scale have been confirmed, yet its Raman characteristics suggest a stress-free tetragonal phase, therefore different type of stabilization mechanism. Presented study suggest that its stabilization could be related to the lattice defects introduced by highstoichiometry of zirconia or presence of heterovalent cations. - Highlights: • The oxide layer consists of a mixture of tetragonal and monoclinic phases, clearly distinguishable by Raman spectroscopy. • The layer located close to the metal/oxide interphase consists mainly of the tetragonal phase. • Small amount of tetragonal layer located in the external oxide scale have been observed. • Stabilization mechanism of the tetragonal phase located in the external part of the oxide have been proposed.

  11. Nanostructures of sodium titanate/zirconium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Carolina M., E-mail: carolina@iqm.unicamp.br; Ferreira, Odair P., E-mail: opferreira@gmail.com; Alves, Oswaldo L., E-mail: oalves@iqm.unicamp.b [Instituto de Quimica, Universidade Estadual de Campinas (UNICAMP), Laboratorio de Quimica do Estado Solido (LQES) (Brazil)

    2010-09-15

    In this work is reported the synthesis of nanotubes and nanoribbons from mixed oxides (Ti{sub 1-x}Zr{sub x}O{sub 2}.nH{sub 2}O), employing hydrothermal treatment in a highly alkaline medium. The morphology and crystal structure of the products obtained via hydrothermal treatment depend on the value of x. For example, for x equal to 0 and 0.50 were observed the presence of nanotubes (diameter around 9 nm) and nanoribbons (diameter around 200 nm), respectively. However, for x values above 0.50, there was no morphological change. Regarding the crystalline structure of these samples, for x equal to 0 was observed the sodium titanate phase; already for x values up to 0.50, we observed the presence of two crystalline phases: sodium titanate and tetragonal ZrO{sub 2}. For x values above 0.50, only tetragonal ZrO{sub 2} was observed. Furthermore, only the product obtained from x equal to 0.15 was observed the presence of three-dimensional flower-like arrangements. The results obtained by the characterization techniques showed the segregation of zirconium after hydrothermal treatment of precursors with x less or equal to 0.50. Thus, we describe the important role that Ti/Zr molar ratio of the precursor plays on the morphology and crystalline phase of the products formed by hydrothermal treatment.

  12. Variation of Zr-L2,3 XANES in tetravalent zirconium oxides.

    Science.gov (United States)

    Ikeno, Hidekazu; Krause, Michael; Höche, Thomas; Patzig, Christian; Hu, Yongfeng; Gawronski, Antje; Tanaka, Isao; Rüssel, Christian

    2013-04-24

    Zr-L2,3 XANESs of tetravalent zirconium oxides with different coordination numbers and local symmetries are systematically investigated by ab initio multiplet calculations using fully relativistic molecular spinors for model clusters. Experimental Zr-L2,3 XANESs are obtained for SrZrO3, m-ZrO2 (monoclinic) and t-ZrO2 (tetragonal). The theoretical spectra are in good agreement with the experimental data. The multiplet effects are found to play essential roles in determining the peak shape. The shapes of L3- and L2-edges are systematically different. The intensity ratios of the doublet peaks at both L3- and L2-edges are found to be sensitive to the coordination number of Zr. The ratio can therefore be used to estimate the coordination number of Zr in such oxides.

  13. Oxidized Zirconium Bearing Surfaces in Total Knee Arthroplasty: Lessons Learned.

    Science.gov (United States)

    Schüttler, Karl Friedrich; Efe, Turgay; Heyse, Thomas J; Haas, Steven B

    2015-10-01

    Polyethylene wear in total knee arthroplasty is a still unsolved problem resulting in osteolysis and long-term failure of knee joint replacement. To address the problem of polyethylene wear, research aimed for an optimal implant design and for an optimal combination of bearing surfaces. Oxidized zirconium was introduced to minimize surface wear and thus potentially increase long-term implant survival. This review comprises the current literature related to in vitro and in vivo studies evaluating performance of oxidized zirconium total knee arthroplasty and results from retrieval analyses.

  14. Quantitative EELS analysis of zirconium alloy metal/oxide interfaces.

    Science.gov (United States)

    Ni, Na; Lozano-Perez, Sergio; Sykes, John; Grovenor, Chris

    2011-01-01

    Zirconium alloys have been long used for fuel cladding and other structural components in water-cooled nuclear reactors, but waterside corrosion is a primary limitation on both high fuel burn-up and extended fuel cycle operation. Understanding the processes that occur at the metal/oxide interface is crucial for a full mechanistic description of the oxidation process. In this paper we show that reliable quantification of the oxygen content at the metal/oxide interface can be obtained by Electron Energy Loss Spectrometry (EELS) if enough care is taken over both the preparation of Transmission Electron Microscopy (TEM) samples and the methodology for quantification of the EELS data. We have reviewed the accuracy of theoretically calculated inelastic partial scattering cross-sections and effective inelastic mean-free-paths for oxygen and zirconium in oxidized Zr-alloy samples. After careful recalibration against a ZrO₂ powder standard, systematic differences in the local oxygen profile across the interface in different zirconium alloys were found. The presence of a sub-stoichiometric oxide layer (a suboxide) was detected under conditions of slow oxide growth but not where growth was more rapid. This difference could arise from the different corrosion resistances of the alloys or, more likely, as a result of the transition in oxidation behaviour, which refers to a sharp increase in the oxidation rate when the oxide is a few microns thick.

  15. Standard Specification for Nuclear Grade Zirconium Oxide Pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This specification applies to pellets of stabilized zirconium oxide used in nuclear reactors. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

  16. MOCVD of zirconium oxide thin films: Synthesis and characterization

    Science.gov (United States)

    Torres-Huerta, A. M.; Domínguez-Crespo, M. A.; Ramírez-Meneses, E.; Vargas-García, J. R.

    2009-02-01

    The synthesis of thin films of zirconia often produces tetragonal or cubic phases, which are stable at high temperatures, but that can be transformed into the monoclinic form by cooling. In the present study, we report the deposition of thin zirconium dioxide films by metalorganic chemical vapor deposition using zirconium (IV)-acetylacetonate as precursor. Colorless, porous, homogeneous and well adherent ZrO 2 thin films in the cubic phase were obtained within the temperature range going from 873 to 973 K. The deposits presented a preferential orientation towards the (1 1 1) and (2 2 0) planes as the substrate temperature was increased, and a crystal size ranging between 20 and 25 nm. The kinetics is believed to result from film growth involving the deposition and aggregation of nanosized primary particles produced during the CVD process. A mismatch between the experimental results obtained here and the thermodynamic prediction was found, which can be associated with the intrinsic nature of the nanostructured materials, which present a high density of interfaces.

  17. MOCVD of zirconium oxide thin films: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Huerta, A.M., E-mail: atohuer@hotmail.com [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Instituto Politecnico Nacional, Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Dominguez-Crespo, M.A.; Ramirez-Meneses, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Instituto Politecnico Nacional, Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Vargas-Garcia, J.R. [ESIQIE, Departamento de Metalurgia y Materiales, Instituto Politecnico Nacional. A.P. 75-876, 07300 Mexico, D.F. (Mexico)

    2009-02-15

    The synthesis of thin films of zirconia often produces tetragonal or cubic phases, which are stable at high temperatures, but that can be transformed into the monoclinic form by cooling. In the present study, we report the deposition of thin zirconium dioxide films by metalorganic chemical vapor deposition using zirconium (IV)-acetylacetonate as precursor. Colorless, porous, homogeneous and well adherent ZrO{sub 2} thin films in the cubic phase were obtained within the temperature range going from 873 to 973 K. The deposits presented a preferential orientation towards the (1 1 1) and (2 2 0) planes as the substrate temperature was increased, and a crystal size ranging between 20 and 25 nm. The kinetics is believed to result from film growth involving the deposition and aggregation of nanosized primary particles produced during the CVD process. A mismatch between the experimental results obtained here and the thermodynamic prediction was found, which can be associated with the intrinsic nature of the nanostructured materials, which present a high density of interfaces.

  18. Zirconium

    Science.gov (United States)

    Bedinger, G.M.

    2013-01-01

    Zirconium is the 20th most abundant element in the Earth’s crust. It occurs in a variety of rock types and geologic environments but most often in igneous rocks in the form of zircon (ZrSiO4). Zircon is recovered as a coproduct of the mining and processing of heavy mineral sands for the titanium minerals ilmenite and rutile. The sands are formed by the weathering and erosion of rock containing zircon and titanium heavy minerals and their subsequent concentration in sedimentary systems, particularly in coastal environments. A small quantity of zirconium, less than 10 kt/a (11,000 stpy), compared with total world production of 1.4 Mt (1.5 million st) in 2012, was derived from the mineral baddeleyite (ZrO2), produced from a single source in Kovdor, Russia.

  19. Standard specification for nuclear-grade zirconium oxide powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification defines the physical and chemical requirements for zirconium oxide powder intended for fabrication into shapes, either entirely or partially of zirconia, for use in a nuclear reactor core. 1.2 The material described herein shall be particulate in nature. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  20. The role of subsurface oxygen in the local oxidation of zirconium and zirconium nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, N.; Zhang, G.; Donnelly, K.M.; Evans, E.A.; Ramsier, R.D.; Dagata, J.A

    2004-01-30

    This paper discusses the growth kinetics of nanometer scale oxide structures grown by atomic force microscope (AFM) assisted lithography. The addition of nitrogen into the sputtering gas during zirconium deposition results in a crystalline ZrN material with oxygen held in solid solution. The diffusion rate of oxygen is high through the crystalline material, allowing it to participate in local anodization and resulting in tall oxide features at low relative humidity. These nanostructures are, in some cases, an order of magnitude higher than previously seen in other material systems. Higher nitrogen content in the plasma results in a crystalline to amorphous transition in the films, and the height enhancement of the AFM-grown features disappears. We propose that mass transport of subsurface oxygen has an influence on surface oxidation kinetics in this material system.

  1. The effect of zirconium on the cyclic oxidation of NiCrAl alloys

    Science.gov (United States)

    Barrett, C. A.; Khan, A. S.; Lowell, C. E.

    1981-01-01

    This paper examines results with cyclic oxidation tests of Ni(9-20) Cr(15-30) Al-(x)Zr alloys carried out at 1100 C and 1200 C in static air. The concentration of zirconium varies from 0 to 0.63 atomic percent. Significant aluminum penetration is found in metallographic and electron microscopic examination of oxidized surfaces. Small amounts of zirconium lead to minimal penetration, and with increased zirconium content pronounced oxide penetration is observed.

  2. Efficient One-Pot Synthesis of Colloidal Zirconium Oxide Nanoparticles for High-Refractive-Index Nanocomposites.

    Science.gov (United States)

    Liu, Chao; Hajagos, Tibor Jacob; Chen, Dustin; Chen, Yi; Kishpaugh, David; Pei, Qibing

    2016-02-01

    Zirconium oxide nanoparticles are promising candidates for optical engineering, photocatalysis, and high-κ dielectrics. However, reported synthetic methods for the colloidal zirconium oxide nanoparticles use unstable alkoxide precursors and have various other drawbacks, limiting their wide application. Here, we report a facile one-pot method for the synthesis of colloidally stable zirconium oxide nanoparticles. Using a simple solution of zirconium trifluoroacetate in oleylamine, highly stable zirconium oxide nanoparticles have been synthesized with high yield, following a proposed amidization-assisted sol-gel mechanism. The nanoparticles can be readily dispersed in nonpolar solvents, forming a long-term stable transparent solution, which can be further used to fabricate high-refractive-index nanocomposites in both monolith and thin-film forms. In addition, the same method has also been extended to the synthesis of titanium oxide nanoparticles, demonstrating its general applicability to all group IVB metal oxide nanoparticles.

  3. Unexpected wear of an unicompartimental knee arthroplasty in oxidized zirconium.

    Science.gov (United States)

    Luyet, Anais; Fischer, Jean-François; Jolles, Brigitte M; Lunebourg, Alexandre

    2015-12-01

    Unicompartimental knee arthroplasty is a successful procedure for the treatment of localized osteoarthritis to one compartment of the knee with good long-term results. However, several modes of failure of unicompartimental knee arthroplasty have been described, namely aseptic or septic loosening, progression of disease, wear, and instability. Metallosis after unicompartimental knee arthroplasty is rarely reported and is most often related with polyethylene wear or break. We report on a case of rapid failure of unicompartimental knee arthroplasty in oxidized zirconium associated with metallosis secondary to the dislocation of the polyethylene.

  4. Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide

    Science.gov (United States)

    Deluca, J. J. (Inventor)

    1979-01-01

    An element comprising sapphire, ruby or blue sapphire can be bonded to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

  5. Selective oxidation of alcohols over copper zirconium phosphate

    Institute of Scientific and Technical Information of China (English)

    Abdol R.Hajipour; Hirbod Karimi

    2014-01-01

    The catalytic activity of copper zirconium phosphate (ZPCu) in the selective oxidation of alcohols to their corresponding ketones or aldehydes, using H2O2 as an oxidizing agent, was studied. The oxida-tion reaction was performed without any organic solvent, phase-transfer catalyst, or additive. Steric factors associated with the substrates influenced the reaction. The catalyst was characterized using X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. It was shown that the interlayer distance increased from 0.74 to 0.80 nm and the crystallinity was reduced after Cu2+intercalation into the layers. This catalyst can be recovered and reused three times without significant loss of activity and selectivity.

  6. Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

    Science.gov (United States)

    Sinmyo, Ryosuke; Bykova, Elena; Ovsyannikov, Sergey V.; McCammon, Catherine; Kupenko, Ilya; Ismailova, Leyla; Dubrovinsky, Leonid

    2016-09-01

    Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

  7. Extensive Bone Reaction From Catastrophic Oxidized Zirconium Wear.

    Science.gov (United States)

    Cassar-Gheiti, Adrian J; Collins, Dennis; McCarthy, Tom

    2016-01-01

    The use of alternative bearing surfaces for total hip arthroplasty has become popular to minimize wear and increase longevity, especially in young patients. Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, Tennessee) femoral heads were introduced in the past decade for use in total hip arthroplasty. The advantages of oxidized zirconium include less risk of fracture compared with traditional ceramic heads. This case report describes a patient with a history of bilateral avascular necrosis of the femoral head after chemotherapy for acute lymphoblastic leukemia. Nonoperative management of avascular necrosis failed, and the patient was treated with bilateral total hip arthroplasty. The patient was followed at regular intervals and had slow eccentric polyethylene wear during a 10-year period. After 10 years, the patient had accelerated wear, with femoral and acetabular bone changes as a result of Oxinium and ultrahigh-molecular-weight polyethylene wear during a 6-month period. This article highlights the unusual accelerated bone changes that occurred as a result of Oxinium wear particles.

  8. KINETIC STUDY OF SELECTIVE GAS-PHASE OXIDATION OF ISOPROPANOL TO ACETONE USING MONOCLINIC ZRO2 AS A CATALYST

    Directory of Open Access Journals (Sweden)

    Mohammad Sadiq

    2015-08-01

    Full Text Available Zirconia was prepared by a precipitation method and calcined at 723 K, 1023 K, and 1253 K in order to obtain monoclinic zirconia. The prepared zirconia was characterized by XRD, SEM, EDX, surface area and pore size analyzer, and particle size analyzer. Monoclinic ZrO2 as a catalyst was used for the gas-phase oxidation of isopropanol to acetone in a Pyrex-glass-flow-type reactor with a temperature range of 443 K - 473 K. It was found that monoclinic ZrO2 shows remarkable catalytic activity (68% and selectivity (100% for the oxidation of isopropanol to acetone. This kinetic study reveals that the oxidation of isopropanol to acetone follows the L-H mechanism.

  9. Zirconium oxidation under high energy heavy ion irradiation

    CERN Document Server

    Bérerd, N; Moncoffre, N; Jaffrezic, H; Balanzat, E; democrite-00023380, ccsd

    2004-01-01

    This paper concerns the study of zirconium oxidation under irradiation with high energetic Xe ions. The irradiations were performed on the IRRSUD beam line at GANIL (Caen). The oxygen partial pressure was fixed at 10$^{-3}$ Pa and two temperature conditions were used, either 480$\\circ$C reached by Joule effect heating or 280$\\circ$C due to Xe energy deposition. Zirconia was fully characterized by Rutherford Backscattering Spectrometry, Transmission Electron Microscopy and Grazing Angle X-ray Diffraction. Apparent diffusion coefficients of oxygen in ZrO2 were determined from these experiments by using a model which takes into account a surface exchange between oxygen gas and the ZrO2 surface. These results are compared with thermal oxidation data.

  10. Oxidized zirconium: a potentially longer lasting hip implant

    Energy Technology Data Exchange (ETDEWEB)

    Good, V. [Smith and Nephew Inc., Memphis, TN 38116 (United States)]. E-mail: victoria.good@smithnephew.com; Widding, K. [Smith and Nephew Inc., Memphis, TN 38116 (United States); Hunter, G. [Smith and Nephew Inc., Memphis, TN 38116 (United States); Heuer, D. [Smith and Nephew Inc., Memphis, TN 38116 (United States)

    2005-07-01

    Because younger, more active patients are receiving total hip replacements, it is necessary to develop materials, which would increase the life span of the implants and challenge their wear potential under adverse conditions. Oxidized zirconium (OxZr) is a metal with the surface transformed to ceramic by oxidation that offers low fracture risk and excellent abrasion resistance. This study compared wear of polyethylene (non-irradiated and highly crosslinked) with OxZr and CoCr heads under smooth and rough (clinically relevant) conditions. Wear was up to 15-fold less and up to 4-fold fewer particles were produced when coupled with OxZr than with CoCr, demonstrating that OxZr heads should increase clinical implant longevity.

  11. Critical role of nitrogen during high temperature scaling of zirconium

    Science.gov (United States)

    Evans, E. B.; Tsangarakis, N.; Probst, H. B.; Garibotti, N. J.

    1973-01-01

    The mechanisms of scale cracking, scale color changes, and scale growth, and their interrelations, were studied in zirconium specimens at elevated temperatures in air, oxygen and nitrogen. Nitrogen was found to be responsible for monoclinic-to-cubic ZrO2 conversion, for scale cracking and breakaway on zirconium nitride, and for the formation of ZrN on the metal interface underneath an outer oxide layer.

  12. Removal of fluoride from fluoride-bering cerium sulfate solution by hydrous zirconium oxide

    Directory of Open Access Journals (Sweden)

    J. G. He

    2014-04-01

    Full Text Available In this paper the removal of fluoride from fluoride-bearing cerium sulfate solution by amorphous hydrous zirconium oxide was studied. The FTIR, SEM, EDS and UV-vis spectra show that fluoride is successfully adsorbed on hydrous zirconium oxide, and cerium exists as Ce4+ in solution. The study indicates that it is feasible to separate fluorine and cerium from fluorine-bearing rare earth sulfate solution using hydrous zirconium oxide, and eliminate the influence of fluoride on the extraction separation of rare earths.

  13. Sulphur mustard degradation on zirconium doped Ti-Fe oxides.

    Science.gov (United States)

    Štengla, Václav; Grygar, Tomáš Matys; Opluštil, František; Němec, Tomáš

    2011-09-15

    Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr(4+) dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr(4+) to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr(4+) doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.

  14. Fabrication of NiO/zirconium oxide nanofibers by electrospinning.

    Science.gov (United States)

    Sundarrajan, Subramanian; Venkatesan, Arunachalam; Agarwal, Satya R; Ahamed, Nabeela Nasreen Shaik Anwar; Ramakrishna, Seeram

    2014-12-01

    The electrospinning technique has been used to fabricate 1D inorganic-organic composite nanofibers from solutions containing poly(vinyl alcohol) (PVA) and suitable aqueous precursors of nickel and zirconium ions. Upon calcination, nickel oxide/zirconia nanofibers retained the original morphological features of as-spun nanofibers. X-ray diffraction was used to identify the crystalline nature of the final product and analytical tools such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were employed to elucidate the pathway of ceramic phase formation and the systematic evolution of morphological features in the as-spun and calcined fibers. These fibers will find potential applications in biomedical field.

  15. Photocatalytic and photoelectrochemical water oxidation over metal-doped monoclinic BiVO(4) photoanodes.

    Science.gov (United States)

    Parmar, Kanak Pal Singh; Kang, Hyun Joon; Bist, Amita; Dua, Piyush; Jang, Jum Suk; Lee, Jae Sung

    2012-10-01

    The visible-light-induced water oxidation ability of metal-ion-doped BiVO(4) was investigated and of 12 metal ion dopants tested, only W and Mo dramatically enhanced the water photo-oxidation activity of bare BiVO(4); Mo had the highest improvement by a factor of about six. Thus, BiVO(4) and W- or Mo-doped (2 atom %) BiVO(4) photoanodes about 1 μm thick were fabricated onto transparent conducting substrate by a metal-organic decomposition/spin-coating method. Under simulated one sun (air mass 1.5G, 100 mW cm(-2)) and at 1.23 V versus a reversible hydrogen electrode, the highest photocurrent density (J(PH)) of about 2.38 mA cm(-2) was achieved for Mo doping followed by W doping (J(PH) ≈ 1.98 mA cm(-2)), whereas undoped BiVO(4) gave a J(PH) value of about 0.42 mA cm(-2). The photoelectrochemical water oxidation activity of W- and Mo-doped BiVO(4) photoanodes corresponded to the incident photon to current conversion efficiency of about 35 and 40 % respectively. Electrochemical impedance spectroscopy and Mott-Schottky analysis indicated a positive flat band shift of about 30 mV, a carrier concentration 1.6-2 times higher, and a charge-transfer resistance reduced by 3-4-fold for W- or Mo-doped BiVO(4) relative to undoped BiVO(4). Electronic structure calculations revealed that both W and Mo were shallow donors and Mo doping generated superior conductivity to W doping. The photo-oxidation activity of water on BiVO(4) photoanodes (undopedphotocatalytic and photoelectrochemical water oxidation activity of monoclinic BiVO(4) by drastically reducing its charge-transfer resistance and thereby minimizing photoexcited electron-hole pair recombination.

  16. Mismatched wear couple zirconium oxide and aluminum oxide in total hip arthroplasty.

    Science.gov (United States)

    Morlock, M; Nassutt, R; Janssen, R; Willmann, G; Honl, M

    2001-12-01

    A patient complained about a squeaking noise in his total hip arthroplasty. Clinical evaluation revealed good function, and there were no signs of loosening on the radiograph. Physiotherapy did not alter this phenomenon, and ultimately a revision was performed 42 months after the first surgery. The analysis of the retrievals revealed that a zirconium oxide ceramic head had been paired with a monolithic alumina ceramic cup. The cup showed large deviations from an ideal sphere but minor wear signs. The head exhibited heavy local damage in the articulation zone. This damage might have been caused by the observed unsatisfactory fit between cup and ball, resulting in high stress concentrations and increased wear of the zirconium head. The characteristics of the zirconium and aluminum ceramics pairing might have worsened the process. The combination of implants used in this retrieved wear couple was never approved. To prevent such problems, components of different manufacturers should never be mixed and matched unless explicitly stated.

  17. Selective oxidation of alcohols over nickel zirconium phosphate

    Institute of Scientific and Technical Information of China (English)

    Abdol R. Hajipour; Hirbod Karimi; Afshin Koohi

    2015-01-01

    Nickel zirconium phosphate nanoparticles were found to function as efficient catalysts for the selec-tive oxidation of a wide range of alcohols to their corresponding ketones and aldehydes using H2O2 as an oxidizing agent and without any organic solvents, phase transfer catalysts, or additives. The steric and electronic properties of various substrates had significant influence on the reaction con-ditions required to achieve acetylation. The results showed that this method can be applied for the chemoselective oxidation of benzyl alcohols in the presence of aliphatic alcohols. The catalyst used in the current study was characterized by ICP-OES, XRD, NH3-TPD, Py-FTIR, N2 adsorp-tion-desorption, SEM and TEM. These analyses revealed that the interlayer distance in the catalyst increased from 0.75 to 0.98 nm when Ni2+ was intercalated between the layers, whereas the crystal-linity of the material was reduced. The nanocatalyst could also be recovered and reused at least seven times without any discernible decrease in its catalytic activity. This new method for the oxi-dation of alcohols has several key advantages, including mild and environmentally friendly reaction conditions, short reaction time, excellent yields and a facile work-up.

  18. Study on Catalysts with Rhodium Loading on Different Cerium-Zirconium Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalysts with Rh loading on different cerium-zirconium mixed oxides were characterized by BET, H2-TPR and OSC. The effects of different cerium-zirconium mixed oxides on catalytic performance and thermal stability of Rh loaded catalyst were studied. The results show that: (1) Rh can enhance cerium-zirconium mixed oxides OSC and catalytic reaction rates; (2) cerium-zirconium mixed oxides with high Ce contents and low Zr contents are more favorable to the stability of catalysts. Moreover, the contents of CeO2 have important effect on catalysts characteristics, and the addition of some rare earth components, such as La, Pr and Nd also have some influences.

  19. SELECTION OF OXIDES FOR STABILIZATION OF ZIRCONIUM DIOXIDE WHILE OBTAINING THERMAL BARRIER COATINGS

    Directory of Open Access Journals (Sweden)

    V. V. Okovity

    2015-01-01

    Full Text Available The paper analyzes selection of oxides and describes in details a majority of oxide systems which are applicable for stabilization of zirconium dioxide while obtaining thermal barrier coatings with maximum amount of tetragonal phase. Methodology of investigation is based on a review of analytical information on the current state of thermal barrier coatings on the basis of zirconium dioxide stabilized by oxides of rare-earth metals. The method used for application of  zirconium dioxide thermal barrier coatings is plasma spraying. Positive results have been also obtained while applying e-beam sputtering, ion-plasma deposition and magnetron sputtering. Nevertheless preferred plasma spraying application for thermal barrier coatings still continues due to its high productivity and versatility that permits to deposit metallic and ceramic materials of the ordered chemical and phase composition.Ytterbium and cerium oxides have been selected as oxides for stabilization of zirconium dioxide in order to obtain thermal barrier coatings. The paper also considers аn oxide system of zirconium dioxide: “hafnium oxide – yttrium oxide”, representing in itself the structure which is similar to zirconium dioxide.

  20. The impact of zirconium oxide radiopacifier on the early hydration behaviour of white Portland cement.

    Science.gov (United States)

    Coleman, Nichola J; Li, Qiu

    2013-01-01

    Zirconium oxide has been identified as a candidate radiopacifying agent for use in Portland cement-based biomaterials. During this study, the impact of 20 wt.% zirconium oxide on the hydration and setting reactions of white Portland cement (WPC) was monitored by powder X-ray diffraction (XRD), (29)Si and (27)Al magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), transmission electron microscopy (TEM) and Vicat apparatus. The presence of 20 wt.% zirconium oxide particles in the size-range of 0.2 to 5 μm was found to reduce the initial and final setting times of WPC from 172 to 147 min and 213 to 191 min, respectively. Zirconium oxide did not formally participate in the chemical reactions of the hydrating cement; however, the surface of the zirconium oxide particles presented heterogeneous nucleation sites for the precipitation and growth of the early C-S-H gel products which accelerated the initial setting reactions. The presence of zirconium oxide was found to have little impact on the development of the calcium (sulpho)aluminate hydrate phases.

  1. Preparation and Characterization of Hydrous Zirconium Oxide Formed by Homogeneous Precipitation

    Directory of Open Access Journals (Sweden)

    Silva G.L.J.P. da

    2002-01-01

    Full Text Available This paper reports on the preparation, characterization and study of the ion exchange behavior of hydrous zirconium oxides formed by homogeneous precipitation from zirconium oxychloride. The precipitants used were obtained by thermal decomposition of urea, sodium nitrite or ammonium carbonate. Seven compounds were prepared and characterized by thermal analysis, X-ray diffractometry and by surface area measurements. Amorphous forms were obtained in each case, a result that agrees with those obtained by conventional gel precipitation methodology. All these materials present surface area values of >148 m².g-1, determined after heat treatment at 50 °C. The ion exchange behavior of each hydrous zirconium oxide prepared was studied using K+ as the exchanged species and the results compared with those obtained for hydrous zirconium oxide originally precipitated by the sol gel method.

  2. Sulphur mustard degradation on zirconium doped Ti-Fe oxides

    Energy Technology Data Exchange (ETDEWEB)

    Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Grygar, Tomas Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno Veslarska 230, 628 00 Brno (Czech Republic)

    2011-09-15

    Highlights: {yields} New stechiometric materials for sulphur mustard degradation. {yields} High degree of degradation, more then 95% h{sup -1}. {yields} One-pot synthesis procedure. - Abstract: Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr{sup 4+} dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr{sup 4+} to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr{sup 4+} doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.

  3. Effects of precipitate aging time on the cerium-zirconium composite oxides

    Institute of Scientific and Technical Information of China (English)

    钟强; 崔梅生; 岳梅; 王琦; 王磊; 郭荣贵; 龙志奇; 黄小卫

    2014-01-01

    Cerium-zirconium composite oxides with high performance were synthesized by a co-precipitation method, using zirco-nium oxychloride and rare earth chloride as raw materials. The effects of precipitate aging time on the properties of cerium-zirconium composite oxides were investigated. The prepared cerium-zirconium composite oxides were characterized by X-ray diffraction (XRD), BET specific surface area, pulsed oxygen chemical adsorption, H2 temperature-programmed-reduction (H2-TPR), scanning electron microscopy (SEM), etc. The results showed that the precipitate aging time caused great effects on the properties of cerium zirconium composite oxides. With the increase of aging time, the cerium zirconium composite oxides showed enhanced specific sur-face area, good thermal stability, and high oxygen storage capacity (OSC). The best performance sample was obtained while the pre-cipitate aging time up to 48 h, with the specific surface area of 140.7 m2/g, and OSC of 657.24μmolO2/g for the fresh sample. Even after thermal aged under 1000 ºC for 4 h, the aged specific surface area was 41.6 m2/g, moreover with a good OSC of 569.9μmolO2/g.

  4. A Raman study of the nanocrystallite size effect on the pressure temperature phase diagram of zirconia grown by zirconium-based alloys oxidation

    Science.gov (United States)

    Bouvier, P.; Godlewski, J.; Lucazeau, G.

    2002-02-01

    The pressure-temperature phase diagrams of different zirconia samples prepared by oxidation of Zircaloy-4 and Zr-1%Nb-0.12O alloys were monitored by Raman spectrometry from 0.1 MPa to 12 GPa and from 300 to 640 K. These new diagrams show that the monoclinic-tetragonal equilibrium line is strongly downshifted in temperature compared to literature measurements performed on usual polycrystalline zirconia. In addition, the monoclinic-orthorhombic equilibrium line is slightly shifted to higher pressure (i.e. 6 GPa). The crystallite sizes smaller than 30 nm, are thought to be responsible for these equilibrium line displacements. The tetragonal phase obtained in temperature under high pressure can be quenched at room temperature, if the pressure is maintained, and it is destabilised and transforms completely into monoclinic phase if the pressure is released. These results confirm that coupled effects of stress, temperature and nanosized grain are responsible for the formation of the tetragonal phase near the metal/oxide interface during the oxidation of zirconium-based alloys.

  5. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R. [Bhabha Atomic Research Centre, Mumbai (India)

    2017-04-15

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

  6. Fabrication of NiO/zirconium oxide nanofibers by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Sundarrajan, Subramanian, E-mail: sundarnus1@gmail.com [Department of Mechanical Engineering, NUS, 117576 (Singapore); Venkatesan, Arunachalam; Agarwal, Satya R.; Shaik Anwar Ahamed, Nabeela Nasreen [Department of Mechanical Engineering, NUS, 117576 (Singapore); Ramakrishna, Seeram, E-mail: seeram@nus.edu.sg [Department of Mechanical Engineering, NUS, 117576 (Singapore); King Saud University, Riyadh 11451 (Saudi Arabia); Institute of Materials Research and Engineering, 117602 (Singapore)

    2014-12-01

    The electrospinning technique has been used to fabricate 1D inorganic–organic composite nanofibers from solutions containing poly(vinyl alcohol) (PVA) and suitable aqueous precursors of nickel and zirconium ions. Upon calcination, nickel oxide/zirconia nanofibers retained the original morphological features of as-spun nanofibers. X-ray diffraction was used to identify the crystalline nature of the final product and analytical tools such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were employed to elucidate the pathway of ceramic phase formation and the systematic evolution of morphological features in the as-spun and calcined fibers. These fibers will find potential applications in biomedical field. - Highlights: • PVA/NiO/zirconia composite nanofibers were synthesized via electrospinning. • Green processing of nanofibers using only water as solvent. • Calcination of composite nanofibers to yield ceramic nanofibers. • High aspect ratio nanofibers with diameters 106 ± 25 nm • The application of these fibers as dental composites and bone tissue engineering.

  7. Comparative X-ray diffraction study of the crystalline microstructure of tetragonal and monoclinic vanadium-zirconium dioxide solid solutions produced from gel precursors

    Energy Technology Data Exchange (ETDEWEB)

    Kojdecki, Marek Andrzej [Wojskowa Akademia Techniczna, Warszawa (Poland). Inst. Matematyki i Kryptologii; Ruiz de Sola, Esther; Alarcon, Javier [Valencia Univ., Burjasot (Spain). Dept. de Quimica Inorganica; Serrano, Francisco Javier; Amigo, Jose Maria [Valencia Univ., Burjasot (Spain). Dept. de Geologia

    2009-04-15

    The microstructural characteristics of solid solutions, prepared by heating dried gel precursors with nominal compositions V{sub x}Zr{sub 1-x}O{sub 2} (0{<=}x{<=}0.1) at 723 and 1573 K, were determined from X-ray diffraction patterns. The crystalline microstructure of the resulting specimens, characterized by a prevalent crystallite shape, a volume-weighted crystallite size distribution and a second-order lattice strain distribution, was found to depend on the vanadium content. A characteristic feature of all size distributions was their bimodality, explained as a result of transformations between tetragonal and monoclinic phases during thermal treatment. A comparative study of the microstructure of both zirconia phases has been carried out, enabling reconstruction of a probable course of crystallization of both pure and vanadium-doped zirconias: on heating a sample, nucleation and the early growth stages involve crystallites of both phases; then on annealing and cooling, the crystallites of one phase transform into the other, depending on the thermal treatment temperature. Each logarithmic normal component of the crystallite size distribution of the resulting phase can be attributed to one of these processes. The limit of solubility of vanadium in tetragonal and monoclinic zirconia is estimated from the microstructural characteristics. (orig.)

  8. Corrosion evaluation of zirconium doped oxide coatings on aluminum formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Bajat, Jelena; Mišković-Stanković, Vesna; Vasilić, Rastko; Stojadinović, Stevan

    2014-01-01

    The plasma electrolytic oxidation (PEO) of aluminum in sodium tungstate (Na(2)WO(4) · (2)H(2)O) and Na(2)WO(4) · (2)H(2)O doped with Zr was analyzed in order to obtain oxide coatings with improved corrosion resistance. The influence of current density in PEO process and anodization time was investigated, as well as the influence of Zr, with the aim to find out how they affect the chemical content, morphology, surface roughness, and corrosion stability of oxide coatings. It was shown that the presence of Zr increases the corrosion stability of oxide coatings for all investigated PEO times. Evolution of EIS spectra during the exposure to 3% NaCl, as a strong corrosive agent, indicated the highest corrosion stability for PEO coating formed on aluminum at 70 mA/cm(2) for 2 min in a zirconium containing electrolyte.

  9. Zirconium nanoparticles prepared by the reduction of zirconium oxide using the RAPET method

    Directory of Open Access Journals (Sweden)

    Michal Eshed

    2011-04-01

    Full Text Available The aim of the current work is the synthesis and characterization of metallic Zr nanoparticles. The preparation is carried out by using the RAPET method (Reaction under Autogenic Pressure at Elevated Temperatures developed in our lab. The RAPET reaction of commercial ZrO2 with Mg powder was carried out in a closed stainless steel cell, at 750 °C. On completion of the reaction, the additionally formed MgO is removed by treatment with acid. The characterization of the product was performed by XRD, X-ray absorption spectroscopy, SEM, TEM and elemental analysis. The XRD pattern reveals that the product is composed of pure metallic zirconium, without any traces of the MgO by-product.

  10. The air oxidation behavior of lanthanum ion implanted zirconium at 500 deg. C

    CERN Document Server

    Peng, D Q; Chen, X W; Zhou, Q G

    2003-01-01

    The beneficial effect of lanthanum ion implantation on the oxidation behavior of zirconium at 500 deg. C has been studied. Zirconium specimens were implanted by lanthanum ions using a MEVVA source at energy of 40 keV with a fluence range from 1x10 sup 1 sup 6 to 1x10 sup 1 sup 7 ions/cm sup 2 at maximum temperature of 130 deg. C, The weight gain curves were measured after being oxidized in air at 500 deg. C for 100 min, which showed that a significant improvement was achieved in the oxidation behavior of zirconium ion implanted with lanthanum compared with that of the as-received zirconium. The valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy; and then the depth distributions of the elements in the surface of the samples were obtained by Auger electron spectroscopy. Glancing angle X-ray diffraction at 0.3 deg. incident angles was employed to examine the modification of its phase transformation because of the lanthanum ion implantation in the oxide films. It was obviously fou...

  11. Joint Test Protocol: Environmentally Friendly Zirconium Oxide Pretreatment Demonstration

    Science.gov (United States)

    2013-12-01

    ferrous -based alloy exhibiting hardness greater than Rc39 (e.g., high-strength steel) requires testing and heat treatment according to Federal...compatibility with the current suite of military coatings and a range of ferrous and nonferrous substrates. The proposed zirconium-based pretreatment was...types of ferrous , zinc, and aluminum substrates by immersing the metal into a dilute solution of fluoro-zirconic acid (FZA) and proprietary additives at

  12. Palm fibers modified with zirconium oxide; Fibras da palmeira modificadas com oxido de zirconio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The objective of this work was to study the chemical modification of the fibers from palm with zirconium oxide in granulometric proportion different. The modification of the fibers by techniques scanning electron microscopy, X-ray diffractometry and infrared spectrophotometer was evaluated. Results showed that particle size of the fiber influenced in the modification. (author)

  13. Mossbauer investigations of corrosion environment influence on Fe valence states in oxide films of zirconium alloys

    NARCIS (Netherlands)

    Filippov, V. P.; Petrov, V. I.; Shikanova, Yu. A.

    2006-01-01

    Mossbauer investigations about iron atom redistribution in oxide films of zirconium alloys subjected to corrosion at 500 degrees C in pure oxygen and water pair have been analysed. The alloys were also subjected to autoclave conditions at a pressure of 10.0 MPa and autoclave conditions at 350 degree

  14. Clinical Outcomes of Zirconium-Oxide Posts: Up-to-Date Systematic Review.

    Science.gov (United States)

    Al-Thobity, Ahmad M

    2016-06-01

    The aim of this systematic review was to investigate the clinical outcomes of the use of zirconium-oxide posts in the past 20 years. The addressed question was: Do zirconium-oxide posts maintain the long-term survival rate of endodontically treated teeth? A database search was made of articles from January 1995 to December 2014; it included combinations of the following keywords: "zirconia," "zirconium oxide," "dowel/dowels," "post/posts," and "post and core." Exclusion criteria included review articles, experimental studies, case reports, commentaries, and articles published in a language other than English. Articles were reviewed by the titles, followed by the abstracts, and, finally, the full text of the selected studies. Four studies were included after filtering the selected studies according to the inclusion and exclusion criteria. In one study, the prefabricated zirconia posts with indirect glass-ceramic cores had significantly higher failure rates than other posts with direct composite cores. In two studies, no failure of the cemented posts was observed throughout the follow-up period. Due to the limited number of clinical studies, it can be concluded that the long-term success rate of prefabricated zirconium-oxide posts is unclear.

  15. Mossbauer investigations of corrosion environment influence on Fe valence states in oxide films of zirconium alloys

    NARCIS (Netherlands)

    Filippov, V. P.; Petrov, V. I.; Shikanova, Yu. A.

    2006-01-01

    Mossbauer investigations about iron atom redistribution in oxide films of zirconium alloys subjected to corrosion at 500 degrees C in pure oxygen and water pair have been analysed. The alloys were also subjected to autoclave conditions at a pressure of 10.0 MPa and autoclave conditions at 350

  16. Mild oxide-hydrothermal synthesis of different aspect ratios of monoclinic BiVO{sub 4} nanorods tuned by temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Fengqiang; Wu, Qingsheng; Ma, Jie; Chen, Yijun [Department of Chemistry, Tongji University, Shanghai (China)

    2009-01-15

    The monoclinic scheelite BiVO{sub 4} nanocrystals were easily prepared via an oxide-hydrothermal synthesis (OHS) method directly utilizing bulk-phase materials of V{sub 2}O{sub 5} and Bi{sub 2}O{sub 3} as precursor. In the presence of PEG 4000, the reactions were performed in the mild temperature range from 130 C to 200 C. The products were characterized with FTIR, XRD, TEM and UV-vis DRS. These data clearly demonstrated that monoclinic scheelite structure BiVO{sub 4} could be synthesized by the feasible OHS route. The aspect ratios of nanorods were increased with the synthesized temperature. The as-prepared BiVO{sub 4} showed high photocatalytic activity, which was demonstrated by degradation of methylene blue (MB) solution under visible-light irradiation ({lambda}>420 nm). A growth mechanism of bismuth vanadate was proposed. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. The Effect of Zirconium Addition on the Oxidation Resistance of Aluminide Coatings

    Science.gov (United States)

    Zagula-Yavorska, Maryana; Pytel, Maciej; Romanowska, Jolanta; Sieniawski, Jan

    2015-04-01

    Nickel, Mar M247, and Mar M200 superalloys were coated with zirconium-doped aluminide deposited by the chemical vapor deposition method. All coatings consisted of two layers: an additive one, comprising of the β-NiAl phase and the interdiffusion one. The interdiffusion layer on pure nickel consisted of the γ'-Ni3Al phase and β-NiAl phase on superalloys. Precipitations of zirconium-rich particles were found near the coating's surface and at the interface between the additive and the interdiffusion layer. Zirconium doping of aluminide coating improved the oxidation resistance of aluminide coatings deposited both on the nickel substrate and on the Mar M200 superalloy. Precipitations of ZrO2 embedded by the Al2O3 oxide were formed during oxidation. It seems that the ZrO2 oxide increases adhesion of the Al2O3 oxide to the coating and decreases the propensity of the Al2O3 oxide rumpling and spalling.

  18. Characterization of the porosity of thin zirconium oxide coatings prepared at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ugas-Carrion, R. [Technische Universitaet Darmstadt, Department of Materials Science, Darmstadt (Germany); Sittner, F. [Technische Universitaet Darmstadt, Department of Materials Science, Darmstadt (Germany)], E-mail: sittner@ca.tu-darmstadt.de; Ochs, C.J.; Flege, S.; Ensinger, W. [Technische Universitaet Darmstadt, Department of Materials Science, Darmstadt (Germany)

    2009-01-30

    In this work we investigated the possibilities to reduce the porosity of thin protective zirconium oxide films deposited with the sol-gel technique at low temperatures. Electrochemical investigations showed that the concentration of the stabilizing agent acetylacetone is a crucial parameter for the protection performance of the zirconium oxide films and that it is possible to run the deposition process at much lower temperatures with the optimum stabilizer concentration. This allows the application of the process to sensitive substrates that cannot be treated at high temperatures and reduces energy costs as well. Characterization of the film structure with secondary ion mass spectrometry revealed that the stabilizing agent is responsible for the formation of a mixed oxide layer at the interface of substrate and coating. The thickness of this layer can be tuned with the concentration of the stabilizing agent.

  19. Wet Etching of Heat Treated Atomic Layer Chemical Vapor Deposited Zirconium Oxide in HF Based Solutions

    Science.gov (United States)

    Balasubramanian, Sriram; Raghavan, Srini

    2008-06-01

    Alternative materials are being considered to replace silicon dioxide as gate dielectric material. Of these, the oxides of hafnium and zirconium show the most promise. However, integrating these new high-k materials into the existing complementary metal-oxide-semiconductor (CMOS) process remains a challenge. One particular area of concern is the wet etching of heat treated high-k dielectrics. In this paper, work done on the wet etching of heat treated atomic layer chemical vapor deposited (ALCVD) zirconium oxide in HF based solutions is presented. It was found that heat treated material, while refractory to wet etching at room temperature, is more amenable to etching at higher temperatures when methane sulfonic acid is added to dilute HF solutions. Selectivity over SiO2 is still a concern.

  20. The effect of zirconium on the isothermal oxidation of nominal Ni-14Cr-24Al alloys

    Science.gov (United States)

    Kahn, A. S.; Lowell, C. E.; Barrett, C. A.

    1980-01-01

    The isothermal oxidation of Ni-14Cr-24Al-xZr-type alloys was performed in still air at 1100, 1150, and 1200 C for times up to 200 hr. The zirconium content of the alloys varied from 0-0.63 atom percent (a/o). The oxidized surfaces were studied by optical microscopy, X-ray diffraction, and scanning electron microscopy. The base alloy was an alumina former with the zirconium-containing alloys also developing some ZrO2. The addition of zirconium above 0.066 a/o increased the rate of weight gain relative to the base alloy. Due to oxide penetratio, the weight gain increased with Zr content; however, the scale thickness did not increase. The Zr did increase the adherence of the oxide, particularly at 1200 C. The delta W/A vs. time data fit the parabolic model of oxidation. The specific diffusion mechanism operative could not be identified by analysis of the calculated activation energies. Measurements of the Al2O3 scale lattice constants yielded the same values for all alloys.

  1. Thermoluminescence properties of copper doped zirconium oxide for UVR dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN, 11500 Mexico D.F. (Mexico)], E-mail: trivera@ipn.mx; Olvera, L. [Universidad Autonoma Metropolitana-Iztapalapa, 11500 Mexico D.F. (Mexico); Martinez, A.; Molina, D. [Centro de Proteccion e Higiene de las Radiaciones, Habana (Cuba); Azorin, J.; Barrera, M.; Soto, A.M.; Sosa, R. [Universidad Autonoma Metropolitana-Iztapalapa, 11500 Mexico D.F. (Mexico); Furetta, C. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN, 11500 Mexico D.F. (Mexico)

    2007-04-15

    The synthesized ZrO{sub 2}:Cu particles were characterized using X-ray diffraction (XRD) to determine the nanocrystallite size and crystal structure, respectively. The ZrO{sub 2}:Cu powder with a crystallite size of 30-40 nm has a monoclinic structure and exhibit a thermoluminescent (TL) glow curve with two peaks centered at 130 and 180{sup 0}C. The TL response of ZrO{sub 2}:Cu as a function of wavelength exhibited two maxima at 260 and 290 nm. The TL response of ZrO{sub 2}:Cu as a function of the UV light spectral irradiance was linear in the range from 10 to 2300mJ/cm{sup 2}. Fading and reusability of the phosphor were also studied. The results showed that ZrO{sub 2}:Cu nanopowder has potential to be used as a UV dosimeter in UV radiation monitoring.

  2. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; Haasterecht, van T.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  3. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  4. The origin of 2.7 eV blue luminescence band in zirconium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Perevalov, T. V., E-mail: timson@isp.nsc.ru; Zhuravlev, K. S.; Gritsenko, V. A. [Rzhanov Institute of Semiconductor Physics SB RAS, 13 Lavrentiev ave., 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 2 Pirogov str., 630090 Novosibirsk (Russian Federation); Gulyaev, D. V.; Aliev, V. S. [Rzhanov Institute of Semiconductor Physics SB RAS, 13 Lavrentiev ave., 630090 Novosibirsk (Russian Federation); Yelisseyev, A. P. [Sobolev Institute of Geology and Mineralogy SB RAS, 3 Koptyug ave., 630090 Novosibirsk (Russian Federation)

    2014-12-28

    The luminescence spectra of non-stoichiometric zirconium oxide film series with different oxygen vacancies' concentrations show the blue photoluminescence band centered near a 2.7 eV peak. There is a broad band at 5.2 eV in the luminescence excitation spectrum for blue emission. The ab-initio quantum-chemical calculation gives a peak in the optical absorption at 5.1 eV for the oxygen vacancy in cubic ZrO{sub 2}. It was concluded that the 2.7 eV blue luminescence excited near 5.2 eV in a zirconium oxide film is associated with the oxygen vacancy.

  5. Development of wear resistant zirconium oxide thin films on stainless steel substrates

    Energy Technology Data Exchange (ETDEWEB)

    Then, I.K.; Mujahid, M. [School of Materials Engineering, Nanyang Technological Univ. (Singapore); Zhang, B. [Dou Yee Technologies Pte Ltd, Bedok Industrial Park C (Singapore)

    2005-07-01

    The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 {mu}m in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650 C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced. (orig.)

  6. Transport Properties of Aqueous Glycerol and Aqueous Mannitol through the Zirconium Oxide Membrane

    Science.gov (United States)

    Blokhra; Sharma; Blokhra

    1997-08-15

    The transport properties of aqueous glycerol and aqueous mannitol across a zirconium oxide membrane are, investigated from the point of view of irreversible thermodynamics. The data on hydrodynamic permeability are analyzed in terms of frictional coefficients and entropy of activation. The phenomenological coefficient characterizing the electroosmotic flow and the membrane characteristics are also estimated for the various solutions with the object of determining the efficiencies of electrokinetic energy conversion and zeta potential. Copyright 1997Academic Press

  7. Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

    OpenAIRE

    Ryosuke Sinmyo; Elena Bykova; Ovsyannikov, Sergey V.; Catherine McCammon; Ilya Kupenko; Leyla Ismailova; Leonid Dubrovinsky

    2016-01-01

    Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 ...

  8. Study of diffusion processes in the oxide layer of zirconium alloys

    Directory of Open Access Journals (Sweden)

    Sialini P.

    2016-03-01

    Full Text Available In the active zone of a nuclear reactor where zirconium alloys are used as a coating material, this material is subject to various harmful impacts. During water decomposition reactions, hydrogen and oxygen are evolved that may diffuse through the oxidic layer either through zirconium dioxide (ZrO2 crystals or along ZrO2 grains. The diffusion mechanism can be studied using the Ion Beam Analysis (IBA method where nuclear reaction 18O(p,α15N is used. A tube made of zirconium alloy E110 (with 1 wt. % of Nb was used for making samples that were pre-exposed in UJP PRAHA a.s. and subsequently exposed to isotopically cleansed environment of H2 18O medium in an autoclave. The samples were analysed with gravimetric methods and IBA methods performed at the electrostatic particle accelerator Tandetron 4130 MC in the Nucler Physics Institute of the CAS, Řež. With IBA methods, the overall thicknesses of corrosion layers on the samples, element composition of the alloy and distribution of oxygen isotope 18O in the corrosion layer and its penetration in the alloy were identified. The retrieved data shows at the oxygen diffusion along ZrO2 grains because there are two peaks of 18O isotope concentrations in the corrosion layer. These peaks occur at the environment-oxide and oxide-metal interface. The element analysis identified the presence of undesirable hafnium.

  9. Enantioselective α-Hydroxylation by Modified Salen-Zirconium(IV)-Catalyzed Oxidation of β-Keto Esters.

    Science.gov (United States)

    Yang, Fan; Zhao, Jingnan; Tang, Xiaofei; Zhou, Guangli; Song, Wangze; Meng, Qingwei

    2017-02-03

    The highly enantioselective α-hydroxylation of β-keto esters using cumene hydroperoxide (CHP) as the oxidant was realized by a chiral (1S,2S)-cyclohexanediamine backbone salen-zirconium(IV) complex as the catalyst. A variety of corresponding chiral α-hydroxy β-keto esters were obtained in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). The zirconium-catalyzed enantioselective α-hydroxylation of β-keto esters was scalable, and the zirconium catalyst was recyclable. The reaction can be performed in gram scale, and corresponding chiral products were acquired in 95% yield and 99% ee.

  10. Structural Analysis of Surface-Modified Oxidation-Resistant Zirconium Alloy Cladding for Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youho; No, Hee Cheon; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    While the current zirconium-based alloy cladding (Zircaloy, here after) has served well for fission-product barrier and heat transfer medium for the nuclear fuel of light water reactors (LWRs) in steady-states, concerns surrounding its mechanical behavior during accidents have drawn serious attentions. In accidents, strength degradation of the current-zirconium based alloy cladding manifests at temperature around ∼800 .deg. C, which results in fuel ballooning. Above 1000 .deg. C, zircaloy undergoes rapid oxidation with steam. Formation of brittle oxide (ZrO{sub 2}) and underlying oxygen-saturated α-zircaloy as a consequence of steam oxidation leads to loss of cladding ductility. Indeed, the loss of zircaloy ductility upon the steam oxidation has been taken as a measure of fuel failure criteria as stated in 10 CFR 50.46. In addition, zircaloy steam oxidation is an exothermic reaction, which is an energy source that sharply accelerates temperature increase under loss of coolant accidents, decreasing allowable coping time for loss of coolant accidents, decreasing allowable coping time for loss of coolant accidents (LOCA) before significant fuel/core melting starts. Hydrogen generated as a result of zircaloy oxidation could cause an explosion if certain conditions are met. In steady-state operation, zircaloy embrittlement limits the burnup of the fuel rod to assure remaining cladding ductility to cope with accidents. As a way to suppress hydrogen generation and cladding embrittlement by oxidation, ideas of cladding coating with an oxidation-preventive layer have emerged. Indeed, among a numbers of 'accident-tolerant-fuel (ATF)' concepts, the concept of coating the current fuel rod. Some signs of success on the lab-scale oxidation-prevention have been confirmed with a few coating candidates. Yet, relatively less attention has been given to structural integrity of coated zirconium-based alloy cladding. It is important to note that oxidation

  11. Pyroelectric response in crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films

    Science.gov (United States)

    Smith, S. W.; Kitahara, A. R.; Rodriguez, M. A.; Henry, M. D.; Brumbach, M. T.; Ihlefeld, J. F.

    2017-02-01

    Pyroelectric coefficients were measured for 20 nm thick crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films across a composition range of 0 ≤ x ≤ 1. Pyroelectric currents were collected near room temperature under zero applied bias and a sinusoidal oscillating temperature profile to separate the influence of non-pyroelectric currents. The pyroelectric coefficient was observed to correlate with zirconium content, increased orthorhombic/tetragonal phase content, and maximum polarization response. The largest measured absolute value was 48 μCm-2 K-1 for a composition with x = 0.64, while no pyroelectric response was measured for compositions which displayed no remanent polarization (x = 0, 0.91, and 1).

  12. Luminescence properties of 100 MeV swift Si{sup 7+} ions irradiated nanocrystalline zirconium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Lokesha, H.S. [Physics R & D Centre, PES Institute of Technology, BSK 3rd Stage, Bangalore, 560 085 (India); Nagabhushana, K.R., E-mail: bhushankr@gmail.com [Physics R & D Centre, PES Institute of Technology, BSK 3rd Stage, Bangalore, 560 085 (India); Singh, Fouran [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110 067 (India)

    2015-10-25

    Nanocrystalline zirconium oxide (ZrO{sub 2}) has been synthesized by combustion technique. The X-ray diffraction (XRD) pattern of ZrO{sub 2} confirms the monoclinic phase. The average crystallite sizes are estimated using Scherrer's formula and found to be ∼35 nm. Surface morphology and elemental composition of the ZrO{sub 2} is analyzed using the field emission scanning electron microscope (FESEM) equipped with Energy dispersive x-ray analysis (EDX). ZrO{sub 2} pellets are irradiated with 100 MeV swift Si{sup 7+} heavy ions in the fluence range of 1 × 10{sup 10}–1 × 10{sup 14} ions cm{sup −2}. The broad photoluminescence (PL) emission with peak at ∼ 466 nm is observed and attributed to F-centers. Thermoluminescence (TL) glow curves of ion irradiated samples reveal a well resolve peak at ∼ 418 K (T{sub m1}) and an unresolved peak at ∼ 502 K (T{sub m2}). TL intensity increases up to 3 × 10{sup 11} ions cm{sup −2} and then TL intensity decreases as increase in fluence. TL parameters of ion irradiated ZrO{sub 2} samples are described by general order kinetics. - Graphical abstract: Thermoluminescence glow curves of 100 MeV swift Si{sup 7+} ion irradiated ZrO{sub 2}. - Highlights: • Single phase of ZrO{sub 2} synthesized by combustion technique. • Sample irradiated with 100 MeV Si{sup 7+} ions for various fluence. • Highest PL and TL response at same fluence due to defect concentration. • New TL glow peak appear at 455 K for above fluence 1 × 10{sup 11} ions cm{sup −2}.

  13. Zirconium Micro-Arc Oxidation as a Method for Producing Heat Insulation Elements in Spacecraft

    Directory of Open Access Journals (Sweden)

    V. K. Shatalov

    2014-01-01

    Full Text Available Application of coatings on the surface of materials as well as their composition and structure control in the near-surface layer enables us to use properties of base material and modified layers in the most rational and profitable way and save expensive and rare metals and alloys.The space telescope of T-170M will be the main tool of the international space observatory "Spektr-UF".It is being understood that the main mirror shade, which is in the outer space and has a considerable height will act as a radiator cooling a unit (cage of the main mirror. Therefore it is necessary to create heat insulation between the shade of the main mirror and the frame of the main mirror unit. From the thermal calculations a detail to provide heat insulation must possess thermal conductivity, at most, 2,5 and a conditional limit of fluidity for compression, at least, 125 MPas to ensure that the shade diaphragms position of the main mirror is stable with respect to the optical system of telescope.Considering that oxide of zirconium possesses one of the lowest thermal conductivities among oxides of metals, it is offered to use zirconium, as a material of base, and to put the MAO-covering (micro-arc oxide on its surface.As a result of studying the features of MAO-coverings on zirconium it is:1 found that the composite material consisting of zirconium and MAO-covering on it, has low thermal conductivity (less than 2 , and thus, because of small oxide layer thickness against the thickness of base material, possesses the mechanical properties which are slightly different from the pure zirconium ones;2 found that the composite material possesses the low gas release, allowing its use in the outer space conditions; the material processed in two electrolytes i.e. phosphate and acid ones has the lowest gas release;3 found that with growing thickness of MAO-covering its porosity decreases, thus the average pore diameter grows thereby leading to increasing thermal

  14. Nanoscale Zirconium-(oxyhydr)oxide in Contaminated Sediments From Hanford, WA - A New Host for Uranium

    Science.gov (United States)

    Stubbs, J. E.; Elbert, D. C.; Veblen, L. A.; Zachara, J. M.; Davis, J. A.; Veblen, D. R.

    2008-12-01

    Zirconium-, uranium-, and copper-bearing wastes have leached from former disposal ponds into vadose zone sediments in the 300 Area at the Department of Energy's Hanford Site. Zirconium is enriched in the shallow portion of the vadose zone, and we have discovered an amorphous Zr-(oxyhydr)oxide that contains 16% of the total uranium budget (84.24 ppm) in one of the shallow samples. We have characterized the oxide using electron microprobe analysis (EMPA), a focused ion beam (FIB) instrument, and transmission electron microscopy (TEM). It occurs in fine-grained coatings found on lithic and mineral fragments in these sediments. The oxide is intimately intergrown with the phyllosilicates and other minerals of the coatings, and in places can be seen coating individual, nano-sized phyllosilicate mineral grains. Electron energy-loss spectroscopy (EELS) shows that the Zr-(oxyhydr)oxide has a P:Zr atomic ratio around 0.2, suggesting it is either intergrown with minor amounts of a Zr-phosphate or has adsorbed a significant amount of phosphate. This material has adsorbed or incorporated a substantial amount of uranium. Thus, understanding its nature is critical to predicting the long-term fate of U in the Hanford vadose zone. While the low-temperature uptake of U by Zr-(oxhydr)oxides and phosphates has been studied for several decades in laboratory settings, to our knowledge ours is the first report of such uptake in the field.

  15. The effect of sulfur and zirconium co-doping on the oxidation of NiCrAl

    Science.gov (United States)

    Smialek, James L.

    1988-01-01

    The adhesion behavior of Al2O3 scales formed on NiCrAl+Zr alloys was examined as a function of both sulfur and zirconium doping levels. In general, very high levels of zirconium were required to counteract the detrimental effects of sulfur. A sulfur-zirconium adherence map was constructed, as determined from the oxidation and spalling behavior in 1100 C cyclic tests. For low sulfur alloys (less than 500 ppma), the amount of zirconium required for adherence at any given sulfur level can be described by Zr greater than 600 S(0.2) (in ppma). These results underscore the importance of sulfur to adhesion mechanisms and suggest that sulfur gettering is a first order effect of reactive element additions to MCrAl alloys.

  16. Role of electrolyte composition on structural, morphological and in-vitro biological properties of plasma electrolytic oxidation films formed on zirconium

    Energy Technology Data Exchange (ETDEWEB)

    M, Sandhyarani [Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirappalli 620015, Tamilnadu (India); T, Prasadrao [Department of Physics, Koneru Lakshmaiah University, Vaddeswaram, Guntur 522502, Andhra Pradesh (India); N, Rameshbabu, E-mail: rameshrohith@gmail.com [Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirappalli 620015, Tamilnadu (India)

    2014-10-30

    Highlights: • Uniform oxide films were formed on zirconium by plasma electrolytic oxidation. • Silicate in electrolyte alter the growth of m-ZrO{sub 2} from (1{sup ¯}11) to (2 0 0) orientation. • Addition of KOH to electrolyte improved the corrosion resistance of oxide films. • Silicon incorporated oxide films showed higher surface roughness and wettability. • Human osteosarcoma cells were strongly adhered and spreaded on all the oxide films. - Abstract: Development of oxide films on metallic implants with a good combination of corrosion resistance, bioactivity and cell adhesion can greatly improve its biocompatibility and functionality. Thus, the present work is aimed to fabricate oxide films on metallic Zr by plasma electrolytic oxidation (PEO) in methodically varied concentrations of phosphate, silicate and KOH based electrolyte systems using a pulsed DC power source. The oxide films fabricated on Zr are characterized for its phase composition, surface morphology, chemical composition, roughness, wettability, surface energy, corrosion resistance, apatite forming ability and osteoblast cell adhesion. Uniform films with thickness varying from 6 to 11 μm are formed. XRD patterns of all the PEO films showed the predominance of monoclinic zirconia phase. The film formed in phosphate + KOH electrolyte showed superior corrosion resistance, which can be ascribed to its pore free morphology. The films formed in silicate electrolyte showed higher apatite forming ability with good cell adhesion and spreading over its surface which is attributed to its superior surface roughness and wettability characteristics. Among the five different electrolyte systems employed in the present study, the PEO film formed in an electrolyte system with phosphate + silicate + KOH showed optimum corrosion resistance, apatite forming ability and biocompatibility.

  17. Nanofiber of ultra-structured aluminum and zirconium oxide hybrid.

    Science.gov (United States)

    Kim, Hae-Won; Kim, Hyoun-Ee

    2006-02-01

    An internally ultrastructured Al- and Zr-oxide hybrid was developed into a nanofiber. As a precursor for the generation of nanofiber, a hybridized sol was prepared using the Pechini-type sol-gel process, whereby the Al- and Zr-metallic ions were to be efficiently distributed and stabilized within the polymeric network. The hybridized sol was subsequently electrospun and heat treated to a nanofiber with diameters of tens to hundreds of nanometers. The internal structure of the nanofiber was organized at the molecular level, with the Al- and Zr-oxide regions being interspaced at distances of less than ten nanometers. This ultrastructured Al- and Zr-oxide hybrid nanofiber is considered to be potentially applicable in numerous fields.

  18. Retention of implant-supported zirconium oxide ceramic restorations using different luting agents.

    Science.gov (United States)

    Nejatidanesh, Farahnaz; Savabi, Omid; Shahtoosi, Mojtaba

    2013-08-01

    The aim of this study was to evaluate the retention value of implant-supported zirconium oxide ceramic copings using different luting agents. Twenty ITI solid abutments of 5.5 mm height and ITI implant analogs were mounted vertically into autopolymerizing acrylic resin blocks. Ninety zirconium oxide copings (Cercon, Degudent) with a loop on the occlusal portion were made. All samples were airborne particle abraded with 110 μm Al₂O₃ and luted using different types of luting agents: resin cements (Clearfil SA, Panavia F2.0, Fuji Plus), conventional cements (Fleck's, Poly F, Fuji I), and temporary cements (Temp Bond, GC free eugenol, TempSpan) with a load of 5 Kg. (N = 10) All copings were incubated at 37°C for 24 h and conditioned in artificial saliva for 1 week, and thermal cycled for 5000 cycles 5-55°C with a 30-s dwell time. The dislodging force of the copings along the long axis of the implant-abutment complex was recorded using universal testing machine with 5 mm/min crosshead speed. Data were subjected to Kruskal-Wallis (α = 0.05) and Mann-Whitney tests with Bonferroni step down correction (α = 0.001). There was significant difference between the mean rank retention values of different luting agents (P ceramic restorations, over ITI solid abutments may be influenced by the type of cement. The application of an MDP-containing resin and resin-modified glass ionomer luting agents increase the retentive value of implant-supported zirconium oxide restorations. © 2011 John Wiley & Sons A/S.

  19. Characterization of the sorption behavior of trivalent actinides on zirconium(IV) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Eibl, Manuel; Huittinen, Nina [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Virtanen, S.; Merilaeinen, S.; Lehto, J. [Helsinki Univ. (Finland); Rabung, T. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Nuclear Waste Disposal

    2017-06-01

    The uptake of trivalent Eu and Cm on zirconium(IV) oxide was investigated in batch sorption and TRLFS studies, respectively. Sorption of Eu{sup 3+} was found to start at a pH-value of 4. Based on TRLFS results, sorption of Cm{sup 3+} was assigned to occur through innersphere complex formation at the zirconia surface. A deconvolution of the TRLFS emission spectra gave three different sorption species with strong red-shifts of the peak positions (600.3 nm, 604.3 nm and 608.2 nm) compared to similar systems.

  20. Experimental Calcium Silicate-Based Cement with and without Zirconium Oxide Modulates Fibroblasts Viability.

    Science.gov (United States)

    Slompo, Camila; Peres-Buzalaf, Camila; Gasque, Kellen Cristina da Silva; Damante, Carla Andreotti; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro; de Oliveira, Rodrigo Cardoso

    2015-01-01

    The aim of this study was to verify whether the use of zirconium oxide as a radiopacifier of an experimental calcium silicate-based cement (WPCZO) leads to cytotoxicity. Fibroblasts were treated with different concentrations (10 mg/mL, 1 mg/mL, and 0.1 mg/mL) of the cements diluted in Dulbecco's modified Eagle's medium (DMEM) for periods of 12, 24, and 48 h. Groups tested were white Portland cement (WPC), white Portland cement with zirconium oxide (WPCZO), and white mineral trioxide aggregate Angelus (MTA). Control group cells were not treated. The cytotoxicity was evaluated through mitochondrial-activity (MTT) and cell-density (crystal violet) assays. All cements showed low cytotoxicity. In general, at the concentration of 10 mg/mL there was an increase in viability of those groups treated with WPC and WPCZO when compared to the control group (pzirconium oxide as the radiopacifier showed low cytotoxicity as a promising material to be exploited for root-end filling.

  1. Effect of Surface Treatments on Leakage of Zirconium Oxide Ceramics

    OpenAIRE

    Göknil Alkan Demetoğlu; Mustafa Zortuk

    2016-01-01

    Objective: The aim of this pilot study was to compare the effects of pretreatments on leakage of zirconia ceramics. Materials and Methods: The speciments divided into 6 groups that were subsequently treated as follows: group 1, no treatment (control); group 2, the ceramic surfaces were airborne-particle abraded with 110 μm aluminum-oxide (Al2O3) particles; group 3, after abrasion of the surfaces with 110 μm Al2O3 particles, silica coating using 30 μm (Al2O3) particles modified by silica (r...

  2. Studies of the formation of homogeneous mixed silicon-titanium/zirconium oxides by the sol-gel route

    OpenAIRE

    Hudson, Melanie

    1994-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. This thesis is concerned with the preparation of mixed silicon-titanium oxides (Ti02=4.1-21.9wt%) and silicon-zirconium oxides (Zr02=4.1-22.Iwt%) by the sol-gel route. Methods of preparing homogeneous Si02-TiO2 gels and SiO2-Zr02 gels have been explored. In this work bis(acetylacetonato)titanium diisopropoxide or bis(acetylacetonato)zirconium dipropoxide and tetraethyl orthosilicate (TEOS...

  3. Opportunities for functional oxides in yttrium oxide-titanium oxide-zirconium oxide system: Applications for novel thermal barrier coatings

    Science.gov (United States)

    Francillon, Wesley

    This dissertation is an investigation of materials and processed under consideration for next generation thermal structural oxides with potential applications as thermal barrier coatings; wherein, high temperature stability and mechanical properties affect durability. Two notable next generation materials systems under investigation are pyrochlore and co-doped zirconia oxides. The motivation for this work is based on current limitations of the currently used thermal barrier material of yttria stabilized zirconia (YSZ) deposited by the plasma spray processes. The rapid quenching associated with the plasma spray process, results in a metastable structure that is a non-transformable tetragonal structure in the yttria partially stabilized zirconia system rather than the equilibrium anticipated two phase mixture of cubic and monoclinic phases. It has been shown that this metastable structure offers enhanced toughness and thus durability during thermomechanical cycling from the operating temperatures in excess of 1000C to ambient. However, the metastable oxides are susceptible to partitioning at temperatures greater than 1200C, thus resulting in a transformation of the tetragonal phase oxides. Transformations of the tetragonal prime phase into the parent cubic and tetragonal prime phase result in coating degradation. Several of the emerging oxides are based on rare earth additions to zirconia. However, there is limited information of the high temperature stability of these oxide coatings and more notably these compositions exhibit limited toughness for durable performance. A potential ternary composition based on the YSZ system that offers the ability to tailor the phase structure is based YO1.5-TiO2 -ZrO2. The ternary of YO1.5-TiO2-ZrO 2 has the current TBC composition of seven molar percent yttria stabilized zirconia, pyrochlore phase oxide and zirconia doped with yttria and titania additions (Ti-YSZ). The Ti-YSZ phase field is of interest because at equilibrium it is

  4. Effect of Surface Treatments on Leakage of Zirconium Oxide Ceramics

    Directory of Open Access Journals (Sweden)

    Göknil Alkan Demetoğlu

    2016-08-01

    Full Text Available Objective: The aim of this pilot study was to compare the effects of pretreatments on leakage of zirconia ceramics. Materials and Methods: The speciments divided into 6 groups that were subsequently treated as follows: group 1, no treatment (control; group 2, the ceramic surfaces were airborne-particle abraded with 110 μm aluminum-oxide (Al2O3 particles; group 3, after abrasion of the surfaces with 110 μm Al2O3 particles, silica coating using 30 μm (Al2O3 particles modified by silica (rocatec system and application of the silane coupling agent (espe-sil; group 4, ceramic surfaces irritated with neodymium-doped yttrium aluminium garnet (Nd:YAG laser [fidelis plus 3 foton (Ljubljana, Slovenia] at 20 hz, 100 mj, 2 w, 100 μs; group 5, ceramic surfaces irritated with Nd:YAG laser at fidelis plus 3 fotona (Ljubljana, Slovenia at 20 hz, 100 mj, 2 w, 100 μs; group 6; application of a zirconia primer (z-prime plus bisco, IL, USA agent. And all ceramics tested for leakage. Results: For marginal leakage, score 0 was found in all groups. Conclusion: No significant differences were found in marginal leakage under all conditions.

  5. Removal of methylene blue and rhodamine B from water by zirconium oxide/graphene

    Directory of Open Access Journals (Sweden)

    Sumita Rani

    2016-04-01

    Full Text Available Methylene blue (MB and rhodamine B dyes (RB were degraded from water using zirconium oxide (ZrO2 and zirconium oxide/graphene composites (ZrO2/GR as photocatalyst. The photocatalytic efficiency was calculated from absorption spectra obtained using UV–visible spectroscopy. It has been observed that photodegradation time as well as photocatalytic efficiency increase with the concentration of catalyst up to a certain limit after which effect was reversed. The degradation was studied as a function of pH also. It was found that photocatalytic efficiency was more in alkaline medium than acidic medium. Degradation of RB takes place at higher value of pH as compared to MB. The degradation time for MB was 1 h using ZrO2 which get reduced to 32 min using ZrO2/GR composite and for RB it reduced to 40 min (using ZrO2/GR from 80 min (ZrO2.

  6. Zirconium oxide aerogel for effective enrichment of phosphopeptides with high binding capacity.

    Science.gov (United States)

    Zhang, Liyuan; Xu, Jin; Sun, Liangliang; Ma, Junfeng; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-04-01

    In this study, zirconium oxide (ZrO(2)) aerogel was synthesized via a green sol-gel approach, with zirconium oxychloride, instead of the commonly used alkoxide with high toxicity, as the precursor. With such material, phosphopeptides from the digests of 4 pmol of β-casein with the coexistence of 100 times (mol ratio) BSA could be selectively captured, and identified by MALDI-TOF MS. Due to the large surface area (416.0 m(2) g(-1)) and the mesoporous structure (the average pore size of 10.2 nm) of ZrO(2) aerogel, a 20-fold higher loading capacity for phosphopeptide, YKVPQLEIVPN[pS]AEER (MW 1952.12), was obtained compared to that of commercial ZrO(2) microspheres (341.5 vs. 17.87 mg g(-1)). The metal oxide aerogel was further applied in the enrichment of phosphopeptides from 100 ng nonfat milk, and 17 phosphopeptides were positively identified, with a 1.5-fold improvement in phosphopeptide detection compared with previously reported results. These results demonstrate that ZrO(2) aerogel can be a powerful enrichment material for phosphoproteome study.

  7. Irradiation effects of the zirconium oxidation and the uranium diffusion in zirconia; Effets d'irradiation sur l'oxydation du zirconium et la diffusion de l'uranium dans la zircone

    Energy Technology Data Exchange (ETDEWEB)

    Bererd, N

    2003-07-01

    The context of this study is the direct storage of spent fuel assemblies after operation in reactor. In order to obtain data on the capacities of the can as the uranium diffusion barrier, a fundamental study has been carried out for modelling the internal cladding surface under and without irradiation. The behaviour of zirconium in reactor conditions has at first been studied. A thin uranium target enriched with fissile isotope has been put on a zirconium sample, the set being irradiated by a thermal neutrons flux leading to the fission of the deposited uranium. The energetic history of the formed fission products has revealed two steps: 1)the zirconium oxidation and 2)the diffusion of uranium in the zirconia formed at 480 degrees C. A diffusion coefficient under irradiation has been measured. Its value is 10{sup -15} cm{sup 2}.s{sup -1}. In order to be able to reveal clearly the effect of the irradiation by the fission products on the zirconium oxidation, measurements of thermal oxidation and under {sup 129}Xe irradiation have been carried out. They have shown that the oxidation is strongly accelerated by the irradiation and that the temperature is negligible until 480 degrees C. On the other hand, the thermal diffusion of the uranium in zirconium and in zirconia has been studied by coupling ion implantation and Rutherford backscattering spectroscopy. This study shows that the uranium diffuses in zirconium and is trapped in zirconia in a UO{sub 3} shape. (O.M.)

  8. Electrochromic Performance of Nanocomposite Nickel Oxide Counter Electrodes Containing Lithium and Zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Engtrakul, Chaiwat [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lin, Feng [Formerly NREL; Colorado School of Mines; Montano, Manuel [Colorado School of Mines; Tian, Chixia [Colorado School of Mines; Ji, Yazhou [Colorado School of Mines; Nordlund, Dennis [SLAC National Accelerator Laboratory; Weng, Tsu-Chien [SLAC National Accelerator Laboratory; Moore, Rob G. [SLAC National Accelerator Laboratory; Gillaspie, Dane T. [Formerly NREL; Jones, Kim M. [Formerly NREL; Dillon, Anne C. [Formerly NREL; Richards, Ryan M. [Colorado School of Mines

    2013-12-02

    Nickel oxide materials are suitable for counter electrodes in complementary electrochromic devices. The state-of-the-art nickel oxide counter electrode materials are typically prepared with multiple additives to enhance peformance. Herein, nanocomposite nickel oxide counter electrodes were fabricated via RF magnetron co-sputtering from Ni-Zr alloy and Li2O ceramic targets. The as-deposited nanocomposite counter electrodes were characterized with inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). It was found that the stoichiometry, crystal structure and electronic structure of the nickel oxide-based materials could be readily tuned by varying the Li2O sputter deposition power level. Comprehensive electrochromic evaluation demonstrated that the performance of the nickel oxide-based materials was dependent on the overall Li stoichiometry. Overall, the nanocomposite nickel oxide counter electrode containing lithium and zirconium synthesized with a Li2O deposition power of 45 W exhibited the optimal performance with an optical modulation of 71% and coloration efficiency of 30 cm2/C at 670 nm in Li-ion electrolyte.

  9. Adsorption of ammonia on graphite oxide/aluminium polycation and graphite oxide/zirconium-aluminium polyoxycation composites.

    Science.gov (United States)

    Seredych, Mykola; Bandosz, Teresa J

    2008-08-01

    Graphite oxide (GO) synthesized from commercial graphite was modified with aluminium or zirconium-aluminium polyoxycations and then calcined at 350 degrees C. On the samples obtained adsorption of ammonia from moist air was investigated. The surface of materials before and after exposure to ammonia was characterized using adsorption of nitrogen, XRD, SEM, FTIR, TA, CHN analysis, and potentiometric titration. The results showed that in spite of the fact that graphite composites/pillared graphites (PG) have Keggin-like ions located between the layers, that space blocked for nitrogen molecules used to determine the specific surface area. During calcinations, the deflagration of layers occurred as a result of decomposition of epoxy groups. This results in formation of disordered graphitic carbons with some mesoporosity. Even though these materials were not porous, the significant amount of ammonia was retained on the surface. Since ammonia molecule is able to specifically interact with oxygen groups of graphite oxide and Brønsted centers of inorganic pillars, it is likely intercalated between the composite layers. While the best performance was found for GO modified with aluminium-zirconium species, after calcinations the samples containing Keggin Al(13) like cations revealed the high capacity which is linked to the high acidity of incorporated inorganic compounds.

  10. In Vivo Wear Performance of Cobalt-Chromium Versus Oxidized Zirconium Femoral Total Knee Replacements.

    Science.gov (United States)

    Gascoyne, Trevor C; Teeter, Matthew G; Guenther, Leah E; Burnell, Colin D; Bohm, Eric R; Naudie, Douglas R

    2016-01-01

    This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design.

  11. Studies on Acetone Powder and Purified Rhus Laccase Immobilized on Zirconium Chloride for Oxidation of Phenols

    Directory of Open Access Journals (Sweden)

    Rong Lu

    2012-01-01

    Full Text Available Rhus laccase was isolated and purified from acetone powder obtained from the exudates of Chinese lacquer trees (Rhus vernicifera from the Jianshi region, Hubei province of China. There are two blue bands appearing on CM-sephadex C-50 chromatography column, and each band corresponding to Rhus laccase 1 and 2, the former being the major constituent, and each had an average molecular weight of approximately 110 kDa. The purified and crude Rhus laccases were immobilized on zirconium chloride in ammonium chloride solution, and the kinetic properties of free and immobilized Rhus laccase, such as activity, molecular weight, optimum pH, and thermostability, were examined. In addition, the behaviors on catalytic oxidation of phenols also were conducted.

  12. Critical assessment of finite element analysis applied to metal–oxide interface roughness in oxidising zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Platt, P., E-mail: Philip.Platt@manchester.ac.uk [University of Manchester, School of Materials, Materials Performance Centre, Manchester M13 9PL (United Kingdom); Frankel, P. [University of Manchester, School of Materials, Materials Performance Centre, Manchester M13 9PL (United Kingdom); Gass, M. [AMEC, Walton House, Faraday Street, Birchwood Park, Risley, Warrington WA3 6GA (United Kingdom); Preuss, M. [University of Manchester, School of Materials, Materials Performance Centre, Manchester M13 9PL (United Kingdom)

    2015-09-15

    As a nuclear fuel cladding material, zirconium alloys act as a barrier between the fuel and pressurised steam or lithiated water environment. Controlling degradation mechanisms such as oxidation is essential to extending the in-service lifetime of the fuel. At temperatures of ∼360 °C zirconium alloys are known to exhibit cyclical, approximately cubic corrosion kinetics. With acceleration in the oxidation kinetics occurring every ∼2 μm of oxide growth, and being associated with the formation of a network of lateral cracks. Finite element analysis has been used previously to explain the lateral crack formation by the development of localised out-of-plane tensile stresses at the metal–oxide interface. This work uses the Abaqus finite element code to assess critically current approaches to representing the oxidation of zirconium alloys, with relation to undulations at the metal–oxide interface and localised stress generation. This includes comparison of axisymmetric and 3D quartered modelling approaches, and investigates the effect of interface geometry and plasticity in the metal substrate. Particular focus is placed on the application of the anisotropic strain tensor used to represent the oxidation mechanism, which is typically applied with a fixed coordinate system. Assessment of the impact of the tensor showed that 99% of the localised tensile stresses originated from the out-of-plane component of the strain tensor, rather than the in-plane expansion as was previously thought. Discussion is given to the difficulties associated with this modelling approach and the requirements for future simulations of the oxidation of zirconium alloys.

  13. Microstructure Refinement and Strengthening Mechanisms of a 9Cr Oxide Dispersion Strengthened Steel by Zirconium Addition

    Directory of Open Access Journals (Sweden)

    Haijian Xu

    2017-02-01

    Full Text Available To study the effects of zirconium (Zr addition on the microstructure, hardness and the tensile properties of oxide dispersion strengthened (ODS ferritic–martensitic steels, two kinds of 9Cr-ODS ferritic–martensitic steels with nominal compositions (wt.% of Fe-9Cr-2W-0.3Y2O3 and Fe-9Cr-2W-0.3Zr-0.3Y2O3 were fabricated by the mechanical alloying (MA of premixed powders and then consolidated by hot isostatic pressing (HIP techniques. The experimental results showed that the average grain size decreases with Zr addition. The trigonal δ-phase Y4Zr3O12 oxides and body-centered cubic Y2O3 oxides are formed in the 9Cr-Zr-ODS steel and 9Cr non-Zr ODS steel, respectively, and the average size of Y4Zr3O12 particles is much smaller than that of Y2O3. The dispersion morphology of the oxide particles in 9Cr-Zr-ODS steel is significantly improved and the number density is 1.1×1023/m3 with Zr addition. The 9Cr-Zr-ODS steel shows much higher tensile ductility, ultimate tensile strength and Vickers hardness at the same time.

  14. Effect of carbon on the oxidation of zirconium; Influence du carbone sur l'oxygenation du zirconium a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, G.; Boudouresques, B.; Coriou, H.; Hure, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The study of specimens contaminated by different amounts of carbon shows a deleterious effect of this element in the resistance of zirconium to high temperature oxidation (700 to 900 deg. C). We drew the following results: a) the white spots or 'pimples' observed by numerous authors seem to be caused by the oxidation of precipitated carbides. We suggest a mechanism of formation and growth of these pimples; b) for a certain carbon content, the resistance to oxidation is increased by an uniform dispersion of the carbide phase and decreased, for instance, by extrusion textures. In this case, for the more marked textures, the more oriented corrosion was observed; c) by burning of the carbide phase it can result a second reaction increasing the corrosion rate; d) thin zirconium foils undergoes dimensional changes when scaling in oxygen. This unusual feature is also subordinated to carbon content and specially to the carbide phase dispersion. (author) [French] L'etude d'echantillons differemment contamines par le carbone nous a permis de mettre en evidence l'action particulierement nocive de cet element sur la resistance du zirconium a la corrosion par l'oxygene a haute temperature (700 a 900 deg. C). Nous avons pu degager les resultats essentiels suivants: a) l'origine des pustules d'oxyde blanc signalees par de nombreux auteurs doit etre recherchee dans l'oxydation des carbures precipites. Nous suggerons un mecanisme de formation et de croissance de ces pustules, b) la tenue du metal est d'autant meilleure que, pour une meme teneur en carbone, la phase 'carbure' est plus uniformement dispersee. En consequence, si la dispersion est mauvaise, on observe selon l'axe des textures de filage, par exemple, une corrosion preferentielle d'autant plus accentuee que les textures sont plus marquees, c) la combustion de la phase 'carbure' peut engendrer une reaction secondaire susceptible d

  15. Reactive removal of 2-chloroethyl ethyl sulfide vapors under visible light irradiation by cerium oxide modified highly porous zirconium (hydr) oxide

    Science.gov (United States)

    Mitchell, Joshua K.; Arcibar-Orozco, Javier A.; Bandosz, Teresa J.

    2016-12-01

    Highly porous cerium oxide modified Zr(OH)4 samples were synthesized using a simple one stage urea precipitation method. The amorphicity level of zirconium hydroxide did not change upon addition of cerium oxide particles. A unique aspect of the cerium oxide-modified materials is the presence of both the oxide (CeO2) and hydroxide (Zr(OH)4) phases resulting in a unique microporous structure of the final material. Extensive characterization using various chemical and physical methods revealed significant differences in the surface features. All synthesized materials were microporous and small additions of cerium oxide affected the surface chemistry. These samples were found as effective catalysts for a decontamination of mustard gas surrogate, 2-chloroethyl ethyl sulfide (CEES). Cerium oxide addition significantly decreased the band gap of zirconium hydroxide. Ethyl vinyl sulfide and 1,2-bis (Ethyl thio) ethane were identified as surface reaction products.

  16. Mesoporous zirconium titanium oxides. Part 1: Porosity modulation and adsorption properties of xerogels.

    Science.gov (United States)

    Griffith, Christopher S; Sizgek, G Devlet; Sizgek, Erden; Scales, Nicholas; Yee, Patrick J; Luca, Vittorio

    2008-11-01

    A series of zirconium titanium oxide mesophases containing 33 atom % Zr have been prepared using carboxylic acids of different alkyl chain lengths (Cy ) from y=4-18 through organic-inorganic polymer phase segregation as the gel transition is approached. Thermal treatment of these transparent gels up to 450 degrees C eliminated the organic template, and domain coarsening occurred affording stable worm-hole mesoporous materials of homogeneous composition and pore diameters varying from about 3 to 4 nm in fine increments. With such materials, it was subsequently possible to precisely study the adsorption of vanadium oxo-anions and cations from aqueous solutions and, more particularly, probe the kinetics of intraparticle mass transport as a function of the associated pore dimension. The kinetics of mass transport through the pore systems was investigated using aqueous vanadyl (VO2+) and orthovanadate (VO3(OH)2-) probe species at concentrations ranging from 10 to 200 ppm (0.2 to 4 mmol/L) and pH values of 0 and 10.5, respectively. In the case of both of these vanadium species, the zirconium titanate mesophases displayed relatively slow kinetics, taking in excess of about 500 min to achieve maximum uptake. By using a pseudo-second-order rate law, it was possible to extract the instantaneous and overall rate of the adsorption processes and then relate these to the pore diameters. Both the instantaneous and overall rates of adsorption increased with increasing surface area and pore diameter over the studied pore size range. However, the equilibrium adsorption capacity increased linearly with pore diameter only for the higher concentrations and was independent of pore diameter for the lower concentration. These results have been interpreted using a model in which discrete adsorption occurs at low concentrations and is then followed by multilayer adsorption at higher concentration.

  17. Size Resolved High Temperature Oxidation Kinetics of Nano-Sized Titanium and Zirconium Particles.

    Science.gov (United States)

    Zong, Yichen; Jacob, Rohit J; Li, Shuiqing; Zachariah, Michael R

    2015-06-18

    While ultrafine metal particles offer the possibility of very high energy density fuels, there is considerable uncertainty in the mechanism by which metal nanoparticles burn, and few studies that have examined the size dependence to their kinetics at the nanoscale. In this work we quantify the size dependence to the burning rate of titanium and zirconium nanoparticles. Nanoparticles in the range of 20-150 nm were produced via pulsed laser ablation, and then in-flight size-selected using differential electrical mobility. The size-selected oxide free metal particles were directly injected into the post flame region of a laminar flame to create a high temperature (1700-2500 K) oxidizing environment. The reaction was monitored using high-speed videography by tracking the emission from individual nanoparticles. We find that sintering occurs prior to significant reaction, and that once sintering is accounted for, the rate of combustion follows a near nearly (diameter)(1) power-law dependence. Additionally, Arrhenius parameters for the combustion of these nanoparticles were evaluated by measuring the burn times at different ambient temperatures. The optical emission from combustion was also used to model the oxidation process, which we find can be reasonably described with a kinetically controlled shrinking core model.

  18. Two-photon polymerization of 3-D zirconium oxide hybrid scaffolds for long-term stem cell growth.

    Science.gov (United States)

    Skoog, Shelby A; Nguyen, Alexander K; Kumar, Girish; Zheng, Jiwen; Goering, Peter L; Koroleva, Anastasia; Chichkov, Boris N; Narayan, Roger J

    2014-06-01

    Two-photon polymerization is a technique that involves simultaneous absorption of two photons from a femtosecond laser for selective polymerization of a photosensitive material. In this study, two-photon polymerization was used for layer-by-layer fabrication of 3-D scaffolds composed of an inorganic-organic zirconium oxide hybrid material. Four types of scaffold microarchitectures were created, which exhibit layers of parallel line features at various orientations as well as pores between the line features. Long-term cell culture studies involving human bone marrow stromal cells were conducted using these 3-D scaffolds. Cellular adhesion and proliferation were demonstrated on all of the scaffold types; tissuelike structure was shown to span the pores. This study indicates that two-photon polymerization may be used to create microstructured scaffolds out of an inorganic-organic zirconium oxide hybrid material for use in 3-D tissue culture systems.

  19. Odontogenic effects of a fast-setting calcium-silicate cement containing zirconium oxide.

    Science.gov (United States)

    Kim, Kyoung-A; Yang, Yeon-Mi; Kwon, Young-Sun; Hwang, Yun-Chan; Yu, Mi-Kyung; Min, Kyung-San

    2015-01-01

    A fast-setting calcium-silicate cement (Endocem) was introduced in the field of dentistry for use in vital pulp therapy. Similar to mineral trioxide aggregate (MTA), it contains bismuth oxide to provide radiopacity. Recently, another product, EndocemZr, which contains zirconium oxide (ZrO2) as a radiopacifier, was developed by the same company. In this study, the biological/odontogenic effects of EndocemZr were investigated in human primary dental pulp cells (hpDPCs) in vitro and on capped rat teeth in vivo. The biocompatibility of EndocemZr was similar to that of ProRoot and Endocem on the basis of cell viability tests and cell morphological analysis. The mineralization nodule formation, expression of odontogenic-related markers, and reparative dentin formation of EndocemZr group was similar to those of other material groups. Our results suggest that EndocemZr has the potential to be used as an effective material for vital pulp therapy, similar to ProRoot and Endocem.

  20. Enhanced moisture-barrier property and flexibility of zirconium oxide/polymer hybrid structures

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Se Hee; Seo, Seung-Woo; Jung, Eun; Chae, Heeyeop; Cho, Sung Min [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-03-15

    New zirconium oxide (ZrO{sub 2})-based organic-inorganic multilayers were fabricated and tested for flexible moisture barriers and compared with typical aluminum oxide (Al{sub 2}O{sub 3})-based multilayers. We report that amorphous ZrO{sub 2} had a better intrinsic barrier property than that of amorphous Al{sub 2}O{sub 3}. Due to the lower elastic modulus of ZrO{sub 2}, the ZrO{sub 2}-based structures had better flexibility than that of the Al{sub 2}O{sub 3}-based structures. The ZrO{sub 2}-based barrier was superior to the Al{sub 2}O{sub 3}-based barrier not only for flexibility but also for barrier performance. The barrier property and flexibility of the ZrO{sub 2}-based structures were enhanced by about 20% and 30% over those of the Al{sub 2}O{sub 3}-based structures, respectively.

  1. Zirconium oxide nanotube-Nafion composite as high performance membrane for all vanadium redox flow battery

    Science.gov (United States)

    Aziz, Md. Abdul; Shanmugam, Sangaraju

    2017-01-01

    A high-performance composite membrane for vanadium redox flow battery (VRB) consisting of ZrO2 nanotubes (ZrNT) and perfluorosulfonic acid (Nafion) was fabricated. The VRB operated with a composite (Nafion-ZrNT) membrane showed the improved ion-selectivity (ratio of proton conductivity to permeability), low self-discharge rate, high discharge capacity and high energy efficiency in comparison with a pristine commercial Nafion-117 membrane. The incorporation of zirconium oxide nanotubes in the Nafion matrix exhibits high proton conductivity (95.2 mS cm-1) and high oxidative stability (99.9%). The Nafion-ZrNT composite membrane exhibited low vanadium ion permeability (3.2 × 10-9 cm2 min-1) and superior ion selectivity (2.95 × 107 S min cm-3). The VRB constructed with a Nafion-ZrNT composite membrane has lower self-discharge rate maintaining an open-circuit voltage of 1.3 V for 330 h relative to a pristine Nafion membrane (29 h). The discharge capacity of Nafion-ZrNT membrane (987 mAh) was 3.5-times higher than Nafion-117 membrane (280 mAh) after 100 charge-discharge cycles. These superior properties resulted in higher coulombic and voltage efficiencies with Nafion-ZrNT membranes compared to VRB with Nafion-117 membrane at a 40 mA cm-2 current density.

  2. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

    Science.gov (United States)

    Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

    2016-06-29

    A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

  3. Electroless deposition process for zirconium and zirconium alloys

    Science.gov (United States)

    Donaghy, Robert E.; Sherman, Anna H.

    1981-01-01

    A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer.

  4. Development of bone-like zirconium oxide nanoceramic modified chitosan based porous nanocomposites for biomedical application.

    Science.gov (United States)

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

    2017-02-01

    Here, zirconium oxide nanoparticles (ZrO2 NPs) were incorporated for the first time in organic-inorganic hybrid composites containing chitosan, poly(ethylene glycol) and nano-hydroxypatite (CS-PEG-HA) to develop bone-like nanocomposites for bone tissue engineering application. These nanocomposites were characterized by FT-IR, XRD, TEM combined with SAED. SEM images and porosity measurements revealed highly porous structure having pore size of less than 1μm to 10μm. Enhanced water absorption capacity and mechanical strengths were obtained compared to previously reported CS-PEG-HA composite after addition of 0.1-0.3wt% of ZrO2 NPs into these nanocomposites. The mechanical strengths and porosities were similar to that of human spongy bone. Strong antimicrobial effects against gram-negative and gram-positive bacterial strains were also observed. Along with getting low alkalinity pH (7.4) values, similar to the pH of human plasma, hemocompatibility and cytocompatibility with osteoblastic MG-63 cells were also established for these nanocomposites. Addition of 15wt% HA-ZrO2 (having 0.3wt% ZrO2 NPs) into CS-PEG (55:30wt%) composite resulted in greatest mechanical strength, porosity, antimicrobial property and cytocompatibility along with suitable water absorption capacity and compatibility with human pH and blood. Thus, this nanocomposite could serve as a potential candidate to be used for bone tissue engineering.

  5. Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery.

    Science.gov (United States)

    Qiu, Hui; Liang, Chen; Zhang, Xiaolin; Chen, Mindong; Zhao, Yunxia; Tao, Tao; Xu, Zhengwen; Liu, Gang

    2015-09-23

    Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws-N-Zr. The biomass-based Ws-N-Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws-N-Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws-N-Zr could be employed for repeated use without significant capacity loss, when the binary NaOH-NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws-N-Zr has a great potential in efficient removal of phosphate in contaminated waters.

  6. Preferable removal of phosphate from water using hydrous zirconium oxide-based nanocomposite of high stability.

    Science.gov (United States)

    Chen, Liang; Zhao, Xin; Pan, Bingcai; Zhang, Weixian; Hua, Ming; Lv, Lu; Zhang, Weiming

    2015-03-02

    In this study, we employed a new nanocomposite adsorbent HZO-201, which featured high stability under varying solution chemistry, for preferable removal of phosphate from synthetic solution and a real effluent. An anion exchange resin (D-201) was employed as the host of HZO-201, where nano-hydrous zirconium oxide (HZO) was encapsulated as the active species. D-201 binds phosphate through nonspecific electrostatic affinity, whereas the loaded HZO nanoparticles capture phosphate through formation of the inner-sphere complexes. Quantitative contribution of both species to phosphate adsorption was predicted based on the double-Langmuir model. Preferable removal of phosphate by HZO-201 was observed in the presence of the competing anions at higher levels (Cl(-), NO3(-), SO4(2-), HCO3(-)). Fixed-bed adsorption indicated that the effective volume capacity of a synthetic water (2.0 mg P-PO4(3-)/L) by using HZO-201 was ∼1600 BV in the first run (<0.5mg P-PO4(3-)/L), comparable to Fe(III)-based nanocomposite HFO-201 (∼1500 BV) and much larger than D-201 (<250 BV). The exhausted HZO-201 can be in situ regenerated by using a binary NaOH-NaCl solution for cyclic runs, whether fed with the synthetic solution or real effluent. In general, HZO-201 is a promising alternative to Fe(III)-based adsorbents for trace phosphate removal from effluent particularly at acidic pH.

  7. Adsorption of phosphate in water using one-step synthesized zirconium-loaded reduced graphene oxide

    Science.gov (United States)

    Luo, Xin; Wang, Xiurong; Bao, Shaopan; Liu, Xiawei; Zhang, Weicheng; Fang, Tao

    2016-12-01

    In this account, a one-step green hydrothermal method for zirconium-loaded reduced graphene oxide (RGO-Zr) adsorbent was developed in pure water. It is based on the formation of initially strong-coupling RGO-Zr nanocomposites followed by in situ reduction of GO to RGO during the hydrothermal treatment. The phosphate adsorption performance of the as-prepared nanocomposites was investigated in aqueous environment under various conditions. The characterization results of RGO-Zr nanocomposites showed that ZrO2 was successfully integrated onto the RGO sheets in amorphous. The data from equilibrium phosphate adsorption on RGO-Zr revealed that the adsorption kinetics followed a pseudo-second-order kinetic model, where the adsorption isotherm fitted the Langmuir isotherm model with a maximum adsorption capacity of 27.71 mg P/g at pH 5 and 298 K. The improved phosphate adsorption on RGO-Zr was caused by the dispersion of ZrO2 on the RGO surface. Furthermore, the phosphate adsorption was found insensitive to the increase in pH while it was sensitive to the increase in temperature. The coexisting anions of SO42-, F-, Cl-, NO3- and CO32- affected the phosphate adsorption in a different way. Results suggest that the present RGO-Zr adsorbent has the potential for controlling phosphorus pollution in water.

  8. Enhanced removal of fluoride by polystyrene anion exchanger supported hydrous zirconium oxide nanoparticles.

    Science.gov (United States)

    Pan, Bingcai; Xu, Jingsheng; Wu, Bing; Li, Zhigang; Liu, Xitong

    2013-08-20

    Here we fabricated a novel nanocomposite HZO-201, an encapsulated nanosized hydrous zirconium oxide (HZO) within a commercial porous polystyrene anion exchanger D201, for highly efficient defluoridation of water. HZO-201 exhibited much higher preference than activated alumina and D201 toward fluoride removal when competing anions (chloride, sulfate, nitrate, and bicarbonate) coexisted at relatively high levels. Fixed column adsorption indicated that the effective treatable volume of water with HZO-201 was about 7-14 times as much as with D201 irrespective of whether synthetic solution or groundwater was the feeding solution. In addition, HZO-201 could treat >3000 BV of the acidic effluent (around 3.5 mg F(-)/L) per run at pH 3.5, compared to only ∼4 BV with D201. The exhausted HZO-201 could be regenerated by NaOH solution for repeated use without any significant capacity loss. Such attractive performance of HZO-201 resulted from its specific hybrid structure, that is, the host anion exchanger D201 favors the preconcentration of fluoride ions inside the polymer based on the Donnan principle, and the encapsulated nanosized HZO exhibits preferable sequestration of fluoride through specific interaction, as further demonstrated by XPS spectra. The influence of solution pH, competitive anions, and contact time was also examined. The results suggested that HZO-201 has a great potential in efficient defluoridation of groundwater and acidic mine drainage.

  9. Thermoluminescence of zirconium oxide nanostructured to mammography X-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, L.L. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Rivera, T., E-mail: trivera@ipn.mx [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Roman, J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa. Av. San Rafael Atlixco 187, 09340 Mexico D.F. (Mexico); Gaona, E. [Universidad Autonoma Metropolitana-Xochimilco. Calz. Del Hueso 1100, 04960 Mexico D.F. (Mexico)

    2012-07-15

    In the present work thermoluminescent (TL) response of zirconium oxide (ZrO{sub 2}) nanostructured induced by mammography X-ray radiation was investigated. Measurements were made of the response per unit air kerma of ZrO{sub 2} with mammography equipment parameters (semiautomatic exposure control, 24 kVp and 108 mAs). The calibration curves were obtained by simultaneously irradiating ZrO{sub 2} samples and ion chamber. Samples of ZrO{sub 2} showed a linear response as a function of entrance skin air kerma. The observed results in TL properties suggest that ZrO{sub 2} nanostructured could be considered as an effective material for X-ray beams dosimetry if appropriate calibration procedures are performed. - Highlights: Black-Right-Pointing-Pointer X-ray low energy thermoluminescent of ZrO{sub 2} dosimeter is developed. Black-Right-Pointing-Pointer Air kerma measurements were made by thermoluminescent dosimeter ZrO{sub 2} using mammography equipment parameters. Black-Right-Pointing-Pointer Entrance surface skin doses were made using thermoluminescent dosimeter of ZrO{sub 2} to X-ray beam quality control.

  10. Effects of Oxidation and fractal surface roughness on the wettability and critical heat flux of glass-peened zirconium alloy tubes

    Energy Technology Data Exchange (ETDEWEB)

    Fong, R.W.L.; Nitheanandan, T.; Bullock, C.D.; Slater, L.F.; McRae, G.A

    2003-05-01

    Glass-bead peening the outside surfaces of zirconium alloy tubes has been shown to increase the Critical Heat Flux (CHF) in pool boiling of water. The CHF is found to correlate with the fractal roughness of the metal tube surfaces. In this study on the effect of oxidation on glass-peened surfaces, test measurements for CHF, surface wettability and roughness have been evaluated using various glass-peened and oxidized zirconium alloy tubes. The results show that oxidation changes the solid-liquid contact angle (i.e., decreases wettability of the metal-oxide surface), but does not change the fractal surface roughness, appreciably. Thus, oxidation of the glass-peened surfaces of zirconium alloy tubes is not expected to degrade the CHF enhancement obtained by glass-bead peening. (author)

  11. Effect of zirconium oxide nanofiller and dibutyl phthalate plasticizer on ionic conductivity and optical properties of solid polymer electrolyte.

    Science.gov (United States)

    Yasin, Siti Mariah Mohd; Ibrahim, Suriani; Johan, Mohd Rafie

    2014-01-01

    New solid polymer electrolytes (SPE) based on poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (LiCF3SO3), dibutyl phthalate (DBP) plasticizer, and zirconium oxide (ZrO2) nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP) plasticizer and ZrO2 nanofiller with maximum conductivity (1.38 × 10(-4) Scm(-1)). The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased.

  12. Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva.

    Science.gov (United States)

    Romonti, Daniela E; Gomez Sanchez, Andrea V; Milošev, Ingrid; Demetrescu, Ioana; Ceré, Silvia

    2016-05-01

    The paper is focused on elaboration of ZrO2 films on pure zirconium via anodizing in phosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. The structure and composition of the films were investigated using scanning electronic microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition of the oxides formed at both potentials can be identified as monoclinic ZrO2. In addition to Zr and O, the layers formed in phosphoric acid contain phosphorus originating from the phosphoric acid. When the phosphoric acid solution contains NaF, fluorine is also incorporated into the oxide layer. The oxides formed at a higher voltage have greater roughness than those formed at 30 V. Anodized samples exhibit smaller current densities during anodic polarization compared to the as-received zirconium covered with native oxide.

  13. Microparticulated and nanoparticulated zirconium oxide added to calcium silicate cement: Evaluation of physicochemical and biological properties.

    Science.gov (United States)

    Silva, Guilherme F; Bosso, Roberta; Ferino, Rafael V; Tanomaru-Filho, Mário; Bernardi, Maria I B; Guerreiro-Tanomaru, Juliane M; Cerri, Paulo S

    2014-12-01

    The physicochemical and biological properties of calcium silicate-based cement (CS) associated to microparticulated (micro) or nanoparticulated (nano) zirconium oxide (ZrO2 ) were compared with CS and bismuth oxide (BO) with CS. The pH, release of calcium ions, radiopacity, setting time, and compression strength of the materials were evaluated. The tissue reaction promoted by these materials in the subcutaneous was also investigated by morphological, immunohistochemical, and quantitative analyses. For this purpose, polyethylene tubes filled with materials were implanted into rat subcutaneous. After 7, 15, 30, and 60 days, the tubes surrounded by capsules were fixed and embedded in paraffin. In the H&E-stained sections, the number of inflammatory cells (ICs) in the capsule was obtained. Moreover, detection of interleukin-6 (IL-6) by immunohistochemistry and number of IL-6 immunolabeled cells were carried out. von Kossa method was also performed. The differences among the groups were subjected to Tukey test (p ≤ 0.05). The solutions containing the materials presented an alkaline pH and released calcium ions. The addition of radiopacifiers increased setting time and radiopacity of CS. A higher compressive strength in the CS + ZrO2 (micro and nano) was found compared with CS + BO. The number of IC and IL-6 positive cells in the materials with ZrO2 was significantly reduced in comparison with CS + BO. von Kossa-positive structures were observed adjacent to implanted materials. The ZrO2 associated to the CS provides satisfactory physicochemical properties and better biological response than BO. Thus, ZrO2 may be a good alternative for use as radiopacifying agent in substitution to BO.

  14. Immunosensor based on nanocomposite of nanostructured zirconium oxide and gelatin-A.

    Science.gov (United States)

    Bagbi, Yana; Sharma, Anshu; Bohidar, H B; Solanki, Pratima R

    2016-01-01

    We have reported the studies related to the fabrication of a nanocomposite, comprising of sol-gel derived inorganic zirconium oxide nanoparticles (ZrO2 NPs) and organic biopolymer gelatin-A (GA), deposited on indium-tin-oxide (ITO) coated glass substrate by drop casting method. The GA-ZrO2/ITO electrode was used for immobilization of monoclonal antibodies (Ab) specific to antigen Vibrio cholerae (Vc) followed by bovine serum albumin (BSA) for antigen Vc detection using electrochemical techniques. The structural and morphological behaviour of these ZrO2 NPs, GA-ZrO2/ITO electrode and BSA/Ab/GA-ZrO2/ITO immunosensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The transmission electron microscopy study exhibited a spherical shape ZrO2 NPs. The average crystalline size of ZrO2 NPs was obtained as 10.3 ± 1 nm from X-ray diffraction measurement and 72 nm hydrodynamic radius measured by dynamic light scattering. GA-ZrO2 nanocomposite provides a porous structure which assists to higher loading of Ab on the matrix surface that improved the biosensing properties. The electrochemical response studies of the fabricated BSA/Ab/GA-ZrO2/ITO immunosensor exhibited good linearity in the range of 50-400 ng mL(-1), low limit of detection of 0.74 ng/mL, sensitivity as 0.03 Ω ng(-1)mL(-1)cm(-2) and reproducibility more than 10 times.

  15. Biocompatibility study of lithium disilicate and zirconium oxide ceramics for esthetic dental abutments

    Science.gov (United States)

    2016-01-01

    Purpose The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate (LS2) and zirconium oxide (ZrO2) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Methods Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). Results The best cell migration was observed on ZrO2 ceramic. Cell adhesion was also drastically lower on the polished ZrO2 ceramic than on both the raw and polished LS2. Evaluating various surface topographies of LS2 showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Conclusions Our results demonstrate that a biomaterial, here LS2, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of LS2 and ZrO2 ceramic showed that LS2 was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical

  16. Performance of magnetic zirconium-iron oxide nanoparticle in the removal of phosphate from aqueous solution

    Science.gov (United States)

    Zhang, Chang; Li, Yongqiu; Wang, Fenghua; Yu, Zhigang; Wei, Jingjing; Yang, Zhongzhu; Ma, Chi; Li, Zihao; Xu, ZiYi; Zeng, Guangming

    2017-02-01

    In this study, magnetic zirconium-iron oxide nanoparticles (MZION) of different Fe/Zr molar ratios were successfully prepared using the co-precipitation method, and their performance for phosphate removal was systematically evaluated. The as-obtained adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential analyzer, Fourier transform infrared spectroscopy (FT-IR) and Brunauer Emmett Teller (BET) specific surface area analysis. The effects of pH, ionic strength, and co-existing ions (including Cl-, SO42-, NO3- and HCO3-) were measured to evaluate the adsorption performance in batch experiments. The results showed that decreasing the Fe/Zr molar ratios increased the specific surface area that was propitious to adsorption process, but the adsorption capacity enhanced with the decrease of Fe/Zr molar ratios. Phosphate adsorption on MZION could be well described by the Freundlich equilibrium model and pseudo-second-order kinetics. The adsorption of phosphate was highly pH dependent and decreased with increasing pH from 1.5 to 10.0. The adsorption was slightly affected by ionic strength. With the exception of HCO3-, co-existing anions showed minimum or no effect on their adsorption performance. After adsorption, phosphate on these MZION could be easily desorbed by 0.1 M NaOH solution. The phosphate adsorption mechanism of MZION followed the inner-sphere complexing mechanism, and the surface sbnd OH groups played a significant role in the phosphate adsorption. Additionally, the main advantages of MZION consisted in its separation convenience and highly adsorption capacity compared to other adsorbents.

  17. Biocompatibility study of lithium disilicate and zirconium oxide ceramics for esthetic dental abutments.

    Science.gov (United States)

    Brunot-Gohin, Céline; Duval, Jean-Luc; Verbeke, Sandra; Belanger, Kayla; Pezron, Isabelle; Kugel, Gérard; Laurent-Maquin, Dominique; Gangloff, Sophie; Egles, Christophe

    2016-12-01

    The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate (LS2) and zirconium oxide (ZrO2) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). The best cell migration was observed on ZrO2 ceramic. Cell adhesion was also drastically lower on the polished ZrO2 ceramic than on both the raw and polished LS2. Evaluating various surface topographies of LS2 showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Our results demonstrate that a biomaterial, here LS2, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of LS2 and ZrO2 ceramic showed that LS2 was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

  18. 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.

  19. The Fouling of Zirconium(IV) Hydrous Oxide-Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions.

    Science.gov (United States)

    Polom, Ewa

    2013-12-10

    The results of investigations of flux decline during nanofiltration (NF) of lactic acid solutions using dynamically formed zirconium(IV) hydrous oxide/polyacrylate membranes (Zr(IV)/PAA) under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations showed that the reduction of fouling effects in the investigated system could be achieved due to appropriate hydrodynamic process conditions and regular rinsing with deionized water.

  20. Digital data acquisition for a CAD/CAM-fabricated titanium framework and zirconium oxide restorations for an implant-supported fixed complete dental prosthesis.

    Science.gov (United States)

    Lin, Wei-Shao; Metz, Michael J; Pollini, Adrien; Ntounis, Athanasios; Morton, Dean

    2014-12-01

    This dental technique report describes a digital workflow with digital data acquisition at the implant level, computer-aided design and computer-aided manufacturing fabricated, tissue-colored, anodized titanium framework, individually luted zirconium oxide restorations, and autopolymerizing injection-molded acrylic resin to fabricate an implant-supported, metal-ceramic-resin fixed complete dental prosthesis in an edentulous mandible. The 1-step computer-aided design and computer-aided manufacturing fabrication of titanium framework and zirconium oxide restorations can provide a cost-effective alternative to the conventional metal-resin fixed complete dental prosthesis.

  1. Diagnostic study of the roughness surface effect of zirconium on the third-order nonlinear-optical properties of thin films based on zinc oxide nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Bahedi, K., E-mail: bahedikhadija@yahoo.com [Laboratoire Optoelectronique et Physico-chimie des Materiaux Universite Ibn Tofail, Faculte des Sciences BP 133 Kenitra 14000, Maroc (Morocco); Addou, M.; El Jouad, M.; Sofiani, Z.; Alaoui Lamrani, M.; El Habbani, T.; Fellahi, N.; Bayoud, S.; Dghoughi, L. [Laboratoire Optoelectronique et Physico-chimie des Materiaux Universite Ibn Tofail, Faculte des Sciences BP 133 Kenitra 14000, Maroc (Morocco); Sahraoui, B.; Essaidi, Z. [Laboratoire POMA, UMR CNRS 6136, Universite d' Angers 2, Bd Lavoisier, 49045 France (France)

    2009-02-01

    Zinc oxide (ZnO) and zirconium doped zinc oxide (ZnO:Zr) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 500 deg. C using zinc and zirconium chlorides as precursors. Effects of zirconium doping agent and surface roughness on the nonlinear optical properties were investigated in detail using atomic force microscopy (AFM) and third harmonic generation (THG) technique. The best value of nonlinear optical susceptibility {chi}{sup (3)} was obtained from the doped films with less roughness. A strong third order nonlinear optical susceptibility {chi}{sup (3)} = 20.12 x 10{sup -12} (esu) of the studied films was found for the 3% doped sample.

  2. Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva

    Energy Technology Data Exchange (ETDEWEB)

    Romonti, Daniela E. [Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, district 1, Bucharest Ro-011061 (Romania); Gomez Sanchez, Andrea V. [INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo, 4302, B7608FDQ Mar del Plata (Argentina); Milošev, Ingrid [Jožef Stefan Institute, Department of Physical and Organic Chemistry, Jamova c. 39, SI-1000 Ljubljana (Slovenia); Demetrescu, Ioana [Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, district 1, Bucharest Ro-011061 (Romania); Ceré, Silvia, E-mail: smcere@fi.mdp.edu.ar [INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo, 4302, B7608FDQ Mar del Plata (Argentina)

    2016-05-01

    The paper is focused on elaboration of ZrO{sub 2} films on pure zirconium via anodizing in phosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. The structure and composition of the films were investigated using scanning electronic microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition of the oxides formed at both potentials can be identified as monoclinic ZrO{sub 2.} In addition to Zr and O, the layers formed in phosphoric acid contain phosphorus originating from the phosphoric acid. When the phosphoric acid solution contains NaF, fluorine is also incorporated into the oxide layer. The oxides formed at a higher voltage have greater roughness than those formed at 30 V. Anodized samples exhibit smaller current densities during anodic polarization compared to the as-received zirconium covered with native oxide. - Highlights: • Anodic oxide layer formed on Zr in phosphoric acid with fluoride is monoclinic ZrO{sub 2}. • Fluorine ions from the electrolyte are incorporated in the oxide layer. • Anodic polarization in Afnor solution evidences breakdown of the passive films. • Decrease of breakdown potential may be induced by defects caused by fluorine.

  3. Effect of Zirconium Oxide Nanofiller and Dibutyl Phthalate Plasticizer on Ionic Conductivity and Optical Properties of Solid Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Siti Mariah Mohd Yasin

    2014-01-01

    Full Text Available New solid polymer electrolytes (SPE based on poly(ethylene oxide (PEO doped with lithium trifluoromethanesulfonate (LiCF3SO3, dibutyl phthalate (DBP plasticizer, and zirconium oxide (ZrO2 nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP plasticizer and ZrO2 nanofiller with maximum conductivity (1.38×10-4 Scm-1. The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased.

  4. Zirconium oxide coatings on P91 and zircaloy (Zr-2.5%Nb) substrates for use in SCWRs

    Energy Technology Data Exchange (ETDEWEB)

    Cook, W.; Miles, J. [Univ. of New Brunswick, Dept. of Chemical Engineering, Fredericton, New Brunswick (Canada); Hui, R. [National Research Council Canada, Inst. for Fuel Cell Innovation, Vancouver, British Columbia (Canada)

    2011-07-01

    The CANDU-SCWR presents difficult operating conditions for materials of construction and innovative methods, such as corrosion-resistant coatings, are being developed for reactor materials. In this study, Zircaloy (Zr-2.5%Nb) and P91 were coated with tightly adhering layers of zirconium-based oxides (ZrO{sub 2} or Zr-NbO{sub 2}) through a plasma spray deposition (PSD) process. The coupons were exposed to deoxygenated supercritical water at 500{sup o}C and 25 MPa for increasing durations, up to 900 hours. Coated coupons showed a reduced weight gain at all exposure times when compared to uncoated samples however SEM work reveals that poor coating adhesion resulted in degradation of the coating through oxide loss by spallation or dissolution processes. (author)

  5. Oxide-Bridged Heterobimetallic Aluminum/Zirconium Catalysts for Ethylene Polymerization

    NARCIS (Netherlands)

    Boulho, Cedric; Zijlstra, Harmen S.; Harder, Sjoerd

    2015-01-01

    A bimetallic aluminum/zirconium complex Cp*Zr-2(Me)OAl(DIPH) [DIPH-H-2 = 3,3-bis(2-methylallyl)-(1,1-biphenyl)-2,2-diol; Cp* = C5Me5] was prepared in good yield by the reaction of (DIPH)AlMe with Cp*Zr-2(Me)OH. In contrast to Roesky's catalyst, Cp2Zr(Me)O(Me)Al(DIPP-nacnac) {DIPP-nacnac = CH[(CMe)(2

  6. Synthesis of amorphous zirconium oxide with luminescent characteristics; Sintesis de oxido de circonio amorfo con caracteristicas luminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Barrera S, M.; Chavez G, M.; Soto E, A.M.; Velasquez O, C.; Garcia S, M.A.; Olvera T, L.; Rivera M, T. [UAM-I, 09340 Mexico D.F. (Mexico)

    2004-07-01

    It was prepared zirconium oxide, ZrO{sub 2}, by means of hydrolysis-condensation reactions (sol-gel method), using zirconium propoxide, Zr(C{sub 3}H{sub 7}O){sub 4}, as precursor and nitric acid, HNO{sub 3}, as catalyst of the hydrolysis reaction. In this synthesis it was used a molar ratio water-alkoxide, r=n{sub H2O}/n{sub Zr}(C{sub 3}H{sub 7}0){sub 4}, high, similar to 200, so that the hydrolysis happens quickly and the nucleation and growth are completed in very little time. The solid was characterized with Ftir spectrophotometry, Differential thermal analysis (Dta), Thermal gravimetric analysis (T G), X-ray diffraction of powders, Scanning electron microscopy (Sem) and X-ray Dispersion energy (EDX). The ZrO{sub 2} obtained by this way is amorphous even to 300 C and it consists of big aggregates. The amorphous ZrO{sub 2}, presents thermoluminescent behavior, after it was irradiated with UV radiation and beta particles of {sup 90}Sr/{sup 90}Y and it was thermally stimulated. (Author)

  7. Examination of the chemical composition of irradiated zirconium based fuel claddings at the metal/oxide interface by TEM

    Science.gov (United States)

    Abolhassani, S.; Bart, G.; Jakob, A.

    2010-04-01

    Detailed post-irradiation examinations have been performed at PSI on three fuel rods with differing cladding materials revealing different corrosion behaviour. The rods had been irradiated for 3-5 cycles at Gösgen nuclear power plant (pressurised water reactor), Switzerland. As zirconium corrosion is proceeding at the metal/oxide interface, extended micro-structural analyses were performed by transmission electron microscopy (TEM), expecting to possibly reveal phenomena explaining the varying corrosion resistance. This paper reports on the distribution of oxygen at the metal/oxide interface examined by energy dispersive X-ray spectroscopy (EDS) in TEM, while other micro-structural investigations have been published earlier [1]. In order to get some statistical confidence in the analyses, three neighbouring TEM samples of each cladding variant were studied. The oxygen concentration profiles of the three alloys (i.e. low-tin Zircaloy-4, Zr2.5%Nb and extra low-tin (Sn 0.56%)) both in the oxide and metal close to the metal/oxide interface are compared. The results of the examinations show the composition of the oxide in the vicinity of the interface to be sub-stoichiometric for all three materials, indicating an oxide layer adjacent to the interface, with diffusion-controlled access of oxygen to the metal/oxide interface. The metallic parts show highest oxygen concentrations at the metal/oxide interface which are reduced towards the bulk metal, pointing towards the expected second diffusion-controlled process leading to α-Zr (O). Based on the experimental results values for the diffusion coefficients in the range of 0.8-6.0 × 10 -20 m 2 s -1 are estimated for the oxygen dissolution process, the diffusion coefficient in Zircaloy-4 being six times higher than for the other two less corroding alloys. This finding is in contradiction with the present assumptions about the corrosion mechanism, and confirms the expected but not so far reported diffusion controlled

  8. Physical characterization of a new composition of oxidized zirconium-2.5 wt% niobium produced using a two step process for biomedical applications

    Science.gov (United States)

    Pawar, V.; Weaver, C.; Jani, S.

    2011-05-01

    Zirconium and particularly Zr-2.5 wt%Nb (Zr2.5Nb) alloy are useful for engineering bearing applications because they can be oxidized in air to form a hard surface ceramic. Oxidized zirconium (OxZr) due to its abrasion resistant ceramic surface and biocompatible substrate alloy has been used as a bearing surface in total joint arthroplasty for several years. OxZr is characterized by hard zirconium oxide (oxide) formed on Zr2.5Nb using one step thermal oxidation carried out in air. Because the oxide is only at the surface, the bulk material behaves like a metal, with high toughness. The oxide, furthermore, exhibits high adhesion to the substrate because of an oxygen-rich diffusion hardened zone (DHZ) interposing between the oxide and the substrate. In this study, we demonstrate a two step process that forms a thicker DHZ and thus increased depth of hardening than that can be obtained using a one step oxidation process. The first step is thermal oxidation in air and the second step is a heat treatment in vacuum. The second step drives oxygen from the oxide formed in the first step deeper into the substrate to form a thicker DHZ. During the process only a portion of the oxide is dissolved. This new composition (DHOxZr) has approximately 4-6 μm oxide similar to that of OxZr. The nano-hardness of the oxide is similar but the DHZ is approximately 10 times thicker. The stoichiometry of the oxide is similar and a secondary phase rich in oxygen is present through the entire thickness. Due to the increased depth of hardening, the critical load required for the onset of oxide cracking is approximately 1.6 times more than that of the oxide of OxZr. This new composition has a potential to be used as a bearing surface in applications where greater depth of hardening is required.

  9. Thermodynamic and kinetic studies of As(V) removal from water by zirconium oxide-coated marine sand.

    Science.gov (United States)

    Khan, Tabrez Alam; Chaudhry, Saif Ali; Ali, Imran

    2013-08-01

    Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100-1,000 μg/L), dose (1-8 g/L), pH of the solution (2-14), contact time (15-150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 μg/L, after 75 min at dosage of 5.0 g/L, pH 7.0 and 27 ± 2 °C. For 600 μg/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 μg/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ΔH°, was -57.782, while the values of ΔG° were -9.460, -12.183, -13.343 and -13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ΔS°= -0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 μg/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10

  10. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.

    Science.gov (United States)

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

    2013-03-01

    Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition.

  11. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell

    Science.gov (United States)

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

    2013-03-01

    Zinc zirconate (ZnZrO3) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO2) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO3 as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff = 56%) compared to ZnO working electrode (ff = 40%) under the same condition.

  12. Synthesis, characterization, and catalytic activity of Zirconium oxide nitrides supported on high-surface SiO{sub 2}; Praeparation und Charakterisierung von SiO{sub 2}-getraegerten Zirconiumoxidnitriden mit hoher Oberflaeche und Untersuchung ihrer katalytischen Aktivitaet bei der Ammoniakzersetzung

    Energy Technology Data Exchange (ETDEWEB)

    Frenzel, Nancy; Otremba, Thorsten; Schomaecker, Reinhard; Ressler, Thorsten; Lerch, Martin [Technische Univ. Berlin (Germany). Inst. fuer Chemie

    2011-02-15

    Zirconium oxide nitrides are active ammonia decomposition catalysts for the production of hydrogen. We present a route to zirconium oxide nitrides with high surface area. The precursor used consisted of a high-surface-area silica material coated with zirconium alkoxide. Subsequent hydrolysis and calcination resulted in ZrO{sub 2} supported on SiO{sub 2}. The high surface area of the material could be maintained in the following ammonolysis procedure leading to the corresponding zirconium oxide nitride. In contrast to the as-prepared ZrO{sub 2}, the zirconium oxide nitrides exhibited a significant catalytic activity in ammonia decomposition, but compared to an iron oxide-based reference material, the new oxide nitrides showed a rather low activity. Nevertheless, zirconium oxide nitrides constitute suitable model systems for elucidating the effect of nitrogen in the anion substructure on the activity and selectivity of oxide-based ammonia decomposition catalysts. (orig.)

  13. EFFECTS OF STRUCTURE AND INTERNAL STRESSES IN OXIDE FILMS ON CORROSION MECHANISM OF NEW ZIRCONIUM ALLOY%氧化膜结构及内应力对新锆合金腐蚀机理的影响

    Institute of Scientific and Technical Information of China (English)

    章海霞; 李中奎; 周廉; 许并社; 王永祯

    2014-01-01

    The corrosion resistance of new zirconium alloys containing Nb,used as the fuel cladding materials in water-cooled nuclear power reactors,is closely related to the characteristics of the oxide films,including the internal stresses and the crystal structure.However,the relation of the corrosion kinetics to the internal stresses and the crystal structure of the oxide films has not been well understood,also the corrosion mechanism of new zirconium alloys has not been confirmed.Therefore,it is helpful to solve the above problems,furthermore improve the corrosion resistance of new zirconium alloys,to characterize the internal stresses and the crystal structure of the oxide films accurately.The internal stresses and the crystal structure of the oxide films of NZ2 zirconium alloy,corroded in 360 ℃,18.6 MPa lithiated water and 400 ℃,10.3 MPa steam,were tested by XRD and Raman spectroscopy,and the microstructure of the oxide films was investigated by SEM.The results of the crystal structure show that tetragonal ZrO2 (t-ZrO2) content in the oxide films of NZ2 alloy decreases,monoclinic ZrO2 (m-ZrO2) content increases with the prolongation of the corrosion time,t-ZrO2 transforms into m-ZrO2.And cubic ZrO2 (c-ZrO2) appears in the oxide films when the thickness of the oxide films reaches 2 μm.Corrosion resistance of NZ2 alloy is improved when the content of t-ZrO2 in the oxide films increases.The results of the internal stresses and the microstructure of the oxide films indicate that the high compressive stresses exist in the oxide films.At the beginning of the corrosion,the compressive stresses in the oxide films increase with the corrosion time.When the thickness of the oxide films reaches 2 μm,the compressive stresses exceed the critical value and the stresses are released.The stress relaxation leads to the formation of the cracks,which reduces the protection of the oxide films,therefore the corrosion transition occurs.After the transition,the compressive stresses of

  14. Formation and reduction behaviors of zirconium oxide compounds in LiCl-Li2O melt at 923 K

    Science.gov (United States)

    Sakamura, Yoshiharu; Iizuka, Masatoshi; Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide

    2015-11-01

    The reduction behaviors of ZrO2, Li2ZrO3 and (U,Pu,Zr)O2 in a LiCl-Li2O salt bath at 923 K were investigated. This study was conducted as part of a feasibility study on the pyrochemical treatment of damaged fuel debris generated by severe accidents at light water reactors. It was demonstrated in electrolytic reduction tests that the uranium in synthetic corium specimens of (U,Pu,Zr)O2 with various ZrO2 contents could be reduced to the metallic form and that part of the zirconium was converted to Li2ZrO3. Zirconium metal and Li2ZrO3 were obtained by the reduction of ZrO2. The reduction of Li2ZrO3 did not proceed even in LiCl containing no Li2O. Moreover, the stable chemical forms of the ZrO2-Li2O complex oxide were investigated as a function of the Li2O concentration in LiCl. ZrO2 was converted to Li2ZrO3 at a Li2O concentration of 0.018 wt%. As the Li2O concentration was increased, Li2ZrO3 was converted to Li6Zr2O7 and then to Li8ZrO6. It is suggested that the removal of Li2ZrO3 from the reduction product is a key point in the pyrochemical treatment of corium.

  15. Hysteresis in Lanthanide Zirconium Oxides Observed Using a Pulse CV Technique and including the Effect of High Temperature Annealing

    Directory of Open Access Journals (Sweden)

    Qifeng Lu

    2015-07-01

    Full Text Available A powerful characterization technique, pulse capacitance-voltage (CV technique, was used to investigate oxide traps before and after annealing for lanthanide zirconium oxide thin films deposited on n-type Si (111 substrates at 300 °C by liquid injection Atomic Layer Deposition (ALD. The results indicated that: (1 more traps were observed compared to the conventional capacitance-voltage characterization method in LaZrOx; (2 the time-dependent trapping/de-trapping was influenced by the edge time, width and peak-to-peak voltage of a gate voltage pulse. Post deposition annealing was performed at 700 °C, 800 °C and 900 °C in N2 ambient for 15 s to the samples with 200 ALD cycles. The effect of the high temperature annealing on oxide traps and leakage current were subsequently explored. It showed that more traps were generated after annealing with the trap density increasing from 1.41 × 1012 cm−2 for as-deposited sample to 4.55 × 1012 cm−2 for the 800 °C annealed one. In addition, the leakage current density increase from about 10−6 A/cm2 at Vg = +0.5 V for the as-deposited sample to 10−3 A/cm2 at Vg = +0.5 V for the 900 °C annealed one.

  16. A sensitive determination of terbutaline in pharmaceuticals and urine samples using a composite electrode based on zirconium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Baytak, Aysegul Kutluay; Teker, Tugce; Duzmen, Sehriban; Aslanoglu, Mehmet, E-mail: maslanoglu@harran.edu.tr

    2016-10-01

    An accurate and precise determination of terbutaline has been carried out using a glassy carbon electrode (GCE) modified with a composite of multi-walled carbon nanotubes (MWCNTs) and nanoparticles of zirconium oxide (ZrO{sub 2}NPs). Energy dispersive X-ray and scanning electron microscopic techniques were utilized for the characterization of the composite layer. Terbutaline exhibited a broad oxidation peak at 770 mV on a GCE. However, MWCNTs/GCE presented an electrocatalytic effect toward the oxidation of terbutaline with a better anodic peak at 660 mV. Furthermore, the electrochemical behavior of terbutaline has greatly been improved at a GCE modified with a composite of MWCNTs and nanoparticles of ZrO{sub 2}. The ZrO{sub 2}NPs/MWCNTs/GCE exhibited a sharp anodic wave at 645 mV with a large enhancement of the current response for terbutaline. Square wave voltammetry (SWV) was performed for the determination of terbutaline at ZrO{sub 2}NPs/MWCNTs/GCE. A linear plot was obtained for the current responses of terbutaline against concentrations in the range of 10–160 nM yielding a detection limit of 2.25 nM (based on 3S{sub b}/m). Improved voltammetric behavior, long-time stability and good reproducibility were obtained for terbutaline at the proposed electrode. A mean recovery of 101.2% with an RSD% of 1.9 was obtained for the analysis of the drug formulation. The accurate and precise quantification of terbutaline makes the ZrO{sub 2}NPs/MWCNTs/GCE system of great interest for monitoring its therapeutic use. - Graphical abstract: A sensitive determination of terbutaline in pharmaceuticals and urine samples using a composite electrode based on zirconium oxide nanoparticles. Display Omitted - Highlights: • A composite electrode was prepared using nanoparticles of ZrO{sub 2} and MWCNTs. • The ZrO{sub 2}NPs/MWCNTs/GCE has greatly improved the voltammetry of terbutaline • The proposed electrode enabled a detection limit of 2.25 nM. • The proposed electrode

  17. Porous Silicates Modified with Zirconium Oxide and Sulfate Ions for Alcohol Dehydration Reactions

    Directory of Open Access Journals (Sweden)

    Heriberto Esteban Benito

    2015-01-01

    Full Text Available Porous silicates were synthesized by a nonhydrothermal method, using sodium silicate as a source of silica and cetyltrimethylammonium bromide as a template agent. Catalysts were characterized using thermogravimetric analysis, N2 physisorption, X-ray diffraction, FTIR spectroscopy, pyridine adsorption, potentiometric titration with n-butylamine, scanning electronic microscopy, and transmission electronic microscopy. The surface area of the materials synthesized was greater than 800 m2/g. The introduction of zirconium atoms within the porous silicates increased their acid strength from −42 to 115 mV, while the addition of sulfate ions raised this value to 470 mV. The catalytic activity for the dehydration of alcohols yields conversions of up to 70% for ethanol and 30% for methanol.

  18. Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique

    Institute of Scientific and Technical Information of China (English)

    Qin Sun; Yifei Chen; Di Xu; Yan Wang; Shiming Ding

    2013-01-01

    A diffusive gradients in thin films (DGT) technique based on hydrous zirconium oxide (Zr-oxide) has been recently developed for the measurement of dissolved reactive phosphate (DRP).In this study,the detailed performance of the DGT technique is reported.Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP.However,such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters.The presence of Cl-(up to 106 g/L),SO42-(up to 16 g/L),HCO3-(up to 817 g/L),and AsO2-and AsO43-(both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP.The threshold concentrations of Cl-,SO42-and HCO3-have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques.The capacity for DGT measurements of DRP decreased with increasing solution pH (4.2-9.2).The lowest capacity (95 μg P/cm2 at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2-12 μg P/cm2).The Zr-oxide binding gel could be stored for up to 2 years without any aging effect.This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices (6 months).The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.

  19. An In Vivo Evaluation of the Fit of Zirconium-Oxide Based, Ceramic Single Crowns with Vertical and Horizontal Finish Line Preparations.

    Science.gov (United States)

    Vigolo, Paolo; Mutinelli, Sabrina; Biscaro, Leonello; Stellini, Edoardo

    2015-12-01

    Different types of tooth preparations influence the marginal precision of zirconium-oxide based ceramic single crowns. In this in vivo study, the marginal fits of zirconium-oxide based ceramic single crowns with vertical and horizontal finish lines were compared. Forty-six teeth were chosen in eight patients indicated for extraction for implant placement. CAD/CAM technology was used for the production of 46 zirconium-oxide-based ceramic single crowns: 23 teeth were prepared with vertical finishing lines, 23 with horizontal finishing lines. One operator accomplished all clinical procedures. The zirconia crowns were cemented with glass ionomer cement. The teeth were extracted 1 month later. Marginal gaps along vertical planes were measured for each crown, using a total of four landmarks for each tooth by means of a microscope at 50× magnification. On conclusion of microscopic assessment, ESEM evaluation was completed on all specimens. The comparison of the gap between the two types of preparation was performed with a nonparametric test (two-sample Wilcoxon rank-sum test) with a level of significance fixed at p finish line preparations, the median value of the gap was 35.45 μm (Iqr, 0.33); for the vertical finish line group, the median value of the gap was 35.44 μm (Iqr, 0.40). The difference between the two groups was not statistically significant (two-sample Wilcoxon rank-sum test, p = 0.0872). Within the limitations of this study, the gaps of the zirconium-oxide-based ceramic CAD/CAM crowns with vertical and horizontal finish line preparations were not different. © 2015 by the American College of Prosthodontists.

  20. Investigation of nano-structured Zirconium oxide film on Ti6Al4V substrate to improve tribological properties prepared by PIII&D

    Science.gov (United States)

    Saleem, Sehrish; Ahmad, R.; Ayub, R.; Ikhlaq, Uzma; Jin, Weihong; Chu, Paul K.

    2017-02-01

    Plasma immersion ion implantation and deposition (PIII&D) is the most attractive and efficient technique used in the medical field to tailor materials for biomedical applications. In the present study zirconium oxide nano-structured thin films were deposited on surface of Ti6Al4V alloy for bias voltages of 15, 20 and 25 kV. The chemical composition, surface roughness and thickness of deposited films were characterized by the x-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometry respectively. The XPS results confirm the formation of a dense zirconium oxide film of the treated specimens. AFM results exhibit a smooth film with maximum roughness of about 8.4 nm is formed. The thickness of the film is increased with the increase in bias voltages and is maximum at 25 kV. The effect of bias voltages on wear characteristics was further investigated by pin-on-disk test. It is observed that the friction coefficient is reduced, whereas wear resistance is enhanced and it is found to be maximum at 25 kV compared to the other bias voltages. Nanohardness is improved up to twice compared to untreated specimen at the maximum bias voltage. Therefore, it is concluded that deposition of zirconium oxide using the PIII&D is produced a dense layer on the substrate surface, which can be used as a promising candidate for the improved tribological properties of Ti6Al4V.

  1. The solubilities and solubility products of zirconium hydroxide and oxide after aging at 278, 313, and 333 K

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Taishi; Uemura, Takuya; Sasaki, Takayuki; Takagi, Ikuji [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Moriyama, Hirotake [Kyoto Univ. (Japan). Research Reactor Inst.

    2016-07-01

    The solubilities of zirconium hydroxide and oxide after aging at 278, 313, and 333 K were measured at 278, 298, 313, and 333 K in the pH{sub c} range of 0.3-7 in a 0.5 M ionic strength solution of NaClO{sub 4} and HClO{sub 4}. Size distributions of the colloidal species were investigated by ultrafiltration using membranes with different pore sizes, and the solid phases were examined by X-ray diffraction. The apparent solubility of zirconium amorphous hydroxide (Zr(OH){sub 4}(am)), prepared by the oversaturation method, decreased with increasing aging temperature (T{sub a}), and the size distributions obtained after aging at elevated temperatures indicated the growth of the colloidal species. We, therefore, suggested that agglomeration of the colloidal species and dehydration and crystallization of Zr(OH){sub 4}(am) as the solubility-limiting solid phase occurred over the course of aging at elevated temperatures. For sample solutions of the crystalline oxide (ZrO{sub 2}(cr)), the aging temperature had no significant effect on the solubility, but the solubility data at lower temperatures were found to be slightly higher than those at higher temperatures, implying a small fraction of the amorphous components. In the analysis of different solid phases (Zr(OH){sub 4}(s,T{sub a}), T{sub a} = 278, 313, and 333 K) depending on the aging temperatures, the solubility products (K{sub sp}, T{sub a}) were determined at different measurement temperatures, and the enthalpy change (Δ{sub r}H {sup circle}) for Zr{sup 4+} 4OH{sup -} <=> Zr(OH){sub 4}(s,T{sub a}) was calculated using the van't Hoff equation. The solid-phase-transformation process at elevated temperatures was also analyzed based on the obtained K{sub sp}, T{sub a} and Δ{sub r}H {sup circle} values.

  2. Effects of duty cycle and electrolyte concentration on the microstructure and biocompatibility of plasma electrolytic oxidation treatment on zirconium metal

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shao-Fu [Department of Materials and Mineral Resources Engineering, Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China); Lou, Bih-Show [Chemistry Division, Center for General Education, Chang Gung University, Taoyuan 333, Taiwan (China); Yang, Yung-Chin [Department of Materials and Mineral Resources Engineering, Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China); Wu, Pei-Shan [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China); Chung, Ren-Jei [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 10608, Taiwan (China); Lee, Jyh-Wei, E-mail: jefflee@mail.mcut.edu.tw [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China); Center for Thin Film Technologies and Applications, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China); Department of Electronic Engineering, Chang Gung University, Taoyuan 333, Taiwan (China)

    2015-12-01

    Recently, the plasma electrolytic oxidation (PEO) process has been widely studied and applied in the industrial setting due to its ability to create functional oxide layers on Al, Ti, Mg, and Zr alloys. In this work, a pulsed direct current (DC) power supply was adopted to grow the zirconia coating on pure Zr metal by PEO treatment. A fixed frequency of 1000 Hz and constant current of 2 A were used to fabricate all zirconia coatings. Duty cycle values of 25%, 75%, and 100% were used and 0.1 M K{sub 3}PO{sub 4} aqueous solution containing three different concentrations of KOH, 0.01, 0.05 and 0.1 M, was also used in fabrication. The plasma breakdown voltage decreased with increasing KOH concentration due to its higher electrolyte conductivity. The PEO oxide coating consisted of a thin continuous barrier layer and a thick porous outermost layer, which consisted of mainly monoclinic and minor tetragonal ZrO{sub 2} phases. The PEO treatment of Zr metal provided excellent corrosion resistance in Hank's solution and good biocompatibility for 3T3 and MG63 cells. These results suggest that PEO coatings having potential applications in the biomedical field were confirmed in this study. - Highlights: • Plasma electrolytic oxidation (PEO) treated coating consists of a continuous thin layer and a thick porous outermost layer. • The PEO coating thickness decreases with increasing content of KOH in electrolyte at duty cycles of 75% and 100%. • All PEO coatings provide good biocompatibility and no toxicity to both 3T3 and MG63 cells. • The PEO process greatly enhances the corrosion resistance of Zr metal to Hank's solution.

  3. Formation of inorganic nanofibers by heat-treatment of poly(vinyl alcohol-zirconium compound hybrid nanofibers

    Directory of Open Access Journals (Sweden)

    Nakane K.

    2013-01-01

    Full Text Available Poly(vinyl alcohol-zirconium compound hybrid nanofibers (precursors were formed by electrospinning employing water as a solvent for the spinning solution. The precursors were converted into oxide (ZrO2, carbide (ZrC or nitride (ZrN nanofibers by heating them in air, Ar or N2 atmospheres. Monoclinic ZrO2 nanofibers with high-specific surface area were obtained by heat-treatment of the precursors in air. ZrC and ZrN nanofibers could be obtained below theoretical temperatures calculated from thermodynamics data.

  4. A sensitive determination of terbutaline in pharmaceuticals and urine samples using a composite electrode based on zirconium oxide nanoparticles.

    Science.gov (United States)

    Baytak, Aysegul Kutluay; Teker, Tugce; Duzmen, Sehriban; Aslanoglu, Mehmet

    2016-10-01

    An accurate and precise determination of terbutaline has been carried out using a glassy carbon electrode (GCE) modified with a composite of multi-walled carbon nanotubes (MWCNTs) and nanoparticles of zirconium oxide (ZrO2NPs). Energy dispersive X-ray and scanning electron microscopic techniques were utilized for the characterization of the composite layer. Terbutaline exhibited a broad oxidation peak at 770mV on a GCE. However, MWCNTs/GCE presented an electrocatalytic effect toward the oxidation of terbutaline with a better anodic peak at 660mV. Furthermore, the electrochemical behavior of terbutaline has greatly been improved at a GCE modified with a composite of MWCNTs and nanoparticles of ZrO2. The ZrO2NPs/MWCNTs/GCE exhibited a sharp anodic wave at 645mV with a large enhancement of the current response for terbutaline. Square wave voltammetry (SWV) was performed for the determination of terbutaline at ZrO2NPs/MWCNTs/GCE. A linear plot was obtained for the current responses of terbutaline against concentrations in the range of 10-160nM yielding a detection limit of 2.25nM (based on 3Sb/m). Improved voltammetric behavior, long-time stability and good reproducibility were obtained for terbutaline at the proposed electrode. A mean recovery of 101.2% with an RSD% of 1.9 was obtained for the analysis of the drug formulation. The accurate and precise quantification of terbutaline makes the ZrO2NPs/MWCNTs/GCE system of great interest for monitoring its therapeutic use.

  5. The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate.

    Science.gov (United States)

    Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

    2016-03-25

    The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns.

  6. Zirconium oxide ceramic foam: a promising supporting biomaterial for massive production of glial cell line-derived neurotrophic factor.

    Science.gov (United States)

    Liu, Zhong-wei; Li, Wen-qiang; Wang, Jun-kui; Ma, Xian-cang; Liang, Chen; Liu, Peng; Chu, Zheng; Dang, Yong-hui

    2014-12-01

    This study investigated the potential application of a zirconium oxide (ZrO2) ceramic foam culturing system to the production of glial cell line-derived neurotrophic factor (GDNF). Three sets of ZrO2 ceramic foams with different pore densities of 10, 20, and 30 pores per linear inch (PPI) were prepared to support a 3D culturing system. After primary astrocytes were cultured in these systems, production yields of GDNF were evaluated. The biomaterial biocompatibility, cell proliferation and activation of cellular signaling pathways in GDNF synthesis and secretion in the culturing systems were also assessed and compared with a conventional culturing system. In this study, we found that the ZrO2 ceramic foam culturing system was biocompatible, using which the GDNF yields were elevated and sustained by stimulated cell proliferation and activation of signaling pathways in astrocytes cultured in the system. In conclusion, the ZrO2 ceramic foam is promising for the development of a GDNF mass production device for Parkinson's disease treatment.

  7. Synthesis of hydrous zirconium oxide-impregnated chitosan beads and their application for removal of fluoride and lead

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dong-Wan [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of); Jeon, Byong-Hun, E-mail: bhjeon@hanyang.ac.kr [Department of Natural Resources and Environmental Engineering, Hanyang University, 222 6 Wangsimni-ro, Seongdong-gu, Seoul, 133-791 (Korea, Republic of); Jeong, Yoojin [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of); Nam, In-Hyun [Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon (Korea, Republic of); Choi, Ui-Kyu [Mine reclamation corporation, Coal Center, 2 Segye-ro, Wonju, Gangwon-do, 16464 (Korea, Republic of); Kumar, Rahul [Department of Natural Resources and Environmental Engineering, Hanyang University, 222 6 Wangsimni-ro, Seongdong-gu, Seoul, 133-791 (Korea, Republic of); Song, Hocheol, E-mail: hcsong@sejong.ac.kr [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of)

    2016-05-30

    A composite adsorbent capable of simultaneous removal of both cationic and anionic contaminants from aqueous solutions was developed by impregnating hydrous zirconium oxide (HZO) into chitosan beads (CB). The optimal mass ratio of chitosan to HZO was 2:2. The composite adsorbent (HZOCB) had the rugged surface (52.74 m{sup 2} g{sup −1}) with irregular cracks caused by HZO inclusion and amine functional groups. The rate of Pb{sup 2+} adsorption by HZOCB was relatively rapid. Most of Pb{sup 2+} (89%) was adsorbed within 2.5 h. A binary sorbate system was noticeably favorable for F{sup −} adsorption as compared to single sorbate system. Adsorption of F{sup −} and Pb{sup 2+} followed pseudo-second order kinetics. The maximum sorption capacities obtained from Langmuir isotherm model were 22.1 and 222.2 mg g{sup −1}, respectively. The study demonstrates that the developed composite could be a potential adsorbent for the simultaneous remediation of F{sup −} and Pb{sup 2+} contamination in water.

  8. Amperometric choline biosensor based on multiwalled carbon nanotubes/zirconium oxide nanoparticles electrodeposited on glassy carbon electrode.

    Science.gov (United States)

    Pundir, S; Chauhan, N; Narang, J; Pundir, C S

    2012-08-01

    A bienzymatic choline biosensor was constructed by coimmobilizing acetylcholinesterase (AChE) and choline oxidase (ChO) onto nanocomposite of carboxylated multiwalled carbon nanotubes (c-MWCNTs) and zirconium oxide nanoparticles (ZrO(2)NPs) electrodeposited on the surface of a glassy carbon electrode (GCE) and using it (AChE-ChO/c-MWCNT/ZrO(2)NPs/GCE) as working electrode, Ag/AgCl as reference electrode, and Pt wire as auxiliary electrode connected through a potentiostat. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and cyclic voltammetry (CV) studies, optimized, and evaluated. The biosensor exhibited optimum response within 4 s at +0.2V, pH 7.4, and 25 °C. The detection limit and working range of the biosensor were 0.01 μM and 0.05 to 200 μM, respectively. The half-life of the enzyme electrode was 60 days at 4 °C. The serum choline level, as measured by the biosensor, was 9.0 to 12.8 μmol/L (with a mean of 10.81 μmol/L) in apparently healthy persons and 5.0 to 8.4 μmol/L (with a mean of 6.53 μmol/L) in persons suffering from Alzheimer's disease. The enzyme electrode was unaffected by a number of serum substances.

  9. Clinical Results of Oxidized Zirconium Femoral Component in TKA. A Review of Long-Term Survival: Review Article.

    Science.gov (United States)

    Civinini, Roberto; Matassi, Fabrizio; Carulli, Christian; Sirleo, Luigi; Lepri, Andrea Cozzi; Innocenti, Massimo

    2017-02-01

    Oxidized zirconium (OxZr) femoral component for total knee arthroplasty (TKA) have been introduced in an attempt to reduce polyethylene wear and secondary osteolysis and improve longevity of implants. We reviewed clinical studies in literature evaluating OxZr femoral component for TKA. The aim of this review was to evaluate the clinical outcome and survival rate of TKA with an OxZr femoral component. A review of the existing literature was undertaken to collect data on the OxZr femoral component in order to provide a better understanding of its performance. Of 34 studies published in the literature, 8 met the eligibility criteria and were included in the final analysis. Findings indicated that the mean Knee Society knee score improved in all series from preoperative to postoperative evaluation. The postoperative Knee Society knee score reported range from 84 to 95 and mean postoperative Knee Society functional score range from 74 to 90. The revision rate with this implant is low with up to 12.6 years of follow-up, with three revisions in total. The survival rate ranged from 100-98.7% at 5-7 years to 97.8% at 10 years. Excellent clinical outcome and high survival rate has been demonstrated for OxZr femoral component in TKA. No adverse reaction has been described for this new material.

  10. Chemical characterization and bioactivity of epoxy resin and Portland cement-based sealers with niobium and zirconium oxide radiopacifiers.

    Science.gov (United States)

    Viapiana, Raqueli; Guerreiro-Tanomaru, Juliane Maria; Hungaro-Duarte, Marco Antonio; Tanomaru-Filho, Mário; Camilleri, Josette

    2014-09-01

    The purpose of this study was to characterize and to evaluate the bioactivity potential of experimental root canal sealers (ES) based on Portland cement, epoxy resin with nano- and micro-particles of niobium or zirconium oxide used as radiopacifiers in comparison to AH Plus and MTA Fillapex. Specimens of the sealers (10 mm in diameter×1 mm thick) were prepared and the radiopacity was evaluated according to ISO 6876 (2012) specifications. Characterization of the sealers was performed under the scanning electron microscope (SEM) immediately after setting and after immersion for 28 days in Hank's balanced salt solution (HBSS). In addition X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were also performed. The pH and calcium ion release were measured after 1, 7, 14, 21 and 28 days after completion of seating using a digital pH meter and an atomic absorption spectrophotometer, respectively. The experimental sealers exhibited an average radiopacity of 2.5 mm thickness of aluminum, which was similar to MTA Fillapex (P>0.05) and inferior to AH Plus (Pepoxy resin and radiopacifier exhibited a degree of bioactivity although no evidence of cement hydration was demonstrated on material characterization. The radiopacifier particle size had limited effect on the sealer microstructure and chemical properties. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

    KAUST Repository

    Kelly, Michael J.

    2017-06-12

    A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

  12. An investigation of the oxidation behaviour of zirconium alloys using isotopic tracers and high resolution SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Yardley, Sean S., E-mail: sean.yardley@materials.ox.ac.uk [Department of Materials, Oxford University, Parks Road, Oxford OX1 3PH (United Kingdom); Moore, Katie L. [Department of Materials, Oxford University, Parks Road, Oxford OX1 3PH (United Kingdom); Ni, Na [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Wei, Jang Fei; Lyon, Stuart; Preuss, Michael [School of Materials, University of Manchester, Materials Performance Centre, Manchester, Lancashire M13 9PL (United Kingdom); Lozano-Perez, Sergio; Grovenor, Chris R.M. [Department of Materials, Oxford University, Parks Road, Oxford OX1 3PH (United Kingdom)

    2013-11-15

    Highlights: •Zr alloys were oxidised for various times in an autoclave to simulate PWR conditions. •Isotopic tracers {sup 18}O and {sup 2}H were added to reveal active oxidation sites by NanoSIMS analysis. •Hydrides were present in all samples, even those with short oxidation times. •Porosity mediated transitions between corrosion regimes occur at critical oxide thicknesses. -- Abstract: High resolution secondary ion mass spectrometry (SIMS) analysis has been used to study the oxidation mechanisms when commercial low tin ZIRLO™ and Zircaloy 4 materials are exposed to corroding environments containing both {sup 18}O and {sup 2}H isotopes. Clear evidence has been shown for different characteristic distributions of {sup 18}O before and after the kinetic transitions, and this behaviour has been correlated with the development of porosity in the oxide which allows the corroding medium to penetrate locally to the metal/oxide interface.

  13. A Review of Nanoscale Channel and Gate Engineered FINFETs for VLSI Mixed Signal Applications Using Zirconium-di-Oxide Dielectrics

    Directory of Open Access Journals (Sweden)

    D.Nirmal

    2014-07-01

    Full Text Available In the past, most of the research and development efforts in the area of CMOS and IC’s are oriented towards reducing the power and increasing the gain of the circuits. While focusing the attention on low power and high gain in the device, the materials of the device also been taken into consideration. In the present technology, Computationally intensive devices with low power dissipation and high gain are becoming a critical application domain. Several factors have contributed to this paradigm shift. The primary driving factor being the increase in scale of integration, the chip has to accommodate smaller and faster transistors than their predecessors. During the last decade semiconductor technology has been led by conventional scaling. Scaling, has been aimed towards higher speed, lower power and higher density of the semiconductor devices. However, as scaling approached its physical limits, it has become more difficult and challenging for fabrication industry. Therefore, tremendous research has been carried out to investigate the alternatives, and this led to the introduction of new Nano materials and concepts to overcome the difficulties in the device fabrications. In order to reduce the leakage current and parasitic capacitance in devices, gate oxide high-k dielectric materials are explored. Among the different high-k materials available the nano size Zirconium dioxide material is suggested as an alternate gate oxide material for devices due to its thermal stability and small grain size of material. To meet the requirements of ITRS roadmap 2012, the Multi gate devices are considered to be one of the most promising technologies for the future microelectronics industry due to its excellent immunity to short channel effects and high value of On current. The double gate or multi gate devices provide a better scalability option due to its excellent immunity to short-channel effects. Here the different high-k materials are replaced in different

  14. Quaternary Oxide of Cerium, Terbium, Praseodymium and Zirconium for Three-Way Catalysts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Oxygen storagecapacity (OSC), oxygen buffer capacity (OBC), X-ray diffraction and electron diffraction pattern, high resolution electron microscopy were used to study the quaternary oxides, i.e., of Ce, Tb, Pr and Zr. (Ce0.6Tb0.2Zr0.2O2-δ and Ce0.6Pr0.2Zr0.2O2-δ). OSC and OBC data indicate that these oxides have very good oxygen transfer capacity (OTC) and their pseudo-solid solutions exhibit fluorite-type structure. These oxides may act as a good candidate for three-way catalysts (TWC).

  15. Formation and dielectric properties of anodic oxide films on Zr–Al alloys

    OpenAIRE

    Koyama, Shun; Aoki, Yoshitaka; Nagata, Shinji; Habazaki, Hiroki

    2011-01-01

    Zr–Al alloys containing up to 26 at.% aluminum, prepared by magnetron sputtering, have been anodized in 0.1 mol dm−3 ammonium pentaborate electrolyte, and the structure and dielectric properties of the resultant anodic oxide films have been examined by grazing incidence X-ray diffraction, transmission electron microscopy, Rutherford backscattering spectroscopy, and AC impedance spectroscopy. The anodic oxide film formed on zirconium consists of monoclinic and tetragonal ZrO2 with the fo...

  16. Microstructure analysis of Kr+ irradiation and post-irradiation corrosion of modified N36 zirconium alloy

    Science.gov (United States)

    Lei, Penghui; Ran, Guang; Liu, Chenwei; Shen, Qiang; Zhang, Ruiqian; Ye, Chao; Li, Ning; Yang, Peihua; Yang, Yungchun

    2017-09-01

    The irradiation behaviors and corrosion properties of a modified N36 zirconium alloy with the composition of Zr-0.8Sn-1Nb-0.3Fe, developed by Nuclear Power Institute of China, were investigated by transmission electron microscopy and focused ion beam. The polished samples were irradiated by 400 keV Kr+ ions up to 25 dpa at 360 °C using a NEC 400 kV ion implanter. The as-received and irradiated samples were corroded for 14 days at the water-vapor environment with 10.3 MPa and 400 °C. The krypton gas bubbles were formed in zirconium matrix and their size was increased with increasing ion dose. Meanwhile, a model that related with gas bubble size and displacement damage had been established. After the corrosion, a layer composed of zircona with different stoichiometric composition was formed on the sample surface. The higher the displacement damage was, the thicker the corrosion layer would be. An empirical equation between oxide thickness and displacement damage was provided. From sample surface to matrix inner, the oxygen content was decreased with increasing corrosion depth. Correspondingly, the zircona was changed from ZrO2 with monoclinic structure on the sample surface to the mixtures of ZrO2 with tetragonal structure and ZrO2 with monoclinic structure in the middle of corrosion layer, and then to ZrO2 with tetragonal structure near alloy matrix.

  17. PROCESS OF DISSOLVING ZIRCONIUM ALLOYS

    Science.gov (United States)

    Shor, R.S.; Vogler, S.

    1958-01-21

    A process is described for dissolving binary zirconium-uranium alloys where the uranium content is about 2%. In prior dissolution procedures for these alloys, an oxidizing agent was added to prevent the precipitation of uranium tetrafluoride. In the present method complete dissolution is accomplished without the use of the oxidizing agent by using only the stoichiometric amount or slight excess of HF required by the zirconium. The concentration of the acid may range from 2M to 10M and the dissolution is advatageously carried out at a temperature of 80 deg C.

  18. Improvement in performance of solution-processed indium-zinc-tin oxide thin-film transistors by UV/O3 treatment on zirconium oxide gate insulator

    Science.gov (United States)

    Naik, Bukke Ravindra; Avis, Christophe; Delwar Hossain Chowdhury, Md; Kim, Taehun; Lin, Tengda; Jang, Jin

    2016-03-01

    We studied solution-processed amorphous indium-zinc-tin oxide (a-IZTO) thin-film transistors (TFTs) with spin-coated zirconium oxide (ZrOx) as the gate insulator. The ZrOx gate insulator was used without and with UV/O3 treatment. The TFTs with an untreated ZrOx gate dielectric showed a saturation mobility (μsat) of 0.91 ± 0.29 cm2 V-1 s-1, a threshold voltage (Vth) of 0.28 ± 0.36 V, a subthreshold swing (SS) of 199 ± 37.17 mV/dec, and a current ratio (ION/IOFF) of ˜107. The TFTs with a UV/O3-treated ZrOx gate insulator exhibited μsat of 2.65 ± 0.43 cm2 V-1 s-1, Vth of 0.44 ± 0.35 V, SS of 133 ± 24.81 mV/dec, and ION/IOFF of ˜108. Hysteresis was 0.32 V in the untreated TFTs and was eliminated by UV/O3 treatment. Also, the leakage current decreased significantly when the IZTO TFT was coated onto a UV/O3-treated ZrOx gate insulator.

  19. Oxidation resistance, thermal conductivity, and spectral emittance of fully dense zirconium diboride with silicon carbide and tantalum diboride additives

    Science.gov (United States)

    Van Laningham, Gregg Thomas

    Zirconium diboride (ZrB2) is a ceramic material possessing ultra-high melting temperatures. As such, this compound could be useful in the construction of thermal protection systems for aerospace applications. This work addresses a primary shortcoming of this material, namely its propensity to destructively oxidize at high temperatures, as well as secondary issues concerning its heat transport properties. To characterize and improve oxidation properties, thermogravimetric studies were performed using a specially constructed experimental setup. ZrB 2-SiC two-phase ceramic composites were isothermally oxidized for ~90 min in flowing air in the range 1500-1900°C. Specimens with 30 mol% SiC formed distinctive reaction product layers which were highly protective; 28 mol% SiC - 6 mol% TaB2 performed similarly. At higher temperatures, specimens containing lower amounts of SiC were shown to be non-protective, whereas specimens containing greater amounts of SiC produced unstable oxide layers due to gas evolution. Oxide coating thicknesses calculated from weight loss data were consistent with those measured from SEM micrographs. In order to characterize one aspect of the materials' heat transport properties, the thermal diffusivities of ZrB2-SiC composites were measured using the laser flash technique. These were converted to thermal conductivities using temperature dependent specific heat and density data; thermal conductivity decreased with increasing temperature over the range 25-2000°C. The composition with the highest SiC content showed the highest thermal conductivity at room temperature, but the lowest at temperatures in excess of ~400°C, because of the greater temperature sensitivity of the thermal conductivity of the SiC phase, as compared to more electrically-conductive ZrB2. Subsequent finite difference calculations were good predictors of multi-phase thermal conductvities for the compositions examined. The thermal conductivities of pure ZrB2 as a function of

  20. Oxidation Behavior of FeCrAl -coated Zirconium Cladding prepared by Laser Coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il-Hyun; Kim, Hyun-Gil; Choi, Byung-Kwan; Park, Jeong-Yong; Koo, Yang-Hyun; Kim, Jin-Seon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    From the recent research trends, the ATF cladding concepts for enhanced accident tolerance are divided as follows: Mo-Zr cladding to increase the high temperature strength, cladding coating to increase the high temperature oxidation resistance, FeCrAl alloy and SiC/SiCf material to increase the oxidation resistance and strength at high temperature. To commercialize the ATF cladding concepts, various factors are considered, such as safety under normal and accident conditions, economy for the fuel cycle, and developing development challenges, and schedule. From the proposed concepts, it is known that the cladding coating, FeCrAl alloy, and Zr-Mo claddings are considered as a near/mid-term application, whereas the SiC material is considered as a long-term application. Among them, the benefit of cladding coating on Zr-based alloys is the fuel cycle economy regarding the manufacturing, neutron cross section, and high tritium permeation characteristics. However, the challenge of cladding coating on Zr-based alloys is the lower oxidation resistance and mechanical strength at high-temperature than other concepts. Another important point is the adhesion property between the Zr-based alloy and coating materials. A laser coating method supplied with FeCrAl powders was developed to decrease the high-temperature oxidation rate in a steam environment through a systematic study for various coating parameters, and a FeCrAl-coated Zircaloy-4 cladding tube of 100 mm in length to the axial direction can be successfully manufactured.

  1. The comparison of calculated transition probabilities with luminescence characteristics of erbium(III) in fluoride glasses and in the mixed yttrium-zirconium oxide crystal

    Science.gov (United States)

    Reisfeld, R.; Katz, G.; Jacoboni, C.; De Pape, R.; Drexhage, M. G.; Brown, R. N.; Jørgensen, C. K.

    1983-07-01

    Fluorozirconate glasses containing 2 mole% ErF 3 were prepared by melting the binary fluorides with ammonium bifluoride under an atmosphere of carbon tetrachloride and argon at 850°C. Absorption spectra of these glasses were obtained and the Judd-Ofelt parameters were calculated. Emission spectra and lifetimes of erbium in fluorozirconate glass, in lead-gallium-zinc fluoride glass, and in yttrium-zirconium oxide crystal were measured and compared with the theoretical calculations. Laser emission lines in these materials are deduced from these measurements. It is suggested that materials doped with erbium may serve as light sources for fiber optic waveguides made from the undoped materials.

  2. Defect structure of zirconium oxide nanosized powders with Y2O3, Sc2O3, Cr2O3 impurities

    OpenAIRE

    Yurchenko, L.; I. Bykov; Vasylyev, A; Vereshchak, V.; Suchaneck, G.; Jastrabik, L.; Dejneka, A.

    2012-01-01

    Formation mechanisms of paramagnetic centers originating from Zr3+ and Cr3+ ions as well as the influence of composition of nanoparticles on thermogeneration processes of these paramagnetic centers in ZrO2 structure were studied. A set of nanosized powders of zirconium oxide was investigated by electron paramagnetic resonance method: nominally pure ZrO2; ZrO2 with Y2O3 and Sc2O3; ZrO2 with Cr2O3; ZrO2 with Y2O3 and Cr2O3. It is observed that the influence of annealing on EPR lines of Zr...

  3. Influence of the sputtering pressure on the properties of transparent conducting zirconium-doped zinc oxide films prepared by RF magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    刘汉法; 张化福; 类成新; 袁长坤

    2009-01-01

    Transparent conducting zirconium-doped zinc oxide films with high transparency and relatively low re-sistivity have been successfully prepared on water-cooled glass substrate by radio frequency magnetron sputtering at room temperature. The Ar sputtering pressure was varied from 0.5 to 3 Pa. The crystallinity increases and the electri-cal resistivity decreases when the sputtering pressure increases from 0.5 to 2.5 Pa. The cystallinity decreases and the electrical resistivity increases when the sputtering pressure increases from 2.5 to 3 Pa. When the sputtering pressure The deposited films are polycrystalline with a hexagonal structure and a preferred orientation perpendicular to the substrate.

  4. A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

    Science.gov (United States)

    Riedel, S.; Polakowski, P.; Müller, J.

    2016-09-01

    Ferroelectric properties in hafnium oxide based thin films have recovered the scaling potential for ferroelectric memories due to their ultra-thin-film- and CMOS-compatibility. However, the variety of physical phenomena connected to ferroelectricity allows a wider range of applications for these materials than ferroelectric memory. Especially mixed HfxZr1-xO2 thin films exhibit a broad compositional range of ferroelectric phase stability and provide the possibility to tailor material properties for multiple applications. Here it is shown that the limited thermal stability and thick-film capability of HfxZr1-xO2 can be overcome by a laminated approach using alumina interlayers.

  5. Characterisation of a new adsorbent (beta cyclodextrin modified hybrid hydrous iron-zirconium oxide) to remove fluoride from aqueous solution

    Science.gov (United States)

    Saha, Indranil

    2017-04-01

    Prolonged use of fluoride contaminated water (>1.5mg L -1) causes serious problems to public health and ultimately leads to skeletal fluorosis. There is an urgent need to develop more efficient fluoride scavenging materials for designing water filters. A simple and efficient adsorbent (CHIZO, beta-Cyclodextrin (b-CD) amended hydrous iron-zirconium hybrid oxide), has been developed, characterised and tested. The results indicate the efficacy of CHIZO on fluoride removal from an aqueous solution. The agglomerated micro structured composite material has several new features such as very poor crystallinity confirmed from TEM images. BET experiment reveals a surface area of 0.2070 m2 g- 1 and pore volume of 0.0476 cm3 g -1. The findings also indicate the highly pH dependent fluoride adsorption by CHIZO which decreases with an increase in pH, and pseudo-second order kinetics control the reaction.Isotherm study indicates Langmuir isotherm was the best fit model to describe the adsorption equilibrium. Significantly higher monolayer adsorption capacity of fluoride (31.35 mg g -1) than the host hydrous Fe-Zr oxide (8.21 mg g -1) at pH 7.0 and 303 K was observed. Thermodynamic parameter indicates spontaneous nature of CHIZO which is due to the exothermic nature of the reaction. Apart from this phosphate and sulphate have some impact (interference) on fluoride adsorption. b-CD forms inclusion complexes by taking up fluoride ions from water into its central cavity. Several factors are involved regarding high efficacy of the system such as the release of enthalpy-rich water molecules from its cavity, electrostatic interactions, hydrogen bonding and release of conformational strain. However, the regeneration is difficult because of probable entrapping of fluoride inside the cavity of b-CD with hydrogen bonding. It has been found that only 0.9 g of CHIZO is able to reduce the fluoride level to below 1.0 mg L -1 in one-litre of fluoride spiked (5.0 mg L- 1) natural water sample

  6. A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

    Directory of Open Access Journals (Sweden)

    S. Riedel

    2016-09-01

    Full Text Available Ferroelectric properties in hafnium oxide based thin films have recovered the scaling potential for ferroelectric memories due to their ultra-thin-film- and CMOS-compatibility. However, the variety of physical phenomena connected to ferroelectricity allows a wider range of applications for these materials than ferroelectric memory. Especially mixed HfxZr1-xO2 thin films exhibit a broad compositional range of ferroelectric phase stability and provide the possibility to tailor material properties for multiple applications. Here it is shown that the limited thermal stability and thick-film capability of HfxZr1-xO2 can be overcome by a laminated approach using alumina interlayers.

  7. Obtaining solid electrolytes based on zirconium oxide; Obtencao de eletrolitos solidos baseados em oxido de zirconio

    Energy Technology Data Exchange (ETDEWEB)

    Cajas, P.C.; Munoz, R.; Silva, C.R.M da, E-mail: patolacajas@gmail.com [Universidade de Brasilia (UnB), Brasilia, DF (Brazil)

    2014-07-01

    Ceramic materials based on zirconia were synthesized by the controlled precipitation method, ZrO{sub 2}: 3% molY{sub 2}O{sub 3}: η mol% Y{sub 2}O{sub 3} (η = 3,4,5), using commercial zirconia, TZ-3YB-E, and a concentrate of mixed rare earth oxides. The powder samples were thermally treated at 600 ° C (2h) to remove unwanted carbonates formed in the synthesis process, and then subjected to milling using attrition mill and finally compacted by uniaxial pressing and sintered at 1500 ° C (2h). The densities were analyzed by the Archimedes method, obtaining results higher than 96% of theoretical. Using XRD and Rietveld refinements, the phases present in the samples were known qualitatively and quantitatively, observing a mixture of the cubic and tetragonal phases. An improvement in the conductivity in the samples co-doped with complex impedance spectroscopy was determined.

  8. Effect Of The Gadolinium Oxide Addition On The Electrical Properties Of Tetragonal Zirconium Dioxide

    Directory of Open Access Journals (Sweden)

    Cyran J.

    2015-06-01

    Full Text Available The aim of this work was examination of gadolinium-doped 3YSZ electrical and structural properties. Such materials may be used as electrolytes in intermediate temperature solid oxide fuel cells (IT-SOFC. First step of the research was synthesis of 3YSZ with different contents of gadolinium (0.25; 0.5; 1.0 at %. Prepared materials were characterized by high porosity. No effect of gadolinium addition on grain size was observed. The experimentally determined values of grain interiors electrical conductivities for gadolinium doped samples are comparable to grain interior conductivities of gadolinium free tetragonal zirconia. On the other hand, a clear effect of gadolinium addition on electrical conductivity of grain boundaries was observed. It was found that 3YSZ containing 0.25 at. % Gd was the most promising from the investigated materials as a solid electrolyte for IT SOFC.

  9. Lanthanum cobaltite perovskite supported onto mesoporous zirconium dioxide: nature of active sites of VOC oxidation.

    Science.gov (United States)

    Kustov, Alexander L; Tkachenko, Olga P; Kustov, Leonid M; Romanovsky, Boris V

    2011-08-01

    Novel catalytic nano-sized materials based on LaCoO(x) perovskite nanoparticles incapsulated in the mesoporous matrix of zirconia were prepared, characterized by physicochemical methods and tested in complete methanol oxidation. LaCoO(x) nanoparticles were prepared inside the mesopores of ZrO(2) by decomposition of bimetallic La-Co glycine precursor complexes. The catalysts have been studied by diffuse-reflectance FTIR-spectroscopy using such probe molecules as CO, CD(3)CN and CDCl(3) to test low-coordinated metal ions. At low temperatures of decomposition of complexes (up to 400°C), low-coordinated Co(3+) ions predominate in the LaCoO(x) nanoparticles, whereas basically Co(2+) ions are found upon increasing the decomposition temperature to 600°C. The novel nano-sized perovskite catalysts exhibit a very high catalytic activity in the abatement of volatile organic compounds present in air, like methanol and light hydrocarbons.

  10. Biocorrosion resistance of coated magnesium alloy by microarc oxidation in electrolyte containing zirconium and calcium salts

    Science.gov (United States)

    Wang, Ya-Ming; Guo, Jun-Wei; Wu, Yun-Feng; Liu, Yan; Cao, Jian-Yun; Zhou, Yu; Jia, De-Chang

    2014-09-01

    The key to use magnesium alloys as suitable biodegradable implants is how to adjust their degradation rates. We report a strategy to prepare biocompatible ceramic coating with improved biocorrosion resistance property on AZ91D alloy by microarc oxidation (MAO) in a silicate-K2ZrF6 solution with and without Ca(H2PO4)2 additives. The microstructure and biocorrosion of coatings were characterized by XRD and SEM, as well as electrochemical and immersion tests in simulated body fluid (SBF). The results show that the coatings are mainly composed of MgO, Mg2SiO4, m-ZrO2 phases, further Ca containing compounds involve the coating by Ca(H2PO4)2 addition in the silicate-K2ZrF6 solution. The corrosion resistance of coated AZ91D alloy is significantly improved compared with the bare one. After immersing in SBF for 28 d, the Si-Zr5-Ca0 coating indicates a best corrosion resistance performance.

  11. Complex oxide with negative thermal expansion for producing ceramic matrix composites with invar effect

    Science.gov (United States)

    Dedova, Elena S.; Pertushina, Mariya U.; Kondratenko, Anton I.; Gorev, Mikhail V.; Kulkov, Sergei N.

    2016-11-01

    The article investigates the phase composition of (Al2O3-20 wt % ZrO2)-ZrW2O8 ceramic composites obtained by cold-pressing and sintering processes. Using X-ray analysis it has been shown that composites mainly have monoclinic modification of zirconium dioxide and orthorhombic phase of aluminum oxide. After adding zirconium tungstate the phase composition of sintered ceramics changes, followed by the formation of tungsten-aluminates spinel such as Alx(WOy)z. It has been shown that thermal expansion coefficient of material decreases approximatly by 30%, as compared with initial ceramics.

  12. Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

    Science.gov (United States)

    Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

    2015-10-01

    Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

  13. Boron-doped peroxo-zirconium oxide dielectric for high-performance, low-temperature, solution-processed indium oxide thin-film transistor.

    Science.gov (United States)

    Park, Jee Ho; Yoo, Young Bum; Lee, Keun Ho; Jang, Woo Soon; Oh, Jin Young; Chae, Soo Sang; Lee, Hyun Woo; Han, Sun Woong; Baik, Hong Koo

    2013-08-28

    We developed a solution-processed indium oxide (In2O3) thin-film transistor (TFT) with a boron-doped peroxo-zirconium (ZrO2:B) dielectric on silicon as well as polyimide substrate at 200 °C, using water as the solvent for the In2O3 precursor. The formation of In2O3 and ZrO2:B films were intensively studied by thermogravimetric differential thermal analysis (TG-DTA), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT IR), high-resolution X-ray diffraction (HR-XRD), and X-ray photoelectron spectroscopy (XPS). Boron was selected as a dopant to make a denser ZrO2 film. The ZrO2:B film effectively blocked the leakage current at 200 °C with high breakdown strength. To evaluate the ZrO2:B film as a gate dielectric, we fabricated In2O3 TFTs on the ZrO2:B dielectrics with silicon substrates and annealed the resulting samples at 200 and 250 °C. The resulting mobilities were 1.25 and 39.3 cm(2)/(V s), respectively. Finally, we realized a flexible In2O3 TFT with the ZrO2:B dielectric on a polyimide substrate at 200 °C, and it successfully operated a switching device with a mobility of 4.01 cm(2)/(V s). Our results suggest that aqueous solution-processed In2O3 TFTs on ZrO2:B dielectrics could potentially be used for low-cost, low-temperature, and high-performance flexible devices.

  14. The effect of ceramic thickness and number of firings on the color of a zirconium oxide based all ceramic system fabricated using CAD/CAM technology

    Science.gov (United States)

    Aras, Meena Ajay

    2011-01-01

    PURPOSE Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (Lava™) fabricated using CAD/CAM technology. MATERIALS AND METHODS Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems (Lava™, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad Säckingen, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, α=.05). RESULTS L*a*b* values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in L*a*b* values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in L* values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The a* values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The b* values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in L* values (P<.01) were recorded. There were significant increases in both a

  15. Unexpected origin of magnetism in monoclinic Nb12O29 from first-principles calculations

    NARCIS (Netherlands)

    Fang, C. M.; Van Huis, M. A.; Xu, Q.; Cava, R. J.; Zandbergen, H. W.

    2015-01-01

    Nb12O29 is a 4d transition metal oxide that occurs in two forms with different symmetries, monoclinic (m) and orthorhombic (o). The monoclinic form has unusual magnetic properties; below a temperature of 12 K, it exhibits both metallic conductivity and antiferromagnetic ordering. Here, first-princip

  16. In vitro comparative bond strength of contemporary self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion.

    Science.gov (United States)

    Blatz, Markus B; Phark, Jin-Ho; Ozer, Fusun; Mante, Francis K; Saleh, Najeed; Bergler, Michael; Sadan, Avishai

    2010-04-01

    This study compared shear bond strengths of six self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion. One hundred twenty zirconia samples were air-abraded (group SB; n = 60) or left untreated (group NO). Composite cylinders were bonded to the zirconia samples with either BisCem (BC), Maxcem (MC), G-Cem (GC), RelyX Unicem Clicker (RUC), RelyX Unicem Applicator (RUA), or Clearfil SA Cement (CSA). Shear bond strength was tested after thermocycling, and data were analyzed with analysis of variance and Holm-Sidak pairwise comparisons. Without abrasion, RUA (8.0 MPa), GC (7.9 MPa), and CSA (7.6 MPa) revealed significantly higher bond strengths than the other cements. Air-particle abrasion increased bond strengths for all test cements (p MDP/4-META) were superior to other compositions.

  17. Investigation of structure-dielectric property relationships in zirconium oxide, tantalum pentoxide, and oxide-polymer laminate films for high energy density capacitor applications

    Science.gov (United States)

    Sethi, Guneet

    Pulsed power applications involve transformation of electrical energy into high-peak power pulses through capacitors. There is an immediate need for fast-response capacitors with decreased volume, weight, and cost for pulsed power applications and power distribution systems. This research challenge is dominated by energy density. Energy density is directly related to dielectric properties such as dielectric polarization, conductivity and breakdown strength of the capacitor dielectric. This research work correlates processing and microstructure of single and multiple component dielectric films with their dielectric properties. The inorganic materials studied in this dissertation include zirconium oxide (ZrO2) and tantalum pentoxide (Ta 2O5) reactive sputtered films. Film crystallization & structure was studied as a function of sputtering growth variables such as sputtering power, sputtering pressure, source frequency, oxygen pressure, substrate temperature, substrate material, and post-deposition annealing temperature. Polycrystalline phase of ZrO2 and amorphous phase of Ta2O 5 were obtained for most sputtering growth variables. Although the amorphous films have lower permittivity (32 for amorphous & 51 for polycrystalline at 1 kHz), they also have lower AC and DC conductivities (3.4x10-8 S/m for amorphous & 12.2x10 -8 S/m for polycrystalline at 1 kHz), which result in high breakdown strength than polycrystalline films. Amorphous Ta2O5 films are found to be ideal for high-energy density capacitors with energy density of 14 J/cm3 because of their high permittivity, low leakage current density, and high dielectric breakdown strength. Oxide films were combined with different polymers (polyvinyldene flouride-triflouroethylene, polypropylene and polyethylene terephthalate) to produce two different kinds of laminate composites---oxide on polymer and polymer on oxide. Permittivity and conductivity differences in the polymer and oxide films result in an impedance contrast

  18. Preparation and characterization of sugar cane bagasse fiber modified with nanoparticles of zirconium oxide; Preparacao e caracterizacao de fibras de bagaco de cana modificadas com nanoparticulas de oxido de zirconio

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, K.C.C. de; Mulinari, D.R.; Voorwald, H.C.J.; Cioffi, M.O.H., E-mail: kcccarvalho@hotmail.com.b [UNESP, Guaratingueta, SP (Brazil). Fac. de Engenharia. Dept. de Materiais e Tecnologia(FEG)

    2010-07-01

    The sugar cane bagasse fiber are renewable materials and have great application potential when used as reinforcement in a polymer matrix to give rise to composite materials and as supports for adsorption of heavy metals. This paper therefore describes the preparation and characterization of bleached and hydrated zirconium oxide modified sugar cane bagasse fiber by conventional precipitation method. Through the technique of electron microscopy we observed the presence of oxide nanoparticles on the fiber surface, proving the efficiency of the conventional precipitation method. With the X-ray diffraction analysis it was determined a decrease of 6.2% in the crystallinity index of modified fibers when compared to the bleached fibers showing the deposition of amorphous zirconium oxide on the fiber surface. (author)

  19. Role of electrolyte composition on structural, morphological and in-vitro biological properties of plasma electrolytic oxidation films formed on zirconium

    Science.gov (United States)

    Sandhyarani, M.; Prasadrao, T.; Rameshbabu, N.

    2014-10-01

    Development of oxide films on metallic implants with a good combination of corrosion resistance, bioactivity and cell adhesion can greatly improve its biocompatibility and functionality. Thus, the present work is aimed to fabricate oxide films on metallic Zr by plasma electrolytic oxidation (PEO) in methodically varied concentrations of phosphate, silicate and KOH based electrolyte systems using a pulsed DC power source. The oxide films fabricated on Zr are characterized for its phase composition, surface morphology, chemical composition, roughness, wettability, surface energy, corrosion resistance, apatite forming ability and osteoblast cell adhesion. Uniform films with thickness varying from 6 to 11 μm are formed. XRD patterns of all the PEO films showed the predominance of monoclinic zirconia phase. The film formed in phosphate + KOH electrolyte showed superior corrosion resistance, which can be ascribed to its pore free morphology. The films formed in silicate electrolyte showed higher apatite forming ability with good cell adhesion and spreading over its surface which is attributed to its superior surface roughness and wettability characteristics. Among the five different electrolyte systems employed in the present study, the PEO film formed in an electrolyte system with phosphate + silicate + KOH showed optimum corrosion resistance, apatite forming ability and biocompatibility.

  20. In situ electrochemical synthesis of highly loaded zirconium nanoparticles decorated reduced graphene oxide for the selective determination of dopamine and paracetamol in presence of ascorbic acid.

    Science.gov (United States)

    Ezhil Vilian, A T; Rajkumar, Muniyandi; Chen, Shen-Ming

    2014-03-01

    Highly loaded zirconium oxide (ZrO2) nanoparticles were supported on graphene oxide (ERGO/ZrO2) via an in situ, simple and clean strategy on the basis of the electrochemical redox reaction between zirconyl chloride and graphene oxide (ZrOCl2 and GO). The electrochemical measurements and surface morphology of the as prepared nanocomposite were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FESEM). This ZrO2 decorated reduced graphene oxide nanocomposite modified GCE (ERGO/ZrO2) exhibits a prominent electrocatalytic activity toward the selective detection and determination of dopamine (DA) and paracetamol (PA) in presence of ascorbic acid (AA). The peaks of linear sweep voltammetry (LSV) for DA and PA oxidation at ERGO/ZrO2 modified electrode surface were clearly separated from each other when they co-existed in the physiological pH (pH 7.0) with a potential value of 140 mV (between AA and DA) and 330 mV (between AA and PA). It was, therefore, possible to simultaneously determine DA and PA in the samples at ERGO/ZrO2 nanocomposite modified GCE. Linear calibration curves were obtained for 9-237 μM of PA and DA. The ERGO/ZrO2 nanocomposite electrode has been satisfactorily used for the determination of DA and PA in the presence of AA at pharmaceutical formulations in human urine samples with a linear range of 3-174 μM. The proposed biosensor shows a wide linear range, low detection limit, good reproducibility and acceptable stability, providing a biocompatible platform for bio sensing and bio catalysis.

  1. PLUTONIUM-ZIRCONIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.; Waber, J.T.

    1960-08-30

    A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.

  2. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Lazarin, Angélica M., E-mail: amlazarin2@uem.br [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Andreotti, Elza I.S.; Sernaglia, Rosana L. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Gushikem, Yoshitaka [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13084-971 Campinas, São Paulo (Brazil)

    2014-10-15

    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN){sub 6}]{sup 4−} complex ion initially. The reaction of this material with [Ru(edta)H{sub 2}O]{sup −} complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr){sub 5}[(edta)RuNCFe(CN){sub 5}]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success.

  3. Synthesis and Dielectric Studies of Monoclinic Nanosized Zirconia

    Directory of Open Access Journals (Sweden)

    I. Flavia Princess Nesamani

    2014-01-01

    Full Text Available Zirconium dioxide is a prospective high-κ material that can replace silicon dioxide. Zirconium dioxide nanoparticle has been synthesized using sol-gel process at room temperature. The structural and morphological characterization of the nanoscaled zirconium dioxide is done using FTIR, SEM, X-ray diffraction, and TEM. The particle size of the synthesized ZrO2 is observed in the range of 50–80 nm with an average crystallite size of 2–10 nm. The results are compared with commercial coarse zirconia which showed a particle size in the range of 900 nm–2.13 µm and crystallite size of 5.3 nm–20 nm. It is expected that both nanoscaling and the high dielectric constant of ZrO2 would be useful in replacing the low-κ SiO2 dielectric with high-κ ZrO2 for CMOS fabrication technology. The synthesized ZrO2 is subjected to impedance analysis and it exhibited a dielectric constant of 25 to find its application in short channel devices like multiple gate FinFETS and as a suitable alternative for the conventional gate oxide dielectric SiO2 with dielectric value of 3.9, which cannot survive the challenge of an end of oxide thickness ≤ 1 nm.

  4. PREPARATION OF SUPPORTED AND NANOSIZED ZIRCONIUM OXIDE WITH PURE MONOCLINIC CRYSTAL PHASE%负载型纯单斜相态纳米氧化锆的制备

    Institute of Scientific and Technical Information of China (English)

    赵玉宝; 李伟; 张明慧; 陶克毅

    2001-01-01

    采用溶胶沉积法,在γ-Al2O3及锐钛矿型TiO2上制备出了纯单斜相态的负载型纳米ZrO2.此一次粒子约为5nm的负载型ZrO2,聚集成尺度约为50nm的纺锤形,均匀分布于载体上.

  5. Cationic polyelectrolyte induced separation of some inorganic contaminants and their mixture (zirconium silicate, kaolin, K-feldspar, zinc oxide) as well as of the paraffin oil from water.

    Science.gov (United States)

    Ghimici, Luminita

    2016-03-15

    The flocculation efficiency of a cationic polyelectrolyte with quaternary ammonium salt groups in the backbone, namely PCA5 was evaluated on zirconium silicate (kreutzonit), kaolin, K- feldspar and zinc oxide (ZnO) suspensions prepared either with each pollutant or with their mixture. The effect of several parameters such as settling time, polymer dose and the pollutant type on the separation efficacy was evaluated and followed by optical density and zeta potential measurements. Except for ZnO, the interactions between PCA5 and suspended particles led to low residual turbidity values (around 4% for kreutzonit, 5% for kaolin and 8% for K-feldspar) as well as to the reduction of flocs settling time (from 1200 min to 30 min and 120 min in case of kaolinit and K-feldspar, respectively), that meant a high efficiency in their separation. The negative value of the zeta potential and flocs size measurements, at the optimum polymer dose, point to contribution from charge patch mechanism for the particles flocculation. A good efficiency of PCA5 in separation of paraffin oil (a minimum residual turbidity of 9.8%) has been also found. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Application of poly(dimethylsiloxane) fiber sol-gel coated onto NiTi alloy electrodeposited with zirconium oxide for the determination of organochlorine pesticides in herbal infusions.

    Science.gov (United States)

    Budziak, Dilma; Martendal, Edmar; Carasek, Eduardo

    2008-08-01

    A PDMS fiber sol-gel coated onto an NiTi alloy previously electrodeposited with zirconium oxide (named NiTi-ZrO(2)-PDMS) was applied to the determination of organochlorine pesticides (OCPs) in infusions of peppermint (Mentha piperita L.), lemon grass (Cymbopogon citratus Stapf), chamomile (Matricaria recutita L.), lemon balm (Melissa officinalis L.), and anise seeds (Pimpinella anisum L.). Salting-out effect, extraction time, and extraction temperature were optimized firstly by means of a full-factorial design and then using a Doehlert matrix. No salt addition and 50 min of extraction at 70 degrees C were the optimum conditions. Satisfactory LODs in the range of 2-17 ng/L, as well as good correlation coefficients (at least 0.9981) in the linear range studied, were obtained. Calibration was successfully applied using an infusion of M. recutita L. and recovery tests were performed to ensure the accuracy of the method, with values in the range of 77-120%. Comparison of the NiTi-ZrO(2)-PDMS with commercially available PDMS fibers showed that the proposed fiber has an extraction efficiency comparable to that of PDMS 30 microm for the compounds evaluated, demonstrating its potential applicability.

  7. Fabrication of Transparent Conductive Zinc Oxide Co-Doped with Fluorine and Zirconium Thin Solid Films by Ultrasonic Chemical Pyrolysis: Effects of Precursor Solution Aging and Substrate Temperature

    Directory of Open Access Journals (Sweden)

    Luis Castañeda

    2013-01-01

    Full Text Available Highly transparent, conducting zinc oxide [ZnO] thin films co-doped with fluorine and zirconium have been deposited on glass substrates by the ultrasonic chemical spraying technique. The effects of aging of the starting solution and substrate temperature on the structural, morphological, and electrical properties of the ZnO:F:Zr films have been studied. The resistivity of the films decreases with the aging time of the starting solution until the seventeenth day reaching a minimum of about 1.2×10−2 Ω cm and then increases. Though all the samples are of polycrystalline hexagonal wurtzite type and grow preferentially with (002 plane parallel to the substrate, their morphology depends strongly on the aging time of the reaction solution. The optical transmittance of all the films remained around 80% in the visible spectral range. These highly transparent, low resistive thin films are expected to be highly useful as transparent electrodes in the fabrication of thin film solar cells.

  8. Zirconium oxide based ceramic solid electrolytes for oxygen detection; Eletrolitos solidos ceramicos a base de oxido de zirconio para a deteccao de oxigenio

    Energy Technology Data Exchange (ETDEWEB)

    Caproni, Erica

    2007-07-01

    Taking advantage of the high thermal shock resistance of zirconia-magnesia ceramics and the high oxide ion conductivity of zirconia-yttria ceramics, composites of these ceramics were prepared by mixing, pressing and sintering different relative concentrations of ZrO{sub 2}: 8.6 mol% MgO and ZrO{sub 2}: 3 mol% Y{sub 2}O{sub 3} solid electrolytes. Microstructural analysis of the composites was carried out by X-ray diffraction and scanning electron microscopy analyses. The thermal behavior was studied by dilatometric analysis. The electrical behavior was evaluated by the impedance spectroscopy technique. An experimental setup was designed for measurement the electrical signal generated as a function of the amount of oxygen at high temperatures. The main results show that these composites are partially stabilized (monoclinic, cubic and tetragonal) and the thermal behavior is similar to that of ZrO{sub 2}: 8.6 mol% MgO materials used in disposable high temperature oxygen sensors. Moreover, the results of analysis of impedance spectroscopy show that the electrical conductivity of zirconia:magnesia is improved with zirconia-yttria addition and that the electrical signal depends on the amount of oxygen at 1000 deg C, showing that the ceramic composites can be used in oxygen sensors. (author)

  9. Effect of 0.1 at. pct Zirconium on the cyclic oxidation resistance of beta-NiAl

    Science.gov (United States)

    Barrett, Charles A.

    1988-01-01

    The effect of 0.1 at. pct Zr on the cyclic oxidation of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1100-1200 C, using 1-hr exposure cycles for test times up to 3000 hr. The weight change versus time data were modeled with the COSP computer program to analyze and predict cyclic-oxidation behavior. Zr additions significantly change the nature of the scale-spalling process during cooling, so that the oxide spalls near the oxide-air interface at a relatively low depth within the scale. Without Zr, the predominantly alpha-Al2O3 scale tends to spall randomly to bare metal at relatively high effective-scale-loss rates, particularly at 1150 C and 1200 C. This leads to higher rates of Al consumption for the Zr-free aluminide and much earlier depletion of Al, leading to eventual breakaway (i.e., failure).

  10. Zirconium modified nickel-copper alloy

    Science.gov (United States)

    Whittenberger, J. D. (Inventor)

    1977-01-01

    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  11. Experiments on interactions between zirconium-containing melt and water (ZREX). Hydrogen generation and chemical augmentation of energetics

    Energy Technology Data Exchange (ETDEWEB)

    Cho, D.H.; Armstrong, D.R.; Gunther, W.H. [Argonne National Lab., IL (United States); Basu, S.

    1998-01-01

    The results of the first data series of experiments on interactions between zirconium-containing melt and water are described. These experiments involved dropping 1-kg batches of pure zirconium or zirconium-zirconium dioxide mixture melt into a column of water. A total of nine tests were conducted, including four with pure zirconium melt and five with Zr-ZrO{sub 2} mixture melt. Explosions took place only in those tests which were externally triggered. While the extent of zirconium oxidation in the triggered experiments was quite extensive, the estimated explosion energetics were found to be very small compared to the combined thermal and chemical energy available. (author)

  12. Experiments on explosive interactions between zirconium-containing melt and water (ZREX).

    Energy Technology Data Exchange (ETDEWEB)

    Cho, D. H.

    1998-04-10

    The results of two series of experiments on explosive interactions between zirconium-containing melt and water are described. The first series of experiments involved dropping 1-kg batches of zirconium-zirconium dioxide mixture melt into a column of water while the second series employed 1.2-kg batches of zirconium-stainless steel mixture melt. Explosions took place only in those tests which were externally triggered. While the extent of zirconium oxidation in the triggered experiments was quite large, the explosion energies estimated from the experimental measurements were found to be small compared to the combined thermal and chemical energy available.

  13. Designing Zirconium Coated Polystyrene Colloids and Application

    Directory of Open Access Journals (Sweden)

    Diana Chira

    2009-01-01

    Full Text Available A simple technique has been developed to prepare core colloids that are modified using zirconium oxychloride, based on heating a solution of core colloid composites, consisting of poly (ethylenimine (PEI and zirconium oxychloride. The interaction of zirconium oxychloride with the polystyrene (PS core colloids has been investigated using Fourier transform-infrared spectroscopy (FT-IR, energy dispersive X-ray spectroscopy (EDX, and scanning electron microscopy (SEM data. FT-IR studies confirm the occurrence of amine groups present in PEI which are oxidized to carboxyl groups after the reaction. The EDX data and the SEM images confirm the presence of zirconium particles immobilized on the polystyrene surfaces. Demeton, a highly toxic nerve agent, was used due to its ability to easily bind through its organophosphate group illustrating a practical application of the PS-PEI-Zr particles. Attenuated Total Reflection (ATR Spectroscopy was used to assess the interactions between the toxic nerve agent demeton-S and the PS-PEI-Zr particles. The results show that the presented technique for coating polystyrene core colloids with zirconium was successfully accomplished, and the newly formed particles easily bond with demeton agents through the P=O functional group.

  14. Solid State Synthesis and Properties of Monoclinic Celsian

    Science.gov (United States)

    Bansal, Narottam P.

    1996-01-01

    Monoclinic celsian of Ba(0.75)Sr(0.25)Al2Si2O8 (BSAS-1) and B(0.85)Sr(O.15)Al2Si2O8 (BSAS-2) compositions have been synthesized from metal carbonates and oxides by solid state reaction. A mixture of BaCO3, SrCO3, Al2O3, and SiO2 powders was precalcined at approx. 900-940 C to decompose the carbonates followed by hot pressing at approx. 1300 C. The hot pressed BSAS-1 material was almost fully dense and contained the monoclinic celsian phase, with complete absence of the undesirable hexacelsian as indicated by x-ray diffraction. In contrast, a small fraction of hexacelsian was still present in hot pressed BSAS-2. However, on further heat treatment at 1200 C for 24 h, the hexacelsian phase was completely eliminated. The average linear thermal expansion coefficients of BSAS-1 and BSAS-2 compositions, having the monoclinic celsian phase, were measured to be 5.28 x 10(exp -6)/deg C and 5.15 x 10(exp -6)/deg C, respectively from room temperature to 1200 C. The hot pressed BSAS-1 celsian showed room temperature flexural strength of 131 MPa, elastic modulus of 96 GPa and was stable in air up to temperatures as high as approx. 1500 C.

  15. Influence of Oxidation Behavior of Feedstock on Microstructure and Ablation Resistance of Plasma-Sprayed Zirconium Carbide Coating

    Science.gov (United States)

    Hu, Cui; Ge, Xuelian; Niu, Yaran; Li, Hong; Huang, Liping; Zheng, Xuebin; Sun, Jinliang

    2015-10-01

    Plasma spray is one of the suitable technologies to deposit carbide coatings with high melting point, such as ZrC. However, in the spray processes performed under atmosphere, oxidation of the carbide powder is inevitable. To investigate the influence of the oxidation behavior of feedstock on microstructure and ablation resistance of the deposited coating, ZrC coatings were prepared by atmospheric and vacuum plasma spray (APS and VPS) technologies, respectively. SiC-coated graphite was applied as the substrate. The obtained results showed that the oxidation of ZrC powder in APS process resulted in the formation of ZrO and Zr2O phases. Pores and cracks were more likely to be formed in the as-sprayed APS-ZrC coating. The VPS-ZrC coating without oxides possessed denser microstructure, higher thermal diffusivity, and lower coefficients of thermal expansion as compared with the APS-ZrC coating. A dense ZrO2 layer would be formed on the surface of the VPS-ZrC-coated sample during the ablation process and the substrate can be protected sufficiently after being ablated in high temperature plasma jet. However, the ZrO2 layer, formed by oxidation of the APS-ZrC coating having loose structure, was easy to be washed away by the shearing action of the plasma jet.

  16. Can anodised zirconium implants stimulate bone formation? Preliminary study in rat model

    OpenAIRE

    Katunar, Maria Rosa; Gomez Sanchez, Andrea Valeria; Ballarre, Josefina; Baca, Matías; Vottola, Carlos; Orellano, Juan C.; Schell, Hanna; Duffo, Gustavo Sergio; Cere, Silvia

    2014-01-01

    Mechanical properties and good biocompatibility of zirconium and some of its alloys focus these materials as good candidates for biomedical applications. The attractive in vivo performance of zirconium is mainly due to the presence of a protective oxide layer. In this preliminary study, surface modification of pure zirconium was made by anodisation in acidic media at low potentials, enhancing the barrier protection given by the oxides and the osseointegration. Electrochemical and SEM (scan...

  17. Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave

    Science.gov (United States)

    Filippov, V. P.; Bateev, A. B.; Lauer, Yu. A.

    2016-12-01

    Mössbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350-360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α-Fe(Cr), α-Fe(Cu), α-Fe 2O3 and Fe 3O4 compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

  18. Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave

    Energy Technology Data Exchange (ETDEWEB)

    Filippov, V. P., E-mail: vpfilippov@mephi.ru; Bateev, A. B.; Lauer, Yu. A. [National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute) (Russian Federation)

    2016-12-15

    Mössbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350–360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α–Fe(Cr), α–Fe(Cu), α–Fe {sub 2}O{sub 3} and Fe {sub 3}O{sub 4} compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

  19. SEPARATING HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Lister, B.A.J.; Duncan, J.F.

    1956-08-21

    A dilute aqueous solution of zirconyl chloride which is 1N to 2N in HCl is passed through a column of a cation exchange resin in acid form thereby absorbing both zirconium and associated hafnium impurity in the mesin. The cation exchange material with the absorbate is then eluted with aqueous sulfuric acid of a O.8N to 1.2N strength. The first portion of the eluate contains the zirconium substantially free of hafnium.

  20. Adsorption of As(III), As(V) and Cu(II) on zirconium oxide immobilized alginate beads in aqueous phase.

    Science.gov (United States)

    Kwon, Oh-Hun; Kim, Jong-Oh; Cho, Dong-Wan; Kumar, Rahul; Baek, Seung Han; Kurade, Mayur B; Jeon, Byong-Hun

    2016-10-01

    A composite adsorbent to remove arsenite [As(III)], arsenate [As(V)], and copper [Cu(II)] from aqueous phase was synthesized by immobilizing zirconium oxide on alginate beads (ZOAB). The composition (wt%) of ZOAB (Zr-34.0; O-32.7; C-21.3; Ca-1.0) was confirmed by energy dispersive X-ray (EDX) analysis. Sorption studies were conducted on single and binary sorbate systems, and the effects of contact time, initial adsorbate concentration, and pH on the adsorption performance of ZOAB (pHPZC = 4.3) were monitored. The sorption process for As(III)/As(V) and Cu(II) reached an equilibrium state within 240 h and 24 h, respectively, with maximum sorption capacities of 32.3, 28.5, and 69.9 mg g(-1), respectively. The addition of Cu(II) was favorable for As(V) sorption in contrast to As(III). In the presence of 48.6 mg L(-1) Cu(II), the sorption capacity of As(V) increased from 1.5 to 3.8 mg g(-1) after 240 h. The sorption data for As(III)/As(V) and Cu(II) conformed the Freundlich and Langmuir isotherm models, respectively. The adsorption of As(III), As(V), and Cu(II) followed pseudo second order kinetics. The effect of arsenic species on Cu(II) sorption was insignificant. The results of present study demonstrated that the synthesized sorbent could be useful for the simultaneous removal of both anionic and cationic contaminants from wastewaters.

  1. Synthesis of monoclinic zinc diphosphide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mowles, T.A.

    1978-05-01

    Monoclinic zinc diphosphide is a cheap, plentiful, direct-gap semiconductor with an optimum transition energy for solar absorption. Single crystals were grown from the vapor to be evaluated as a new photovoltaic material. Monoclinic and tetragonal crystal formed within evacuated quartz ampules that were charged with zinc and excess phosphorous and heated in a temperature gradient to give phosphorous pressures from 0.07 to 8.5 atmospheres. The monoclinic form melts incongruently near 990/sup 0/C. The tetragonal form is metastable; its growth is enhanced by impurities but retarded by high phosphorous pressures. The mechanism of the synthesis indicates that a tightly-controlled vapor deposition is possible and that high-quality thin films should form at temperatures from 950 to 990/sup 0/C at pressures below 10 atmospheres. By a modification of the technique, sesquizinc phosphide single crystals were grown for comparison.

  2. Stabilization of the high-temperature phases in ceramic coatings on zirconium alloy produced by plasma electrolytic oxidation

    Science.gov (United States)

    Apelfeld, A. V.; Betsofen, S. Y.; Borisov, A. M.; Vladimirov, B. V.; Savushkina, S. V.; Knyazev, E. V.

    2016-09-01

    The composition and structure of ceramic coatings obtained on Zr-1%Nb alloy by plasma electrolytic oxidation (PEO) in aqueous electrolyte comprising 2 g/L KOH, 6 g/L NaAlO2 and 2 g/L Na2SiO3 with addition of yttria nanopowder, have been studied. The PEO coatings of thickness ∼⃒20 μm were studied using scanning electron microscopy, X-ray microanalysis and X-ray phase analysis. Additives in the electrolyte of yttria nanopowder allowed stabilizing the high-temperature tetragonal and cubic zirconia in the coating.

  3. Zero-Thermal Expansion and Heat Capacity of Zirconium Pyrovanadate Doped with Zirconia and Vanadium (V) Oxide

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dominant phase ZrV2O7 material, doped with zirconia and vanadium (V) oxide, was synthesized by solid state reaction and sol-gel methods. X-ray power diffraction patterns show that it is cubic structure. Thermal mechanic analysis measurements exhibit a zero-thermal expansion of this material above 150 ℃. Meanwhile, the heat capacity dependent on temperature, determined by differential scanning calorimetry, keeps in constant almost in the same temperature range. The relationship between unusual thermal expansion and abnormal heat capacity is discussed with Gr€黱eisen parameter.

  4. ZIRCONIUM-CLADDING OF THORIUM

    Science.gov (United States)

    Beaver, R.J.

    1961-11-21

    A method of cladding thorium with zirconium is described. The quality of the bond achieved between thorium and zirconium by hot-rolling is improved by inserting and melting a thorium-zirconium alloy foil between the two materials prior to rolling. (AEC)

  5. Study of Degradation Kinetics of Parathion Methyl On Mixed Nanocrystalline Titania-Zirconium and Titania-Cerium Oxides

    Science.gov (United States)

    Kuráň, Pavel; Pšenička, Martin; Šťastný, Martin; Benkocká, Monika; Janoš, Pavel

    2016-10-01

    The unique surface properties of some nanocrystalline metal oxides and their application for removal of various toxic compounds were reported in early 1990s. Recently, a reliable method for the preparation of reactive cerium dioxide sorbent and its application for degradation of the organophosphate pesticides, such as parathion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothioate (VX) was published. This paper reports on the kinetics study of degradation of parathion methyl as a representative organophosphate on nanocrystalline metal oxides TiO2, ZrO2, CeO2 and their mixtures in different molar ratios of particular elements. The tested sorbents except of CeO2 were prepared by different methods (e.g. sol-gel, precipitation) in cooperation with Institute of Inorganic Chemistry (Rez, Czech Republic). The degradation kinetics of parathion methyl on tested sorbents was followed by HPLC equipped with diode array detector. The basic kinetics parameters (half-lives of parathion methyl degradation, rate constants of degradation product formation) were calculated for each sorbent from Weber-Morris equation of 1st order diffusion kinetic model. The results proved the ability of prepared sorbents to degrade parathion methyl under formation of 4-nitrophenol as the main degradation product. The most efficient sorbents were TiCe (2:8), TiCe (1:1), TiCe (0:1) (50-70 %) followed by TiZr (1:1), TiCe (8:2), TiZr (8:2), TiZr (2:8) (20-30%) and TiO2, ZrO2 (less than 5 %).

  6. MICROSTRUCTURE AND WEAR PROPERTIES OF ZIRCONIUM NANO METAL MATRIX COMPOSITES

    OpenAIRE

    Rishav Kumar*, RamachandraNaik AL, Sameer Ahamed, Nitish Kumar Chaubey, Prof.Girish K.B

    2016-01-01

    A356.1 Aluminium alloy reinforced with Nano-sized ZrO2 particle are widely used for high performance applications such as automotive, military, aerospace, and electric  industries because of their improved physical and mechanical properties. In this research, Zirconium Oxide (ZrO2) Nano particle were synthesized by Solution Combustion Synthesis process. Prepared Nano particles were characterized by Powder X-ray diffraction (PXRD). Nano sized Zirconium Particle were reinforced with A356.1...

  7. Electrochemical behaviour of passive zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patrito, E.M.; Torresi, R.M.; Leiva, E.P.M.; Macagno, V.A. (Universidad Nacional de Cordoba (Argentina). Inst. de Investigaciones en Fisicoquimica de Cordoba)

    1991-02-01

    The potentiodynamic oxidation of zirconium, zircaloy-2 (Zry-2) and zircaloy-4 (Zry-4) was studied in the O V{<=}V{<=}8 V potential range. Side reactions take place during the oxidation of Zry-2 and Zry-4 in phosphate electrolytes. With Zry-2, oxygen evolution occurs at high anodic potentials. The oxidation of the alloys in nitric acid shows dissolution of their minor alloying elements but no oxygen evolution at high potentials. The role played by the alloying elements in connection with the appearance of side reactions is discussed. The oxide film were characterized by impedance measurements, X-ray photoelectron spectroscopy and Auger spectroscopy. (author).

  8. Analysis of the deconvolution of the thermoluminescent curve of the zirconium oxide doped with graphite; Analisis de la deconvolucion de la curva termoluminiscente del oxido de zirconio dopado con grafito

    Energy Technology Data Exchange (ETDEWEB)

    Salas C, P. [IMP, 07000 Mexico D.F. (Mexico); Estrada G, R. [Depto. de Fisica y Matematicas, UIA, Unidad Stanta Fe, 01000 Mexico D.F. (Mexico); Gonzalez M, P.R.; Mendoza A, D. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2003-07-01

    In this work, we present a mathematical analysis of the behavior of the thermoluminescent curve (Tl) induced by gamma radiation in samples made of zirconium oxide doped with different amounts of graphite. In accordance with the results gamma radiation induces a Tl curve with two maximum of emission localized in the temperatures at 139 and 250 C, the area under the curve is increasing as a function of the time of exposition to the radiation. The analysis of curve deconvolution, in accordance with the theory which indicates that this behavior must be obey a Boltzmann distribution, we found that each one of them has a different growth velocity as the time of exposition increase. In the same way, we observed that after the irradiation was suspended each one of the maximum decrease with different velocity. The behaviour observed in the samples is very interesting because the zirconium oxide has attracted the interest of many research groups, this material has demonstrated to have many applications in thermoluminescent dosimetry and it can be used in the quantification of radiation. (Author)

  9. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    Science.gov (United States)

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-02

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  10. Direct solid-sampling electrothermal atomic absorption spectrometry methods for the determination of silicon in oxides of niobium, titanium and zirconium

    Science.gov (United States)

    Dong, Huang Mao; Krivan, Viliam

    2001-09-01

    An electrothermal atomic absorption spectrometer with a transversely heated graphite tube and a solid sampling system based on the boat technique was used for the development of methods for direct determination of silicon in powdered niobium pentoxide, titanium dioxide and zirconium dioxide. In the analysis of niobium pentoxide, serious matrix-caused non-spectral interferences and background were avoided by conversion of the niobium pentoxide matrix into the thermally stable niobium carbide using a methane atmosphere during the pyrolysis stage. For all three materials, calibration procedures using aqueous standard solutions were developed. For titanium dioxide and zirconium dioxide, the accuracy was checked by comparison of the results with those of independent methods, whereby good agreement was achieved. Owing to the high applicable sample amount per atomization (3-15 mg) and almost complete freedom of interference from the blank, limits of detection at the 10-ng g -1 level were achieved.

  11. Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24

    The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase α and β phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

  12. Synthesis and characterization of monoclinic TiO2 nanosheets

    Institute of Scientific and Technical Information of China (English)

    WU Yu; XU Boqing

    2005-01-01

    A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is presented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated temperatures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air calcining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150―200℃, and then by washing with hydrochloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the temperature of the hydrothermal treatment, the calcination at 400―500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180―200℃) produced monoclinic TiO2 nanosheets with a uniform morphology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles.

  13. Environmentally Friendly Zirconium Oxide Pretreatment

    Science.gov (United States)

    2013-05-01

    were commercially-available synthetic clays which have a much smaller particle size than naturally occurring clays such as Bentonite ,21 and have...NO3)2 (35 weight % solution) from Sigma-Aldrich  H2ZrO(SO4)2 from Fisher Scientific Rheology Modifiers:  Laponite® OG from Southern Clay ...Products  Laponite® XL21 from Southern Clay Products Flash Rust Inhibitors:  Sodium nitrite from BASF Corp.   2-Amino-2-methyl-1-propanol (AMP95

  14. Zirconium carbide as an electrocatalyst for the chromous-chromic redox couple

    Science.gov (United States)

    Gahn, R. F.; Reid, M. A.; Yang, C. Y. (Inventor)

    1981-01-01

    Zirconium carbide is used as a catalyst in a REDOX cell for the oxidation of chromous ions to chromic ions and for the reduction of chromic ions to chromous ions. The zirconium carbide is coated on an inert electronically conductive electrode which is present in the anode fluid of the cell.

  15. Solid-State Coexistance of (Zr12) and (Zr6) Zirconium Oxocarboxylate Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Malaestean, Lurie [RWTH Aachen University; Alici, Meliha Kutluca [RWTH Aachen University; Besson, Claire [RWTH Aachen University; Ellern, Arkady [Ames Laboratory; Kogerler, Paul [RWTH Aachen University

    2013-10-30

    Ligand metathesis, Co(II) coordination, and partial condensation reactions of an archetypal {Zr6} zirconium oxocarboxylate cluster result in the first example of the coexistence of the distinct zirconium oxide frameworks {Zr6O8} and {Zr12O22}. Even minor modifications to the reaction conditions push this apparent equilibrium towards the {Zr6O8}-based product.

  16. 锆溶胶的稳定性及氧化锆粉体的特性研究%Stability of Zirconium Sol and Characteristics of ZrO2 Powder

    Institute of Scientific and Technical Information of China (English)

    李建平; 吴娇洁; 王萍

    2015-01-01

    T he characteristics of zirconium sol preparation , stability and pow der w ere studied .With zirconium oxychloride and zirconium n-propanol as the precursor ,two kinds of zirconium sol with the positive and negative charges w ere prepared by sol-gel method respectively .T he effect of polyethylene glycol on the stability of tw o kinds of zirconium sol w as characterized ,using measured size of particle , zeta potential ,and TEM .The hydrolysis process of different precursor zirconium sol was verified using FTIR ,and its reaction equation of hydrolysis was deduced .The thermal decomposition process and the structure change of xerogel were analyzed by means of TG-DTA and XRD .The results show :The particle size is reduced ,the distribution is narrower ,colloidal particles are positively charged ,zeta potential was increased to 36 .7 mV ,and the dispersion of sol is favorable after the polyethylene glycol is added to zirconium sol with zirconium oxychloride as the precursor ;The particle size is increased ,the distribution becomes wider ,colloidal particles are negatively charged ,zeta potential is reduced which close to the isoelectric point ,and the sol is reunited after the polyethylene glycol is added to zirconium sol with zirconium n-propanol as the precursor .According to the hydrolysis of sol equation and TG-DTA curve ,zirconium sol with zirconium n-propanol as the precursor has better high temperature stability . Zirconium oxide xerogel with oxygen zirconium chloride as the precursor is tetragonal phase at 400~600℃ ,a small amount of monoclinic phase occurs from 700 ℃ .In the zirconium sol with zirconium n-propanol as the precursor ,the tetragonal phase is stable at 350 ℃ ,and the tetragonal phase is stable at 450~550 ℃ ,a small amount of monoclinic phase occurs from 650 ℃ .%研究了锆溶胶的制备、稳定及粉体的特性.分别以氧氯化锆和正丙醇锆为前驱体,采用溶胶-凝胶法制备了分别带正电和负电的两种氧

  17. FABRICATION AND PROPERTIES OF SiO2/ZIRCONIUM PHOSPHATE-B2O3-SiO2 ANTI-OXIDATION COATINGS FOR Cf/SiC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Xue-Jin Yang

    2015-09-01

    Full Text Available This paper reports the fabrication of a novel SiO2/zirconium phosphate (ZrP-B2O3-SiO2 double-layer coating on Cf/SiC composites via brushing and sol-gel routes for achieving better anti-oxidation performance. The composition of raw materials and sintering temperature were studied to explore the possibility of development of ZrP coatings to meet the demand for oxidation resistance at high temperature. It was attempted to improve the self-healing ability of coatings via an additional SiO2 layer. Such double-layer coatings developed were characterized by Scanning Electron Microscopy (SEM, Energy Dispersive Spectrometer (EDS, X-ray Diffraction (XRD. The results showed that such coating was composed of a ZrP-B2O3-SiO2 multi-phase inner layer and a SiO2 outer layer. Better oxidation resistance was observed for coatings with higher contents of ZrP powders. After static oxidation at 1500oC for 20 min, the flexural strength of specimens containing 80 wt. % ZrP was up to 314.6 MPa, retaining 89.1 % of the original value of Cf/SiC composites.

  18. Synthesis of zirconium oxynitride in air under DC electric fields

    Science.gov (United States)

    Morisaki, Nobuhiro; Yoshida, Hidehiro; Matsui, Koji; Tokunaga, Tomoharu; Sasaki, Katsuhiro; Yamamoto, Takahisa

    2016-08-01

    We synthesized zirconium oxynitride from yttria-stabilized zirconia (YSZ) in air by applying DC electric fields that produced a controlled electric current in the specimen. When YSZ was heated under an applied DC electric field, the electric current of the specimen steeply increased at a critical temperature, called a flash event, during flash sintering. By keeping the electric current of the specimen constant during the flash event and then holding the specimen at the critical temperature, YSZ was transformed into zirconium oxynitride under the optimal conditions of 50 V/cm, 500 mA, and 1000 °C. We confirmed that zirconium oxynitride formed using high-resolution transmission electron microscopy, electron energy-loss spectroscopy, and energy-dispersive spectrometry. To convert oxides to nitrides, reducing conditions are necessary to form excess oxygen vacancies. Our technique produced the strong reducing conditions necessary to form nitrides from the oxides by delivering a controlled electric current to the specimen.

  19. Fluorometric determination of zirconium in minerals

    Science.gov (United States)

    Alford, W.C.; Shapiro, L.; White, C.E.

    1951-01-01

    The increasing use of zirconium in alloys and in the ceramics industry has created renewed interest in methods for its determination. It is a common constituent of many minerals, but is usually present in very small amounts. Published methods tend to be tedious, time-consuming, and uncertain as to accuracy. A new fluorometric procedure, which overcomes these objections to a large extent, is based on the blue fluorescence given by zirconium and flavonol in sulfuric acid solution. Hafnium is the only element that interferes. The sample is fused with borax glass and sodium carbonate and extracted with water. The residue is dissolved in sulfuric acid, made alkaline with sodium hydroxide to separate aluminum, and filtered. The precipitate is dissolved in sulfuric acid and electrolysed in a Melaven cell to remove iron. Flavonol is then added and the fluorescence intensity is measured with a photo-fluorometer. Analysis of seven standard mineral samples shows excellent results. The method is especially useful for minerals containing less than 0.25% zirconium oxide.

  20. 2-(4-Fluorobenzylidenepropanedinitrile: monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Ahmed M. El-Agrody

    2013-04-01

    Full Text Available The title compound, C10H5FN2, is a monoclinic (P21/c polymorph of the previously reported triclinic (P-1 form [Antipin et al. (2003. J. Mol. Struct. 650, 1–20]. The 13 non-H atoms in the title polymorph are almost coplanar (r.m.s. deviation = 0.020 Å; a small twist between the fluorobenzene and dinitrile groups [C—C—C—C torsion angle = 175.49 (16°] is evident in the triclinic polymorph. In the crystal, C—H...N interactions lead to supramolecular layers parallel to (-101; these are connected by C—F...π interactions.

  1. Monoclinic zirconia distributions in plasma-sprayed thermal barrier coatings

    Science.gov (United States)

    Lance, M. J.; Haynes, J. A.; Ferber, M. K.; Cannon, W. R.

    2000-03-01

    Phase composition in an air plasma-sprayed Y2O3-stabilized ZrO2 (YSZ) top coating of a thermal barrier coating (TBC) system was characterized. Both the bulk phase content and localized pockets of monoclinic zirconia were measured with Raman spectroscopy. The starting powder consisted of ˜15 vol.% monoclinic zirconia, which decreased to ˜2 vol.% in the as-sprayed coating. Monoclinic zirconia was concentrated in porous pockets that were evenly distributed throughout the TBC. The pockets resulted from the presence of unmelted granules in the starting powder. The potential effect of the distributed monoclinic pockets on TBC performance is discussed.

  2. ZIRCONIUM PHOSPHATE ADSORPTION METHOD

    Science.gov (United States)

    Russell, E.R.; Adamson, A.S.; Schubert, J.; Boyd, G.E.

    1958-11-01

    A method is presented for separating plutonium values from fission product values in aqueous acidic solution. This is accomplished by flowing the solutlon containing such values through a bed of zirconium orthophosphate. Any fission products adsorbed can subsequently be eluted by washing the column with a solution of 2N HNO/sub 3/ and O.lN H/sub 3/PO/sub 4/. Plutonium values may subsequently be desorbed by contacting the column with a solution of 7N HNO/sub 3/ .

  3. Modification in band gap of zirconium complexes

    Science.gov (United States)

    Sharma, Mayank; Singh, J.; Chouhan, S.; Mishra, A.; Shrivastava, B. D.

    2016-05-01

    The optical properties of zirconium complexes with amino acid based Schiff bases are reported here. The zirconium complexes show interesting stereo chemical features, which are applicable in organometallic and organic synthesis as well as in catalysis. The band gaps of both Schiff bases and zirconium complexes were obtained by UV-Visible spectroscopy. It was found that the band gap of zirconium complexes has been modified after adding zirconium compound to the Schiff bases.

  4. Modification in band gap of zirconium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mayank, E-mail: mayank30134@gmail.com; Singh, J.; Chouhan, S. [Department of Physics, ISLE, IPS Academy, Indore (M.P.) (India); Mishra, A. [School of Physics, Devi Ahilya Vishwavidyalaya, Indore (M.P.) (India); Shrivastava, B. D. [Govt. P. G. College, Biora (M.P.) (India)

    2016-05-06

    The optical properties of zirconium complexes with amino acid based Schiff bases are reported here. The zirconium complexes show interesting stereo chemical features, which are applicable in organometallic and organic synthesis as well as in catalysis. The band gaps of both Schiff bases and zirconium complexes were obtained by UV-Visible spectroscopy. It was found that the band gap of zirconium complexes has been modified after adding zirconium compound to the Schiff bases.

  5. Mineral resource of the month: zirconium and hafnium

    Science.gov (United States)

    Gambogi, Joseph

    2007-01-01

    Zirconium and hafnium are corrosion-resistant metals that are grouped in the same family as titanium on the periodic table. The two elements commonly occur in oxide and silicate minerals and have significant economic importance in everything from ink, ceramics and golf shoes to nuclear fuel rods.

  6. Separation of zirconium by thin-layer chromatography.

    Science.gov (United States)

    Oguma, K

    1969-03-01

    The thin-layer Chromatographie separation of a number of metal ions [Sc, Y, Zr, La, Sm, Th, U(VI), etc.] with solvent mixtures of mesityl oxide, ethanol and 5M nitric acid on silica gel-cellulose (5:1) thin-layer plates is reported. Zirconium remains stationary whilst the other metal ions move with the solvent, thus allowing a selective separation of zirconium from about 20 metal ions in ratios ranging from 100:1 to 1:100. Mixtures of various metal ions can also be separated.

  7. Recovery of Niobium and Zirconium from the Cyclone Discharge of Chlorination Plant Producing Titanium Tetrachloride

    Directory of Open Access Journals (Sweden)

    V. S. Gireesh

    2014-03-01

    Full Text Available This paper describes a method for recovering niobium and zirconium from the cyclone solid residues arising from chlorination of titaniferrous ores. The residue contains beneficiated ilmenite (BI fines, calcined petroleum coke (CPC and metal chlorides of niobium, aluminium, zirconium, iron, manganese, vanadium etc. The BI fines and CPC present in the residue were removed by soaking the residue with water and by separating the insoluble fraction contain BI and CPC by filtration. The filtrate containing the soluble metal chlorides was acidified with hydrochloric acid followed by agitation and heating in the presence of sulphate ions (sulphuric acid to precipitate niobium and zirconium as their oxo sulphate which is filtered, dried and calcined to convert niobium and zirconium oxides. The optimum amount of sulphuric acid was found to be 3 % and the optimum pH and temperature for precipitation of niobium and zirconium is 0.5 and 90 oC respectively.

  8. SEPARATION OF HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Overholser, L.B.; Barton, C.J. Sr.; Ramsey, J.W.

    1960-05-31

    The separation of hafnium impurities from zirconium can be accomplished by means of organic solvent extraction. The hafnium-containing zirconium feed material is dissolved in an aqueous chloride solution and the resulting solution is contacted with an organic hexone phase, with at least one of the phases containing thiocyanate. The hafnium is extracted into the organic phase while zirconium remains in the aqueous phase. Further recovery of zirconium is effected by stripping the onganic phase with a hydrochloric acid solution and commingling the resulting strip solution with the aqueous feed solution. Hexone is recovered and recycled by means of scrubbing the onganic phase with a sulfuric acid solution to remove the hafnium, and thiocyanate is recovered and recycled by means of neutralizing the effluent streams to obtain ammonium thiocyanate.

  9. Synthesis and Dielectric Studies of Monoclinic Nanosized Zirconia

    OpenAIRE

    I. Flavia Princess Nesamani; V. Lakshmi Prabha; Aswathy Paul; Nirmal, D.

    2014-01-01

    Zirconium dioxide is a prospective high-κ material that can replace silicon dioxide. Zirconium dioxide nanoparticle has been synthesized using sol-gel process at room temperature. The structural and morphological characterization of the nanoscaled zirconium dioxide is done using FTIR, SEM, X-ray diffraction, and TEM. The particle size of the synthesized ZrO2 is observed in the range of 50–80 nm with an average crystallite size of 2–10 nm. The results are compared with commercial coarse zircon...

  10. Properties of hydrogen permeation barrier on the surface of zirconium hydride

    Institute of Scientific and Technical Information of China (English)

    CHEN Weidong; WANG Lijun; HAN Lin; CHEN Song

    2008-01-01

    A hydrogen permeation barrier was manufactured by the in situ reaction of zirconium hydride with oxygen.A reduction in the hydrogen permeation of the oxide films was detected by measuring the mass difference of the zirconium hydride samples after the dehydrogenation experiment.The reaction of zirconium hydride with oxygen occurs only under the condition that the temperature is higher than 673 K in the oxygen partial pressure of 0.1 MPa.The oxide film is composed of two layers,a permeable oxide layer and a dense oxide layer,and the main phase of the oxide film is ZrO2 with baddeleyite structure.The XPS analysis shows that O-H bonds exist in the oxide film,which are helpful for resisting hydrogen diffusion through the oxide film.

  11. Structural, microstructural and vibrational analyses of the monoclinic tungstate BiLuWO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Ait Ahsaine, H. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Taoufyq, A. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Patout, L. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Ezahri, M.; Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Villain, S.; Guinneton, F. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Gavarri, J.-R., E-mail: gavarri.jr@univ-tln.fr [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France)

    2014-10-15

    The bismuth lutetium tungstate phase BiLuWO{sub 6} has been prepared using a solid state route with stoichiometric mixtures of oxide precursors. The obtained polycrystalline phase has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. In the first step, the crystal structure has been refined using Rietveld method: the crystal cell was resolved using monoclinic system (parameters a, b, c, β) with space group A2/m. SEM images showed the presence of large crystallites with a constant local nominal composition (BiLuW). TEM analyses showed that the actual local structure could be better represented by a superlattice (a, 2b, c, β) associated with space groups P2 or P2/m. The Raman spectroscopy showed the presence of vibrational bands similar to those observed in the compounds BiREWO{sub 6} with RE=Y, Gd, Nd. However, these vibrational bands were characterized by large full width at half maximum, probably resulting from the long range Bi/Lu disorder and local WO{sub 6} octahedron distortions in the structure. - Graphical abstract: The average structure of BiLuWO{sub 6} determined from X-ray diffraction data can be represented by A2/m space group. Experimental Electron Diffraction patterns along the [0vw] zone axes of the monoclinic structure and associated simulated patterns show the existence of a monoclinic superstructure with space group P2 or P2/m. - Highlights: • A new monoclinic BiLuWO{sub 6} phase has been elaborated from solid-state reaction. • The space group of the monoclinic disordered average structure should be A2/m. • Transmission electron microscopy leads to a superlattice with P2/m space group. • Raman spectroscopy suggests existence of local disorder.

  12. Recovery of zirconium from pickling solution, regeneration and its reuse

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, D. [Nuclear Fuel Complex, Hyderabad 500062 (India); Mandal, D., E-mail: dmandal10@gmail.com [Alkali Material & Metal Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Visweswara Rao, R.V.R.L.; Sairam, S.; Thakur, S. [Nuclear Fuel Complex, Hyderabad 500062 (India)

    2017-05-15

    Graphical abstract: The following compares the performance of fresh pickling solution (PS) and regenerated and used pickling solution (UPS). - Highlights: • Pickling of zircaloy tubes and appendages is carried out to remove oxide layer. • The pickling solution become saturated with zirconium due to reuse. • As NaNO{sub 3} concentration increases, conc. of Zr in pickling solution decreases. • Experimental results shows that, used pickling solution can be regenerated. • Regenerated solution may be reused by adding makeup quantities of HF-HNO{sub 3}. - Abstract: The pressurized heavy water reactors use natural uranium oxide (UO{sub 2}) as fuel and uses cladding material made up of zircaloy, an alloy of zirconium. Pickling of zircaloy tubes and appendages viz., spacer and bearing pads is carried out to remove the oxide layer and surface contaminants, if present. Pickling solution, after use for many cycles i.e., used pickling solution (UPS) is sold out to vendors, basically for its zirconium value. UPS, containing a relatively small concentration of hydrofluoric acid. After repeated use, pickling solution become saturated with zirconium fluoride complex and is treated by adding sodium nitrate to precipitate sodium hexafluro-zirconate. The remaining solution can be recycled after suitable makeup for further pickling use. The revenue lost by selling UPS is very high compared to its zirconium value, which causes monetary loss to the processing unit. Experiments were conducted to regenerate and reuse UPS which will save a good amount of revenue and also protect the environment. Experimental details and results are discussed in this paper.

  13. Corrosion resistance of high-performance materials titanium, tantalum, zirconium

    CERN Document Server

    2012-01-01

    Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

  14. Monoclinic deformation of calcite crystals at ambient conditions

    Science.gov (United States)

    Przeniosło, R.; Fabrykiewicz, P.; Sosnowska, I.

    2016-09-01

    High resolution synchrotron radiation powder diffraction shows that the average crystal structure of calcite at ambient conditions is described with the trigonal space group R 3 bar c but there is a systematic hkl-dependent Bragg peak broadening. A modelling of this anisotropic peak broadening with the microstrain model from Stephens (1999) [15] is presented. The observed lattice parameters' correlations can be described by assuming a monoclinic-type deformation of calcite crystallites. A quantitative model of this monoclinic deformation observed at ambient conditions is described with the space group C 2 / c . The monoclinic unit cell suggested at ambient conditions is related with the monoclinic unit cell reported in calcite at high pressure (Merrill and Bassett (1975) [10]).

  15. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode.

    Science.gov (United States)

    Zhou, Bin; Qu, Jiuhui; Zhao, Xu; Liu, Huijuan

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating. After annealation at 400, 500, and 600 degrees C, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry. The BiVO4 particles on the ITO glass surface had a monoclinic structure. The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV. In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichlorophenol and Bisphenol A degradation under visible light irradiation (lambda > 420 nm). Over 90% of the two organic pollutants were removed in 5 hr. A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  16. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode

    Institute of Scientific and Technical Information of China (English)

    Bin Zhou; Jiuhui Qu; Xu Zhao; Huijuan Liu

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating.After annealation at 400, 500, and 600℃, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry.The BiVO4 particles on the ITO glass surface had a monoclinic structure.The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV.In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichiorophenol and Bisphenol A degradation under visible light irradiation (λ.> 420 nm).Over 90% of the two organic pollutants were removed in 5 hr.A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  17. Ablation Resistant Zirconium and Hafnium Ceramics

    Science.gov (United States)

    Bull, Jeffrey (Inventor); White, Michael J. (Inventor); Kaufman, Larry (Inventor)

    1998-01-01

    High temperature ablation resistant ceramic composites have been made. These ceramics are composites of zirconium diboride and zirconium carbide with silicon carbide, hafnium diboride and hafnium carbide with silicon carbide and ceramic composites which contain mixed diborides and/or carbides of zirconium and hafnium. along with silicon carbide.

  18. Zirconium and hafnium in meteorites

    Science.gov (United States)

    Ehmann, W. D.; Chyi, L. L.

    1974-01-01

    The abundances of zirconium and hafnium have been determined in nine stony meteorites by a new, precise neutron-activation technique. The Zr/Hf abundance ratios for the chondrites vary in a rather narrow range, consistent with previously published observations from our group. Replicate analyses of new, carefully selected clean interior samples of the Cl chondrite Orgueil yield mean zirconium and hafnium abundances of 5.2 and 0.10 ppm, respectively. These abundances are lower than we reported earlier for two Cl chondrite samples which we now suspect may have suffered contamination. The new Cl zirconium and hafnium abundances are in closer agreement with predictions based on theories of nucleosynthesis than the earlier data.

  19. Study of propane partial oxidation on vanadium-containing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Komashko, G.A.; Khalamejda, S.V.; Zazhigalov, V.A. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fizicheskoj Khimii

    1998-12-31

    The present results indicate that maximum selectivity to acrylic acid can be reached over V-P-Zr-O catalysts. When the hydrocarbon concentration is 5.1 vol.% the selectivity is about 30% at quite high paraffin conversion. Conclusively, some explanations to the observed facts can be given. The V-P-O catalyst promotion with lanthanum by means of mechanochemical treatment is distinguished by the additive uniform spreading all over the matrix surface. Such twophase system is highly active in propane conversion (lanthanum oxide) and further oxidation of the desired products. The similar properties are attributed to V-P-Bi-La-O catalyst. Bismuth, tellurium and zirconium additives having clearly defined acidic properties provoke the surface acidity strengthening and make easier desorption of the acidic product (acrylic acid) from the surface lowering its further oxidation. Additionally, since bismuth and zirconium are able to form phosphates and, according to, to create space limitations for the paraffin molecule movement out of the active group boundaries, this can be one more support in favour of the selectivity increase. With this point of view very interesting results were obtained. It has been shown that the more limited the size of the vanadium unit, the higher the selectivity is. Monoclinic phase AV{sub 2}P{sub 2}O{sub 10} which consists in clusters of four vanadium atoms is sensibly more reactive than the orthorhombic phase consists in V{sub {infinity}} infinite chains. (orig.)

  20. The effect of 0.1 atomic percent zirconium on the cyclic oxidation behavior of beta-NiAl for 3000 hours at 1200 C

    Science.gov (United States)

    Barrett, C. A.

    1989-01-01

    The long time effect of 0.1 at percent Zr (0.2 wt percent Zr) on the cyclic oxidation behavior of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1200 C for up to 3000 one-hour exposure cycles. Specific weight change versus time data was modeled with the COSP computer program to analyze cyclic oxidation behavior. The Zr-free stoichiometric alloy oxidized and spalled randomly to bare metal between cycles at a rate high enough to deplete Al to a low enough level that oxidation breakaway took place as nonprotective NiO replaced the alpha-Al203/NiAl204 scale as the controlling oxide. The Zr minimized this severe type of spalling maintaining the protective alpha-Al203 scale even out to 3000 hours for the stoichiometric alloy with no significant Al depletion. A third beta-NiAl alloy containing 0.1 at percent Zr but with 10 percent less Al than the stoichiometric alloy was also tested and showed some depletion of Al, but the protective Al203/NiAl204 was still maintained to close to 2700 hours.

  1. The effect of 0.1 atomic percent zirconium on the cyclic oxidation behavior of beta-NiAl for 300 hours at 1200 C

    Science.gov (United States)

    Barrett, C. A.

    1988-01-01

    The long time effect of 0.1 at percent Zr (0.2 wt percent Zr) on the cyclic oxidation behavior of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1200 C for up to 3000 one-hour exposure cycles. Specific weight change versus time data was modeled with the COSP computer program to analyze cyclic oxidation behavior. The Zr-free stoichiometric alloy oxidized and spalled randomly to bare metal between cycles at a rate high enough to deplete Al to a low enough level that oxidation breakaway took place as nonprotective NiO replaced the alpha-Al2O3/NiAl2O4 scale as the controlling oxide. The Zr minimized this severe type of spalling maintaining the protective alpha-Al2O3 scale even out to 3000 hours for the stoichiometric alloy with no significant Al depletion. A third beta-NiAl alloy containing 0.1 at percent Zr but with 10 percent less Al than the stoichiometric alloy was also tested and showed some depletion of Al, but the protective Al2O3/NiAl2O4 was still maintained to close to 2700 hours.

  2. 四种黏结剂黏结氧化锆全瓷嵌体边缘微渗漏研究%Microleakage study of zirconium oxide inlays using four kinds of etching bonding agents

    Institute of Scientific and Technical Information of China (English)

    陈觉清; 段昌华; 邹康元; 邓向东

    2013-01-01

    Objective To evaluate the microleakage and penetration ability of zirconium oxide inlays using different self-etching bonding agents in vitro. Methods Forty caries-free extracted human third molars were randomly divided into four groups with ten teeth each. Class V cavities were prepared on the buccal surfaces of forty human extracted third molars using diamond burs. The zirconium oxide inlays were placed with Adper Singlebond 2,ClearFil SE Bond,Multil-ink Sprint and Adper Easy One. The microleakage scores were examined on the occlusal and gingival margins at 30 × magnification after each sample was stained. Results Statistically significant differences were observed between the groups in both occlusal and gingival margins. Microleakage scores of Multilink Sprint were significantly higher than other groups on both margins. Group of ClearFil SE Bond and Adper Easy One showed no statistical differences with etch-and-rinse resin cement. Conclusion ClearFil SE Bond and Adper Easy One show comparable microleakage re-sults with etch-and-rinse resin cement.%目的评价4种黏结剂对氧化锆全瓷嵌体边缘微渗漏的影响。方法选取2012年8月佛山市禅城区向阳医院口腔科新鲜拔除的上颌第三磨牙40颗,随机分为A、B、C、D组,每组10颗,制备Ⅴ类洞形。4组离体牙分别采用全酸蚀黏结剂Adper Singlebond 2(A组)及自酸蚀黏结剂ClearFil SE Bond(B组)、Multilink Sprint(C组)和Adper Easy One(D组)黏结氧化锆全瓷嵌体,修复后离体牙经冷热循环后行2%亚甲基蓝染色,根管显微镜下观察各组微渗漏程度并进行比较。结果在牙合壁,C组微渗漏明显高于A和B组,差异均有统计学意义(P0.05)。在龈壁,C组微渗漏明显高于其他3组,差异均有统计学意义(P0.05)。结论自酸蚀黏结剂ClearFil SE Bond和Adper Easy One的封闭能力较好,且较全酸蚀黏结剂操作简单方便,推荐临床使用。

  3. Pervaporation Separation and Catalysis Activity of Novel Zirconium Silicalite-1 Zeolite Membrane

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei; CHEN Xinbing; CHEN Xiangshu; AN Zhongwei; KITA Hidetoshi

    2009-01-01

    Novel zirconium silicalite-1 zeolite membrane was hydrothermally prepared on the mullite porous support at 150-185 ℃ for 40-72 h by an "in situ" method using tetraethyl orthosilicate(TEOS),zirconium butoxide (ZBOT)and tetrapropylammonium hydroxide(TPAOH)as silica source,zirconium source and organic structure directing agent,respectively.X-ray diffraction(XRD)patterns,fourier transformed infrared(FT-IR)spectra,and inductively coupled plasma-atomic emission spectrometry(ICP)of the accompanying zeolite powder confirmed that the zirconium was isomorphously incorporated into the zeolite framework.The surface chemical compositions of the obtained membrane were measured with an energy-dispersive X-ray spectral analyzer(EDS),and the membrane morphologies were observed by a scanning electron microscope(SEM).The results showed that the zeolite crystals growing on the support were zirconium silicalite-1 zeolites,and the dense membrane layer was composed of the well inter-growing zeolite crystals.The zirconium silicalite-1 zeolite membrane,which was derived from the synthesis solution having a molar ratio of 1.00SiO2:0.01ZrO2:0.17TPAOH:12OH2O,showed high ethanol w/w)system under a pervaporation condition at 60℃.Moreover,this membrane displayed pervaporation-aided catalysis activity for iso-propanol oxidation with hydrogen peroxide as oxidant,and the corresponding iso-propanol conversion was 35%.

  4. Assembly of crosslinked oxo-cyanoruthenate and zirconium oxide bilayers: Application in electrocatalytic films based on organically modified silica with templated pores

    Science.gov (United States)

    Rutkowska, Iwona A.; Sek, Jakub P.; Mehdi, B. Layla; Kulesza, Pawel J.; Cox, James A.

    2014-01-01

    Electrochemical deposition of crosslinked oxo-cyanoruthenate, Ru-O/CN-O, from a mixture of RuCl3 and K4Ru(CN)6 is known to yield a film on glassy carbon that promotes oxidations by a combination of electron and oxygen transfer. Layer-by-layer (LbL) deposition of this species and of a film formed by cycling of the electrode potential in a ZrO2 solution systematically increases the number of catalytically active sites of the Ru-O/CN-O on the electrode. The evaluation of the electrocatalytic activity was by cyclic voltammetric oxidation of cysteine at pH 2. Plots of the anodic peak current vs. the square root of scan rate were indicative of linear diffusion control of this oxidation, even in the absence of ZrO2, but the slopes of these linear plots increased with bilayer number, n, of (ZrO2 | Ru-O/CN-O)n. The latter observation is hypothesized to be due to an increased number of active sites for a given geometric electrode area, but proof required further study. To optimize utilization of the catalyst and to provide a size-exclusion characteristic to the electrode, the study was extended to LbL deposition of the composite in 50-nm pores of an organically modified silica film deposited by electrochemically assisted sol-gel processing using surface-bound poly(styrene sulfonate) nanospheres as a templating agent. PMID:24683266

  5. Assembly of crosslinked oxo-cyanoruthenate and zirconium oxide bilayers: Application in electrocatalytic films based on organically modified silica with templated pores.

    Science.gov (United States)

    Rutkowska, Iwona A; Sek, Jakub P; Mehdi, B Layla; Kulesza, Pawel J; Cox, James A

    2014-03-10

    Electrochemical deposition of crosslinked oxo-cyanoruthenate, Ru-O/CN-O, from a mixture of RuCl3 and K4Ru(CN)6 is known to yield a film on glassy carbon that promotes oxidations by a combination of electron and oxygen transfer. Layer-by-layer (LbL) deposition of this species and of a film formed by cycling of the electrode potential in a ZrO2 solution systematically increases the number of catalytically active sites of the Ru-O/CN-O on the electrode. The evaluation of the electrocatalytic activity was by cyclic voltammetric oxidation of cysteine at pH 2. Plots of the anodic peak current vs. the square root of scan rate were indicative of linear diffusion control of this oxidation, even in the absence of ZrO2, but the slopes of these linear plots increased with bilayer number, n, of (ZrO2 | Ru-O/CN-O) n . The latter observation is hypothesized to be due to an increased number of active sites for a given geometric electrode area, but proof required further study. To optimize utilization of the catalyst and to provide a size-exclusion characteristic to the electrode, the study was extended to LbL deposition of the composite in 50-nm pores of an organically modified silica film deposited by electrochemically assisted sol-gel processing using surface-bound poly(styrene sulfonate) nanospheres as a templating agent.

  6. Synthesis of zirconium oxynitride in air under DC electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Morisaki, Nobuhiro; Tokunaga, Tomoharu; Sasaki, Katsuhiro; Yamamoto, Takahisa, E-mail: yamataka@numse.nagoya-u.ac.jp [Department of Quantum Engineering, Nagoya University, Furocho, Chikusa-ku, Nagoya 464–8603 (Japan); Yoshida, Hidehiro [National Institute for Materials Science, 1–2–1 Sengen, Tsukuba, Ibaraki 305–0047 (Japan); Matsui, Koji [Inorganic Materials Research Laboratory, Tosoh Corporation, 4560 Kaisei-cho, Shunan, Yamaguchi 746-8501 (Japan)

    2016-08-22

    We synthesized zirconium oxynitride from yttria-stabilized zirconia (YSZ) in air by applying DC electric fields that produced a controlled electric current in the specimen. When YSZ was heated under an applied DC electric field, the electric current of the specimen steeply increased at a critical temperature, called a flash event, during flash sintering. By keeping the electric current of the specimen constant during the flash event and then holding the specimen at the critical temperature, YSZ was transformed into zirconium oxynitride under the optimal conditions of 50 V/cm, 500 mA, and 1000 °C. We confirmed that zirconium oxynitride formed using high-resolution transmission electron microscopy, electron energy-loss spectroscopy, and energy-dispersive spectrometry. To convert oxides to nitrides, reducing conditions are necessary to form excess oxygen vacancies. Our technique produced the strong reducing conditions necessary to form nitrides from the oxides by delivering a controlled electric current to the specimen.

  7. Zirconium diboride-based composites

    Energy Technology Data Exchange (ETDEWEB)

    Monteverde, F.; Dalle Fabbriche, D.; Bellosi, A. [CNR-IRTEC, Faenza (Italy). Research Inst. for Ceramics Technology

    2002-07-01

    Two zirconium diboride-based composites were produced and characterised. The starting compositions (wt%) were: 55ZrB{sub 2} + 41TiB{sub 2} + 4Ni and 83ZrB{sub 2} + 13B{sub 4}C + 4Ni. Microstructure, mechanical and physical properties of the hot pressed composites were studied. In both the cases, the nickel introduced as sintering aid promoted the densification during sintering. (orig.)

  8. Solid-state coexistence of {Zr12} and {Zr6} zirconium oxocarboxylate clusters

    Energy Technology Data Exchange (ETDEWEB)

    Malaestean, Iurie L. [RWTH Aachen Univ. (Germany); Alici, Meliha Kutluca [RWTH Aachen Univ. (Germany); Besson, Claire [RWTH Aachen Univ. (Germany); Ellern, Arkady [Iowa State Univ., Ames, IA (United States); Kogerler, Paul [RWTH Aachen Univ. (Germany)

    2013-10-30

    Ligand metathesis, Co(II) coordination, and partial condensation reactions of an archetypal {Zr6} zirconium oxocarboxylate cluster result in the first example of the coexistence of the distinct zirconium oxide frameworks {Zr6O8} and {Zr12O22}. Even minor modifications to the reaction conditions push this apparent equilibrium towards the {Zr6O8}-based product.

  9. Process for separating hafnium and zirconium

    NARCIS (Netherlands)

    Xiao, Y.; Van Sandwijk, A.

    2010-01-01

    The invention is directed to a process for separating a mixture comprising hafnium and zirconium. The process of the present invention comprises a step in which a molten metal phase comprising zirconium and hafnium dissolved in a first metal M1 and a second metal M2 is contacted with a molten salt

  10. Process for separating hafnium and zirconium

    NARCIS (Netherlands)

    Xiao, Y.; Van Sandwijk, A.

    2010-01-01

    The invention is directed to a process for separating a mixture comprising hafnium and zirconium. The process of the present invention comprises a step in which a molten metal phase comprising zirconium and hafnium dissolved in a first metal M1 and a second metal M2 is contacted with a molten salt p

  11. Zirconium oxide deposits (ZrO{sub 2}) and titanium oxide (TiO{sub 2}) on 304l stainless steel; Depositos de oxido de circonio (ZrO{sub 2}) y oxido de titanio (TiO{sub 2}) sobre acero inoxidable 304L

    Energy Technology Data Exchange (ETDEWEB)

    Davila N, M. L.

    2015-07-01

    This research project aims to carry out the surface and electrochemical characterization to obtain the optimum conditions of the hydrothermal deposits of zirconium oxide ZrO{sub 2} (baddeleyite) and titanium oxide TiO{sub 2} (anatase and rutile phases) on 304l stainless steel, simulating an inhibiting protective layer. 304l steel specimens were cut, pre-oxidized in water at a temperature of 288 degrees Celsius and 8 MPa, similar to those of a typical BWR conditions. From the titanium oxide anatase crystalline phase, the rutile phase was obtained by a heat treatment at 1000 degrees Celsius. The Sigma-Aldrich pre-oxidized powders and steel 304l were characterized using techniques of X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, chemical mapping and Raman spectrometry. The pre-oxidized steel has two oxide layers, an inner layer with nano metric crystals and another outer of larger crystals to 1μm, with the formation of hematite and magnetite, this predominating. The surface that contacted the sample holder has larger crystals. Hydrothermal deposits were carry out from suspensions of 10, 100 and 1000 ppm, of the crystal phases of anatase, rutile and baddeleyite, on the pre-oxidized steel at a temperature of 150 degrees Celsius for 2 and 7 days, samples were analyzed by X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, Raman spectrometry and Tafel polarization. The suspension to 1000 ppm for 7 days coated surface most; the baddeleyite deposit is noticed more homogeneous than anatase and rutile. The deposit is favored when hematite and magnetite crystals are larger. The chemical mapping on deposits show that even after being immersed in water to 288 degrees Celsius during 30 days, the deposits are still present although a loss is observed. A reference electrode was assembled to conduct electrochemical tests of Tafel able to withstand a temperature of 288 degrees Celsius and pressure of 8 MPa. The baddeleyite deposit

  12. Non-laminate Microstructures in Monoclinic-I Martensite

    CERN Document Server

    Chenchiah, Isaac Vikram

    2012-01-01

    We study the symmetrised rank-one convex hull of monoclinic-I martensite (a twelve-variant material) in the context of geometrically-linear elasticity. We show that this hull is strictly larger than the symmetrised lamination convex hull by constructing sets of T3s, which are (non-trivial) symmetrised rank-one convex hulls of 3-tuples of pairwise incompatible strains. Moreover we construct a five-dimensional continuum of T3s and show that its intersection with the boundary of the symmetrised rank-one convex hull is four-dimensional. Along the way we show that there is another kind of monoclinic-I martensite with qualitatively different semi-convex hulls which, so far as we know, has not been experimentally observed. Our strategy is to combine understanding of the algebraic structure of symmetrised rank-one convex cones with knowledge of the faceting structure of the convex polytope formed by the strains.

  13. Non-Laminate Microstructures in Monoclinic-I Martensite

    Science.gov (United States)

    Chenchiah, Isaac Vikram; Schlömerkemper, Anja

    2013-01-01

    We study the symmetrised rank-one convex hull of monoclinic-I martensite (a twelve-variant material) in the context of geometrically-linear elasticity. We construct sets of T 3s, which are (non-trivial) symmetrised rank-one convex hulls of three-tuples of pairwise incompatible strains. In addition, we construct a fivedimensional continuum of T 3s and show that its intersection with the boundary of the symmetrised rank-one convex hull is four-dimensional.We also show that there is another kind of monoclinic-I martensite with qualitatively different semi-convex hulls which, as far as we know, has not been experimentally observed. Our strategy is to combine understanding of the algebraic structure of symmetrised rank-one convex cones with knowledge of the faceting structure of the convex polytope formed by the strains.

  14. Nicral ternary alloy having improved cyclic oxidation resistance

    Science.gov (United States)

    Barrett, C. A.; Lowell, C. E.; Khan, A. S.

    1982-01-01

    NiCrAl alloys are improved by the addition of zirconium. These alloys are in the Beta or gamma/gamma' + Beta region of the ternary system. Zirconium is added in a very low amount between 0.06 and 0.20 weight percent. There is a narrow optimum zirconium level at the low value of 0.13 weight percent. Maximum resistance to cyclic oxidation is achieved when the zirconium addition is at the optimum value.

  15. Protection of zirconium by alumina- and chromia-forming iron alloys under high-temperature steam exposure

    Science.gov (United States)

    Terrani, Kurt A.; Parish, Chad M.; Shin, Dongwon; Pint, Bruce A.

    2013-07-01

    The viability of advanced oxidation-resistant Fe-base alloys to protect zirconium from rapid oxidation in high-temperature steam environments has been examined. Specimens were produced such that outer layers of FeCrAl ferritic alloy and Type 310 austenitic stainless steel were incorporated on the surface of zirconium metal slugs. The specimens were exposed to high-temperature 0.34 MPa steam at 1200 and 1300 °C. The primary degradation mechanism for the protective layer was interdiffusion with the zirconium, as opposed to high-temperature oxidation in steam. The FeCrAl layer experienced less degradation and protected the zirconium at 1300 °C for 8 h. Constituents of the Fe-base alloys rapidly diffused into the zirconium and resulted in the formation of various intermetallic layers at the interface and precipitates inside the bulk zirconium. The nature of this interaction for FeCrAl and 310SS has been characterized by use of microscopic techniques as well as computational thermodynamics. Finally, a reactor physics discussion on the applicability of these protective layers in light-water-reactor nuclear fuel structures is offered.

  16. Method of making crack-free zirconium hydride

    Science.gov (United States)

    Sullivan, Richard W.

    1980-01-01

    Crack-free hydrides of zirconium and zirconium-uranium alloys are produced by alloying the zirconium or zirconium-uranium alloy with beryllium, or nickel, or beryllium and scandium, or nickel and scandium, or beryllium and nickel, or beryllium, nickel and scandium and thereafter hydriding.

  17. Crystal growth and structural analysis of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2008-08-01

    A series of zirconium sulphoselenide (ZrSSe3–, where = 0, 0.5, 1, 1.5, 2, 2.5, 3) single crystals have been grown by chemical vapour transport technique using iodine as a transporting agent. The optimum condition for the growth of these crystals is given. The stoichiometry of the grown crystals were confirmed on the basis of energy dispersive analysis by X-ray (EDAX) and the structural characterization was accomplished by X-ray diffraction (XRD) studies. The crystals are found to possess monoclinic structure. The lattice parameters, volume, particle size and X-ray density have been carried out for these crystals. The effect of sulphur proportion on the lattice parameter, unit cell volume and X-ray density in the series of ZrSSe3– single crystals have been studied and found to decrease in all these parameters with rise in sulphur proportion. The grown crystals were examined under optical zoom microscope for their surface topography study. Hall effect measurements were carried out on grown crystals at room temperature. The negative value of Hall coefficient implies that these crystals are -type in nature. The conductivity is found to decrease with increase of sulphur content in the ZrSSe3– series. The electrical resistivity parallel to c-axis as well as perpendicular to -axis have been carried out in the temperature range 303–423 K. The results obtained are discussed in detail.

  18. Structural transformations in nanosized zirconium oxide

    Science.gov (United States)

    Jouanne, M.; Morhange, J. F.; Kanehisa, M. A.; Haro-Poniatowski, E.; Fuentes, G. A.; Torres, E.; Hernández-Tellez, E.

    2001-10-01

    Structural properties of calcined ZrO2 nanopowders having various sizes were investigated by Raman spectroscopy, x-ray diffraction, and high-resolution transmission electron microscopy. For grain sizes of the order of a few nanometers the Raman spectrum is typical of an amorphous material as is the corresponding x-ray diffractogram. As the size of the grains increases, the spectra progressively evolve towards that of a crystallized sample, furthermore, two regimes of growth, vitreous and crystalline, are evidenced. As opposed to the acoustical, the optical branches exhibit a strong discontinuity near the amorphous-crystalline transition. From the analysis of the Raman spectra as a function of size one can infer the phonon dispersion curves that has so far been inaccessible by neutron diffraction. A simple analysis using a classic elastic model shows that the Raman frequencies of the acoustical phonon bands of the nanograins are linearly dependent upon their size.

  19. Solvothermal, chloroalkoxide-based synthesis of monoclinic WO(3) quantum dots and gas-sensing enhancement by surface oxygen vacancies.

    Science.gov (United States)

    Epifani, Mauro; Comini, Elisabetta; Díaz, Raül; Andreu, Teresa; Genç, Aziz; Arbiol, Jordi; Siciliano, Pietro; Faglia, Guido; Morante, Joan R

    2014-10-01

    We report for the first time the synthesis of monoclinic WO3 quantum dots. A solvothermal processing at 250 °C in oleic acid of W chloroalkoxide solutions was employed. It was shown that the bulk monoclinic crystallographic phase is the stable one even for the nanosized regime (mean size 4 nm). The nanocrystals were characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis, Fourier transform infrared and Raman spectroscopy. It was concluded that they were constituted by a core of monoclinic WO3, surface covered by unstable W(V) species, slowly oxidized upon standing in room conditions. The WO3 nanocrystals could be easily processed to prepare gas-sensing devices, without any phase transition up to at least 500 °C. The devices displayed remarkable response to both oxidizing (nitrogen dioxide) and reducing (ethanol) gases in concentrations ranging from 1 to 5 ppm and from 100 to 500 ppm, at low operating temperatures of 100 and 200 °C, respectively. The analysis of the electrical data showed that the nanocrystals were characterized by reduced surfaces, which enhanced both nitrogen dioxide adsorption and oxygen ionosorption, the latter resulting in enhanced ethanol decomposition kinetics.

  20. The solar photospheric abundance of zirconium

    CERN Document Server

    Caffau, Elisabetta; Ludwig, Hans-Günter; Bonifacio, Piercarlo; Steffen, Matthias

    2010-01-01

    Zirconium (Zr), together with strontium and yttrium, is an important element in the understanding of the Galactic nucleosynthesis. In fact, the triad Sr-Y-Zr constitutes the first peak of s-process elements. Despite its general relevance not many studies of the solar abundance of Zr were conducted. We derive the zirconium abundance in the solar photosphere with the same CO5BOLD hydrodynamical model of the solar atmosphere that we previously used to investigate the abundances of C-N-O. We review the zirconium lines available in the observed solar spectra and select a sample of lines to determine the zirconium abundance, considering lines of neutral and singly ionised zirconium. We apply different line profile fitting strategies for a reliable analysis of Zr lines that are blended by lines of other elements. The abundance obtained from lines of neutral zirconium is very uncertain because these lines are commonly blended and weak in the solar spectrum. However, we believe that some lines of ionised zirconium are...

  1. Thermal Hydrolysis Synthesis and Characterization of Monoclinic Metahewettite CaV6O16•3H2O

    Institute of Scientific and Technical Information of China (English)

    LI Lanjie; ZHENG Shili; WANG Shaona; DU Hao; ZHANG Yi

    2014-01-01

    Monoclinic metahewettite CaV6O16•3H2O has been fabricated via thermal hydrolysis of calcium vanadate (Ca10V6O25). High purity calcium vanadate precipitate, featuring column structure with surface area of 8.61 m2/g, can be obtained by reacting sodium orthovanadate (Na3VO4) with calcium oxide at 90℃for 2 h. By acidification of calcium vanadate in hot water at pH of 1.0-3.0, the monoclinic metahewettite crystals with uniform particle distribution, layered structure and nonporous structure can be fabricated. With the well crystallized layered structure, CaV6O16•3H2O may be a potential cathode material for secondary batteries as well as super capacitor materials.

  2. Zirconium-modified materials for selective adsorption and removal of aqueous arsenic

    Science.gov (United States)

    Zhao, Hongting; Moore, Robert C.

    2004-11-30

    A method, composition, and apparatus for removing contaminant species from an aqueous medium comprising: providing a material to which zirconium has been added, the material selected from one or more of zeolites, cation-exchangeable clay minerals, fly ash, mesostructured materials, activated carbons, cellulose acetate, and like porous and/or fibrous materials; and contacting the aqueous medium with the material to which zirconium has been added. The invention operates on all arsenic species in the form of arsenate, arsenite and organometallic arsenic, with no pretreatment necessary (e.g., oxidative conversion of arsenite to arsenate).

  3. URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

    Science.gov (United States)

    Vogler, S.; Beederman, M.

    1961-05-01

    A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

  4. A comparative study of zirconium and titanium implants in rat: osseointegration and bone material quality.

    Science.gov (United States)

    Hoerth, Rebecca M; Katunar, María R; Gomez Sanchez, Andrea; Orellano, Juan C; Ceré, Silvia M; Wagermaier, Wolfgang; Ballarre, Josefina

    2014-02-01

    Permanent metal implants are widely used in human medical treatments and orthopedics, for example as hip joint replacements. They are commonly made of titanium alloys and beyond the optimization of this established material, it is also essential to explore alternative implant materials in view of improved osseointegration. The aim of our study was to characterize the implant performance of zirconium in comparison to titanium implants. Zirconium implants have been characterized in a previous study concerning material properties and surface characteristics in vitro, such as oxide layer thickness and surface roughness. In the present study, we compare bone material quality around zirconium and titanium implants in terms of osseointegration and therefore characterized bone material properties in a rat model using a multi-method approach. We used light and electron microscopy, micro Raman spectroscopy, micro X-ray fluorescence and X-ray scattering techniques to investigate the osseointegration in terms of compositional and structural properties of the newly formed bone. Regarding the mineralization level, the mineral composition, and the alignment and order of the mineral particles, our results show that the maturity of the newly formed bone after 8 weeks of implantation is already very high. In conclusion, the bone material quality obtained for zirconium implants is at least as good as for titanium. It seems that the zirconium implants can be a good candidate for using as permanent metal prosthesis for orthopedic treatments.

  5. Simulating the corrosion of zirconium alloys in the water coolant of VVER reactors

    Science.gov (United States)

    Kritskii, V. G.; Berezina, I. G.; Motkova, E. A.

    2013-07-01

    A model for predicting the corrosion of cladding zirconium alloys depending on their composition and operating conditions is proposed. Laws of thermodynamics and chemical kinetics of the reactions through which the multicomponent zirconium alloy is oxidized in the reactor coolant constitute the physicochemical heart of the model. The developed version of the model is verified against the results obtained from tests of fuel rod claddings made of commercial-grade and experimental zirconium alloys carried out by different researchers under autoclave and reactor conditions. It is shown that the proposed model adequately describes the corrosion of alloys in coolants used at nuclear power stations. It is determined that, owing to boiling of coolant and its acidification in a VVER-1200 reactor, Zr-1% Nb alloys with additions of iron and oxygen must be more resistant to corrosion than the commercial-grade alloy E110.

  6. Optical properties of zirconium oxynitride films: The effect of composition, electronic and crystalline structures

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, P. [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal); Borges, J., E-mail: joelborges@fisica.uminho.pt [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal); Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Rodrigues, M.S. [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (km 139,7), 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Espinós, J.P.; González-Elipe, A.R. [Instituto de Ciencia de Materiales de Sevilla (CSIC-University Sevilla), Avda. Américo Vespucio 49, 41092 Sevilla (Spain); Cunha, L.; Marques, L.; Vasilevskiy, M.I.; Vaz, F. [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal)

    2015-12-15

    Highlights: • Optical behaviour of ZrO{sub x}N{sub y} films were correlated with structural properties. • A continuous depopulation of the d-band and an opening of an energy gap was observed. • Drude–Lorentz parameters changed for the metallic samples. • Optical bandgap of the films increases with non-metallic elements incorporation. - Abstract: This work is devoted to the investigation of zirconium oxynitride (ZrO{sub x}N{sub y}) films with varied optical responses prompted by the variations in their compositional and structural properties. The films were prepared by dc reactive magnetron sputtering of Zr, using Ar and a reactive gas mixture of N{sub 2} + O{sub 2} (17:3). The colour of the films changed from metallic-like, very bright yellow-pale and golden yellow, for low gas flows to red-brownish for intermediate gas flows. Associated to this colour change there was a significant decrease of brightness. With further increase of the reactive gas flow, the colour of the samples changed from red-brownish to dark blue or even to interference colourations. The variations in composition disclosed the existence of four different zones, which were found to be closely related with the variations in the crystalline structure. XRD analysis revealed the change from a B1 NaCl face-centred cubic zirconium nitride-type phase for films prepared with low reactive gas flows, towards a poorly crystallized over-stoichiometric nitride phase, which may be similar to that of Zr{sub 3}N{sub 4} with some probable oxygen inclusions within nitrogen positions, for films prepared with intermediate reactive gas flows. For high reactive gas flows, the films developed an oxynitride-type phase, similar to that of γ-Zr{sub 2}ON{sub 2} with some oxygen atoms occupying some of the nitrogen positions, evolving to a ZrO{sub 2} monoclinic type structure within the zone where films were prepared with relatively high reactive gas flows. The analysis carried out by reflected electron energy

  7. AM50镁合金表面含氧化锆的微弧氧化复合涂层的形成过程%Formation process of composite plasma electrolytic oxidation coating containing zirconium oxides on AM50 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    刘锋; 单大勇; 宋影伟; 韩恩厚

    2011-01-01

    The formation processes of a composite ceramic coating on AM50 magnesium alloy prepared by plasma electrolytic oxidation (PEO) in a K2ZrF6 electrolyte solution were studied by scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDX). Electrochemical impedance spectroscopy (EIS) tests were used to study the variation of the corrosion resistance of the coating during the PEO treatment. The results show that the coating formed on Mg alloy is mainly composed of MgO and MgF2 when the applied voltage is lower than the sparking voltage, and zirconium oxides start to be deposited on Mg substrate after the potential exceeding the sparking voltage. The corrosion resistance of the coating increases with increasing the applied voltage.%采用扫描电镜(SEM)和电子衍射能谱(EDX)研究在含K2ZrF6的溶液中AM50镁合金表而复合微弧体氧化涂层的形成过程.采用电化学阻抗谱(EIS)研究在微弧体氧化制备膜层过程中膜层耐腐蚀性能的变化.结果表明:当电压小于起弧电压时,合金表面膜层的主要成分为MgO和MgF3;当施加电压超过起弧电压时,锆氧化物开始在合金表面沉积,且膜层的耐腐蚀性随着电压的升高而提高.

  8. INVESTIGATION OF BONDING IN OXIDE-FIBER (WHISKER) REINFORCED METALS.

    Science.gov (United States)

    CERAMIC FIBERS , BONDING), (*COMPOSITE MATERIALS, BONDING), (*BONDING, CERAMIC FIBERS ), ALUMINUM COMPOUNDS, OXIDES, ZIRCONIUM, NICKEL, TITANIUM, CHROMIUM, SINGLE CRYSTALS, VACUUM, SHEAR STRESSES, SURFACE PROPERTIES, ADDITIVES.

  9. Zirconium Compound with Boundless Prospects

    Institute of Scientific and Technical Information of China (English)

    LUO FangCheng; ZHENG JingYi; LV WenGuang; CHEN ZhongXi; WU FengFeng

    2001-01-01

    @@ Zirconium compound has a wide-ranging use in the field of high and new technology. It is published in 2000'CHINA HIGH AND NEW TECHNOLOGY PRODUCT CATALOGUE , CHINA HIGH and NEW TECHNOLOGY PRODUCT EXPORT CATALOGUE, and INTERNATIONAL KEY AND URGING DEVELOPMENT CATALOGUE OF PROPERTY, COMMODITY AND TECHNOLNGY Zirconia with the characteristic of electricity, magnetism, optics and mechanies, has good advantageous in making configurable ceramic and functional ceramic, such as band filter, resonator, buzzer and other electronic elements; optical lens, upholster crystallize glasses and other glass; synthetic tooth, synthetic bones and other biological ceramic products; new type axletree, engine, valve, airproof loop and other components of internal-combustion engine and steamship; ferrozirconium and other high temperature ceramic paint. It become a new material which has a wide-ranging use in the field of electron, spaceflight, aerospace, metallurgy, chemistry, biology, medicine and etc.

  10. Zirconium Compound with Boundless Prospects

    Institute of Scientific and Technical Information of China (English)

    LUO; FangCheng

    2001-01-01

    Zirconium compound has a wide-ranging use in the field of high and new technology. It is published in 2000'CHINA HIGH AND NEW TECHNOLOGY PRODUCT CATALOGUE , CHINA HIGH and NEW TECHNOLOGY PRODUCT EXPORT CATALOGUE, and INTERNATIONAL KEY AND URGING DEVELOPMENT CATALOGUE OF PROPERTY, COMMODITY AND TECHNOLNGY Zirconia with the characteristic of electricity, magnetism, optics and mechanies, has good advantageous in making configurable ceramic and functional ceramic, such as band filter, resonator, buzzer and other electronic elements; optical lens, upholster crystallize glasses and other glass; synthetic tooth, synthetic bones and other biological ceramic products; new type axletree, engine, valve, airproof loop and other components of internal-combustion engine and steamship; ferrozirconium and other high temperature ceramic paint. It become a new material which has a wide-ranging use in the field of electron, spaceflight, aerospace, metallurgy, chemistry, biology, medicine and etc.  ……

  11. DISSOLUTION OF ZIRCONIUM AND ALLOYS THEREFOR

    Science.gov (United States)

    Swanson, J.L.

    1961-07-11

    The dissolution of zirconium cladding in a water solution of ammonium fluoride and ammonium nitrate is described. The method finds particular utility in processing spent fuel elements for nuclear reactors. The zirconium cladding is first dissolved in a water solution of ammonium fluoride and ammonium nitrate; insoluble uranium and plutonium fiuorides formed by attack of the solvent on the fuel materiai of the fuel element are then separated from the solution, and the fuel materiai is dissolved in another solution.

  12. METHOD OF IMPROVING CORROSION RESISTANCE OF ZIRCONIUM

    Science.gov (United States)

    Shannon, D.W.

    1961-03-28

    An improved intermediate rinse for zirconium counteracts an anomalous deposit that often results in crevices and outof-the-way places when ordinary water is used to rinse away a strong fluoride etching solution designed to promote passivation of the metal. The intermediate rinse, which is used after the etching solution and before the water, is characterized by a complexing agent for fluoride ions such as aluminum or zirconium nitrates or chlorides.

  13. 2,3-Dibromo-3-phenylpropanoic acid: a monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Trent R. Howard

    2016-11-01

    Full Text Available Bromination of trans-cinnamic acid resulted in the formation of 2,3-dibromo-3-phenylpropanoic acid, C9H8Br2O2. Crystallization from ethanol–water (1:1 gave crystals of different shapes. One is in the form of rods, that crystallized as the orthorhombic polymorph (Pnma, and whose structure has been described [Thong et al. (2008. Acta Cryst. E64, o1946]. The other are thin plate-like crystals which are the monoclinic polymorph (P21/n. The structure of this monoclinic polymorph is similar to that of the orthorhombic polymorph; here the aliphatic C atoms are disordered over three sets of sites (occupancy ratio 0.5:0.25:0.25. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with an R22(8 ring motif. The dimers are linked by weak C—H...Br hydrogen bonds, forming chains propagating along the a-axis direction.

  14. Dynamic Heterogeneity In The Monoclinic Phase Of CCl$_4$

    CERN Document Server

    Caballero, Nirvana B; Carignano, Marcelo; Serra, Pablo

    2016-01-01

    Carbon tetrachloride (CCl$_4$) is one of the simplest compounds having a translationally stable monoclinic phase while exhibiting a rich rotational dynamics below 226 K. Recent nuclear quadrupolar resonance (NQR) experiments revealed that the dynamics of CCl$_4$ is similar to that of the other members of the isostructural series CBr$_{n}$Cl$_{4-n}$, suggesting that the universal relaxation features of canonical glasses such as $\\alpha$- and $\\beta$-relaxation are also present in non-glass formers. Using molecular dynamics (MD) simulations we studied the rotational dynamics in the monoclinic phase of CCl$_4$. The molecules undergo $C3$ type jump-like rotations around each one of the four C-Cl bonds. The rotational dynamics is very well described with a master equation using as the only input the rotational rates measured from the simulated trajectories. It is found that the heterogeneous dynamics emerges from faster and slower modes associated with different rotational axes, which have fixed orientations relat...

  15. Synthesis of aluminium borate-boron oxide and binary titanium-boron and zirconium-boron oxides from metal alkoxides and (MeO)3B3O3 in non-aqueous solvents.

    Science.gov (United States)

    Beckett, Michael A; Rugen-Hankey, Martin P; Timmis, James L; Varma, K Sukumar

    2008-03-21

    The reaction of metal alkoxides M(OR)4 (M = Ti, Zr; R = organyl) with (MeO)3B3O3 (1 : 0.67) in dry propan-2-one at room temperature led to gels which when dried and calcined in air for 24 h at 500-1000 degrees C afforded bi-phased mixed-oxide materials formulated as 4TiO2 x 3B2O3 and ZrO2 x B2O3 in high ceramic yields and purity; the B2O3 phases of these materials were amorphous. The materials remained amorphous upon calcination at lower temperatures. The TiO2 phase of the 4TiO2 x 3B2O3 was crystalline when calcined at higher temperatures with either anatase (600 degrees C) or rutile (>800 degrees C) being obtained. The ZrO2 phase of the ZrO2 x B2O3 was crystalline when calcined at higher temperatures and was obtained as a metastable tetragonal phase (800 degrees C). In a similar reaction, Al(O(i)Pr)3 (2 : 1) gave a bi-phased aluminium borate-boron oxide (Al18B4O(33).7B2O3) after calcination at >700 degrees C. The dried gels and oxide materials were all characterized by elemental analysis, TGA-DSC, and powder XRD.

  16. Artefacts in multimodal imaging of titanium, zirconium and binary titanium-zirconium alloy dental implants: an in vitro study.

    Science.gov (United States)

    Smeets, Ralf; Schöllchen, Maximilian; Gauer, Tobias; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

    2017-02-01

    To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium-zirconium alloy dental implants. Zirconium, titanium and titanium-zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line-distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. While titanium and titanium-zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium-zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium-zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium-zirconium alloy induced more severe artefacts than zirconium and titanium. MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium-zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting.

  17. 1-Nitro-4-(4-nitrophenoxybenzene: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Arif Nadeem

    2013-12-01

    Full Text Available In the title compound, C12H8N2O5, the aromatic rings are inclined to one another by 56.14 (7°. The nitro groups are inclined by to the benzene rings to which they are attached by 3.86 (17 and 9.65 (15°. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming a three-dimensional structure. The title compound is a new monoclinic polymorph, crystallizing in space group P21/c. The first polymorph crystallized in space group C2/c and the molecule possesses twofold rotation symmetry. Two low-temperature structures of this polymorph (150 K and 100 K, respectively have been reported [Meciarova et al. (2004. Private Communication (refcode IXOGAD. CCDC, Cambridge, England, and Dey & Desiraju (2005. Chem. Commun. pp. 2486–2488].

  18. A monoclinic polymorph of 2-(4-nitrophenylacetic acid

    Directory of Open Access Journals (Sweden)

    Alan R. Kennedy

    2016-12-01

    Full Text Available A new monoclinic form of 4-nitrophenylacetic acid, C8H7NO4, (I, differs from the known orthorhombic form both in its molecular conformation and in its intermolecular contacts. The conformation is different as the plane of the carboxylic acid group in (I is more nearly perpendicular to the plane of the aromatic ring [dihedral angle = 86.9 (3°] than in the previous form (74.5°. Both polymorphs display hydrogen-bonded R22(8 carboxylic acid dimeric pairs, but in (I, neighbouring dimers interact through nitro–nitro N...O dipole–dipole contacts rather than the nitro–carbonyl contacts found in the orthorhombic form.

  19. Monoclinic polymorph of poly[aqua(μ4-hydrogen tartratosodium

    Directory of Open Access Journals (Sweden)

    Mohammad T. M. Al-Dajani

    2010-02-01

    Full Text Available A monoclinic polymorph of the title compound, [Na(C4H5O6(H2O]n, is reported and complements an orthorhombic form [Kubozono, Hirano, Nagasawa, Maeda & Kashino (1993. Bull. Chem. Soc. Jpn, 66, 2166–2173]. The asymmetric unit contains a hydrogen tartrate anion, an Na+ cation and a water molecule. The Na+ ion is surrounded by seven O atoms derived from one independent and three symmetry-related hydrogen tartrate anions, and a water molecule, forming a distorted pentagonal–bipyramidal geometry. Independent units are linked via a pair of intermolecular bifurcated O—H...O acceptor bonds, generating an R21(6 ring motif to form polymeric two-dimensional arrays parallel to the (100 plane. In the crystal packing, the arrays are linked by adjacent ring motifs, together with additional intermolecular O—H...O interactions, into a three-dimensional network.

  20. Corrosion resistance and biocompatibility of zirconium oxynitride thin film growth by RF sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cubillos, G. I.; Olaya, J. J.; Clavijo, D.; Alfonso, J. E. [Universidad Nacional de Colombia, Carrera 45 No. 26-85, AA 14490 Bogota D. C. (Colombia); Bethencourt, M., E-mail: jealfonsoo@unal.edu.co [Universidad de Cadiz, Centro Andaluz de Ciencia y Tecnologia Marinas, Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Av. Republica de Saharaui, Puerto Real, E-11510 Cadiz (Spain)

    2012-07-01

    Thin films of zirconium oxynitride were grown on common glass, silicon (100) and stainless steel 316 L substrates using the reactive RF magnetron sputtering technique. The films were analyzed through structural, morphological and biocompatibility studies. The structural analysis was carried out using X-ray diffraction (XRD), and the morphological analysis was carried out using scanning electron microscopy (Sem) and atomic force microscopy (AFM). These studies were done as a function of growth parameters, such as power applied to the target, substrate temperature, and flow ratios. The corrosion resistance studies were made on samples of stainless steel 316 L coated and uncoated with Zr{sub x}N{sub y}O films, through of polarization curves. The studies of biocompatibility were carried out on zirconium oxynitride films deposited on stainless steel 316 L through proliferation and cellular adhesion. The XRD analysis shows that films deposited at 623 K, with a flow ratio {Phi}N{sub 2}/{Phi}O{sub 2} of 1.25 and a total deposit time of 30 minutes grew preferentially oriented along the (111) plane of the zirconium oxynitride monoclinic phase. The Sem analyses showed that the films grew homogeneously, and the AFM studies indicated that the average rugosity of the film was 5.9 nm and the average particle size was 150 nm. The analysis of the corrosion resistant, shows that the stainless steel coated with the film was increased a factor 10. Finally; through the analysis of the biocompatibility we established that the films have a better surface than the substrate (stainless steel 316 L) in terms of the adhesion and proliferation of bone cells. (Author)

  1. Zirconium: biomedical and nephrological applications.

    Science.gov (United States)

    Lee, David B N; Roberts, Martin; Bluchel, Christian G; Odell, Ross A

    2010-01-01

    Recent years have witnessed a rapid increase in the use of zirconium (Zr)-containing compounds in artificial internal organs. Examples include dental implants and other restorative practices, total knee and hip replacement, and middle-ear ossicular chain reconstruction. In nephrological practice, Zr-containing sorbents have been used in hemofiltration, hemodialysis, peritoneal dialysis, and in the design and construction of wearable artificial kidneys. Zr compounds continue to be widely and extensively used in deodorant and antiperspirant preparations. In the public health arena, Zr compounds have been studied or used in controlling phosphorus pollution and in the reclamation of poison and bacteria-contaminated water. Experimental and clinical studies support the general consensus that Zr compounds are biocompatible and exhibit low toxicity. Reports on possible Zr-associated adverse reactions are rare and, in general, have not rigorously established a cause-and-effect relationship. Although publications on the use of Zr compounds have continued to increase in recent years, reports on Zr toxicity have virtually disappeared from the medical literature. Nevertheless, familiarity with, and continued vigilant monitoring of, the use of these compounds are warranted. This article provides an updated review on the biomedical use of Zr compounds.

  2. Processing fissile material mixtures containing zirconium and/or carbon

    Science.gov (United States)

    Johnson, Michael Ernest; Maloney, Martin David

    2013-07-02

    A method of processing spent TRIZO-coated nuclear fuel may include adding fluoride to complex zirconium present in a dissolved TRIZO-coated fuel. Complexing the zirconium with fluoride may reduce or eliminate the potential for zirconium to interfere with the extraction of uranium and/or transuranics from fission materials in the spent nuclear fuel.

  3. 40 CFR 721.9973 - Zirconium dichlorides (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Zirconium dichlorides (generic). 721... Substances § 721.9973 Zirconium dichlorides (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as zirconium dichlorides (PMNs...

  4. Processing fissile material mixtures containing zirconium and/or carbon

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael Ernest; Maloney, Martin David

    2013-07-02

    A method of processing spent TRIZO-coated nuclear fuel may include adding fluoride to complex zirconium present in a dissolved TRIZO-coated fuel. Complexing the zirconium with fluoride may reduce or eliminate the potential for zirconium to interfere with the extraction of uranium and/or transuranics from fission materials in the spent nuclear fuel.

  5. Crystallography of shear transformations in zirconium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Cassidy, Michael Philip [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1978-01-01

    The crystallography and substructure of the transformations which have been hypothesized as involving a martensitic shear, and which occur between zirconium hydrides were investigated. Specifically, the formation of gamma zirconium hydride from delta hydride and the delta hydride to epsilon hydride transformation were studied. The habit planes, orientation relationships, lattice invariant shears, and interface structures were determined by transmission electron microscopy and diffraction. Surface tilts were observed and measured with an interference microscope. The direction and magnitude of the shape strain produced by the formation of gamma were determined by the measurement of fiducial scratch displacements. These results were compared with the phenomenological crystallographic theory of martensitic transformations.

  6. What causes the Besnus transition in monoclinic pyrrhotite?

    Science.gov (United States)

    Gehring, A. U.; Koulialias, D.; Löffler, J. F.; Charilaou, M.

    2016-12-01

    Monoclinic 4C pyrrhotite (ideal formula Fe7S8) is a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials. Because of its low-temperature magnetic transition around 30 K also known as Besnus transition, this mineral phase is easily detectable in rock samples. An intrinsic origin of the Besnus transition due to a crystallographic change similar to that in the Verwey transition has generally been postulated (1). Although the physical properties of pyrrhotite have intensively been studied, the physics behind the pronounced change in magnetization at the low-temperature transition is still unresolved. To address this question we performed structural and magnetic analyses on a natural pyrrhotite single crystal (Fe6.6S8) from Auerbach, Germany (2,3). Chemical analysis, X-ray diffractometry and transmission electron microscopy show that this pyrrhotite consists of an intergrowth of 4C and an incommensurate 5C* superstructure that are polymorphs with different vacancy distributions. The occurrence of two superstructures is magnetically confirmed by symmetric inflection points in the hysteresis measurements above the transition at about 30 K. The disappearance of the inflection points and the associated change of the hysteresis parameters indicate that the two superstructures become embedded to form a unitary magnetic anisotropy system at the transition. This embedding of the 5C* into the 4C pyrrhotite at about 30 K is directly visible by the occurrence of additional 4-fold and 12-fold symmetry terms in magnetic anisotropy and anisotropic magnetic resistivity mesarurements, respectively. From this it follows that the Besnus transition in monoclinic pyrrhotite is an extrinsic magnetic phenomenon with respect to the 4C superstructure, i.e., a coupling effect, and therefore the physics behind it is in fact different from that of the well-known Verwey transition. (1) Rochette et al., The IRM Quarterly, 21, 1 (2011); (2) Charilaou et al., J

  7. Monoclinic high-pressure polymorph of AlOOH predicted from first principles

    Science.gov (United States)

    Zhong, Xin; Hermann, Andreas; Wang, Yanchao; Ma, Yanming

    2016-12-01

    Aluminum oxide hydroxide, AlOOH, is a prototypical hydrous mineral in the geonomy. The study of the high-pressure phase evolution of AlOOH is of fundamental importance in helping to understand the role of hydrous minerals in the water storage and transport in Earth, as in other planets. Here, we have systematically investigated the high-pressure phase diagram of AlOOH up to 550 GPa using the efficient crystal structure analysis by particle swarm optimization (CALYPSO) algorithm in conjunction with first principles calculations. We predict a peculiar monoclinic phase (space group P 21/c , 16 atoms/cell, Z =4 ) as the most stable phase for AlOOH above 340 GPa. The occurrence of this new phase results in the breakup of symmetric linear O-H-O hydrogen bonds into asymmetric, bent O-H-O linkages and in sevenfold coordinated metal cations. The new P 21/c phase turns out to be a universal high-pressure phase in group 13 oxide hydroxides, and stable for both compressed GaOOH and InOOH. The formation of the new phase in all compounds is favored by volume reduction due to denser packing.

  8. Dispersion of Love Waves in a Composite Layer Resting on Monoclinic Half-Space

    Directory of Open Access Journals (Sweden)

    Sukumar Saha

    2011-01-01

    Full Text Available Dispersion of Love waves is studied in a fibre-reinforced layer resting on monoclinic half-space. The wave velocity equation has been obtained for a fiber-reinforced layer resting on monoclinic half space. Shear wave velocity ratio curve for Love waves has been shown graphically for fibre reinforced material layer resting on various monoclinic half-spaces. In a similar way, shear wave velocity ratio curve for Love waves has been plotted for an isotropic layer resting on various monoclinic half-spaces. From these curves, it has been observed that the curves are of similar type for a fibre reinforced layer resting on monoclinic half-spaces, and the shear wave velocity ratio ranges from 1.14 to 7.19, whereas for the case isotropic layer, this range varies from 1.0 to 2.19.

  9. Bis[2-(hydroxyiminomethylphenolato]nickel(II: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Julia A. Rusanova

    2011-02-01

    Full Text Available The title compound, [Ni(C7H6NO22], (I, is a second monoclinic polymorph of the compound, (II, reported by Srivastava et al. [Acta Cryst. (1967, 22, 922] and Mereiter [Private communication (2002 CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The molecule in both structures lies on a crystallographic inversion center and both have an internal hydrogen bond. The title compound crystallizes in the space group P21/c (Z = 2, whereas compound (II is in the space group P21/n (Z = 2 with a similar cell volume but different cell parameters. In both polymorphs, molecules are arranged in the layers but in contrast to the previously published compound (II where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I is stabilized by strong intramolecular O—H...O hydrogen bonding between the O—H group and the phenolate O atom.

  10. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F

    2015-01-01

    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  11. METHOD AND ALLOY FOR BONDING TO ZIRCONIUM

    Science.gov (United States)

    McCuaig, F.D.; Misch, R.D.

    1960-04-19

    A brazing alloy can be used for bonding zirconium and its alloys to other metals, ceramics, and cermets, and consists of 6 to 9 wt.% Ni, 6 to 9 wn~.% Cr, Mo, or W, 0 to 7.5 wt.% Fe, and the balance Zr.

  12. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, Jan [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Zima, Vítězslav, E-mail: vitezslav.zima@upce.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Melánová, Klára [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Beneš, Ludvík [Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice (Czech Republic); Trchová, Miroslava [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic)

    2013-12-15

    Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4′-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described.

  13. International strategic minerals inventory summary report; zirconium

    Science.gov (United States)

    Towner, R.R.

    1992-01-01

    Zircon, a zirconium silicate, is currently the most important commercial zirconium-bearing mineral. Baddeleyite, a natural form of zirconia, is less important but has some specific end uses. Both zircon and baddeleyite occur in hard-rock and placer deposits, but at present all zircon production is from placer deposits. Most baddeleyite production is from hard-rock deposits, principally as a byproduct of copper and phosphate-rock mining. World zirconium resources in identified, economically exploitable deposits are about 46 times current production rates. Of these resources, some 71 percent are in South Africa, Australia, and the United States. The principal end uses of zirconium minerals are in ceramic applications and as refractories, abrasives, and mold linings in foundries. A minor amount, mainly of zircon, is used for the production of hafnium-free zirconium metal, which is used principally for sheathing fuel elements in nuclear reactors and in the chemical-processing industry, aerospace engineering, and electronics. Australia and South Africa are the largest zircon producers and account for more than 70 percent of world output; the United States and the Soviet Union account for another 20 percent. South Africa accounts for almost all the world's production of baddeleyite, which is about 2 percent of world production of contained zirconia. Australia and South Africa are the largest exporters of zircon. Unless major new deposits are developed in countries that have not traditionally produced zircon, the pattern of world production is unlikely to change by 2020. The proportions, however, of production that come from existing producing countries may change somewhat.

  14. ZIRCONIUM (IV) COMPLEXES WITH SOME ...

    African Journals Online (AJOL)

    DR. AMINU

    infrared spectra, elemental analysis and other properties suggest that the complexes are six coordinate. The schiff ... paper reports the synthesis and partial characterization of ... filtered, dried in a desiccator over phosphorus(v) oxide and yield ...

  15. Identification of monoclinic θ-phase dispersoids in a 6061 aluminium alloy

    Science.gov (United States)

    Buchanan, Karl; Ribis, Joël; Garnier, Jérôme; Colas, Kimberly

    2016-04-01

    Intermetallic dispersoids play an important role in controlling the 6xxx alloy series' grain distribution and increasing the alloy's toughness. The dispersoid distribution in a 6061 aluminium alloy (Al-Mg-Si) was analysed by transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The dispersoids had three unique crystal structures: simple cubic ?, body-centred cubic ? and monoclinic (C2/m). While the SC and BCC dispersoids have been well characterized in the literature, a detailed analysis of monoclinic dispersoids has not been presented. Therefore, the current work discusses the chemical composition, crystal structure and morphology of the monoclinic dispersoids.

  16. Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

    Directory of Open Access Journals (Sweden)

    Xiaoyan Lu

    2016-10-01

    Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

  17. Specific features of the initial stages of the aluminothermic reduction of zirconium from ZrO2

    Science.gov (United States)

    Chumarev, V. M.; Mansurova, A. N.; Gulyaeva, R. I.; Trubachev, M. V.; Larionov, A. V.

    2015-09-01

    The phase composition of the products of the low-temperature stage of the reaction of ZrO2 with aluminum is studied. The influence of charge compacting and particle size of the reagents is revealed. The onset temperatures for the reaction of zirconium oxide (TsrO-1 and TsrO-S trade marks) and aluminum (APZh and PA-4 trade marks) are determined by differential scanning calorimetry. A high dispersity of ZrO2 and the presence of zircon ZrSiO4 in zirconium oxide (TsrO-S) are found to provide a decrease in the onset temperatures for the reaction. Intermetallic compound ZrAl3 is predominantly formed at the low-temperature stage of the reaction of ZrO2 with aluminum. Zirconium is reduced from ZrO2 by aluminum stage by stage through the formation of lower oxides ZrO and Zr3O. Suboxide AlO is detected in the products of reaction of ZrO2 with aluminum. The heat flow rates are estimated, according to which the reduction of zirconium from ZrO2 by aluminum is formally characterized by the first order, and the activation energy is E = 160-170 kJ/mol.

  18. Zirconium oxide ceramic foam:a promising supporting biomaterial for massive production of glial cell line-derived neurotrophic factor%氧化锆陶瓷泡沫:一种有望大规模生产GDNF的生物支持材料

    Institute of Scientific and Technical Information of China (English)

    Zhong-wei LIU; Wen-qiang LI; Jun-kui WANG; Xian-cang MA; Chen LIANG; Peng LIU; Zheng CHU; Yong-hui DANG

    2014-01-01

    This study investigated the potential application of a zirconium oxide (ZrO2) ceramic foam culturing system to the production of glial cel line-derived neurotrophic factor (GDNF). Three sets of ZrO2 ceramic foams with different pore densities of 10, 20, and 30pores per linear inch (PPI) were prepared to support a 3D culturing system. After primary astrocytes were cultured in these systems, production yields of GDNF were evaluated. The biomaterial bio-compatibility, cel proliferation and activation of celular signaling pathways in GDNF synthesis and secretion in the culturing systems were also assessed and compared with a conventional culturing system. In this study, we found that the ZrO2 ceramic foam culturing system was biocompatible, using which the GDNF yields were elevated and sustained by stimulated cel proliferation and activation of signaling pathways in astrocytes cultured in the system. In conclusion, the ZrO2 ceramic foam is promising for the development of a GDNF mass production device for Parkinson’s disease treatment.

  19. METHOD OF MAKING DELTA ZIRCONIUM HYDRIDE MONOLITHIC MODERATOR PIECES

    Science.gov (United States)

    Vetrano, J.B.

    1962-01-23

    A method is given for preparing large, sound bodies of delta zirconium hydride. The method includes the steps of heating a zirconium body to a temperature of not less than l000 deg C, providing a hydrogen atmosphere for the zirconium body at a pressure not greater than one atmosphere, reducing the temperature slowly to 800 deg C at such a rate that cracks do not form while maintaining the hydrogen pressure substantially constant, and cooling in an atmosphere of hydrogen. (AEC)

  20. Enrichment/isolation of phosphorylated peptides on hafnium oxide prior to mass spectrometric analysis.

    Science.gov (United States)

    Rivera, José G; Choi, Yong Seok; Vujcic, Stefan; Wood, Troy D; Colón, Luis A

    2009-01-01

    Hafnium oxide (hafnia) exhibits unique enrichment properties towards phosphorylated peptides that are complementary to those of titanium oxide (titania) and zirconium oxide (zirconia) for use with mass spectrometric analysis in the field of proteomics.

  1. Phase field modeling of tetragonal to monoclinic phase transformation in zirconia

    Science.gov (United States)

    Mamivand, Mahmood

    Zirconia based ceramics are strong, hard, inert, and smooth, with low thermal conductivity and good biocompatibility. Such properties made zirconia ceramics an ideal material for different applications form thermal barrier coatings (TBCs) to biomedicine applications like femoral implants and dental bridges. However, this unusual versatility of excellent properties would be mediated by the metastable tetragonal (or cubic) transformation to the stable monoclinic phase after a certain exposure at service temperatures. This transformation from tetragonal to monoclinic, known as LTD (low temperature degradation) in biomedical application, proceeds by propagation of martensite, which corresponds to transformation twinning. As such, tetragonal to monoclinic transformation is highly sensitive to mechanical and chemomechanical stresses. It is known in fact that this transformation is the source of the fracture toughening in stabilized zirconia as it occurs at the stress concentration regions ahead of the crack tip. This dissertation is an attempt to provide a kinetic-based model for tetragonal to monoclinic transformation in zirconia. We used the phase field technique to capture the temporal and spatial evolution of monoclinic phase. In addition to morphological patterns, we were able to calculate the developed internal stresses during tetragonal to monoclinic transformation. The model was started form the two dimensional single crystal then was expanded to the two dimensional polycrystalline and finally to the three dimensional single crystal. The model is able to predict the most physical properties associated with tetragonal to monoclinic transformation in zirconia including: morphological patterns, transformation toughening, shape memory effect, pseudoelasticity, surface uplift, and variants impingement. The model was benched marked with several experimental works. The good agreements between simulation results and experimental data, make the model a reliable tool for

  2. Zirconium phosphate binder for periclase refractories

    Energy Technology Data Exchange (ETDEWEB)

    Volceanov, E. [ICEM S.A., Bucharest (Romania). Metallurgical Research Inst.; Georgescu, M.; Volceanov, A. [Universitatea Politehnica, Bucharest (Romania). Faculty of Industrial Chemistry; Mihalache, F. [REAL S.A., Ploiesti (Romania)

    2002-07-01

    Present paper brings information concerning the physical-mechanical properties of some high thermal resistant composites with phosphate bonding obtained from periclase clinker as solid component and various zirconium phosphates solutions as liquid component: ZI, ZII and ZIII. All these solutions were prepared from hydrous zirconia and orthophosphoric acid. The batches corresponding to a weight ratio solid / liquid = 3 / 1, have shown a good hardening behavior at normal temperature, especially for the ZII binder. Such compositions exhibit a very good thermal-mechanical behavior in the temperature range 1400 C - 1750 C. X-ray diffraction and electronomicroscopy (TEM) analysis provided information concerning the evolution of phase composition and microstructure during heating of the thermal resistant specimens chemically bound with a zirconium phosphate binder. (orig.)

  3. Effects of titanium and zirconium on iron aluminide weldments

    Energy Technology Data Exchange (ETDEWEB)

    Mulac, B.L.; Edwards, G.R. [Colorado School of Mines, Golden, CO (United States). Center for Welding, Joining, and Coatings Research; Burt, R.P. [Alumax Technical Center, Golden, CO (United States); David, S.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    When gas-tungsten arc welded, iron aluminides form a coarse fusion zone microstructure which is susceptible to hydrogen embrittlement. Titanium inoculation effectively refined the fusion zone microstructure in iron aluminide weldments, but the inoculated weldments had a reduced fracture strength despite the presence of a finer microstructure. The weldments fractured by transgranular cleavage which nucleated at cracked second phase particles. With titanium inoculation, second phase particles in the fusion zone changed shape and also became more concentrated at the grain boundaries, which increased the particle spacing in the fusion zone. The observed decrease in fracture strength with titanium inoculation was attributed to increased spacing of second phase particles in the fusion zone. Current research has focused on the weldability of zirconium- and carbon-alloyed iron aluminides. Preliminary work performed at Oak Ridge National Laboratory has shown that zirconium and carbon additions affect the weldability of the alloy as well as the mechanical properties and fracture behavior of the weldments. A sigmajig hot cracking test apparatus has been constructed and tested at Colorado School of Mines. Preliminary characterization of hot cracking of three zirconium- and carbon-alloyed iron aluminides, each containing a different total concentration of zirconium at a constant zirconium/carbon ratio of ten, is in progress. Future testing will include low zirconium alloys at zirconium/carbon ratios of five and one, as well as high zirconium alloys (1.5 to 2.0 atomic percent) at zirconium/carbon ratios of ten to forty.

  4. Zirconium doped TiO2 thin films: A promising dielectric layer

    Science.gov (United States)

    Kumar, Arvind; Mondal, Sandip; Rao, K. S. R. Koteswara

    2016-05-01

    In the present work, we have fabricated the zirconium doped TiO2 thin (ZTO) films from a facile spin - coating method. The addition of Zirconium in TiO2 offers conduction band offset to Si and consequently decreased the leakage current density by approximately two orders as compared to pure TiO2 thin (TO) films. The ZTO thin film shows a high dielectric constant 27 with a very low leakage current density ˜10-8 A/cm2. The oxide capacitate, flat band voltage and change in flat band voltage are 172 pF, -1.19 V and 54 mV. The AFM analysis confirmed the compact and pore free flat surface. The RMS surface roughness is found to be 1.5 Å. The ellipsometry analysis also verified the fact with a high refractive index 2.21.

  5. ELECTROLYTIC CLADDING OF ZIRCONIUM ON URANIUM

    Science.gov (United States)

    Wick, J.J.

    1959-09-22

    A method is presented for coating uranium with zircoalum by rendering the uranium surface smooth and oxidefree, immersing it in a molten electrolytic bath in NaCI, K/sub 2/ZrF/sub 6/, KF, and ZrO/sub 2/, and before the article reaches temperature equilibrium with the bath, applying an electrolyzing current of 60 amperes per square dectmeter at approximately 3 volts to form a layer of zirconium metal on the uranium.

  6. Evaluation of a Zirconium Recycle Scrubber System

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-04-01

    A hot-cell demonstration of the zirconium recycle process is planned as part of the Materials Recovery and Waste Forms Development (MRWFD) campaign. The process treats Zircaloy® cladding recovered from used nuclear fuel with chlorine gas to recover the zirconium as volatile ZrCl4. This releases radioactive tritium trapped in the alloy, converting it to volatile tritium chloride (TCl). To meet regulatory requirements governing radioactive emissions from nuclear fuel treatment operations, the capture and retention of a portion of this TCl may be required prior to discharge of the off-gas stream to the environment. In addition to demonstrating tritium removal from a synthetic zirconium recycle off-gas stream, the recovery and quantification of tritium may refine estimates of the amount of tritium present in the Zircaloy cladding of used nuclear fuel. To support these objectives, a bubbler-type scrubber was fabricated to remove the TCl from the zirconium recycle off-gas stream. The scrubber was fabricated from glass and polymer components that are resistant to chlorine and hydrochloric acid solutions. Because of concerns that the scrubber efficiency is not quantitative, tests were performed using DCl as a stand-in to experimentally measure the scrubbing efficiency of this unit. Scrubbing efficiency was ~108% ± 3% with water as the scrubber solution. Variations were noted when 1 M NaOH scrub solution was used, values ranged from 64% to 130%. The reason for the variations is not known. It is recommended that the equipment be operated with water as the scrubbing solution. Scrubbing efficiency is estimated at 100%.

  7. Atomic layer deposition of zirconium dioxide from zirconium tetrachloride and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Kemell, Marianna; Köykkä, Joel [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Mizohata, Kenichiro [Accelerator Laboratory, Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Vehkamäki, Marko; Ritala, Mikko; Leskelä, Markku [Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland)

    2015-08-31

    ZrO{sub 2} films were grown by atomic layer deposition using ZrCl{sub 4} and O{sub 3} as precursors. The films were grown on silicon substrates in the temperature range of 220–500 °C. The ALD rate was monotonously decreasing from 0.085 to 0.060 nm/cycle in this temperature range towards the highest temperatures studied. The content of chlorine in the films did not exceed 0.2 at.% as measured by elastic recoil detection analysis. The content of hydrogen was 0.30 and 0.14 at.% in the films grown at 300 and 400 °C, respectively. Structural studies revealed the films consisting of mixtures of stable monoclinic and metastable tetragonal/cubic polymorphs of ZrO{sub 2}, and dominantly metastable phases of ZrO{sub 2} below and above 300 °C, respectively. Permittivity of dielectric layers in Al/Ti/ZrO{sub 2}/(TiN/)Si capacitors with 15–40 nm thick ZrO{sub 2} ranged between 12 and 25 at 100 kHz and the dielectric breakdown fields were in the range of 1.5–3.0 MV/cm. - Highlights: • ZrO{sub 2} thin films were grown by atomic layer deposition from ZrCl{sub 4} and O{sub 3}. • Relatively high substrate temperatures promoted growth of metastable ZrO{sub 2} phases. • ZrO{sub 2} films exhibited electric properties characteristic of dielectric metal oxides. • ZrO{sub 2} grown in hydrogen- and carbon free process contained low amounts of impurities.

  8. Development of Zirconium alloys (for pressure tubes)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kwon, Sang Chul; Choo, Ki Nam; Jung, Chung Hwan; Yim, Kyong Soo; Kim, Sung Soo; Baek, Jong Hyuk; Jeong, Yong Hwan; Kim, Kyong Ho; Cho, Hae Dong [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of); Hwang, S. K.; Kim, M. H. [Inha Univ., Incheon (Korea, Republic of); Kwon, S. I [Korea Univ., Seoul (Korea, Republic of); Kim, I. S. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

    1997-09-01

    The objective of this research is to set up the basic technologies for the evaluation of pressure tube integrity and to develop improved zirconium alloys to prevent pressure tube failures due to DHC and hydride blister caused by excessive creep-down of pressure tubes. The experimental procedure and facilities for characterization of pressure tubes were developed. The basic research related to a better understanding of the in-reactor performances of pressure tubes leads to noticeable findings for the first time : the microstructural effect on corrosion and hydrogen pick-up behavior of Zr-2.5Nb pressure tubes, texture effect on strength and DHC resistance and enhanced recrystallization by Fe in zirconium alloys and etc. Analytical methodology for the assessment of pressure tubes with surface flaws was set up. A joint research is being under way with AECL to determine the fracture toughness of O-8 at the EOL (End of Life) that had been quadruple melted and was taken out of the Wolsung Unit-1 after 10 year operation. In addition, pressure tube with texture controlled is being made along with VNINM in Russia as a joint project between KAERI and Russia. Finally, we succeeded in developing 4 different kinds of zirconium alloys with better corrosion resistance, low hydrogen pickup fraction and higher creep strength. (author). 121 refs., 65 tabs., 260 figs

  9. Temperature-mediated phase transformation, pore geometry and pore hysteresis transformation of borohydride derived in-born porous zirconium hydroxide nanopowders

    Science.gov (United States)

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-05-01

    Development of in-born porous nature of zirconium hydroxide nanopowders through a facile hydrogen (H2) gas-bubbles assisted borohydride synthesis route using sodium borohydride (NaBH4) and novel information on the temperature-mediated phase transformation, pore geometry as well as pore hysteresis transformation of in-born porous zirconium hydroxide nanopowders with the help of X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) isotherm and Transmission Electron Microscopy (TEM) images are the main theme of this research work. Without any surfactants or pore forming agents, the borohydride derived amorphous nature of porous powders was stable up to 500 °C and then the seed crystals start to develop within the loose amorphous matrix and trapping the inter-particulate voids, which led to develop the porous nature of tetragonal zirconium oxide at 600 °C and further sustain this porous nature as well as tetragonal phase of zirconium oxide up to 800 °C. The novel hydrogen (H2) gas-bubbles assisted borohydride synthesis route led to develop thermally stable porous zirconium hydroxide/oxide nanopowders with an adequate pore size, pore volume, and surface area and thus these porous materials are further suggested for promising use in different areas of applications.

  10. Optical properties and environmental stability of oxide coatings deposited by reactive sputtering.

    Science.gov (United States)

    Edlou, S M; Smajkiewicz, A; Al-Jumaily, G A

    1993-10-01

    Refractory metal-oxide coatings are deposited by reactive dc magnetron sputtering in an oxygen environment. The optical constants and the environmental stability of silicon oxide, aluminium oxide, hafnium oxide, zirconium oxide, tantalum oxide, titanium oxide, and a blend of hafnium oxide with silicon oxide are investigated. Properties of both single-layer and multilayer interference filters are examined.

  11. [The clinical application of zirconium-dioxide-ceramics. Case report].

    Science.gov (United States)

    Somfai, Dóra; Zsigmond, Ágnes; Károlyházy, Katalin; Kispély, Barbara; Hermann, Péter

    2015-12-01

    Due to its outstanding physical, mechanical and esthetic properties, zirconium-dioxide is one of the most popular non-metal denture, capable of surpassing PFM in most cases. The recent advances of CAD/CAM technology makes it a good alternitve. Here we show the usefulness of zirconium-dioxide in everyday dental practice through three case reports.

  12. PROCESS FOR DISSOLVING BINARY URANIUM-ZIRCONIUM OR ZIRCONIUM-BASE ALLOYS

    Science.gov (United States)

    Jonke, A.A.; Barghusen, J.J.; Levitz, N.M.

    1962-08-14

    A process of dissolving uranium-- zirconium and zircaloy alloys, e.g. jackets of fuel elements, with an anhydrous hydrogen fluoride containing from 10 to 32% by weight of hydrogen chloride at between 400 and 450 deg C., preferably while in contact with a fluidized inert powder, such as calcium fluoride is described. (AEC)

  13. Optical, structural and fluorescence properties of nanocrystalline cubic or monoclinic Eu:Lu{sub 2}O{sub 3} films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Martinet, C. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France)]. E-mail: martinet@pcml.univ-lyon1.fr; Pillonnet, A. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France); Lancok, J. [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 18221 Prague (Czech Republic); Garapon, C. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France)

    2007-10-15

    Eu{sup 3+}-doped lutetium oxide (Eu:Lu{sub 2}O{sub 3}) nanocrystalline films were grown on fused-silica substrates by pulsed laser deposition. Depending on deposition conditions (oxygen pressure, temperature and laser energy), the structure of the films changed from amorphous to crystalline and the cubic or monoclinic phases were obtained with varying preferential orientation and crystallite size. The monoclinic phase could be prepared for the first time at temperatures as low as 240 deg. C and in a narrow range of parameters. Although this phase has been previously reported for powder samples, it occurs only for high pressures and high temperatures preparation conditions. The refractive indices were measured by m-lines spectroscopy for both crystalline phases and their dispersion curve fitted by the Sellmeier expression. The specific Eu{sup 3+} fluorescence properties of the different phases, monoclinic and cubic, were registered and show modifications due to the disorder induced by the nanometric size of the crystallites, emphasised in particular by quasi-selective excitation in the charge transfer band.

  14. Zirconium fluoride glass - Surface crystals formed by reaction with water

    Science.gov (United States)

    Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

    1984-01-01

    The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

  15. Zirconium carbide coating for corium experiments related to water-cooled and sodium-cooled reactors

    Science.gov (United States)

    Plevacova, K.; Journeau, C.; Piluso, P.; Zhdanov, V.; Baklanov, V.; Poirier, J.

    2011-07-01

    Since the TMI and Chernobyl accidents the risk of nuclear severe accident is intensively studied for existing and future reactors. In case of a core melt-down accident in a nuclear reactor, a complex melt, called corium, forms. To be able to perform experiments with prototypic corium materials at high temperature, a coating which resists to different corium melts related to Generation I and II Water Reactors and Generation IV sodium fast reactor was researched in our experimental platforms both in IAE NNC in Kazakhstan and in CEA in France. Zirconium carbide was selected as protective coating for graphite crucibles used in our induction furnaces: VCG-135 and VITI. The method of coating application, called reactive wetting, was developed. Zirconium carbide revealed to resist well to the (U x, Zr y)O 2-z water reactor corium. It has also the advantage not to bring new elements to this chemical system. The coating was then tested with sodium fast reactor corium melts containing steel or absorbers. Undesirable interactions were observed between the coating and these materials, leading to the carburization of the corium ingots. Concerning the resistance of the coating to oxide melts without ZrO 2, the zirconium carbide coating keeps its role of protective barrier with UO 2-Al 2O 3 below 2000 °C but does not resist to a UO 2-Eu 2O 3 mixture.

  16. PLASMA THERMAL BARRIER COATINGS BASED ON ZIRCONIUM DIOXIDE WITH HIGH THERMAL STABILITY

    Directory of Open Access Journals (Sweden)

    O. G. Devoino

    2015-01-01

    Full Text Available The paper presents optimization of  processes for obtaining maximum content of tetragonal phase in the initial material and thermal barrier coatings (TBC based on zirconium dioxide and hafnium oxide.  Results of the investigations on phase composition of oxide HfO2 – ZrO2 – Y2O3  system have been given in the paper. The system represents  a microstructure which is similar to  zirconia dioxide and  transformed for its application at 1300 °C. The paper explains a mechanism of hafnium oxide influence on formation of the given microstructure. The research methodology has been based on complex metallography, X – ray diffraction and electron microscopic investigations of  structural elements of the composite plasma coating HfO2 – ZrO2 – Y2O system.In order to stabilize zirconium dioxide  dopant oxide should not only have an appropriate size of  metal ion, but also form a solid solution with the zirconia. This condition severely limits the number of possible stabilizers. In fact, such stabilization is possible only with the help of rare earth oxides (Y2O3, Yb2O3, CeO2, HfO2. Chemical purity of the applied materials plays a significant role for obtaining high-quality thermal barrier coatings. Hafnium oxide has been selected as powder for thermal barrier coatings instead of zirconium dioxide due to their similarities in structural modification, grating, chemical and physical properties and its high temperature structural transformations. It has been established that plasma thermal barrier HfO2 – ZrO2 – Y2O3 coatings consist of  one tetragonal phase. This phase is equivalent to a non-equilibrium tetragonal t' phase in the “zirconium dioxide stabilized with yttrium oxide” system. Affinity of  Hf+4 and Zr+4 cations leads to the formation of identical metastable phases during rapid quenching.

  17. Post-patterning of an electronic homojunction in atomically thin monoclinic MoTe2

    Science.gov (United States)

    Kim, Sera; Kim, Jung Ho; Kim, Dohyun; Hwang, Geunwoo; Baik, Jaeyoon; Yang, Heejun; Cho, Suyeon

    2017-06-01

    Monoclinic group 6 transition metal dichalcogenides (TMDs) have been extensively studied for their intriguing 2D physics (e.g. spin Hall insulator) as well as for ohmic homojunction contacts in 2D device applications. A critical prerequisite for those applications is thickness control of the monoclinic 2D materials, which allows subtle engineering of the topological states or electronic bandgaps. Local thickness control enables the realization of clean homojunctions between different electronic states, and novel device operation in a single material. However, conventional fabrication processes, including chemical methods, typically produce non-homogeneous and relatively thick monoclinic TMDs, due to their distorted octahedral structures. Here, we report on a post-patterning technique using laser-irradiation to fabricate homojunctions between two different thickness areas in monoclinic MoTe2. A thickness-dependent electronic change from a metallic to semiconducting state, resulting in an electronic homojunction, was realized by the optical patterning of pristine MoTe2 flakes, and a pre-patterned device channel of monoclinic MoTe2 with a thickness-resolution of 5 nm. Our work provides insight on an optical post-process method for controlling thickness, as a promising approach for fabricating impurity-free 2D TMDs homojunction devices.

  18. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Science.gov (United States)

    2010-04-01

    ... zirconium. 700.16 Section 700.16 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an ingredient... indicates that certain zirconium compounds have caused human skin granulomas and toxic effects in the...

  19. Doping in the Valley of Hydrogen Solubility: A Route to Designing Hydrogen-Resistant Zirconium Alloys

    Science.gov (United States)

    Youssef, Mostafa; Yang, Ming; Yildiz, Bilge

    2016-01-01

    Hydrogen pickup and embrittlement pose a challenging safety limit for structural alloys used in a wide range of infrastructure applications, including zirconium alloys in nuclear reactors. Previous experimental observations guide the empirical design of hydrogen-resistant zirconium alloys, but the underlying mechanisms remain undecipherable. Here, we assess two critical prongs of hydrogen pickup through the ZrO2 passive film that serves as a surface barrier of zirconium alloys; the solubility of hydrogen in it—a detrimental process—and the ease of H2 gas evolution from its surface—a desirable process. By combining statistical thermodynamics and density-functional-theory calculations, we show that hydrogen solubility in ZrO2 exhibits a valley shape as a function of the chemical potential of electrons, μe . Here, μe , which is tunable by doping, serves as a physical descriptor of hydrogen resistance based on the electronic structure of ZrO2 . For designing zirconium alloys resistant against hydrogen pickup, we target either a dopant that thermodynamically minimizes the solubility of hydrogen in ZrO2 at the bottom of this valley (such as Cr) or a dopant that maximizes μe and kinetically accelerates proton reduction and H2 evolution at the surface of ZrO2 (such as Nb, Ta, Mo, W, or P). Maximizing μe also promotes the predomination of a less-mobile form of hydrogen defect, which can reduce the flux of hydrogen uptake. The analysis presented here for the case of ZrO2 passive film on Zr alloys serves as a broadly applicable and physically informed framework to uncover doping strategies to mitigate hydrogen embrittlement also in other alloys, such as austenitic steels or nickel alloys, which absorb hydrogen through their surface oxide films.

  20. In vitro and in vivo characterization of anodised zirconium as a potential material for biomedical applications.

    Science.gov (United States)

    Katunar, Maria R; Gomez Sanchez, Andrea; Santos Coquillat, Ana; Civantos, Ana; Martinez Campos, Enrique; Ballarre, Josefina; Vico, Tamara; Baca, Matias; Ramos, Viviana; Cere, Silvia

    2017-06-01

    In vitro studies offer the insights for the understanding of the mechanisms at the tissue-implant interface that will provide an effective functioning in vivo. The good biocompatibility of zirconium makes a good candidate for biomedical applications and the attractive in vivo performance is mainly due to the presence of a protective oxide layer. The aim of this study is to evaluate by in vitro and in vivo approach, the influence of surface modification achieved by anodisation at 30 and 60V on zirconium implants on the first steps of the osseointegration process. In this study cell attachment, proliferation and morphology of mouse myoblast C2C12-GFP and in mouse osteoprogenitor MC3T3-E1 cells was evaluated. Also, together with the immune system response, osteoclast differentiation and morphology with RAW 264.7 murine cell line were analysed. It was found that anodisation treatment at 60V enhanced cell spreading and the osteoblastic and osteoclastic cells morphology, showing a strong dependence on the surface characteristics. In vivo tests were performed in a rat femur osteotomy model. Dynamical and static histological and histomorphometric analyses were developed 15 and 30days after surgery. Newly formed bone around Zr60V implants showed a continuous newly compact and homogeneous bone just 15 after surgery, as judged by the enhanced thickness and mineralization rate. The results indicate that anodising treatment at 60V could be an effective improvement in the osseointegration of zirconium by stimulating adhesion, proliferation, morphology, new bone thickness and bone mineral apposition, making zirconium an emerging candidate material for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Cherenkov and Scintillation Properties of Cubic Zirconium

    Science.gov (United States)

    Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

    2008-01-01

    Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

  2. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

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

    1962-06-12

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

  3. The irradiation effects on zirconium alloys

    Science.gov (United States)

    Negut, Gh.; Ancuta, M.; Radu, V.; Ionescu, S.; Stefan, V.; Uta, O.; Prisecaru, I.; Danila, N.

    2007-05-01

    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

  4. Experimental results of core-concrete interactions using molten steel with zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Copus, E.R.; Blose, R.E.; Brockmann, J.E.; Gomez, R.D.; Lucero, D.A. (Sandia National Labs., Albuquerque, NM (USA))

    1990-07-01

    Four inductively sustained experiments, QT-D, QT-E, SURC-3, and SURC-3A, were performed in order to investigate the additional effects of zirconium metal oxidation on core debris-concrete interactions using molten stainless steel as the core debris simulant. The QT-D experiment ablated 18 cm of concrete axially during 50 minutes of interaction on limestone-common sand concrete using a 10 kg charge of 304 stainless steel to which 2 kg of zirconium metal was added subsequent to the onset of erosion. The QT-E experiment ablated 10 cm of limestone-common sand concrete axially and 10 cm radially during 35 minutes of sustained interaction using 50 kg of stainless steel and 10 kg of zirconium. The SURC-3 experiment had a 45 kg charge of stainless steel to which 1.1 kg of zirconium was subsequently added. SURC-3 axially eroded 33 cm of limestone concrete during two hours of interaction. The fourth experiment, SURC-3A, eroded 25 cm of limestone concrete axially and 9 cm radially during 90 minutes of sustained interaction. It utilized 40 kg of stainless steel and 2.2 kg of added zirconium as the charge material. All four experiments showed in a large increase in erosion rate, gas production, and aerosol release following the addition of Zr metal to the melt. In the SURC-3 and SURC-3A tests the measured erosion rates increased from 14 cm/hr to 27 cm/hr, gas release increased from 50 slpm to 100 slpm, and aerosol release increased from .02 q/sec to .04 q/sec. The effluent gas was composed of 80% CO, 10% CO{sub 2}, and 2% H{sub 2} before Zr addition and 92% CO, 4% CO{sub 2}, 4% H{sub 2} during the Zr interactions which lasted 10--20 minutes. Addition measurements indicated that the melt pool temperature ranged from 1600{degree}C--1800{degree} and that the aerosols produced were comprised primarily of Te and Fe oxides. 21 refs., 120 figs., 51 tabs.

  5. Modeling of Some Physical Properties of Zirconium Alloys for Nuclear Applications in Support of UFD Campaign

    Energy Technology Data Exchange (ETDEWEB)

    Michael V. Glazoff

    2013-08-01

    Zirconium-based alloys Zircaloy-2 and Zircaloy-4 are widely used in the nuclear industry as cladding materials for light water reactor (LWR) fuels. These materials display a very good combination of properties such as low neutron absorption, creep behavior, stress-corrosion cracking resistance, reduced hydrogen uptake, corrosion and/or oxidation, especially in the case of Zircaloy-4. However, over the last couple of years, in the post-Fukushima Daiichi world, energetic efforts have been undertaken to improve fuel clad oxidation resistance during off-normal temperature excursions. Efforts have also been made to improve upon the already achieved levels of mechanical behavior and reduce hydrogen uptake. In order to facilitate the development of such novel materials, it is very important to achieve not only engineering control, but also a scientific understanding of the underlying material degradation mechanisms, both in working conditions and in storage of used nuclear fuel. This report strives to contribute to these efforts by constructing the thermodynamic models of both alloys; constructing of the respective phase diagrams, and oxidation mechanisms. A special emphasis was placed upon the role of zirconium suboxides in hydrogen uptake reduction and the atomic mechanisms of oxidation. To that end, computational thermodynamics calculations were conducted concurrently with first-principles atomistic modeling.

  6. A Method for Quantitative Phase Analysis of Nanocrystalline Zirconium Dioxide Polymorphs.

    Science.gov (United States)

    Zhou, Zhiqiang; Guo, Li

    2015-04-01

    A method based on X-ray diffractometry was developed for quantitative phase analysis of nanocrystalline zirconium dioxide polymorphs. Corresponding formulas were derived. The key factors therein were evaluated by rigorous theoretical calculation and fully verified by experimentation. A process of iteration was raised to make the experimental verification proceed in the case of lack of pure ZrO2 crystal polymorphs. By this method, the weight ratios of tetragonal ZrO2 (t-ZrO2) to monoclinic ZrO2 (m-ZrO2) in any a mixture that contains nanocrystalline t-ZrO2 and m-ZrO2 or their weight fractions in a mixture that is composed of nanocrystalline t-ZrO2 and m-ZrO2 can be determined only upon an XRD test. It is proved by both theoretical calculation and experimental test that mutual substitutions of t-ZrO2 and cubic ZrO2 (c-ZrO2) in a wide range show almost no impact on the XRD patterns of their mixtures. And plus the similarity in property of t-ZrO2 and c-ZrO2, they can be treated as one whole phase. The high agreement of the theoretical and experimental results in this work also proves the validity and reliability of the theoretical calculation based on X-ray diffractometry theory for such quantitative phase analysis. This method has the potential to be popularized to other materials.

  7. Petrology of Karoo volcanic rocks in the southern Lebombo monocline, Mozambique

    Science.gov (United States)

    Melluso, Leone; Cucciniello, Ciro; Petrone, Chiara M.; Lustrino, Michele; Morra, Vincenzo; Tiepolo, Massimo; Vasconcelos, Lopo

    2008-11-01

    The Karoo volcanic sequence in the southern Lebombo monocline in Mozambique contains different silicic units in the form of pyroclastic rocks, and two different basalt types. The silicic units in the lower part of the Lebombo sequence are formed by a lower unit of dacites and rhyolites (67-80 wt.% SiO 2) with high Ba (990-2500 ppm), Zr (800-1100 ppm) and Y (130-240 ppm), which are part of the Jozini-Mbuluzi Formation, followed by a second unit, interlayered with the Movene basalts, of high-SiO 2 rhyolites (76-78 wt.%; the Sica Beds Formation), with low Sr (19-54 ppm), Zr (340-480 ppm) and Ba (330-850 ppm) plus rare quartz-trachytes (64-66 wt.% SiO 2), with high Nb and Rb contents (240-250 and 370-381 ppm, respectively), and relatively low Zr (450-460 ppm). The mafic rocks found at the top of the sequence are basalts and ferrobasalts belonging to the Movene Formation. The basalts have roughly flat mantle-normalized incompatible element patterns, with abundances of the most incompatible elements not higher than 25 times primitive mantle. The ferrobasalt has TiO 2 ˜ 4.7 wt.%, Fe 2O 3t = 16 wt.%, and high Y (100 ppm), Zr (420 ppm) and Ba (1000 ppm). The Movene basalts have initial (at 180 Ma) 87Sr/ 86Sr = 0.7052-0.7054 and 143Nd/ 144Nd = 0.51232, and the Movene ferrobasalt has even lower 87Sr/ 86Sr (0.70377) and higher 143Nd/ 144Nd (0.51259). The silicic rocks show a modest range of initial Sr-( 87Sr/ 86Sr = 0.70470-0.70648) and Nd-( 143Nd/ 144Nd = 0.51223-0.51243) isotope ratios. The less evolved dacites could have been formed after crystal fractionation of oxide-rich gabbroic cumulates from mafic parental magmas, whereas the most silica-rich rhyolites could have been formed after fractional crystallization of feldspars, pyroxenes, oxides, zircon and apatite from a parental dacite magma. The composition of the Movene basalts imply different feeding systems from those of the underlying Sabie River basalts.

  8. The Fouling of Zirconium(IV) Hydrous Oxide–Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions

    OpenAIRE

    Ewa Polom

    2013-01-01

    The results of investigations of flux decline during nanofiltration (NF) of lactic acid solutions using dynamically formed zirconium(IV) hydrous oxide/polyacrylate membranes (Zr(IV)/PAA) under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations sh...

  9. Amine-intercalated α-zirconium phosphates as lubricant additives

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Huaping; Dai, Wei [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Kan, Yuwei; Clearfield, Abraham [Department of Chemistry, Texas A& M University, College Station, TX 77843 (United States); Liang, Hong, E-mail: hliang@tamu.edu [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2015-02-28

    In this study, three types of amines intercalated α-zirconium phosphate nanosheets with different interspaces were synthesized and examined as lubricant additives to a mineral oil. Results from tribological experiments illustrated that these additives improved lubricating performance. Results of rheological experiments showed that the viscosity of the mineral oil was effectively reduced with the addition of α-zirconium phosphate nanosheets. The two-dimensional structure, with larger interspaces, resulting from amine intercalation, exhibited improved effectiveness in reducing viscosity. This study demonstrates that the nanosheet structure of α-zirconium phosphates is effective in friction reduction. The manufacture of lubricants with tailored viscosity is possible by using different intercalators.

  10. Layered zirconium phosphate-supported metalloporphyrin:Synthesis and catalytic application

    Institute of Scientific and Technical Information of China (English)

    Hai Yan Wang; Wei Dong Ji; Da Xiong Han

    2008-01-01

    This paper reports a new route for the preparation of layered alpha-zirconium phosphate (a-ZrP)-supponed metalloporphyrin MnTMPyp.MnTMPyP was intercalated into a-ZrP using a-ZrP.BA (i.e.pre-intercalated buitylamine was arranged by a monolayer mode in a-ZrP) as a starting material.The catalytic activity of the supported material for homovanillic acid (HVA) oxidation was investigated.The results showed a promising layered material-supported catalyst in catalytic system.

  11. Hydrogen effect on zirconium alloy surface treated by pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pushilina, N.S.; Lider, A.M. [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Kudiiarov, V.N., E-mail: viktor.kudiiarov@gmail.com [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Chernov, I.P. [Department of General Physics, Institute of Physics and Technology, National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Ivanova, S.V. [National Research Nuclear University “MIFI”, Kashirskoye shosse 31, Moscow 115409 (Russian Federation)

    2015-01-15

    Influence of modification by pulsed electron beam (PEB) and hydrogen adsorption in zirconium alloys have been investigated. Treatment of Zr–1Nb alloy by high-current PEB allows for a decrease in the amount of hydrogen absorbed by the samples during the hydrogenation process from gas atmosphere in the temperature range of (350–550 °S). The effect of the PEB surface treatment on the hydrogen adsorption connected with the formation of a protective oxide film after PEB irradiation and also by the formation of a specific hardening structure under the action of irradiation at temperatures exceeding the melting temperature from the subsequent high-speed surface cooling.

  12. Quantum Mechanical Calculations Of Elastic Properties Of Doped Tetragonal Yttria-Stabilized Zirconium Dioxide

    Directory of Open Access Journals (Sweden)

    Yuriy Natanzon

    2008-01-01

    Full Text Available We report first principles calculations of the electronic and elastic properties of yttriastabilized tetragonal zirconium dioxide doped with metal oxides like: GeO2, TiO2, SiO2,MgO and Al2O3. It is shown that addition of such dopants affects selected elastic propertiesof ZrO2, which is driven by the attraction of electron density by dopant atom and creationof stronger dopant–oxygen bonds. This effect contributes to the increase of superplasticityof doped material.

  13. Ar/O{sub 2} gas pressure dependence of atomic concentration of zirconia prepared by zirconium pulse arc PBII and D

    Energy Technology Data Exchange (ETDEWEB)

    Yukimura, Ken [Department of Electrical Engineering, Doshisha University, 1-3 Tatara-Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan)]. E-mail: kyukimur@mail.doshisha.ac.jp; Yoshinaga, Hiroaki [Department of Electrical Engineering, Doshisha University, 1-3 Tatara-Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Ohtsu, Yasunori [Department of Electrical and Electronic Engineering, Saga University, Honjo-machi1, Saga 840-8502 (Japan); Fujita, Hiroharu [Department of Electrical and Electronic Engineering, Saga University, Honjo-machi1, Saga 840-8502 (Japan); Nakamura, Keiji [Department of Electrical Engineering, College of Engineering, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501 (Japan); Ma Xinxin [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2006-01-15

    Zirconium oxide films were prepared by plasma-based ion implantation and deposition (PBII and D), where a zirconium pulse arc discharge was generated in O{sub 2}/Ar gas mixture. The plasma was maintained for approximately 3 ms, and the ion current at the substrate was detected in a time range from 1 to 10 ms after the arc initiation. At O{sub 2}/Ar pressures of 2.6-3.0 Pa, a stoichiometric film was obtained, while at a pressure lower than 2.2 Pa, the film also contained ZrO {sub x} (x < 2) phase as well as ZrO{sub 2} phase. In the absence of argon gas, the plasma became unstable, which resulted in shortage of zirconium ions in the plasma, and hence, a stoichiometric condition was not found.

  14. Atomistic Studies of Cation Transport in Tetragonal ZrO2 During Zirconium Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-10-01

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is one of the major degradation mechanisms of these alloys. During corrosion the transport of oxidizing species in zirconium dioxide (ZrO2) determines the corrosion kinetics. Previously it has been argued that the outward diffusion of cation ions is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO2. The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration barriers of some defect clusters can be much lower than those of point defects. The migration of Zr interstitials at some special grain boundaries is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed.

  15. Zirconium Phosphate Nanoplatelet Potential for Anticancer Drug Delivery Applications.

    Science.gov (United States)

    González, Millie L; Ortiz, Mayra; Hernández, Carmen; Cabán, Jennifer; Rodríguez, Axel; Colón, Jorge L; Báez, Adriana

    2016-01-01

    Zirconium phosphate (ZrP) nanoplatelets can intercalate anticancer agents via an ion exchange reaction creating an inorganic delivery system with potential for cancer treatment. ZrP delivery of anticancer agents inside tumor cells was explored in vitro. Internalization and cytotoxicity of ZrP nanoplatelets were studied in MCF-7 and MCF-10A cells. DOX-loaded ZrP nanoplatelets (DOX@ZrP) uptake was assessed by confocal (CLSM) and transmission electron microscopy (TEM). Cytotoxicity to MCF-7 and MCF-10A cells was determined by the MTT assay. Reactive Oxy- gen Species (ROS) production was analyzed by fluorometric assay, and cell cycle alterations and induction of apoptosis were analyzed by flow cytometry. ZrP nanoplatelets were localized in the endosomes of MCF-7 cells. DOX and ZrP nanoplatelets were co-internalized into MCF-7 cells as detected by CLSM. While ZrP showed limited toxicity to MCF-7 cells, DOX@ZrP was cytotoxic at an IC₅₀ similar to that of free DOX. Meanwhile, DOX lC₅₀ was significantly lower than the equivalent concentration of DOX@ZrP in MCF-10A cells. ZrP did not induce apoptosis in both cell lines. DOX and DOX@ZrP induced significant oxidative stress in both cell models. Results suggest that ZrP nanoplatelets are promising as carriers of anticancer agents into cancer cells.

  16. Structural evolution of zirconium carbide under ion irradiation

    Science.gov (United States)

    Gosset, D.; Dollé, M.; Simeone, D.; Baldinozzi, G.; Thomé, L.

    2008-02-01

    Zirconium carbide is one of the candidate materials to be used for some fuel components of the high temperature nuclear reactors planned in the frame of the Gen-IV project. Few data exist regarding its behaviour under irradiation. We have irradiated ZrC samples at room temperature with slow heavy ions (4 MeV Au, fluence from 10 11 to 5 × 10 15 cm -2) in order to simulate neutron irradiations. Grazing incidence X-Ray diffraction (GIXRD) and transmission electron microscopy (TEM) analysis have been performed in order to study the microstructural evolution of the material versus ion fluence. A high sensitivity to oxidation is observed with the formation of zirconia precipitates during the ion irradiations. Three damage stages are observed. At low fluence (high micro-strains appear together with small faulted dislocation loops. At the highest fluence (>10 14 cm -2), the micro-strains saturate and the loops coalesce to form a dense dislocation network. No other structural modification is observed. The material shows a moderate cell parameter increase, corresponding to a 0.6 vol.% swelling, which saturates around 10 14 ions/cm 2, i.e., a few Zr dpa. As a result, in spite of a strong covalent bonding component, ZrC seems to have a behaviour under irradiation close to cubic metals.

  17. Microstructure, bioactivity and osteoblast behavior of monoclinic zirconia coating with nanostructured surface.

    Science.gov (United States)

    Wang, Guocheng; Meng, Fanhao; Ding, Chuanxian; Chu, Paul K; Liu, Xuanyong

    2010-03-01

    A monoclinic zirconia coating with a nanostructural surface was prepared on the Ti-6Al-4V substrate by an atmospheric plasma-spraying technique, and its microstructure and composition, as well as mechanical and biological properties, were investigated to explore potential application as a bioactive coating on bone implants. X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Raman spectroscopy revealed that the zirconia coating was composed of monoclinic zirconia which was stable at low temperature, and its surface consists of nano-size grains 30-50 nm in size. The bond strength between the coating and the Ti-6Al-4V substrate was 48.4 + or - 6.1 MPa, which is higher than that of plasma-sprayed HA coatings. Hydrothermal experiments indicated that the coating was stable in a water environment and the phase composition and Vickers hardness were independent of the hydrothermal treatment time. Bone-like apatite is observed to precipitate on the surface of the coating after soaking in simulated body fluid for 6 days, indicating excellent bioactivity in vitro. The nanostructured surface composed of monoclinic zirconia is believed to be crucial to its bioactivity. Morphological observation and the cell proliferation test demonstrated that osteoblast-like MG63 cells could attach to, adhere to and proliferate well on the surface of the monoclinic zirconia coating, suggesting possible applications in hard tissue replacements.

  18. Efficient channel waveguide lasers in monoclinic double tungstates: towards further integration with on-chip mirrors

    NARCIS (Netherlands)

    van Dalfsen, Koop; van Wolferen, Hendricus A.G.M.; Dijkstra, Mindert; Aravazhi, S.; Bernhardi, Edward; García Blanco, Sonia Maria; Pollnau, Markus

    2012-01-01

    By varying the thulium concentration in the range of 1.5 – 8.0 at.% in thulium- gadolinium-lutetium-yttrium-co-doped monoclinic double tungstate channel waveguides, a maximum laser slope efficiency of 70% with respect to the absorbed pump power was obtained. Further integration of these channel

  19. Lifting the geometric frustration through a monoclinic distortion in “114” YBaFe{sub 4}O{sub 7.0}: Magnetism and transport

    Energy Technology Data Exchange (ETDEWEB)

    Duffort, V.; Sarkar, T. [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Caignaert, V., E-mail: vincent.caignaert@ensicaen.fr [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Pralong, V.; Raveau, B. [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Avdeev, M. [Bragg Institute, Australian Nuclear Science and Technology Organization, PMB 1, Menai, NSW 2234 (Australia); Cervellino, A. [Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen (Switzerland); Waerenborgh, J.C.; Tsipis, E.V. [UCQR, IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, CFMC-UL, 2686-953 Sacavém (Portugal)

    2013-09-15

    The possibility to lift the geometric frustration in the “114” stoichiomeric tetragonal oxide YBaFe{sub 4}O{sub 7.0} by decreasing the temperature has been investigated using neutron and synchrotron powder diffraction techniques. Besides the structural transition from tetragonal to monoclinic symmetry that appears at T{sub S}=180 K, a magnetic transition is observed below T{sub N}=95 K. The latter corresponds to a lifting of the 3D geometric frustration toward an antiferromagnetic long range ordering, never observed to date in a cubic based “114’” oxide. The magnetic structure, characterized by the propagation vector k{sub 1}=(0,0,½), shows that one iron Fe2 exhibits a larger magnetic moment than the three others, suggesting a possible charge ordering according to the formula YBaFe{sup 3+}Fe{sub 3}{sup 2+}O{sub 7.0}. The magnetic M(T) and χ′(T) curves, in agreement with neutron data, confirm the structural and magnetic transitions and evidence the coexistence of residual magnetic frustration. Moreover, the transport measurements show a resistive transition from a thermally activated conduction mechanism to a variable range hopping mechanism at T{sub S}=180 K, with a significant increase of the dependence of the resistivity vs. temperature. Mössbauer spectroscopy clearly evidences a change in the electronic configuration of the iron framework at the structural transition as well as coexistence of several oxidation states. The role of barium underbonding in these transitions is discussed. - Graphical abstract: Atomic displacements at the tetragonal-monoclinic transition in YBaFe{sub 4}O{sub 7}. Display Omitted - Highlights: • The structural and magnetic phase transitions of YBaFe{sub 4}O{sub 7} were studied below room temperature. • The tetragonal to monoclinic transition, characterized by NPD and SXRD, was studied using mode crystallography approach. • Monoclinic distortion allows the lifting of the geometrical frustration on the iron sublattice

  20. Effects of zirconium oxide on the sintering of SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5)

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Kai-Ti, E-mail: kady0525@hotmail.com [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Jang, Jason Shian-Ching, E-mail: jscjang@ncu.edu.tw [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Department of Mechanical Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Ren, Yu-Jing; Tsai, Pei-Hua [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Li, Chuan; Tseng, Chung-Jen [Department of Mechanical Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Lin, Jing-Chie [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Hsi, Chi-Shiung [Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan, ROC (China); Hung, I-Ming [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Taoyuan 32003, Taiwan, ROC (China)

    2014-12-05

    Graphical abstract: SEM cross-sectional microstructures of (a) the HTM with multilayer-supported structure sintered at 1550 °C for 4 h; the sequence of distinct layer is SrCeO{sub 3}, SrCe{sub 0.6}Zr{sub 0.4}O{sub 3-δ}, and SrZrO{sub 3} from the middle to the outer surface. (b) Enlaged image from circle A in Fig. 7(a). (c) Enlarged image from circle B in Fig. 7(a). - Highlights: • The sinterability of SrCe{sub 1-x}Zr{sub x}O{sub 3-δ} (0.0 ≦ x ≦ 0.5) oxides decreased with increasing Zr contents. • The porosities of sintered SrCe{sub 1-x}Zr{sub x}O{sub 3-δ}(0.0 ≦ x ≦ 0.5) oxides increased with increasing Zr contents. • SrCe{sub 0.6}Zr{sub 0.4}O{sub 3-δ} ceramics sintered at 1500 °C has the largest porosity in the SrCe{sub 1-x}Zr{sub x}O{sub 3-δ}(0.0 ≦ x ≦ 0.5) ceramics system. • A flat HTM with porous supporting layers was fabricated by constrained sintering. - Abstract: SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5) proton-conducting oxides had been successfully prepared using a solid state reaction method. In this study, the relationships between the Zr contents and microstructures, shrinkages, and sintering of these SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5) were systemically studied by using X-ray Diffraction, Scanning Electron Microscopy, and Thermal dilatometer analysis (TDA). The XRD results showed that no second phase could be found from the 1500 °C sintered SrCe{sub 1−x}Zr{sub x}O{sub 3−δ}. The SEMs shows that the porosities of sintered SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} increased with increasing the Zr contents. The largest porosity about 27.53% could be obtained at the SrCe{sub 0.6}Zr{sub 0.4}O{sub 3−δ} ceramics sintered at 1500 °C for 2 h in the SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} ceramics. According to the sintering behaviour and properties characterizations, a flat HTM with porous supporting layers of SrCe{sub 0.6}Zr{sub 0.4}O{sub 3−δ} and SrZrO{sub 3} was fabricated by constrained

  1. Nucleation Pathways For Freezing Of Two Grades Of Zirconium

    Science.gov (United States)

    Rhim, Won-Kyu; Rulison, Aaron; Bayuzick, Robert; Hofmeister, William; Morton, Craig

    1996-01-01

    Report discusses classical nucleation theory of freezing and describes experimental study of nucleation mechanisms that predominate during freezing of spherical specimens of initially molten zirconium levitated electrostatically in vacuum.

  2. Project on New Domestic Zirconium Alloy Fuel Assembly Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Pei-sheng; ZHANG; Ai-min

    2012-01-01

    <正>The objectives of the project is to conduct irradiation at research reactor for small fuel assembly with domestic new zirconium alloy, and then to carry out post irradiation examination, and finally to acquire

  3. Hydrogenation of zirconium film by implantation of hydrogen ions

    Science.gov (United States)

    Yang, LIU; Kaihong, FANG; Huiyi, LV; Jiwei, LIU; Boyu, WANG

    2017-03-01

    In order to understand the drive-in target in a D–D type neutron generator, it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogen-absorbing metal film. The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions. Doses of 30 keV hydrogen ions ranging from 4.30 × 1017 to 1.43 × 1018 ions cm‑2 were loaded into the zirconium film through the ion beam implantation technique. Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy, atomic force microscopy and x-ray diffraction. Confirmation of the formation of δ phase zirconium hydride in the implanted samples was first made by x-ray diffraction, and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

  4. China’s Zirconium Industry: Review and Forecast

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>China’s zirconium industry is keeping apace with developments in the national economy Over the past decade,China’s national economy has maintained a growth rate of 9%,resulting in a comprehensive change of fortune

  5. Sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides

    National Research Council Canada - National Science Library

    R.V. Smotraiev; E.O. Sorochkina; А.V. Dzuba; Y.D. Galivets

    2016-01-01

    ...: The aim of this work is to determine the impact of aluminum and manganese ions additives on surface and sorption properties of zirconium oxyhydroxide based sorbents during their production process...

  6. Fluoride removal from water by zirconium (IV) doped chitosan bio ...

    African Journals Online (AJOL)

    Toshiba

    bio-composite was at par with commercial alumina to mitigate water fluoride limit .... analyzed for residual fluoride concentration by ion selective ..... zirconium (IV) doped chitosan were reused in another ... desalination in India: Review Article.

  7. Irradiation effects in hydrated zirconium molybdate

    Science.gov (United States)

    Fourdrin, C.; Esnouf, S.; Dauvois, V.; Renault, J.-P.; Venault, L.; Tabarant, M.; Durand, D.; Chenière, A.; Lamouroux-Lucas, C.; Cochin, F.

    2012-07-01

    Hydrated zirconium molybdate is a precipitate formed during the process of spent nuclear fuel dissolution. In order to study the radiation stability of this material, we performed gamma and electron irradiation in a dose range of 10-100 kGy. XRD patterns showed that the crystalline structure is not affected by irradiation. However, the yellow original sample exhibits a blue-grey color after exposure. The resulting samples were analyzed by means of EPR and diffuse reflectance spectroscopy. Two sites for trapped electrons were evidenced leading to a d1 configuration responsible for the observed coloration. Moreover, a third defect corresponding to a hole trapped on oxygen was observed after electron irradiation at low temperature.

  8. In situ hydrogen loading on zirconium powder

    Energy Technology Data Exchange (ETDEWEB)

    Maimaitiyili, Tuerdi, E-mail: tuerdi.maimaitiyili@mah.se; Blomqvist, Jakob [Malmö University, Östra Varvsgatan 11 A, Malmö, Skane 20506 (Sweden); Steuwer, Axel [Lund University, Ole Römers väg, Lund, Skane 22100 (Sweden); Nelson Mandela Metropolitan University, Gardham Avenue, Port Elizabeth 6031 (South Africa); Bjerkén, Christina [Malmö University, Östra Varvsgatan 11 A, Malmö, Skane 20506 (Sweden); Zanellato, Olivier [Ensam - Cnam - CNRS, 151 Boulevard de l’Hôpital, Paris 75013 (France); Blackmur, Matthew S. [Materials Performance Centre, School of Materials, The University of Manchester, Manchester M1 7HS (United Kingdom); Andrieux, Jérôme [European Synchrotron Radiation Facility, 6 rue J Horowitz, Grenoble 38043 (France); Université de Lyon, 43 Bd du 11 novembre 1918, Lyon 69100 (France); Ribeiro, Fabienne [Institut de Radioprotection et Sûreté Nucléaire, IRSN, BP 3, 13115 Saint-Paul Lez Durance (France)

    2015-06-26

    Commercial-grade Zr powder loaded with hydrogen in situ and phase transformations between various Zr and ZrH{sub x} phases have been monitored in real time. For the first time, various hydride phases in a zirconium–hydrogen system have been prepared in a high-energy synchrotron X-ray radiation beamline and their transformation behaviour has been studied in situ. First, the formation and dissolution of hydrides in commercially pure zirconium powder were monitored in real time during hydrogenation and dehydrogenation, then whole pattern crystal structure analysis such as Rietveld and Pawley refinements were performed. All commonly reported low-pressure phases presented in the Zr–H phase diagram are obtained from a single experimental arrangement.

  9. Synthesis of zirconium by zirconium tetrachloride reduction by magnesio-thermia. Experimental study and modelling; Elaboration de zirconium par reduction de tetrachlorure de zirconium par magnesothermie. Etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Basin, N

    2001-01-01

    This work deals with the synthesis of zirconium. The ore is carbo-chlorinated to obtain the tetrachloride which is then purified by selective condensation and extractive distillation. Zirconium tetrachloride is then reduced by magnesium and the pseudo-alloy is obtained according to the global following reaction (Kroll process): ZrCl{sub 4} + 2 Mg = 2 MgCl{sub 2}. By thermodynamics, it has been shown that the volatilization of magnesium chloride and the formation of zirconium sub-chlorides are minimized when the combined effects of temperature and of dilution with argon are limited. With these conditions, the products, essentially zirconium and magnesium chloride, are obtained in equivalence ratio in the magnesio-thermia reaction. The global kinetics of the reduction process has been studied by a thermal gravimetric method. A thermo-balance device has been developed specially for this kinetics study. It runs under a controlled atmosphere and is coupled to a vapor tetrachloride feed unit. The transformation is modelled supposing that the zirconium and magnesium chloride formation result: 1)of the evaporation of magnesium from its liquid phase 2)of the transfer of magnesium and zirconium tetrachloride vapors towards the front of the reaction located in the gaseous phase 3)of the chemical reaction. In the studied conditions, the diffusion is supposed to be the limiting process. The influence of the following parameters: geometry of the reactive zone, temperature, scanning rate of the argon-zirconium tetrachloride mixture, composition of the argon-zirconium tetrachloride mixture has been experimentally studied and confronted with success to the model. (O.M.)

  10. Quercetin as colorimetric reagent for determination of zirconium

    Science.gov (United States)

    Grimaldi, F.S.; White, C.E.

    1953-01-01

    Methods described in the literature for the determination of zirconium are generally designed for relatively large amounts of this element. A good procedure using colorimetric reagent for the determination of trace amounts is desirable. Quercetin has been found to yield a sensitive color reaction with zirconium suitable for the determination of from 0.1 to 50?? of zirconium dioxide. The procedure developed involves the separation of zirconium from interfering elements by precipitation with p-dimethylaminoazophenylarsonic acid prior to its estimation with quercetin. The quercetin reaction is carried out in 0.5N hydrochloric acid solution. Under the operating conditions it is indicated that quercetin forms a 2 to 1 complex with zirconium; however, a 2 to 1 and a 1 to 1 complex can coexist under special conditions. Approximate values for the equilibrium constants of the complexes are K1 = 0.33 ?? 10-5 and K2 = 1.3 ?? 10-9. Seven Bureau of Standards samples of glass sands and refractories were analyzed with excellent results. The method described should find considerable application in the analysis of minerals and other materials for macro as well as micro amounts of zirconium.

  11. [Preparation and characterization of zirconium hydroxide powder for fluoride adsorption].

    Science.gov (United States)

    Yang, Shuo; Dou, Xiao-min; Liang, Wen-yan; Wang, Yi-li; Lin, Wei

    2010-07-01

    The method co-precipitation was applied to preparation the zirconium hydroxide as a type drinking-water defluoridation adsorbent. The effect of the preparation conditions on the adsorptive capacity was studied. The optimization of preparation condition for zirconium hydroxide concludes that co-precipitation time is 10 h, pH value is 7.0, drying time is 72 h, calcination temperature is below 100 degrees C. Also, the adsorbent samples were characterized. SEM measurements reveal that zirconium hydroxide powder are constructed by several small particles, with a diameter about 20-30 microm. XRD and TG/DTA measurements show that the zirconium hydroxide samples have amorphous phase and converse to tetragonal phase when calcined at 600 degrees C. Nitrogen adsorption/desorption measurements show that samples have large surface areas of 138.4 m2/g and a 2 nm average pore size distribution in the mesopore region. The performance of zirconium hydroxide regeneration process was investigated. The results show that the regeneration techniques are very suitable to restore the fluorine-removal ability for zirconium hydroxide.

  12. Zirconium-cerin solid solutions: thermodynamic model and thermal stability at high temperature; Solutions solides de zirconium dans la cerine: modele thermodynamique et stabilite thermique a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Janvier, C.

    1998-04-02

    The oxides-gaseous dioxygen equilibria and the textural thermal stability of six zirconium-cerin solutions Ce{sub 1-x}Zr{sub x}O{sub 2} (0zirconium concentration. A kinetic study (by calcination at 950 degrees Celsius of the solid solutions) of the specific surface area decrease has revealed a minima (0

  13. TECHNOLOGICAL PECULIARITIES OF THERMAL BARRIER COATINGS BASED ON ZIRCONIUM DIOXIDE

    Directory of Open Access Journals (Sweden)

    V. V. Okovity

    2016-01-01

    Full Text Available A technology for formation of thermal barrier coatings (TBC based on zirconium dioxide has been developed in the paper. The paper investigates structures of phase composition and thermal stability of such developed coatings. Investigation results pertaining to formation of an oxide system ZrO2 – Y2O3, while using plasma spraying and subsequent high-energy processing, which allows to increase resistance of a thermal barrier coating to thermal cycling heat resistance of the coating at temperature of 1100 °C. This leads to longer protection of bottom layer against high-temperature exposure. The methodology is based on complex metallographic, X-ray diffraction and electron microscopy investigations of structural elements in composite plasma coatings of the ZrO2 – Y2O system. Resistance of plasma coatings (Мe – Cr – Al – Y/ZrO2 – Y2O3-type, used as TBC to protect gas turbine engine blades under conditions of frequent thermal cyclings is limited by cleavage of an outer ceramic layer. Structural and electron microprobe investigations have shown that as a result of thermal cycling an outer atmosphere due to porous structure of the ceramic coating layer, migrates to the surface of lower metal coating, causing its oxidation. As a result, the metal-ceramic Al2O3 layer is formed at a metal-ceramic interface and it changes a stress state of the coating that causes a reduction of protective properties. Thus, a high heat resistance of thermal barrier coatings depends on processes occurring at the interface between metal and ceramic coating layers. A laser impact on samples with TBC leads to changes in the structure of the oxide layer of ZrO2 – Y2O3. In this case its initial surface characterized by considerable relief is significantly flattened due to processing and the coating is fractured and it is separated in fragments. As the oxide coating has low thermal conductivity, and the time of laser exposure is about 10–3 sec, a heat flux

  14. Reflection of and SV waves at the free surface of a monoclinic elastic half-space

    Indian Academy of Sciences (India)

    Sarva Jit Singh; Sandhya Khurana

    2002-12-01

    The propagation of plane waves in an anisotropic elastic medium possessing monoclinic symmetry is discussed. The expressions for the phase velocity of qP and qSV waves propagating in the plane of elastic symmetry are obtained in terms of the direction cosines of the propagation vector. It is shown that, in general, qP waves are not longitudinal and qSV waves are not transverse. Pure longitudinal and pure transverse waves can propagate only in certain specific directions. Closed-form expressions for the reflection coefficients of qP and qSV waves incident at the free surface of a homogeneous monoclinic elastic half-space are obtained. These expressions are used for studying numerically the variation of the reflection coefficients with the angle of incidence. The present analysis corrects some fundamental errors appearing in recent papers on the subject.

  15. Evidence for photo-induced monoclinic metallic VO{sub 2} under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Wen-Pin, E-mail: wphsieh@stanford.edu; Mao, Wendy L. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 (United States); Trigo, Mariano [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Reis, David A. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Photon Science and Applied Physics, Stanford University, Stanford, California 94305 (United States); Andrea Artioli, Gianluca; Malavasi, Lorenzo [Dipartimento di Chimica, Sezione di Chimica Fisica, INSTM (UdR Pavia), Università di Pavia, Viale Taramelli 16, 27100 Pavia (Italy)

    2014-01-13

    We combine ultrafast pump-probe spectroscopy with a diamond-anvil cell to decouple the insulator-metal electronic transition from the lattice symmetry changing structural transition in the archetypal strongly correlated material vanadium dioxide. Coherent phonon spectroscopy enables tracking of the photo-excited phonon vibrational frequencies of the low temperature, monoclinic (M{sub 1})-insulating phase that transforms into the metallic, tetragonal rutile structured phase at high temperature or via non-thermal photo-excitations. We find that in contrast with ambient pressure experiments where strong photo-excitation promptly induces the electronic transition along with changes in the lattice symmetry, at high pressure, the coherent phonons of the monoclinic (M{sub 1}) phase are still clearly observed upon the photo-driven phase transition to a metallic state. These results demonstrate the possibility of synthesizing and studying transient phases under extreme conditions.

  16. Seismic Data Interpretation: A Case Study of Southern Sindh Monocline, Lower Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2015-04-01

    Full Text Available The Sindh monocline in Lower Indus Basin is an important oil and gas producing area of Pakistan where a large number of oil, gas and condensate fields have been discovered from structural traps. This research involves the interpretation of stratigraphic and structural styles of Sindh Monocline using 2D (Two-Dimensional seismic reflection and well log. Four reflectors of different formations have been marked and were named as Reflector-1 as of Khadro Formation, Reflector-2 as Upper Goru Member, Reflector-3 as Lower Goru Formation and Reflector-4 as Chiltan Limestone. The average depth of Khadro Formation was marked at 449.0m, Upper Goru Member at 968m, Lower Goru Formation at 1938m and Chiltan Limestone at 2943m. Faults were marked on seismic sections which collectively form horsts and grabens which is the evidence of extensional tectonic in the area. Seismic interpretation was carried out through window based Kingdom Software

  17. Understanding the Irradiation Behavior of Zirconium Carbide

    Energy Technology Data Exchange (ETDEWEB)

    Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States)

    2013-10-11

    Zirconium carbide (ZrC) is being considered for utilization in high-temperature gas-cooled reactor fuels in deep-burn TRISO fuel. Zirconium carbide possesses a cubic B1-type crystal structure with a high melting point, exceptional hardness, and good thermal and electrical conductivities. The use of ZrC as part of the TRISO fuel requires a thorough understanding of its irradiation response. However, the radiation effects on ZrC are still poorly understood. The majority of the existing research is focused on the radiation damage phenomena at higher temperatures (>450{degree}C) where many fundamental aspects of defect production and kinetics cannot be easily distinguished. Little is known about basic defect formation, clustering, and evolution of ZrC under irradiation, although some atomistic simulation and phenomenological studies have been performed. Such detailed information is needed to construct a model describing the microstructural evolution in fast-neutron irradiated materials that will be of great technological importance for the development of ZrC-based fuel. The goal of the proposed project is to gain fundamental understanding of the radiation-induced defect formation in zirconium carbide and irradiation response by using a combination of state-of-the-art experimental methods and atomistic modeling. This project will combine (1) in situ ion irradiation at a specialized facility at a national laboratory, (2) controlled temperature proton irradiation on bulk samples, and (3) atomistic modeling to gain a fundamental understanding of defect formation in ZrC. The proposed project will cover the irradiation temperatures from cryogenic temperature to as high as 800{degree}C, and dose ranges from 0.1 to 100 dpa. The examination of this wide range of temperatures and doses allows us to obtain an experimental data set that can be effectively used to exercise and benchmark the computer calculations of defect properties. Combining the examination of radiation

  18. Crystalline and magnetic ordering in the monoclinic phase of the layered perovskite PAMC

    DEFF Research Database (Denmark)

    Harris, P.; Lebech, B.; Achiwa, N.

    1994-01-01

    of 1/3b*, and below 39 K PAMC is an antiferromagnet with a small ferromagnetic component. The temperature dependence of the monoclinic angle alpha depends on the mosaicity of the crystal which increases with the number of 'cooling cycles'. The satellite reflections do not have any contribution from...... the magnetic ordering, but their intensity has abrupt changes that coincide with changes in either the nuclear or the magnetic ordering parameter. Magnetoelastic effects seem to influence the ordering of the crystal....

  19. Changes in mobility of plastic crystal ethanol during its transformation into the monoclinic crystal state

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, Alejandro, E-mail: alejandro.sanz@csic.es; Nogales, Aurora; Ezquerra, Tiberio A. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain); Puente-Orench, Inés [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Instituto de Ciencia de Materiales de Aragón, ICMA-CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Jiménez-Ruiz, Mónica [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)

    2014-02-07

    Transformation of deuterated ethanol from the plastic crystal phase into the monoclinic one is investigated by means of a singular setup combining simultaneously dielectric spectroscopy with neutron diffraction. We postulate that a dynamic transition from plastic crystal to supercooled liquid-like configuration through a deep reorganization of the hydrogen-bonding network must take place as a previous step of the crystallization process. Once these precursor regions are formed, subsequent crystalline nucleation and growth develop with time.

  20. Electrophoretic enhanced micro arc oxidation of ZrO{sub 2}-HAp-TiO{sub 2} nanostructured porous layers

    Energy Technology Data Exchange (ETDEWEB)

    Samanipour, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Bayati, M.R., E-mail: mbayati@ncsu.edu [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC (United States); Zargar, H.R. [Department of Metals and Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Golestani-Fard, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of); Troczynski, T. [Department of Metals and Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Taheri, M. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of)

    2011-09-22

    Highlights: > ZrO{sub 2}-HA-TiO{sub 2} composite layers were synthesized via EPD/MAO hybrid technique. > Effect of the growth time on properties of the layers was studied. > Effect of the electrolyte composition on properties of the layers was studied. - Abstract: Micro arc oxidation (MAO) and electrophoretic deposition (EPD) processes were simultaneously employed to grow ZrO{sub 2}-HAp-TiO{sub 2} porous layers on titanium substrates under different conditions. Influence of the electrolyte composition and the growth time on surface morphology, topography, phase structure, and stoichiometry of the layers was investigated. The utilized electrolytes consisted of {beta}-glycerophosphate, calcium acetate, sodium phosphate, and micron sized yttria-stabilized zirconia with different concentrations. AFM and SEM evaluations revealed a rough surface with a porous structure with a pores size of 50-750 nm. The pores size increased with the time and the electrolyte concentration. Based on the XRD and XPS results, the layers consisted of anatase, hydroxyapatite, monoclinic ZrO{sub 2}, tetragonal ZrO{sub 2}, ZrO, CaTiO{sub 3}, and {alpha}-TCP phases whose fractions were observed to change depending on the synthesis conditions. The average crystalline size of the HAp phase was determined as {approx}54 nm. The nano-sized zirconia particles (d = 20-60 nm) were dispersed not only on surface, but also in depth of the layers. Utilizing thicker electrolytes and prolonging the growth time resulted in decomposition of hydroxyapatite as well as tetragonal ZrO{sub 2} to monoclinic ZrO{sub 2}. EDX results also showed that the zirconium wt% in the layers increased with the time. EPD-enhanced MAO (EEMAO) technique was expressed as an efficient route to fabricate ZrO{sub 2}-HAp-TiO{sub 2} multiphase systems within short times and only in one step.

  1. Metastable monoclinic ZnMoO4: hydrothermal synthesis, optical properties and photocatalytic performance.

    Science.gov (United States)

    Lv, Li; Tong, Wenming; Zhang, Yanbing; Su, Yiguo; Wang, Xiaojing

    2011-11-01

    Metastable monoclinic ZnMoO4 was successfully synthesized via a hydrothermal route with variation of reaction temperatures and time at pH value of 5.7. Systematic sample characterizations were carried out, including X-ray powder diffraction, scanning electron microscopy, Fourier transformed infrared spectra, UV-visible diffuse reflectance spectra, and photoluminescence spectra. The results show that all as-prepared ZnMoO4 samples were demonstrated to crystallize in a pure-phase of monoclinic wolframite structure. All samples were formed in plate-like morphology. Six IR active vibrational bands were observed in the wave number range of 400-900 cm(-1). The band gap of as-prepared ZnMoO4 was estimated to be 2.86 eV by Tauc equation. Photoluminescence measurement indicates that as-prepared ZnMoO4 exhibits a broad blue-green emission under excitation wavelength of 280 nm at room temperature. Photocatalytic activity of as-prepared ZnMoO4 was examined by monitoring the degradation of methyl orange dye in an aqueous solution under UV radiation of 365 nm. The as-prepared ZnMoO4 obtained at 180 degrees C for 40 h showed the best photocatalytic activity with completing degradation of MO in irradiation time of 120 min. Consequently, monoclinic ZnMoO4 proved to be an efficient near visible light photocatalyst.

  2. Formation energies of intrinsic point defects in monoclinic VO2 studied by first-principles calculations

    Science.gov (United States)

    Cui, Yuanyuan; Liu, Bin; Chen, Lanli; Luo, Hongjie; Gao, Yanfeng

    2016-10-01

    VO2 is an attractive candidate for intelligent windows and thermal sensors. There are challenges for developing VO2-based devices, since the properties of monoclinic VO2 are very sensitive to its intrinsic point defects. In this work, the formation energies of the intrinsic point defects in monoclinic VO2 were studied through the first-principles calculations. Vacancies, interstitials, as well as antisites at various charge states were taken into consideration, and the finite-size supercell correction scheme was adopted as the charge correction scheme. Our calculation results show that the oxygen interstitial and oxygen vacancy are the most abundant intrinsic defects in the oxygen rich and oxygen deficient condition, respectively, indicating a consistency with the experimental results. The calculation results suggest that the oxygen interstitial or oxygen vacancy is correlated with the charge localization, which can introduce holes or electrons as free carriers and subsequently narrow the band gap of monoclinic VO2. These calculations and interpretations concerning the intrinsic point defects would be helpful for developing VO2-based devices through defect modifications.

  3. Critical Role of Monoclinic Polarization Rotation in High-Performance Perovskite Piezoelectric Materials

    Science.gov (United States)

    Liu, Hui; Chen, Jun; Fan, Longlong; Ren, Yang; Pan, Zhao; Lalitha, K. V.; Rödel, Jürgen; Xing, Xianran

    2017-07-01

    High-performance piezoelectric materials constantly attract interest for both technological applications and fundamental research. The understanding of the origin of the high-performance piezoelectric property remains a challenge mainly due to the lack of direct experimental evidence. We perform in situ high-energy x-ray diffraction combined with 2D geometry scattering technology to reveal the underlying mechanism for the perovskite-type lead-based high-performance piezoelectric materials. The direct structural evidence reveals that the electric-field-driven continuous polarization rotation within the monoclinic plane plays a critical role to achieve the giant piezoelectric response. An intrinsic relationship between the crystal structure and piezoelectric performance in perovskite ferroelectrics has been established: A strong tendency of electric-field-driven polarization rotation generates peak piezoelectric performance and vice versa. Furthermore, the monoclinic MA structure is the key feature to superior piezoelectric properties as compared to other structures such as monoclinic MB , rhombohedral, and tetragonal. A high piezoelectric response originates from intrinsic lattice strain, but little from extrinsic domain switching. The present results will facilitate designing high-performance perovskite piezoelectric materials by enhancing the intrinsic lattice contribution with easy and continuous polarization rotation.

  4. Evaluation of physicochemical properties, and antimicrobial efficacy of monoclinic sulfur-nanocolloid

    Energy Technology Data Exchange (ETDEWEB)

    Roy Choudhury, Samrat, E-mail: samratroychoudhury@gmail.com [Indian Statistical Institute, Biological Sciences Division (India); Mandal, Amrita; Chakravorty, Dipankar [Indian Association for the Cultivation of Science (India); Gopal, Madhuban [Indian Agricultural Research Institute, Divisions of Agricultural Chemicals (India); Goswami, Arunava [Indian Statistical Institute, Biological Sciences Division (India)

    2013-04-15

    Stable nanocolloids of monoclinic sulfur ({beta}-SNPs) were prepared through 'water-in-oil microemulsion technique' at room temperature after suitable modifications of the surface. The morphology (rod shaped; {approx}50 nm in diameter) and allotropic nature (monoclinic) of the SNPs were investigated with Transmission Electron Microscopy and X-ray Diffraction technique. The surface modification, colloidal stability, and surface topology of {beta}-SNPs were evaluated with Fourier Transform Infrared Spectroscopy, zeta potential analysis, and Atomic Force Microscopy. Thermal decomposition pattern of these nanosized particles was determined by Thermo Gravimetric Analysis (TGA). {beta}-SNPs-colloids expressed excellent antimicrobial activities against a series of fungal and bacterial isolates with prominent deformities at their surface. In contrast, insignificant cytotoxicity was achieved against the human derived hepatoma (HepG2) cell line upon treatment with {beta}-SNPs. A simultaneous study was performed to determine the stock concentration of {beta}-SNP-colloids using a novel high phase liquid chromatographic method. Cumulative results of this study hence, elucidate the stabilization of nanosized monoclinic sulfur at room temperature and their potential antimicrobial efficacy over micron-sized sulfur.

  5. Stability increase of fuel clad with zirconium oxynitride thin film by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jee, Seung Hyun [Department of Materials Science and Engineering, Yonsei University, 134 Sinchon Dong, Seoul 120-749 (Korea, Republic of); Materials Research and Education Center, Dept. of Mechanical Engineering, Auburn University, 275 Wilmore Labs, AL 36849-5341 (United States); Kim, Jun Hwan; Baek, Jong Hyuk [Recycled Fuel Development Division, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon, 305-600 (Korea, Republic of); Kim, Dong-Joo [Materials Research and Education Center, Dept. of Mechanical Engineering, Auburn University, 275 Wilmore Labs, AL 36849-5341 (United States); Kang, Seong Sik [Regulatory Research Division, Korea Institute of Nuclear Safety, 19, Guseong-Dong, Yuseong-Gu, Daejeon, 305-338 (Korea, Republic of); Yoon, Young Soo, E-mail: yoonys@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 134 Sinchon Dong, Seoul 120-749 (Korea, Republic of)

    2012-06-01

    A zirconium oxynitride (ZON) thin film was deposited onto HT9 steel as a cladding material by a metalorganic chemical vapor deposition (MOCVD) in order to prevent a fuel-clad chemical interaction (FCCI) between a U-10 wt% Zr metal fuel and a clad material. X-ray diffraction spectrums indicated that the mixture of structures of zirconium nitride, oxide and carbide in the MOCVD grown ZON thin films. Also, typical equiaxial grain structures were found in plane and cross sectional images of the as-deposited ZON thin films with a thickness range of 250-500 nm. A depth profile using auger electron microscopy revealed that carbon and oxygen atoms were decreased in the ZON thin film deposited with hydrogen gas flow. Diffusion couple tests at 800 Degree-Sign C for 25 hours showed that the as-deposited ZON thin films had low carbon and oxygen content, confirmed by the Energy Dispersive X-ray Spectroscopy, which showed a barrier behavior for FCCI between the metal fuel and the clad. This result suggested that ZON thin film cladding by MOCVD, even with the thickness below the micro-meter level, has a high possibility as an effective FCCI barrier. - Highlights: Black-Right-Pointing-Pointer Zirconium oxynitride (ZON) deposited by metal organic chemical vapor deposition. Black-Right-Pointing-Pointer Prevention of fuel cladding chemical interaction (FCCI) investigated. Black-Right-Pointing-Pointer Interfusion reduced by between metal fuel (U-10 wt% Zr) and a HT9 cladding material. Black-Right-Pointing-Pointer Hydrogenation of the ZON during growth improved the FCCI barrier performance.

  6. A layered mixed zirconium phosphate/phosphonate with exposed carboxylic and phosphonic groups: X-ray powder structure and proton conductivity properties.

    Science.gov (United States)

    Donnadio, Anna; Nocchetti, Morena; Costantino, Ferdinando; Taddei, Marco; Casciola, Mario; da Silva Lisboa, Fábio; Vivani, Riccardo

    2014-12-15

    A novel mixed zirconium phosphate/phosphonate based on glyphosine, of formula Zr2(PO4)H5(L)2·H2O [L = (O3PCH2)2NCH2COO], was synthesized in mild conditions. The compound has a layered structure that was solved ab initio from laboratory PXRD data. It crystallizes in the monoclinic C2/c space group with the following cell parameters: a = 29.925(3), b = 8.4225(5), c = 9.0985(4) Å, and β = 98.474(6)°. Phosphate groups are placed inside the sheets and connect the zirconium atoms in a tetradentate fashion, while uncoordinated carboxylate and P-OH phosphonate groups are exposed on the layer surface. Due to the presence of these acidic groups, the compound showed remarkable proton conductivity properties, which were studied in a wide range of temperature and relative humidity (RH). The conductivity is strongly dependent on RH and reaches 1 × 10(-3) S cm(-1) at 140 °C and 95% RH. At this RH, the activation energy of conduction is 0.15 eV in the temperature range 80-140 °C. The similarities of this structure with related structures already reported in the literature were also discussed.

  7. SYNTHESIS, CHARACTERIZATION AND APPLICATION IN PEMFC OF ZIRCONIUM OXO PHOSPHATE-SULFATE

    Institute of Scientific and Technical Information of China (English)

    吴宗斌; 于景荣; 刘中民; 田鹏; 杨越; 许磊

    2004-01-01

    Mesoporous zirconium oxo phosphate-sulfate was synthesized by hydrothermal method with hexadecyltrithylammonium bromide(CTAB)as the template and with zirconium nitrate or zirconium oxychloride as zirconium source.The optimum two-stage process was established, ~(31)P MAS NMR showed that the states of phosphate species were changed with further postsynthesis treatment by sulfate acid. The transformations of the structures at different temperatures from room temperature to 1173 K were investigated by XRD. ...

  8. Template-Free Synthesis of Monoclinic BiVO4 with Porous Structure and Its High Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Pengyu Dong

    2016-08-01

    Full Text Available Monoclinic BiVO4 photocatalysts with porous structures were synthesized by a two-step approach without assistance of any templates. The as-prepared samples were characterized by X-ray diffraction pattern (XRD, scanning electron microscopy (SEM, Brunauer–Emmett–Teller (BET, ultraviolet–visible (UV–vis diffuse reflectance spectroscopy (DRS, photocurrent responses, and electrochemical impedance spectra (EIS. It is found that the as-prepared BiVO4 samples had a porous structure with aperture diameter of 50–300 nm. Moreover, the BET specific surface area of the porous BiVO4-200 °C sample reaches up to 5.69 m2/g, which is much higher than that of the sample of BiVO4 particles without porous structure. Furthermore, a possible formation mechanism of BiVO4 with porous structure was proposed. With methylene blue (MB as a model compound, the photocatalytic oxidation of organic contaminants in aqueous solution was investigated under visible light irradiation. It is found that the porous BiVO4-200 °C sample exhibits the best photocatalytic activity, and the photocatalytic rate constant is about three times of that of the sample of BiVO4 particles without porous structure. In addition, the photocurrent responses and electrochemical impedance spectra strongly support this conclusion.

  9. Photocatalytic degradation and removal mechanism of ibuprofen via monoclinic BiVO4 under simulated solar light.

    Science.gov (United States)

    Li, Fuhua; Kang, Yapu; Chen, Min; Liu, Guoguang; Lv, Wenying; Yao, Kun; Chen, Ping; Huang, Haoping

    2016-05-01

    Characterized as by X-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra techniques, BiVO4 photocatalyst was hydrothermally synthesized. The photocatalytic degradation mechanisms of ibuprofen (IBP) were evaluated in aqueous media via BiVO4. Results demonstrated that the prepared photocatalyst corresponded to phase-pure monoclinic scheelite BiVO4. The synthesized BiVO4 showed superior photocatalytic properties under the irradiation of visible-light. The photocatalytic degradation rate of IBP decreased with an increase in the initial IBP concentration. The degradation process followed first-order kinetics model. At an IBP concentration of 10 mg L(-1), while a BiVO4 concentration of 5.0 g L(-1) with pH value of 4.5, the rate of IBP degradation was obtained as 90% after 25 min. The photocatalytic degradation of IBP was primarily accomplished via the generation of superoxide radical (O2(•-)) and hydroxyl radicals ((•)OH). During the process of degradation, part of the (•)OH was converted from the O2(•-). The direct oxidation of holes (h(+)) made a minimal contribution to the degradation of IBP.

  10. Elimination of phosphate and zirconium in the high-activity fraction resulting from TRUEX partitioning of ICPP zirconium calcines

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, K.N.; Tillotson, R.D.; Tullock, P.A. [and others

    1997-07-01

    Laboratory testing was undertaken with the aim of developing a TRUEX flowsheet that would efficiently remove actinides from solutions of dissolved zirconium calcine and minimize the glass volume produced from the ensuing high-activity fraction. A TRUEX flowsheet is recommended for testing in the 2-cm centrifugal contactor pilot-plant based on the results from this testing. These laboratory tests show that zirconium recovery in the high activity fraction is minimized by scrubbing with an optimized NHF concentration of 0.2 M. This NH4F concentration in the scrub allowed the HEDPA strip concentration to be reduced from 0.04 M to 0.004 M because HEDPA is not consumed by zirconium. Complete TRU stripping was also achieved in these laboratory tests with 0.004 M HEDPA. Data from the small-scale laboratory batch contact tests were used in the Generic TRUEX Model (GTM) to evaluate the proposed flowsheet under counter-current conditions. GTM results indicate the raffinate will meet the Class A non-TRU limit of < 10 nCi/g in six extraction stages (O/A = 1), and quantitative actinide recovery will be achieved with the 0.004 M HEDPA in six strip stages (O/A = 1). Only 6.6 % of the initial zirconium concentration is anticipated to be recovered with the actinides, indicating the four scrub stages (O/A = 3) efficiently removes zirconium from the TRUEX solvent. In addition to recommending an improved TRUEX flowsheet for testing in the 2-cm centrifugal contactor pilot-plant, this work has shown that small reductions in zirconium extraction drastically improves flowsheet performance. These small changes in zirconium extraction can be accomplished by modifying the calcine dissolution parameters. Therefore, further calcine dissolution testing followed by TRUEX testing with the resulting feed solutions is also recommended.

  11. Sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides

    Directory of Open Access Journals (Sweden)

    R.V. Smotraiev

    2016-05-01

    Full Text Available The actual problem of water supply in the world and in Ukraine, in particular, is a high level of pollution in water resources and an insufficient level of drinking water purification. With industrial wastewater, a significant amount of pollutants falls into water bodies, including suspended particles, sulfates, iron compounds, heavy metals, etc. Aim: The aim of this work is to determine the impact of aluminum and manganese ions additives on surface and sorption properties of zirconium oxyhydroxide based sorbents during their production process. Materials and Methods: The sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides were prepared by sol-gel method during the hydrolysis of metal chlorides (zirconium oxychloride ZrOCl2, aluminum chloride AlCl3 and manganese chloride MnCl2 with carbamide. Results: The surface and sorption properties of sorbents based on xerogels of zirconium, aluminum and manganese oxyhydroxides were investigated. X-ray amorphous structure and evolved hydroxyl-hydrate cover mainly characterize the obtained xerogels. The composite sorbents based on xerogels of zirconium oxyhydroxide doped with aluminum oxyhydroxide (aS = 537 m2/g and manganese oxyhydroxide (aS = 356 m2/g have more developed specific surface area than single-component xerogels of zirconium oxyhydroxide (aS = 236 m2/g and aluminum oxyhydroxide (aS = 327 m2/g. The sorbent based on the xerogel of zirconium and manganese oxyhydroxides have the maximum SO42--ions sorption capacity. It absorbs 1.5 times more SO42–-ions than the industrial anion exchanger AN-221. The sorbents based on xerogels of zirconium oxyhydroxide has the sorption capacity of Fe3+-ions that is 1.5…2 times greater than the capacity of the industrial cation exchanger KU-2-8. The Na+-ions absorption capacity is 1.47…1.56 mmol/g for each sorbent. Conclusions: Based on these data it can be concluded that the proposed method is effective for sorbents production based on

  12. The Study Programm Report of the Corrosion Behavior of New Zirconium-based Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The corrosion of fuel cladding in PWR limits the extension of burnup. To compare the corrosion resistance of Zr-4 and new zirconium-based alloys, the out-of-pile water-side corrosion test has been conducted for these materials.To study the effects of heat flux on the corrosion of cladding, and keep the surface of cladding as an original ’as-received’ statement, the heat elements are introduced into the inside of the cladding tubes.The materials have been exposed for 205 d till now. The oxide film performed on the surface of cladding is black and glossy. The thickness of oxide is measured by the method of eddy current.

  13. Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

    Science.gov (United States)

    Aryanfar, Asghar; Thomas, John; Van der Ven, Anton; Xu, Donghua; Youssef, Mostafa; Yang, Jing; Yildiz, Bilge; Marian, Jaime

    2016-10-01

    A mesoscopic chemical reaction kinetics model to predict the formation of zirconium oxide and hydride accumulation light-water reactor (LWR) fuel clad is presented. The model is designed to include thermodynamic information from ab initio electronic structure methods as well as parametric information in terms of diffusion coefficients, thermal conductivities and reaction constants. In contrast to approaches where the experimentally observed time exponents are captured by the models by design, our approach is designed to be predictive and to provide an improved understanding of the corrosion process. We calculate the time evolution of the oxide/metal interface and evaluate the order of the chemical reactions that are conducive to a t 1/3 dependence. We also show calculations of hydrogen cluster accumulation as a function of temperature and depth using spatially dependent cluster dynamics. Strategies to further cohesively integrate the different elements of the model are provided.

  14. Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

    Science.gov (United States)

    Aryanfar, Asghar; Thomas, John; Van der Ven, Anton; Xu, Donghua; Youssef, Mostafa; Yang, Jing; Yildiz, Bilge; Marian, Jaime

    2016-11-01

    A mesoscopic chemical reaction kinetics model to predict the formation of zirconium oxide and hydride accumulation light-water reactor (LWR) fuel clad is presented. The model is designed to include thermodynamic information from ab initio electronic structure methods as well as parametric information in terms of diffusion coefficients, thermal conductivities and reaction constants. In contrast to approaches where the experimentally observed time exponents are captured by the models by design, our approach is designed to be predictive and to provide an improved understanding of the corrosion process. We calculate the time evolution of the oxide/metal interface and evaluate the order of the chemical reactions that are conducive to a t 1/3 dependence. We also show calculations of hydrogen cluster accumulation as a function of temperature and depth using spatially dependent cluster dynamics. Strategies to further cohesively integrate the different elements of the model are provided.

  15. Photocatalytic performance of freestanding tetragonal zirconia nanotubes formed in H2O2/NH4F/ethylene glycol electrolyte by anodisation of zirconium

    Science.gov (United States)

    Rozana, Monna; Izza Soaid, Nurul; Kian, Tan Wai; Kawamura, Go; Matsuda, Atsunori; Lockman, Zainovia

    2017-04-01

    ZrO2 nanotubes (ZrNTs) were produced by anodisation of zirconium foil in H2O2/NH4F/ethylene glycol electrolyte. The as-anodised foils were then soaked in the anodising electrolyte for 12 h. Soaking weakens the adherence of the anodic layer from the substrate resulting in freestanding ZrNTs (FS-ZrNTs). Moreover, the presence of H2O2 in the electrolyte also aids in weakening the adhesion of the film from the foil, as foil anodised in electrolyte without H2O2 has good film adherence. The as-anodised FS-ZrNTs film was amorphous and crystallised to predominantly tetragonal phase upon annealing at >300 °C. Annealing must, however, be done at <500 °C to avoid monoclinic ZrO2 formation and nanotubes disintegration. FS-ZrNTs annealed at 450 °C exhibited the highest photocatalytic ability to degrade methyl orange (MO), whereby 82% MO degradation was observed after 5 h, whereas FS-ZrNTs with a mixture of monoclinic and tetragonal degraded 70% of MO after 5 h.

  16. In situ ion irradiation of zirconium carbide

    Science.gov (United States)

    Ulmer, Christopher J.; Motta, Arthur T.; Kirk, Mark A.

    2015-11-01

    Zirconium carbide (ZrC) is a candidate material for use in one of the layers of TRISO coated fuel particles to be used in the Generation IV high-temperature, gas-cooled reactor, and thus it is necessary to study the effects of radiation damage on its structure. The microstructural evolution of ZrCx under irradiation was studied in situ using the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory. Samples of nominal stoichiometries ZrC0.8 and ZrC0.9 were irradiated in situ using 1 MeV Kr2+ ions at various irradiation temperatures (T = 20 K-1073 K). In situ experiments made it possible to continuously follow the evolution of the microstructure during irradiation using diffraction contrast imaging. Images and diffraction patterns were systematically recorded at selected dose points. After a threshold dose during irradiations conducted at room temperature and below, black-dot defects were observed which accumulated until saturation. Once created, the defect clusters did not move or get destroyed during irradiation so that at the final dose the low temperature microstructure consisted only of a saturation density of small defect clusters. No long-range migration of the visible defects or dynamic defect creation and elimination were observed during irradiation, but some coarsening of the microstructure with the formation of dislocation loops was observed at higher temperatures. The irradiated microstructure was found to be only weakly dependent on the stoichiometry.

  17. 40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.

    Science.gov (United States)

    2010-07-01

    ... primary zirconium and hafnium subcategory. 421.330 Section 421.330 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Zirconium and Hafnium Subcategory § 421.330 Applicability: Description of the primary zirconium and hafnium subcategory. The provisions of this subpart are applicable to discharges...

  18. Adsorption Capacity of Zirconium on Silica Gel in Nitric Acid Solution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In Purex process, fission product zirconium is a very troublesome element. Because zirconium canreact chemically with decomposed products from TBP, and further form polymer, surface feculence, andthe third phase. The surface feculence affects the extraction process. Zirconium can be removed by

  19. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  20. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Science.gov (United States)

    2010-07-01

    ... zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL... POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This subpart applies to discharges of pollutants to waters of...

  1. Modified tricalcium silicate cement formulations with added zirconium oxide.

    Science.gov (United States)

    Li, Xin; Yoshihara, Kumiko; De Munck, Jan; Cokic, Stevan; Pongprueksa, Pong; Putzeys, Eveline; Pedano, Mariano; Chen, Zhi; Van Landuyt, Kirsten; Van Meerbeek, Bart

    2017-04-01

    This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO2. TCS powders were prepared by adding ZrO2 at six different concentrations. The powders were mixed with 1 M CaCl2 solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO2) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay. Adding ZrO2 to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p  0.05). EPMA revealed a more even distribution of ZrO2 within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic. ZrO2 can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO2 made TCS cements more biocompatible. TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

  2. Translucency and Strength of High Translucency Monolithic Zirconium Oxide Materials

    Science.gov (United States)

    2016-05-17

    ART 1280477229 ~!~::~.:.:.,.._.._,/’Ut 4th ENDORSEMENT (59 MDW/SGVU Use Only) 43. DATE RECEIVED 144. SENIOR AUTHOR NOTIFIED BY PHONE OF APPROVAL OR...the most esthetic full veneer restorative material in dentistry for many years. In the mid- 1900 ’s, dental materials researchers began marketing and

  3. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    Science.gov (United States)

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications.

  4. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    Directory of Open Access Journals (Sweden)

    Ortal Mizrahy

    Full Text Available The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs, present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH, on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications.

  5. High-pressure syntheses and crystal structures of monoclinic B-Ho{sub 2}O{sub 3} and orthorhombic HoGaO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hering, Stefanie A. [Dept. Chemie und Biochemie, Ludwig-Maximilians-Univ. Muenchen (Germany); Huppertz, Hubert [Inst. fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Univ. Innsbruck (Austria)

    2009-09-15

    Monoclinic holmium sesquioxide B-Ho{sub 2}O{sub 3} and orthorhombic holmium orthogallate HoGaO{sub 3} were synthesized in a Walker-type multianvil apparatus under high-pressure / high-temperature conditions of 11.5 GPa / 1250 C and 7.5 GPa / 1250 C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data, collected at r.t. The monoclinic holmium oxide crystallizes in the space group C2/m (Z = 6) with the parameters a = 1394.7(3), b = 350.83(7), c = 865.6(2) pm, {beta} = 100.23(3) . R1 = 0.0517, wR2 = 0.1130 (all data), and the orthorhombic compound HoGaO{sub 3} in Pnma (Z = 4) with the parameters a = 553.0(2), b = 753.6(2), c = 525.4(2) pm. R1 = 0.0222, and wR2 = 0.0303 (all data). (orig.)

  6. Electron beam niobium oxide powder deposition

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, D.S. [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil); Nono, M.C.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Silva, C.R.M. [Universidade de Brasilia (UnB), Brasilia, DF (Brazil)

    2009-07-01

    Full text: Zirconium oxide applied by Electron Beam –Physical Vapor Deposition can produce high quality coatings for high temperature blades. In this work niobium, yttrium and zirconium oxides were applied on metallic substrates, using EB-PVD, aiming thermal conductivity reduction. Coating characterization has been performed by X-ray diffractometry and scanning electron microscopy. X-ray diffractometry shows only tetragonal phase for the composition range evaluated, with tetragonality increase for higher niobium oxide amounts. Higher amounts of niobium promote reduction of ceramic coating theoretical density and thermal conductivity. (author)

  7. Coordinate-Invariant Lyddane-Sachs-Teller Relationship for Polar Vibrations in Materials with Monoclinic and Triclinic Crystal Systems.

    Science.gov (United States)

    Schubert, Mathias

    2016-11-18

    A coordinate-invariant generalization of the Lyddane-Sachs-Teller relation is presented for polar vibrations in materials with monoclinic and triclinic crystal systems. The generalization is derived from an eigendielectric displacement vector summation approach, which is equivalent to the microscopic Born-Huang description of polar lattice vibrations in the harmonic approximation. An expression for a general oscillator strength is also described for materials with monoclinic and triclinic crystal systems. A generalized factorized form of the dielectric response characteristic for monoclinic and triclinic materials is proposed. The generalized Lyddane-Sachs-Teller relation is found valid for monoclinic β-Ga_{2}O_{3}, where accurate experimental data became available recently from a comprehensive generalized ellipsometry investigation [Phys. Rev. B 93, 125209 (2016)]. Data for triclinic crystal systems can be measured by generalized ellipsometry as well, and are anticipated to become available soon and results can be compared with the generalized relations presented here.

  8. Effect of Chloride ion and Zirconium hydride on thr corrosion and SCC behaviors of functionally graded Zirconium alloy p.683

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y. [Department of Metallurgical and Materials Engineering, Sunmoon University, Asam (Korea, Republic of); Kim, B. G.; Lee, J. W.; Kang, Y. H. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2000-07-01

    Effect of chloride ion and zirconium hydride on the corrosion and stress corrosion cracking behaviors of functionally graded zirconium alloy was studied to develop an advanced nuclear cladding tubing. The functionally graded zirconium alloy had composition gradient of niobium, which was prepared with a hot pressing followed by cold deformation. The corrosion rates and potentials decreased with increasing FeCl{sub 3} and hydride content. The corrosion potentials before and after hydriding are -4.3 V{sub SHE}, 8.8x10{sup -5} A{sub cm}{sup -2} and -12.5 V{sub SHE}, 3.9x10{sup -4} A{sub cm}{sup -2}, respectively. The stress corrosion cracking susceptibility decreased with elongation rate, indicating the saturation value at 5x10{sup -7} sec{sup -1}. SEM observation showed that brittle fracture with corrosion products and pits were observed on the failed surface of hydrided zirconium alloy, suggesting anodic dissolution occurred during exposure after cracking growth along zirconium hydrides. (author)

  9. Process for electroless deposition of metals on zirconium materials

    Science.gov (United States)

    Donaghy, Robert E.

    1978-01-01

    A process for the electroless deposition of a metal layer on an article comprised of zirconium or a zirconium alloy is disclosed. The article is activated in an aged aqueous solution comprising from about 10 to about 20 grams per liter ammonium bifluoride and from about 0.75 to about 2 grams per liter of sulfuric acid. The solution is aged by immersion of pickled zirconium in the solution for at least about 10 minutes. The loosely adhering film formed on the article in the activating step is removed and the article is contacted with an electroless plating solution containing the metal to be deposited on the article upon sufficient contact with the article.

  10. Process for electrolytic deposition of metals on zirconium materials

    Science.gov (United States)

    Donaghy, Robert E.

    1979-01-30

    A process for the electrolytic deposition of a metal layer on an article comprised of zirconium or a zirconium alloy is disclosed. The article is activated in an aged aqueous solution comprising from about 10 to about 20 grams per liter ammonium bifluoride and from about 0.75 to about 2 grams per liter of sulfuric acid. The solution is aged by immersion of pickled zirconium in the solution for at least about 10 minutes. The loosely adhering film formed on the article in the activating step is removed and the article is contacted with an electrolytic plating solution containing the metal to be deposited on the article in the presence of an electrode receiving current.

  11. ZIRCONIUM ALLERGIES CAUSED BY ORAL DENTAL MATERIALS. A GENERAL REVIEW

    Directory of Open Access Journals (Sweden)

    Georgeta SINIŢCHI

    2017-06-01

    Full Text Available Dental materials may provoke general or local pathologies and various immune-allergic manifestations. For example, metal allergies are triggered by environmental or – mainly – occupational factors, being more numerous in recent years, particularly through the introduction, in dentistry, of new types of dentures and implants. Zirconium is a transition metal with several beneficial effects, namely: biocompatibility, good aesthetics, slightly translucent fitting, efficient cohesion with ceramics. Pathological effects of zirconium: systemic toxicity (carcinogenic potential, raising syndrome oral allergic dermatitis. Allergists recommend a thorough knowledge on the medical history of patients, on the data of personal and hereditary allergic investigations confirming a possible sensitivity. General and specific allergic investigations for establishing a possible sensitivity to zirconium are: epicutaneous tests, serological tests (TTL and, and confirmation of allergenic eviction. Equally, balancing of the benefit/cost ratio should be calculated.

  12. Zirconium Diboride Powders Synthesized by Boro/Carbothermal Reaction Using Sol-Gel Technology

    Institute of Scientific and Technical Information of China (English)

    季惠明; 范红娜; 丰红军; 孙晓红

    2015-01-01

    A single phase of zirconium diboride(ZrB2)powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride(ZrOCl2·8H2O), nano-scale boron and sucrose(C12H22O11)as the starting materials and propylene oxide(PO)as complexing agent at a low temperature. Simultaneously, the experimen-tal and theoretical studies of ZrB2 synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO2 phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400℃in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O sys-tem producing ZrB2 by boro/carbothermal reaction was established based on thermodynamic analysis. It was also ob-served that, with the increase of reaction temperature, the reaction which produced ZrB2 powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.

  13. Structural studies of calcium phosphate doped with titanium and zirconium obtained by high-energy mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C C; Sombra, A S B [Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Physics Department, Federal University of Ceara, Campus do Pii, Postal Code 6030, 60455-760, Fortaleza-Ceara (Brazil)], E-mail: sombra@fisica.ufc.br

    2009-12-15

    In this paper, we present a new variation of the solid-state procedure on the synthesis of bioceramics with titanium (CapTi) and zirconium (CapZr), considering that zirconium (ZrO{sub 2}) and titanium oxide (TiO{sub 2}) are strengthening agents, due to their superb force and fracture toughness. The high efficiency of the calcination process opens a new way of producing commercial amounts of nanocrystalline bioceramics. In this work, a new variation of the solid-state procedure method was used to produce nanocrystalline powders of titanium and zirconium, using two different experimental chemical routes: CapTi: Ca(H{sub 2}PO{sub 4}){sub 2}+TiO{sub 2} and CapZr: Ca(H{sub 2}PO{sub 4}){sub 2}+ZrO{sub 2}. The powders were submitted to calcination processes (CapTic and CapZrc) at 800, 900 and 1000 deg. C. The calcium titanium phosphate phase, CaTi{sub 4}P{sub 6}O{sub 24}, was obtained in the CapTic reaction and the calcium zirconium phosphate, CaZr{sub 4}P{sub 6}O{sub 24}, was obtained in the CapZrc reaction. The obtained ceramics were characterized by x-ray powder diffraction (XRD), infrared (IR) spectroscopy, Raman scattering spectroscopy (RSS) and scanning electron microscopy (SEM) analysis. This method was compared with the milling process (CapTim and CapZrm), where in the last process the melting is not necessary and the powder obtained is nanocrystalline. The calcium titanium phosphate phase, CaTi{sub 4}P{sub 6}O{sub 24}, was obtained in the reaction CapTim, but in CapZrm the formation of any calcium phosphate phase even after 15 h of dry mechanical alloying was not observed.

  14. Structural studies of calcium phosphate doped with titanium and zirconium obtained by high-energy mechanical alloying

    Science.gov (United States)

    Silva, C. C.; Sombra, A. S. B.

    2009-12-01

    In this paper, we present a new variation of the solid-state procedure on the synthesis of bioceramics with titanium (CapTi) and zirconium (CapZr), considering that zirconium (ZrO2) and titanium oxide (TiO2) are strengthening agents, due to their superb force and fracture toughness. The high efficiency of the calcination process opens a new way of producing commercial amounts of nanocrystalline bioceramics. In this work, a new variation of the solid-state procedure method was used to produce nanocrystalline powders of titanium and zirconium, using two different experimental chemical routes: CapTi: Ca(H2PO4)2+TiO2 and CapZr: Ca(H2PO4)2+ZrO2. The powders were submitted to calcination processes (CapTic and CapZrc) at 800, 900 and 1000 °C. The calcium titanium phosphate phase, CaTi4P6O24, was obtained in the CapTic reaction and the calcium zirconium phosphate, CaZr4P6O24, was obtained in the CapZrc reaction. The obtained ceramics were characterized by x-ray powder diffraction (XRD), infrared (IR) spectroscopy, Raman scattering spectroscopy (RSS) and scanning electron microscopy (SEM) analysis. This method was compared with the milling process (CapTim and CapZrm), where in the last process the melting is not necessary and the powder obtained is nanocrystalline. The calcium titanium phosphate phase, CaTi4P6O24, was obtained in the reaction CapTim, but in CapZrm the formation of any calcium phosphate phase even after 15 h of dry mechanical alloying was not observed.

  15. Lanthanum and zirconium co-doped ZnO nanocomposites: synthesis, characterization and study of photocatalytic activity.

    Science.gov (United States)

    Moafi, Hadi Fallah; Zanjanchi, Mohammad Ali; Shojaie, Abdollah Fallah

    2014-09-01

    Nanocomposits of zinc oxide co-doped with lanthanum and zirconium were prepared using the modified sol-gel method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), and BET surface area measurement. For comparison, the La and Zr mono doped ZnO have also been prepared under the same conditions. The XRD results revealed that all the materials showed a hexagonal wurtzite crystal structure. It was found that the particle size of La-Zr-doped ZnO is much smaller as compared to that of pure ZnO. The effect of operational parameters such as, doping concentration, catalyst loading, pH and initial concentration of methylene blue on the extent of degradation was investigated. The photocatalytic activity of the undoped ZnO, mono-doped and La-Zr-ZnO photocatalysts was evaluated by the photocatalytic degradation of methylene blue in aqueous solution. The presence of lanthanium and/or zirconium causes a red shift in the absorption band of ZnO. The results show that the photocatalytic activity of the La-Zr-ZnO photocatalyst is much higher than that of undoped and mono-doped ZnO, resulting from the La and Zr synergistic effect. The co-operation of the lanthanum and zirconium ion leads to the narrowing of the band gap and greatly improves the photocatalytic activity. The photocatalyst co-doped with lanthanum and zirconium 4 mol% shows the best photoactivity and photodecomposition efficiencies were improved by 92% under UV-Vis irradiation at the end of 30 min, compared with the pure and mono doped samples.

  16. Post-irradiation evaluation of hydrogen and deuterium concentration in zirconium alloys; Evaluacion post-irradiacion de la concentracion de hidrogeno mas deuterio en aleaciones de circonio

    Energy Technology Data Exchange (ETDEWEB)

    Banchik, A.D.; Bianchi, D.; Rios, R. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza

    1999-11-01

    The mechanical and metallurgical properties of the components of the nucleus of a reactor change along its operation life. The changes in the zirconium components include the pick-up of a fraction of the hydrogen produced by the reaction of zirconium with water and the development of a zirconium oxide layer at the zirconium oxide layer at the zirconium surfaces in contact with water. The amount of pick-up depends of several factors, that way it is necessary to measure it periodically. The PHWR reactors, that work with heavy water, incorporate deuterium instead of hydrogen, which added to the hydrogen incorporated in the matrix during fabrication increases the total content of hydrogen plus deuterium A method for measurement of the deuterium content in the hydrogen plus deuterium mix with a Leco equipment for hydrogen is presented, the statistical errors are estimated with specimen duplicates and the procedure for reducing the normal background is described. A method is developed for measuring the deuterium concentration in a mixture with a Leco equipment for hydrogen. Based in the theory of gas mixture it has been determinate that the deuterium concentration values given by that equipment are in ppm of hydrogen equivalent. The value of the correction factor FC for correcting the digital reading is FC = 1,47 +/- 0,06. The statistical error of the measurements is estimated by duplicates of the active specimens, and it is was determined that more than 90% of the results have an error lower than 2 ppm. A procedure for reducing the background based on a double melting of the tin flux is proposed, the average value is reduced from 0,9 ppm to 0,6 and the standard deviation from 0,35 ppm to 0,15 ppm. (author) 8 refs., 4 figs., 3 tabs.

  17. In-situ stabilization of radioactive zirconium swarf

    Science.gov (United States)

    Hess, Clay C.

    1999-01-01

    The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes.

  18. Determination of uranium and zirconium by flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Alvaro S.F. de; Domingues, Maria de L.F.; Rocha, Valeska P. de Araujo; Jesus, Camila S. de, E-mail: alvaro@ien.gov.br, E-mail: valeska@ien.gov.br, E-mail: luma@ien.gov.br, E-mail: camilasaj@gmail.com [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    As an integral part of chemical quality control of nuclear materials a method for determination of uranium and zirconium, in a mixture is presented. A simple, cheap, selective and quantitative Flow Injection Analysis (FIA) system was developed. Zirconium and uranium were determinate in presence of each other and no prior separation was needed. Arsenazo III was used as a colorimetric reagent and parameters such as acidity and reagents concentration were studied and optimized. An analytical throughput of 30 sample determination per hour was obtained. (author)

  19. Isotopic zirconium as a probe of AGB nucleosynthesis theory

    Science.gov (United States)

    Malaney, R. A.

    Nuclear reaction network calculations of the zirconium relative isotope abundances in AGB stars are presented. It is shown how these isotopic abundances depend on the AGB stellar mass and on the uncertain neutron absorption cross section for Zr-96. With regard to observations of the zirconium isotopes in S stars, it is shown how the many neutron exposure mechanisms associated with AGB thermal pulses cannot be operating in these stars. A less predictable scheme in which only a few neutron exposures take place appears to be more consistent with the reported S star observations.

  20. Zirconium determination by cooling curve analysis during the pyroprocessing of used nuclear fuel

    Science.gov (United States)

    Westphal, B. R.; Price, J. C.; Bateman, K. J.; Marsden, K. C.

    2015-02-01

    An alternative method to sampling and chemical analyses has been developed to monitor the concentration of zirconium in real-time during the casting of uranium products from the pyroprocessing of used nuclear fuel. The method utilizes the solidification characteristics of the uranium products to determine zirconium levels based on standard cooling curve analyses and established binary phase diagram data. Numerous uranium products have been analyzed for their zirconium content and compared against measured zirconium data. From this data, the following equation was derived for the zirconium content of uranium products:

  1. Investigation into reproducibility of a synthesis of modified zirconium phosphate (PZ) samples based on zirconium (4) salts of various quality

    Energy Technology Data Exchange (ETDEWEB)

    Benderskaya, L.A.; Bojchinova, E.S.; Nikolaeva, R.B.; Vinter, I.K. (Leningradskij Tekhnologicheskij Inst. (USSR))

    1982-03-01

    The possibility is studied of producing a PZ ionite with good ion exchange properties, reproducible from one synthesis to another, regardless of the quality of zirconium initial salt. It is established that, during the PZ synthesis on the base of Zr salts of different quality, the TPZ ionites, prepared on the base of Zr (4) soluble complex with EDTA, possess the best sorption properties at the maximum structure reproducibility. Comparatively low and definite degree of zirconium (4) polymerization in the alkaline solution of its complex with EDTA results in the formation of TPZ initial nuclei of reproducible sizes and composition, whereas their slow growth due to a gradual destruction of zirconium (4) complexonate, especially stable in an acid medium, contributes to the formation of reproducible large-globular hydrogel structure in the process of its precipitation.

  2. Seismic transpressive basement faults and monocline development in a foreland basin (Eastern Guadalquivir, SE Spain)

    Science.gov (United States)

    Pedrera, A.; Ruiz-Constán, A.; Marín-Lechado, C.; Galindo-Zaldívar, J.; González, A.; Peláez, J. A.

    2013-12-01

    We examine the late Tortonian to present-day deformation of an active seismic sector of the eastern Iberian foreland basement of the Betic Cordillera, in southern Spain. Transpressive faults affecting Paleozoic basement offset up to Triassic rocks. Late Triassic clays and evaporites constitute a décollement level decoupling the basement rocks and a ~100 m thick cover of Jurassic carbonates. Monoclines trending NE-SW to ENE-WSW deform the Jurassic cover driven by the propagation of high-angle transpressive right-lateral basement faults. They favor the migration of clays and evaporites toward the propagated fault tip, i.e., the core of the anticline, resulting in fluid overpressure, fluid flow, and precipitation of fibrous gypsum parallel to a vertical σ3. The overall geometry of the studied monoclines, as well as the intense deformation within the clays and evaporites, reproduces three-layer discrete element models entailing a weak middle unit sandwiched between strong layers. Late Tortonian syn-folding sediments recorded the initial stages of the fault-propagation folding. Equivalent unexposed transpressive structures and associated monoclines reactivated under the present-day NW-SE convergence are recognized and analyzed in the Sabiote-Torreperogil region, using seismic reflection, gravity, and borehole data. A seismic series of more than 2100 low-magnitude earthquakes was recorded within a very limited area of the basement of this sector from October 2012 to May 2013. Seismic activity within a major NE-SW trending transpressive basement fault plane stimulated rupture along a subsidiary E-W (~N95°E) strike-slip relay fault. The biggest event (mbLg 3.9, MW 3.7) occurred at the junction between them in a transpressive relay sector.

  3. Trivalent metallocene chemistry of some uranium, titanium, and zirconium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lukens, Jr., Wayne Wendell [Univ. of California, Berkeley, CA (United States)

    1995-05-01

    Dicyclopentadienyluranium halide dimers have been prepared and their solution behavior examined. These molecules exist as dimers in solution, and the halide ligands undergo rapid site exchange on the NMR timescale above 50 C. Analogous dicyclopentadienyluranium hydroxide dimers have also been prepared; they oxidatively eliminate hydrogen to give the corresponding oxide dimers. Mechanism of this reaction is consistent with αmigration of one of the hydroxide hydrogen atoms to a uranium center followed by elimination of hydrogen. Ground state of [(Me3Si)2C5H3]3M M = Nd, U and their base adducts has been examined by variable temperature magnetic susceptibility and EPR spectroscopy. The ground state is found to be 4I9/2 with a crystal field state consisting largely of Jz = 1/2 lowest, in agreement with previous studies on tris-cyclopentadienylneodymium complexes. The zirconium metallocene Cp3Zr has been prepared, characterized crystallographically, and its reactivity studied. Its chemical behavior is controlled by presence of an electron in the non-bonding, dz2 orbital which prevents formation of base adducts Of Cp3Zr, but allows Cp3Zr to abstract atoms from other molecules. Electonic and EPR spectra of Cp*2TiX complexes, where Cp* is Me5C5 and X is a monodentate, anionic ligand such as halide, have been studied. A π-bonding spectrochemical series is developed, and trends in π-bonding ability are found similar to those in other inorganic complexes. The β-agostic interactions in Cp*2TiN(Me)Ph have been examined using variable temperature EPR spectroscopy, and the enthalpy/entropy of the interaction determined. In Cp*2TiEt, enthalpy of the β-agostic interaction is -1.9 kcal/mol. The titanocene anion, Cp*2TiLi(TMEDA) (TMEDA is N,N,N`,N`-tetramethylethylenediamine), has been

  4. Characterization of uranium and uranium-zirconium deposits produced in electrorefining of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Totemeier, T.C.

    1997-09-01

    This paper describes the metallurgical characterization of deposits produced in molten salt electrorefining of uranium and uranium - 10.% zirconium alloy. The techniques of characterization are described with emphasis on considerations given to the radioactive and pyrophoric nature of the samples. The morphologies observed and their implications for deposit performance are also presented - samples from pure uranium deposits were comprised of chains of uranium crystals with a characteristic rhomboidal shape, while morphologies of samples from deposits containing zirconium showed more polycrystalline features. Zirconium was found to be present as a second, zirconium metal phase at or very near the uranium-zirconium dendrite surfaces. Higher collection efficiencies and total deposit weights were observed for the uranium-zirconium deposits; this performance increase is likely a result of better mechanical properties exhibited by the uranium-zirconium dendrite morphology. 18 refs., 10 figs., 1 tab.

  5. Identification of monoclinic calcium pyrophosphate dihydrate and hydroxyapatite in human sclera using Raman microspectroscopy

    DEFF Research Database (Denmark)

    Chen, Ko-Hua; Li, Mei-Jane; Cheng, Wen-Ting;

    2009-01-01

    Raman microspectroscopy was first used to determine the composition of a calcified plaque located at the pterygium-excision site of a 51-year-old female patient's left nasal sclera after surgery. It was unexpectedly found that the Raman spectrum of the calcified sample at 1149, 1108, 1049, 756, 517...... to the characteristic peak at 958/cm of hydroxyapatite (HA). This is the first study to report the spectral biodiagnosis of both monoclinic CPPD and HA co-deposited in the calcified plaque of a patient with sclera dystrophic calcification using Raman microspectroscopy....

  6. Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

    Institute of Scientific and Technical Information of China (English)

    Sirikamon Saengmee-anupharb; Toemsak Srikhirin; Boonyanit Thaweboon; Sroisiri Thaweboon; Taweechai Amornsakchai; Surachai Dechkunakorn; Theeralaksna Suddhasthira

    2013-01-01

    Objective: To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods: The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candidaalbicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results: All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5-3.0 µm) and more uniformly shaped than AgZ. Conclusions: Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

  7. Transformation of Oximes and Alcohols to Carbonyl Compounds Using Amberlite IRA-400 Supported Chromic Acid in the Presence of Zirconium Tetrachloride

    Institute of Scientific and Technical Information of China (English)

    BAHRAMI, Kiumars; KHODAEIMohammad-Mehdi; GORGIN-KARAJI, Usef

    2009-01-01

    A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ketones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tetrachlo-ride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other functional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method. A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ke-tones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tet-rachloride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other func-tional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method.

  8. Preparation of nanosized barium zirconate powder by thermal decomposition of urea in an aqueous solution containing barium and zirconium, and by calcination of the precipitate

    OpenAIRE

    Boschini, Frédéric; Robertz, B.; Rulmont, André; Cloots, Rudi

    2003-01-01

    The synthesis of barium zirconate was initiated by urea induced homogeneous precipitation followed by a "low temperature" thermal treatment. The kinetic of the reaction and the optimum urea/cation ratio have been determined by means of X-ray diffraction and Inductive Coupled Plasma analyses. It has been demonstrated that an amorphous zirconium hydrated oxide starts to precipitate followed by the precipitation of barium carbonate. A calcination at 1200 degreesC during 2 h gives rise to the for...

  9. Electronic structure and equilibrium properties of hcp titanium and zirconium

    Indian Academy of Sciences (India)

    B P Panda

    2012-08-01

    The electronic structures of hexagonal-close-packed divalent titanium (3-d) and zirconium (4-d) transition metals are studied by using a non-local model potential method. From the present calculation of energy bands, Fermi energy, density of states and the electronic heat capacity of these two metals are determined and compared with the existing results in the literature.

  10. Surface modification of layered zirconium phosphate with PNIPAM.

    Science.gov (United States)

    Wang, Xuezhen; Zhao, Di; Medina, Ilse B Nava; Diaz, Agustin; Wang, Huiliang; Clearfield, Abraham; Mannan, M Sam; Cheng, Zhengdong

    2016-04-04

    A new method was reported to modify layered zirconium phosphate (ZrP) with thermoresponsive polymer PNIPAM (poly N-isopropylacrylamide). PNIPAM was proved to be covalently grafted onto ZrP. (60)Co γ-rays irradiation produced peroxide groups on the surface which, upon heating, initiated free radical polymerization and subsequent attachment of PNIPAM.

  11. Nanophase Nickel-Zirconium Alloys for Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas

    2008-01-01

    Nanophase nickel-zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes. Nickel-zirconium alloys belong to a class of base metal alloys formed from transition elements of widely different d-electron configurations. These alloys generally exhibit unique physical, chemical, and metallurgical properties that can include corrosion resistance. Inasmuch as corrosion is accelerated by free-energy differences between bulk material and grain boundaries, it was conjectured that amorphous (glassy) and nanophase forms of these alloys could offer the desired corrosion resistance. For experiments to test the conjecture, thin alloy films containing various proportions of nickel and zirconium were deposited by magnetron and radiofrequency co-sputtering of nickel and zirconium. The results of x-ray diffraction studies of the deposited films suggested that the films had a nanophase and nearly amorphous character.

  12. enrichment factor of atmospheric trace metal using zirconium ...

    African Journals Online (AJOL)

    user

    Copper(Cu), 0.20-1.12mg/m3; Zirconium(Zr), 0.01-0.22mg/m3; Vanadium(V), 0.00-0.05mg/m3; Chlorine(Cl), ... enrichment factor formula, the values are in addition ... chemical composition of atmospheric particulate ... serious health effect [26].

  13. Phosphorus Recovery Using Zirconium-Loaded Saponified Orange Juice Residue

    Science.gov (United States)

    Harada, Hiroyuki; Kondo, Mitsunori; Biswas, Biplob K.; Ohura, Seichirou; Inoue, Katsutoshi; Ishikawa, Susumu; Kawakita, Hidetaka; Ohto, Keisuke

    Zirconium was immobilized to orange juice residue, to investigate the feasibility of using zirconium-loaded saponified orange juice residue (Zr-SOJR) for phosphorus recovery from secondary effluent and the extraction solution from incinerated sewage sludge ash by using H2SO4 and HCl. These had phosphorus concentrations of 68.2 mg/dm3 and 5.9 mg/dm3, respectively. The phosphorus removal rate secondary effluent increased with an increasing solid/liquid ratio in batch experiments. The adsorption capacity of Zr-SOJR was also compared with those obtained using a synthetic phosphorus solution and using zirconium-loaded ferrite. The prepared absorbent was effective for phosphorus removal and exhibited a reasonably high sorption capacity, twice that of zirconium ferrite. Secondary effluent was treated by packed column, and this reached break-through after 300 bed volumes. The results from phosphorous extraction from the ash indicate that can be treated with acid to efficiently recover phosphorous and thus can be absorbed by Zr-SOJR.

  14. Cyclic softening and thermally activated deformation of titanium and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, J.I.; Handfield, L.; L' Esperance, G. (Ecole Polytechnique, Montreal, Quebec (Canada). Dept. de Genie Metallurgique)

    1983-08-01

    Cyclic softening in commercial purity zirconium and titanium corresponds principally to a decrease in effective stress and to an increase in screw dislocation mobility. This result indicates that the thermally activated deformation of these metals is not controlled by the overcoming of individual interstitial solute atoms by dislocations as usually proposed.

  15. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO 2 Nanowires

    KAUST Repository

    Asayesh-Ardakani, Hasti

    2015-10-12

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WVO nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122¯) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  16. Monoclinic tridymite in clast-rich impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Jackson, J.C.; Horton, J.W.; Chou, I.-Ming; Belkin, H.E.

    2011-01-01

    X-ray diffraction and Raman spectroscopy confirm a rare terrestrial occurrence of monoclinic tridymite in clast-rich impact melt rock from the Eyreville B drill core in the Chesapeake Bay impact structure. The monoclinic tridymite occurs with quartz paramorphs after tridymite and K-feldspar in a microcrystalline groundmass of devitrified glass and Fe-rich smectite. Electron-microprobe analyses revealed that the tridymite and quartz paramorphs after tridymite contain different amounts of chemical impurities. Inspection by SEM showed that the tridymite crystal surfaces are smooth, whereas the quartz paramorphs contain irregular tabular voids. These voids may represent microporosity formed by volume decrease in the presence of fluid during transformation from tridymite to quartz, or skeletal growth in the original tridymite. Cristobalite locally rims spherulites within the same drill core interval. The occurrences of tridymite and cristobalite appear to be restricted to the thickest clast-rich impact melt body in the core at 1402.02-1407.49 m depth. Their formation and preservation in an alkali-rich, high-silica melt rock suggest initially high temperatures followed by rapid cooling.

  17. The giant piezoelectric effect: electric field induced monoclinic phase or piezoelectric distortion of the rhombohedral parent?

    CERN Document Server

    Kisi, E H; Forrester, J S; Howard, C J

    2003-01-01

    Lead zinc niobate-lead titanate (PZN-PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] sub R. It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral (R3m) to monoclinic (Cm or Pm) symmetry in an essentially continuous manner. Group theoretical analysis using the computer program ISOTROPY indicates phase transitions between R3m and Cm (or Pm) must be discontinuous under Landau theory. An analysis of the symmetry of a strained unit cell in R3m and a simple expansion of the piezoelectric strain equation indicate that the piezoelectric distortion due to an electric field along a cell edge in rhombohedral perovskite-based ferroelectrics is intrinsically monoclinic (Cm), even for infinitesimal electric fields. PZN-PT crystals have up to nine times the elastic compliance of other piezoelectric perovskites and it might be expected that the piezoelectric strains are also very large. ...

  18. Ab initio velocity-field curves in monoclinic β-Ga2O3

    Science.gov (United States)

    Ghosh, Krishnendu; Singisetti, Uttam

    2017-07-01

    We investigate the high-field transport in monoclinic β-Ga2O3 using a combination of ab initio calculations and full band Monte Carlo (FBMC) simulation. Scattering rate calculation and the final state selection in the FBMC simulation use complete wave-vector (both electron and phonon) and crystal direction dependent electron phonon interaction (EPI) elements. We propose and implement a semi-coarse version of the Wannier-Fourier interpolation method [Giustino et al., Phys. Rev. B 76, 165108 (2007)] for short-range non-polar optical phonon (EPI) elements in order to ease the computational requirement in FBMC simulation. During the interpolation of the EPI, the inverse Fourier sum over the real-space electronic grids is done on a coarse mesh while the unitary rotations are done on a fine mesh. This paper reports the high field transport in monoclinic β-Ga2O3 with deep insight into the contribution of electron-phonon interactions and velocity-field characteristics for electric fields ranging up to 450 kV/cm in different crystal directions. A peak velocity of 2 × 107 cm/s is estimated at an electric field of 200 kV/cm.

  19. Imaging metal-like monoclinic phase stabilized by surface coordination effect in vanadium dioxide nanobeam

    Science.gov (United States)

    Li, Zejun; Wu, Jiajing; Hu, Zhenpeng; Lin, Yue; Chen, Qi; Guo, Yuqiao; Liu, Yuhua; Zhao, Yingcheng; Peng, Jing; Chu, Wangsheng; Wu, Changzheng; Xie, Yi

    2017-06-01

    In correlated systems, intermediate states usually appear transiently across phase transitions even at the femtosecond scale. It therefore remains an open question how to determine these intermediate states--a critical issue for understanding the origin of their correlated behaviour. Here we report a surface coordination route to successfully stabilize and directly image an intermediate state in the metal-insulator transition of vanadium dioxide. As a prototype metal-insulator transition material, we capture an unusual metal-like monoclinic phase at room temperature that has long been predicted. Coordinate bonding of L-ascorbic acid molecules with vanadium dioxide nanobeams induces charge-carrier density reorganization and stabilizes metallic monoclinic vanadium dioxide, unravelling orbital-selective Mott correlation for gap opening of the vanadium dioxide metal-insulator transition. Our study contributes to completing phase-evolution pathways in the metal-insulator transition process, and we anticipate that coordination chemistry may be a powerful tool for engineering properties of low-dimensional correlated solids.

  20. Variable defect structures cause the magnetic low-temperature transition in natural monoclinic pyrrhotite

    Science.gov (United States)

    Koulialias, D.; Kind, J.; Charilaou, M.; Weidler, P. G.; Löffler, J. F.; Gehring, A. U.

    2016-02-01

    Non-stoichiometric monoclinic 4C pyrrhotite (Fe7S8) is a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials. Because of its low-temperature magnetic transition around 30 K also known as Besnus transition, which is considered to be an intrinsic property, this mineral phase is easily detectable in natural samples. Although the physical properties of pyrrhotite have intensively been studied, the mechanism behind the pronounced change in magnetization at the low-temperature transition is still debated. Here we report magnetization experiments on a pyrrhotite crystal (Fe6.6S8) that consists of a 4C and an incommensurate 5C* superstructure that are different in their defect structure. The occurrence of two superstructures is magnetically confirmed by symmetric inflection points in hysteresis measurements above the transition at about 30 K. The disappearance of the inflection points and the associated change of the hysteresis parameters indicate that the two superstructures become strongly coupled to form a unitary magnetic anisotropy system at the transition. From this it follows that the Besnus transition in monoclinic pyrrhotite is an extrinsic magnetic phenomenon with respect to the 4C superstructure and therefore the physics behind it is in fact different from that of the well-known Verwey transition.

  1. Crystal structure of a new monoclinic polymorph of N-(4-methylphenyl-3-nitropyridin-2-amine

    Directory of Open Access Journals (Sweden)

    Aina Mardia Akhmad Aznan

    2014-08-01

    Full Text Available The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z′ = 4 of the previously reported monoclinic (P21/c, with Z′ = 2 form [Akhmad Aznan et al. (2010. Acta Cryst. E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of a syn disposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19 to 26.24 (19°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2–3.916 (2 Å].

  2. The Fouling of Zirconium(IV) Hydrous Oxide–Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions

    Science.gov (United States)

    Polom, Ewa

    2013-01-01

    The results of investigations of flux decline during nanofiltration (NF) of lactic acid solutions using dynamically formed zirconium(IV) hydrous oxide/polyacrylate membranes (Zr(IV)/PAA) under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations showed that the reduction of fouling effects in the investigated system could be achieved due to appropriate hydrodynamic process conditions and regular rinsing with deionized water. PMID:24957066

  3. The Fouling of Zirconium(IV Hydrous Oxide–Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions

    Directory of Open Access Journals (Sweden)

    Ewa Polom

    2013-12-01

    Full Text Available The results of investigations of flux decline during nanofiltration (NF of lactic acid solutions using dynamically formed zirconium(IV hydrous oxide/polyacrylate membranes (Zr(IV/PAA under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations showed that the reduction of fouling effects in the investigated system could be achieved due to appropriate hydrodynamic process conditions and regular rinsing with deionized water.

  4. EFFECTS OF ZIRCONIUM ON MICROSTRUCTURES AND MECHANICAL PROPERTIES OF MICROALLOYED STEELS

    Institute of Scientific and Technical Information of China (English)

    T.H. Xi; X. Chen; P.H. Li; Z.X. Yuan

    2006-01-01

    The effects of Zr on the microstructures and mechanical properties of microalloyed steels have been investigated by mechanical tests and microstructural observations. The microstructures in the Zr-doped steels are ferrite plus pearlite, which is similar to those in the Zr-free steel. With the increase in the Zr content, the lamellar structure reduces and even disappears. Sulfides and silicates that exist in the Zr-free steel are modified into fine oxides in the Zr-bearing steel. When the Zr contents range from 0.01wt% to 0.03wt%, the low temperature toughness of the steel can be substantially improved while its room-temperature strength and ductility have no apparent change.The refinement of ferrite grain size by the addition of zirconium is one of the main reasons for this toughness improvement.

  5. The pressure-amorphized state in zirconium tungstate: a precursor to decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Akhilesh K [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Sastry, V S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Sahu, P Ch [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Mary, T A [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States)

    2004-02-25

    In contrast to widely accepted view that pressure-induced amorphization arises due to kinetic hindrance of equilibrium phase transitions, here we provide evidence that the metastable pressure-amorphized state in zirconium tungstate is a precursor to decomposition of the compound into a mixture of simple oxides. This is from the volume collapse {delta}V across amorphization, which is obtained for the first time by measuring linear dimensions of irreversibly amorphized samples during their recovery to the original cubic phase upon isochronal annealing up to 1000 K. The anomalously large {delta}V of 25.7 {+-} 1.2% being the same as that expected for the decomposition indicates that this amorphous state is probably a precursor to kinetically hindered decomposition. A P-T diagram of the compound is also proposed.

  6. Study of the synthesis of nanocrystalline mixed tantalum–zirconium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Simonenko, E. P., E-mail: ep-simonenko@mail.ru; Simonenko, N. P.; Ezhov, Yu. S.; Sevastyanov, V. G.; Kuznetsov, N. T. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)

    2015-12-15

    The synthesis conditions of refractory tantalum–zirconium carbide Ta{sub 0.8}Zr{sub 0.2}C on the basis of Ta{sub 2}O{sub 5}–ZrO{sub 2}–C ultrafine initial blend prepared via the sol–gel method are explored. The initial blend is prepared via hydrolysis in the presence of Ta(OC{sub 5}H{sub 11}){sub 5} and [Zr(O{sub 2}C{sub 5}H{sub 7}){sub 4–x}(OC{sub 5}H{sub 11}){sub x}] carbon source polymer solutions, gel drying, and carbonization at a temperature of 450°C. A series of the carbothermal synthesis experiments is implemented at various temperatures and exposure times. The synthesis conditions are shown to affect not only the phase composition of products but also their oxidation resistance related to the particle size.

  7. Shear Bond Strength of Orthodontic Brackets Bonded to Zirconium Crowns

    Science.gov (United States)

    Mehmeti, Blerim; Azizi, Bleron; Kelmendi, Jeta; Iljazi-Shahiqi, Donika; Alar, Željko

    2017-01-01

    Background An increasing demand for esthetic restorations has resulted in an increased use of all-ceramic restorations, such as zirconium. However, one of the challenges the orthodontist must be willing to face is how to increase bond strength between the brackets and various ceramic restorations.Bond strength can beaffected bybracket type, by the material that bracketsaremade of, and their base surface design or retention mode. ​ Aim: of this study was to perform a comparative analysis of the shear bond strength (SBS) of metallic and ceramic orthodontic brackets bonded to all-zirconium ceramic surfaces used for prosthetic restorations, and also to evaluate the fracture mode of these two types of orthodontic brackets. Material and methods Twenty samples/semi-crowns of all-zirconium ceramic, on which orthodontic brackets were bonded, 10 metallic and 10 ceramic polycrystalline brackets, were prepared for this research. SBS has been testedby Universal Testing Machine, with a load applied using a knife edged rod moving at a fixed rate of 1 mm/min, until failure occurred. The force required to debond the brackets was recorded in Newton, then SBS was calculated to MPa. In addition, the samples were analyzed using a digital camera magnifier to determine Adhesive Remnant Index (ARI). Statistical data were processed using t-test, and the level of significance was set at α = 0.05. Results Higher shear bond strength values were observed in metallic brackets bonded to zirconium crowns compared tothoseof ceramic brackets, with a significant difference. During the test, two of the ceramic brackets were partially or totally damaged. Conclusion Metallic brackets, compared to ceramic polycrystalline brackets, seemed tocreate stronger adhesion with all-zirconium surfaces due to their better retention mode. Also, ceramic brackets showed higher fragility during debonding. PMID:28827846

  8. Synthesis, Characterization and Antimicrobial Activity of Zirconium (IV) Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shobhana; Jain, Asha; Saxena, Sanjiv [Univ. of Rajasthan, Jaipur (India)

    2012-08-15

    Heteroleptic complexes of zirconium (IV) derived from bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic β-diketones of the general formula ZrLL' (where L'H{sub 2}=RCNH(C{sub 6}H{sub 4})SC : C(OH)N(C{sub 6}H{sub 5})N : CCH{sub 3}, R=-C{sub 6}H{sub 5}, -C{sub 6}H{sub 4}Cl(p) and L'H{sub 2}=R'C : (NOH)C : C(OH)N(C{sub 6}H{sub 5})N : CCH{sub 3}, R' = -CH{sub 2}CH{sub 3}, -C{sub 6}H{sub 5}, -C{sub 6}H{sub 4}Cl (p) were prepared by the reactions of zirconium tetrachloride with disodium salts of Schiff bases (L Na{sub 2}) and oximes of heterocyclic β-diketones (L' Na{sub 2}) in 1:1:1 molar ratio in dry refluxing THF. The structures of these monomeric zirconium (IV) complexes were elucidated with the help of elemental analysis, molecular weight measurements, spectroscopic (IR, NMR and mass) studies. A distorted trigonal bipyramidal geometry may be suggested for these heteroleptic zirconium (IV) complexes. The ligands (bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic β-diketones) and their heteroleptic complexes of zirconium (IV) were screened against A. flavus, P. aeruginesa and E. coli.

  9. Low-temperature magnetic properties of monoclinic pyrrhotite with particular relevance to the Besnus transition

    Science.gov (United States)

    Volk, Michael W. R.; Gilder, Stuart A.; Feinberg, Joshua M.

    2016-12-01

    Monoclinic pyrrhotite (Fe7S8) owes its ferrimagnetism to an ordered array of Fe vacancies. Its magnetic properties change markedly around 30 K, in what is known as the Besnus transition. Plausible explanations for the Besnus transition are either due to changes in crystalline anisotropy from a transformation in crystal symmetry or from the establishment of a two-phase system with magnetic interaction between the two phases. To help resolve this discrepancy, we measured hysteresis loops every 5° and backfield curves every 10° in the basal plane of an oriented single crystal of monoclinic pyrrhotite at 300 K and every 2 K from 50 K through the Besnus transition until 20 K. Between 50 and 30 K, hysteresis loops possess double inflections between crystallographic a-axes and only a single inflection parallel to the a-axes. Magnetization energy calculations and relative differences of the loops show a sixfold symmetry in this temperature range. We propose that the inflections stem from magnetic axis switching, which is both field and temperature dependent, in a manner somewhat analogous to an isotropic point where magnetocrystalline constants change their sign. The Besnus transition is best characterized by changes in magnetic remanence and coercivity over a 6° temperature span (28-34 K) with a maximum rate of change at 30 K. A surprising yet puzzling finding is that the coercivity ratio becomes less than unity below the transition when fourfold symmetry arises. Because the changes in magnetic parameters are linked to the crystal structure, we conclude the Besnus transition owes its origin to a distortion of the crystallographic axes below 30 K rather than an apparition of a two-phase system. An isothermal magnetization of natural pyrrhotite cycled from room temperature to successively lower temperatures through the Besnus transition decreases 2-4 times less than equivalent grain sizes of magnetite, with less than a 10 per cent loss in remanence between 300 and 150 K

  10. Strong Bilayer Coupling Induced by the Symmetry Breaking in the Monoclinic Phase of BiS2-Based Superconductors

    Science.gov (United States)

    Ochi, Masayuki; Akashi, Ryosuke; Kuroki, Kazuhiko

    2016-09-01

    We perform first-principles band structure calculations for the tetragonal and monoclinic structures of LaO0.5F0.5BiS2. We find that the Bi 6px,y bands on two BiS2 layers exhibit a sizable splitting at the X = (π ,0,0) and several other k-points for the monoclinic structure. We show that this feature originates from the inter-BiS2 layer coupling strongly enhanced by the symmetry breaking of the crystal structure. The Fermi surface also shows a large splitting and becomes anisotropic with respect to the kx- and ky-directions in the monoclinic structure, whereas it remains almost flat with respect to the kz-direction.

  11. 1-Nitro-4-(4-nitro-phen-oxy)benzene: a second monoclinic polymorph.

    Science.gov (United States)

    Naz, Mehwish; Akhter, Zareen; McKee, Vickie; Nadeem, Arif

    2013-11-01

    In the title compound, C12H8N2O5, the aromatic rings are inclined to one another by 56.14 (7)°. The nitro groups are inclined by to the benzene rings to which they are attached by 3.86 (17) and 9.65 (15)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional structure. The title compound is a new monoclinic polymorph, crystallizing in space group P21/c. The first polymorph crystallized in space group C2/c and the mol-ecule possesses twofold rotation symmetry. Two low-temperature structures of this polymorph (150 K and 100 K, respectively) have been reported [Meciarova et al. (2004). Private Communication (refcode IXOGAD). CCDC, Cambridge, England, and Dey & Desiraju (2005). Chem. Commun. pp. 2486-2488].

  12. Cubic or monoclinic Y 2O 3:Eu 3+ nanoparticles by one step flame spray pyrolysis

    Science.gov (United States)

    Camenzind, Adrian; Strobel, Reto; Pratsinis, Sotiris E.

    2005-11-01

    Continuous, single-step synthesis of monocrystalline Y 2O 3:Eu 3+ nanophosphor particles (10-25 nm in diameter and 5 wt% Eu) was achieved by flame spray pyrolysis (FSP). The effect of FSP process parameters on materials properties was investigated by X-ray diffraction (XRD), nitrogen adsorption (BET) and transmission electron microscopy (TEM). Photoluminescence (PL) emission were measured as well as the time-resolved PL-intensity decay. Controlled synthesis of monoclinic or cubic Y 2O 3:Eu 3+ nanoparticles was achieved without post-treatment by controlling the high temperature residence time of these particles. The cubic nanoparticles exhibited longer decay times but lower maximum PL intensity than commercial micron-sized bulk Y 2O 3:Eu 3+ phosphor powder.

  13. THE MONOCLINIC PHASE IN PZT: NEW LIGHT ON MORPHOTROPIC PHASE BOUNDARIES

    Energy Technology Data Exchange (ETDEWEB)

    NOHEDA,B.; GONZALO,J.A.; GUO,R.; PARK,S.E.; CROSS,L.E.; COX,D.E.; SHIRANE,G.

    2000-03-09

    A summary of the work recently carried out on the morphotropic phase boundary (MPB) of PZT is presented. By means of x-ray powder diffraction on ceramic samples of excellent quality, the MPB has been successfully characterized by changing temperature in a series of closely spaced compositions. As a result, an unexpected monoclinic phase has been found to exist in between the well-known tetragonal and rhombohedral PZT phases. A detailed structural analysis, together with the investigation of the field effect in this region of compositions, have led to an important advance in understanding the mechanisms responsible for the physical properties of PZT as well as other piezoelectric materials with similar morphotropic phase boundaries.

  14. Electronic structure and optical properties of monoclinic clinobisvanite BiVO4.

    Science.gov (United States)

    Zhao, Zongyan; Li, Zhaosheng; Zou, Zhigang

    2011-03-14

    Monoclinic clinobisvanite bismuth vanadate is an important material with wide applications. However, its electronic structure and optical properties are still not thoroughly understood. Density functional theory calculations were adopted in the present work, to comprehend the band structure, density of states, and projected wave function of BiVO(4). In particular, we put more emphasis upon the intrinsic relationship between its structure and properties. Based on the calculated results, its molecular-orbital bonding structure was proposed. And a significant phenomenon of optical anisotropy was observed in the visible-light region. Furthermore, it was found that its slightly distorted crystal structure enhances the lone-pair impact of Bi 6s states, leading to the special optical properties and excellent photocatalytic activities.

  15. A monoclinic polymorph of (1E,5E-1,5-bis(2-hydroxybenzylidenethiocarbonohydrazide

    Directory of Open Access Journals (Sweden)

    Bonell Schmitt

    2011-08-01

    Full Text Available The title compound, C15H14N4O2S, is a derivative of thioureadihydrazide. In contrast to the previously reported polymorph (orthorhombic, space group Pbca, Z = 8, the current study revealed monoclinic symmetry (space group P21/n, Z = 4. The molecule shows non-crystallographic C2 as well as approximate Cs symmetry. Intramolecular bifurcated O—H...(N,S hydrogen bonds, are present. In the crystal, intermolecular N—H...S hydrogen bonds and C—H...π contacts connect the molecules into undulating chains along the b axis. The shortest centroid–centroid distance between two aromatic systems is 4.5285 (12 Å.

  16. Calculation of thermodynamic, electronic, and optical properties of monoclinic Mg2NiH4

    Energy Technology Data Exchange (ETDEWEB)

    Myers, W.R.; Richardson, T.J.; Rubin, M.D.; Wang, L-W.

    2001-10-01

    Ab initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.

  17. Zirconium determination by cooling curve analysis during the pyroprocessing of used nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Westphal, B.R., E-mail: brian.westphal@inl.gov; Price, J.C.; Bateman, K.J.; Marsden, K.C.

    2015-02-15

    An alternative method to sampling and chemical analyses has been developed to monitor the concentration of zirconium in real-time during the casting of uranium products from the pyroprocessing of used nuclear fuel. The method utilizes the solidification characteristics of the uranium products to determine zirconium levels based on standard cooling curve analyses and established binary phase diagram data. Numerous uranium products have been analyzed for their zirconium content and compared against measured zirconium data. From this data, the following equation was derived for the zirconium content of uranium products: Zr=0.14M+131.56-12.63(348.65-0.16LT){sup 1/2} where M is the mass (kg) of the ingot and LT is the liquidus temperature (K) found by cooling curve analyses. Based on this equation, a reasonable fit of calculated to measured zirconium content was established considering the errors in the system.

  18. Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

    Science.gov (United States)

    Zheng, Tao; Yang, Zaixing; Gui, Daxiang; Liu, Zhiyong; Wang, Xiangxiang; Dai, Xing; Liu, Shengtang; Zhang, Linjuan; Gao, Yang; Chen, Lanhua; Sheng, Daopeng; Wang, Yanlong; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Albrecht-Schmitt, Thomas E.; Wang, Shuao

    2017-05-01

    Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.

  19. Monoclinic phase transformation and mechanical durability of zirconia ceramic after fatigue and autoclave aging.

    Science.gov (United States)

    Mota, Yasmine A; Cotes, Caroline; Carvalho, Rodrigo F; Machado, João P B; Leite, Fabíola P P; Souza, Rodrigo O A; Özcan, Mutlu

    2017-10-01

    This study evaluated the influence of two aging procedures on the biaxial flexural strength of yttria-stabilized tetragonal zirconia ceramics. Disc-shaped zirconia specimens and (ZE: E.max ZirCAD, Ivoclar; ZT: Zirkon Translucent, Zirkonzahn) (N = 80) (∅:12 mm; thickness:1.2 mm, ISO 6872) were prepared and randomly divided into four groups (n = 10 per group) according to the aging procedures: C: Control, no aging; M: mechanical cycling (2 × 10(6) cycles/3.8 Hz/200 N); AUT: Aging in autoclave at 134°C, 2 bar for 24 h; AUT + M: Autoclave aging followed by mechanical cycling. After aging, the transformed monoclinic zirconia (%) were evaluated using X-ray diffraction and surface roughness was measured using atomic force microscopy. The average grain size was measured by scanning electron microscopy and the specimens were submitted to biaxial flexural strength testing (1 mm/min, 1000 kgf in water). Data (MPa) were statistically analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). Aging procedures significantly affected (p = 0.000) the flexural strength data but the effect of zirconia type was not significant (p = 0.657). AUTZT (936.4 ± 120.9(b) ) and AUT + MZE (867.2 ± 49.3(b) ) groups presented significantly higher values (p autoclave aging alone or with mechanical aging increased the flexure strength but also induced higher transformation from tetragonal to monoclinic phase in both zirconia materials tested. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1972-1977, 2017. © 2016 Wiley Periodicals, Inc.

  20. Influence of the monoclinic and tetragonal zirconia phases on the water gas shift reaction. A theoretical study.

    Science.gov (United States)

    Cerón, María Luisa; Herrera, Barbara; Araya, Paulo; Gracia, Francisco; Toro-Labbé, Alejandro

    2013-07-01

    We present a theoretical study of the water gas shift reaction taking place on zirconia surfaces modeled by monoclinic and tetragonal clusters. In order to understand the charge transfer between the active species, in this work we analyze the influence of the geometry of monoclinic and tetragonal zirconia using reactivity descriptors such as electronic chemical potential (μ), charge transfer (ΔN) and molecular hardness (η). We have found that the most preferred surface is tetragonal zirconia (tZrO2) indicating also that low charge transfer systems will generate less stable intermediates, that will allow to facilitate desorption process.

  1. Elastic stability and electronic structure of low energy tetragonal and monoclinic PdN2 and PtN2

    Institute of Scientific and Technical Information of China (English)

    Zhao Wen-Jie; Wang Yuan-Xu

    2009-01-01

    This paper studies the elastic and electronic structure properties of two new low-energy structures of PdN2 and PtN2 by first-principles calculations. It finds that tetragonal and monoclinic structures are more stable than a pyrite one. The always positive eigenvalues of the elastic constant matrix confirm that both the tetragonal and monoclinic structures are elastically stable. The origin of the low bulk modulus of the two structures is discussed. The results of the calculated density of states show that both of the two low-energy structures are metallic.

  2. Metal-Element Compounds of Titanium, Zirconium, and Hafnium as Pyrotechnic Fuels

    Science.gov (United States)

    2015-05-04

    1-11 1 METAL-ELEMENT COMPOUNDS OF TITANIUM, ZIRCONIUM , AND HAFNIUM AS PYROTECHNIC FUELS Anthony P. Shaw,* Rajendra K. Sadangi, Jay C...have started to explore the pyrotechnic properties of other inorganic compounds, particularly those of titanium, zirconium , and hafnium. The...The group 4 metals—titanium, zirconium , and hafnium—are potent pyrotechnic fuels. However, the metals themselves are often pyrophoric as fine

  3. Pyroprocessing of Oxidized Sodium-Bonded Fast Reactor Fuel -- an Experimental Study of Treatment Options for Degraded EBR-II Fuel

    Energy Technology Data Exchange (ETDEWEB)

    S. D. Herrmann; L. A. Wurth; N. J. Gese

    2013-09-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electrometallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li2O at 650 °C with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. The experimental study illustrated how zirconium oxide and sodium oxide present different challenges to a lithium-based electrolytic reduction system for conversion of select metal oxides to metal.

  4. Optimization of N18 Zirconium Alloy for Fuel Cladding of Water Reactors

    Institute of Scientific and Technical Information of China (English)

    B.X. Zhou; M. Y. Yao; Z.K. Li; X.M. Wang; J. Zhoua; C.S. Long; Q. Liu; B.F. Luan

    2012-01-01

    In order to optimize the microstructure and composition of N18 zirconium alloy (Zr-1Sn-0.35Nb-0.35Fe-0.1Cr, in mass fraction, %), which was developed in China in 1990s, the effect of microstructure and composition variation on the corrosion resistance of the N18 alloy has been investigated. The autoclave corrosion tests were carried out in super heated steam at 400 ~C/10.3 MPa, in deionized water or lithiated water with 0.01 mol/L LiOH at 360 ~C/18.6 MPa. The exposure time lasted for 300-550 days according to the test temperature. The results show that the microstructure with a fine and uniform distribution of second phase particles (SPPs), and the decrease of Sn content from 1% (in mass fraction, the same as follows) to 0.8% are of benefit to improving the corrosion resistance; It is detrimental to the corrosion resistance if no Cr addition. The addition of Nb content with upper limit (0.35%) is beneficial to improving the corrosion resistance. The addition of Cu less than 0.1% shows no remarkable influence upon the corrosion resistance for N18 alloy. Comparing the corrosion resistance of the optimized N18 with other commercial zirconium alloys, such as Zircaloy-4, ZIRLO, E635 and Ell0, the former shows superior corrosion resistance in all autoclave testing conditions mentioned above. Although the data of the corrosion resistance as fuel cladding for high burn-up has not been obtained yet, it is believed that the optimized N18 alloy is promising for the candidate of fuel cladding materials as high burn-up fuel assemblies. Based on the theory that the microstructural evolution of oxide layer during corrosion process will affect the corrosion resistance of zirconium alloys, the improvement of corrosion resistance of the N18 alloy by obtaining the microstructure with nano-size and uniform distribution of SPPs, and by decreasing the content of Sn and maintaining the content of Cr is discussed.

  5. Growth and high pressure studies of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2009-11-01

    Transition metal trichalcogenides are well suited for extreme pressure lubrication. These materials being semiconducting and of layered structure may undergo structural and electronic transition under pressure. In this paper authors reported the details about synthesis and characterization of zirconium sulphoselenide single crystals. The chemical vapour transport technique was used for the growth of zirconium sulphoselenide single crystals. The energy dispersive analysis by X-ray (EDAX) gave the confirmation about the stoichiometry of the as-grown crystals and other structural characterizations were accomplished by X-ray diffraction (XRD) study. The variation of electrical resistance was monitored in a Bridgman opposed anvil set-up up to 8 GPa pressure to identify the occurrence of any structural transition. These crystals do not possess any structural transitions upto the pressure limit examined.

  6. Reactive Mechanical Alloying Synthesis of Nanocrystalline Cubic Zirconium Nitride

    Institute of Scientific and Technical Information of China (English)

    QIU Li-Xia; YAO Bin; DING Zhan-Hui; ZHAO Xu-Dong; JI Hong; DU Xiao-Bo; JIA Xiao-Peng; ZHENG Wei-Tao

    2008-01-01

    Zirconium nitride powders with rock salt structure (γ-ZrNx) are prepared by mechanical milling of a mixture of Zirconium and hexagonal boron nitride (h-BN) powders.The products are analysed by x-ray diffraction (XRD),scanning electron microscopy (SEM),and Raman spectroscopy (RS).The formation mechanism of γ-ZrNx by ball milling technique is investigated in detail.N atoms diffuse from amorphous BN (a-BN) into Zr to form Zr(N) solid solution alloy,then the Zr(N) solid solution alloy decomposes into γ-ZrNx.No ZrB2 is observed in the as-milled samples or the samples annealed at 1050℃ for 2 h.

  7. Modelling zirconium hydrides using the special quasirandom structure approach

    KAUST Repository

    Wang, Hao

    2013-01-01

    The study of the structure and properties of zirconium hydrides is important for understanding the embrittlement of zirconium alloys used as cladding in light water nuclear reactors. Simulation of the defect processes is complicated due to the random distribution of the hydrogen atoms. We propose the use of the special quasirandom structure approach as a computationally efficient way to describe this random distribution. We have generated six special quasirandom structure cells based on face centered cubic and face centered tetragonal unit cells to describe ZrH2-x (x = 0.25-0.5). Using density functional theory calculations we investigate the mechanical properties, stability, and electronic structure of the alloys. © the Owner Societies 2013.

  8. Asymmetric induction in the zirconium catalyzed ethylmagnesiation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.L.; Whitby, R.J.; Jones, R.V.H. [Univ. of Southampton, Hants (United Kingdom)

    1995-12-31

    In 1985 Dzhemilev reported the zirconium catalysed ethylmagnesiation of terminal alkenes. A chiral centre is formed during the reaction which occurs under mild conditions. The authors have applied this reaction to a number of substrates and a mechanism has been elucidated. In order to induce asymmetry into the reaction, several chiral literature catalysts were synthesised including Ethylenebis(tetrahydroindenyl)zirconium dichloride and two more hindered complexes reported by Erker. All of these catalysts displayed low activity and poor asymmetric induction with terminal alkenes. The synthesis and properties of two novel catalysts will be described. Results show high activity furnishing carbomagnesiated products in excellent yields with as little as 2 mol% catalyst. The enantiomeric excesses induced by the complexes are as high as 79% with terminal alkenes but are >95% with cyclic ethers. The catalyst has proved recoverable. Ethylmagnesiation of an amine followed by an acidic workup furnishes the chiral complex in a quantitative return.

  9. Behavior of Zirconium Sponge Formation in the Kroll Process

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yong-Ik; Sohn, Ho-Sang [Kyungpook National University, Daegu (Korea, Republic of); Jung, Jae-Young [Research Institute of Industrial Science and Technology(RIST), Pohang (Korea, Republic of)

    2014-04-15

    The Kroll process of magnesium reduction of titanium tetrachloride is used for mass production of zirconium sponges. This study is conducted in a laboratory-scale reactor in order to develop a better understanding of the zirconium sponge formation mechanism in the Kroll reactor with respect to the reaction degrees and reaction time. The MgCl{sub 2} produced during the initial stage of the reaction does not sink into the molten magnesium, but remains on the surface of the molten magnesium. As a result, ZrCl{sub 4} feed reacts with the Mg exposed on the edge of the molten MgCl{sub 2} in the crucible. Therefore, the Zr particles produced at the later reaction stage descend into the molten magnesium at the crucible wall.

  10. A zirconium dioxide ammonia microsensor integrated with a readout circuit manufactured using the 0.18 μm CMOS process.

    Science.gov (United States)

    Lin, Guan-Ming; Dai, Ching-Liang; Yang, Ming-Zhi

    2013-03-15

    The study presents an ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated sensor chip consists of a heater, an ammonia sensor and a readout circuit. The ammonia sensor is constructed by a sensitive film and the interdigitated electrodes. The sensitive film is zirconium dioxide that is coated on the interdigitated electrodes. The heater is used to provide a working temperature to the sensitive film. A post-process is employed to remove the sacrificial layer and to coat zirconium dioxide on the sensor. When the sensitive film adsorbs or desorbs ammonia gas, the sensor produces a change in resistance. The readout circuit converts the resistance variation of the sensor into the output voltage. The experiments show that the integrated ammonia sensor has a sensitivity of 4.1 mV/ppm.

  11. 5A Zirconium Dioxide Ammonia Microsensor Integrated with a Readout Circuit Manufactured Using the 0.18 μm CMOS Process

    Science.gov (United States)

    Lin, Guan-Ming; Dai, Ching-Liang; Yang, Ming-Zhi

    2013-01-01

    The study presents an ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated sensor chip consists of a heater, an ammonia sensor and a readout circuit. The ammonia sensor is constructed by a sensitive film and the interdigitated electrodes. The sensitive film is zirconium dioxide that is coated on the interdigitated electrodes. The heater is used to provide a working temperature to the sensitive film. A post-process is employed to remove the sacrificial layer and to coat zirconium dioxide on the sensor. When the sensitive film adsorbs or desorbs ammonia gas, the sensor produces a change in resistance. The readout circuit converts the resistance variation of the sensor into the output voltage. The experiments show that the integrated ammonia sensor has a sensitivity of 4.1 mV/ppm. PMID:23503294

  12. A Zirconium Dioxide Ammonia Microsensor Integrated with a Readout Circuit Manufactured Using the 0.18 μm CMOS Process

    Directory of Open Access Journals (Sweden)

    Ming-Zhi Yang

    2013-03-01

    Full Text Available The study presents an ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS process. The integrated sensor chip consists of a heater, an ammonia sensor and a readout circuit. The ammonia sensor is constructed by a sensitive film and the interdigitated electrodes. The sensitive film is zirconium dioxide that is coated on the interdigitated electrodes. The heater is used to provide a working temperature to the sensitive film. A post-process is employed to remove the sacrificial layer and to coat zirconium dioxide on the sensor. When the sensitive film adsorbs or desorbs ammonia gas, the sensor produces a change in resistance. The readout circuit converts the resistance variation of the sensor into the output voltage. The experiments show that the integrated ammonia sensor has a sensitivity of 4.1 mV/ppm.

  13. Sintering nanodisperse zirconium powders with various stabilizing additives

    Directory of Open Access Journals (Sweden)

    Antsiferov V.N.

    2011-01-01

    Full Text Available Effect of various stabilizing additives on sintering kinetics of nanodisperse powders was studied by thermomechanical analysis. Temperature ranges of the most intense shrinking, characteristic points of shrinking rate changes were established. Peaks characterizing the most intense shrinking of nanodisperse zirconium powder samples were shown to allow to arrange the stabilizing additives as follows: Y2O3→CeO2→TiO2.

  14. Removal of zirconium from aqueous solution by modified clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Faghihian, H., E-mail: h.faghih@sci.ui.ac.ir [Department of Chemistry, University of Isfahan, 81746-73441, Isfahan (Iran, Islamic Republic of); Kabiri-Tadi, M. [Department of Chemistry, University of Isfahan, 81746-73441, Isfahan (Iran, Islamic Republic of)

    2010-06-15

    Adsorptive behavior of natural clinoptilolite was assessed for the removal of zirconium from aqueous solutions. Natural zeolite was characterized by X-ray diffraction, X-ray fluorescence, thermal methods of analysis and FTIR. The zeolite sample composed mainly of clinoptilolite and presented a cation exchange capacity of 1.46 meq g{sup -1}. K, Na and Ca-exchanged forms of zeolite were prepared and their sorption capacities for removal of zirconium from aqueous solutions were determined. The effects of relevant parameters, including initial concentration, contact time, temperature and initial pH on the removal efficiency were investigated in batch studies. The pH strongly influenced zirconium adsorption capacity and maximal capacity was obtained at pH 1.0. The maximum removal efficiency obtained at 40 deg. C and equilibration time of 24 h on the Ca-exchanged form. Kinetics and isotherm of adsorption were also studied. The pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion models were used to describe the kinetic data. The pseudo-second-order kinetic model provided excellent kinetic data fitting (R{sup 2} > 0.998) with rate constant of 1.60 x 10{sup -1}, 1.96 x 10{sup -1}, 2.45 x 10{sup -1} and 2.02 x 10{sup -1} g mmol{sup -1} min{sup -1} respectively for Na, K, Ca-exchanged forms and natural clinoptilolite. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for zirconium uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters were determined and are discussed.

  15. Zirconium as a Structural Material for Naval Systems

    Science.gov (United States)

    2010-08-12

    passive) Silver Solder Cupro Nickels (70-30) Bronzes Copper Brasses Nickel (active) Naval Brass Tin Lead Type 316, 317 Stainless Steels (active) Type...and nitrogen from the atmosphere, embrittling the weld. The techniques used for zirconium welding are gas tungsten arc welding (GTAW), tungsten inert...imposed by the data of Table 4 must be considered, and galvannic couples avoided. 20 NSWC TR 85-48 4-11/2" POROUS BRONZE TYPICAL TRAILING SHIELD DESIGN

  16. Pentamethylcyclopentadienyl Zirconium and Hafnium Polyhydride Complexes : Synthesis, Structure, and Reactivity

    NARCIS (Netherlands)

    Visser, Cindy; Hende, Johannes R. van den; Meetsma, Auke; Hessen, Bart; Teuben, Jan H.

    2001-01-01

    The half-sandwich zirconium and hafnium N,N-dimethylaminopropyl complexes Cp*M[(CH2)3NMe2]Cl2 (Cp* = η5-C5Me5, M = Zr, 1; Hf, 2) and Cp*M[(CH2)3NMe2]2Cl (M = Zr, 3; Hf, 4) were synthesized by mono- or dialkylation of Cp*MCl3 with the corresponding alkyllithium and Grignard reagents. Hydrogenolysis

  17. Synthesis and Characterization of Novel Nanocrystalline Zirconium (IV Tungstate Semiconductor

    Directory of Open Access Journals (Sweden)

    S. Manoj

    2011-01-01

    Full Text Available Nanocrystalline zirconium (IV tungstate is prepared by chemical coprecipitation method using ethylene diamine tetra acetic acid as the templating agent. Elemental composition is determined by EDS. The characteristic bonding position is identified using FTIR. XRD is used to find the theoritical value of size and phase identification using JCPDS. Morphology is examined using SEM and HRTEM. UV absorption at 260 nm corresponds to an energy gap of 4.48 eV, characteristic of semiconducting nanoparticles.

  18. Synthesis and Characterization of Novel Nanocrystalline Zirconium (IV) Tungstate Semiconductor

    OpenAIRE

    Manoj, S.; Beena, B.

    2011-01-01

    Nanocrystalline zirconium (IV) tungstate is prepared by chemical coprecipitation method using ethylene diamine tetra acetic acid as the templating agent. Elemental composition is determined by EDS. The characteristic bonding position is identified using FTIR. XRD is used to find the theoritical value of size and phase identification using JCPDS. Morphology is examined using SEM and HRTEM. UV absorption at 260 nm corresponds to an energy gap of 4.48 eV, characteristic of semiconducting nanopar...

  19. Dissolution-passivation model for zirconium alloys in fluorinated media

    Energy Technology Data Exchange (ETDEWEB)

    Prono, J. [Zircotube, Paimboeuf (France); Caprani, A. [Univ. of Paris VII (France); Jaszay, T.; Frayret, J.P. [Ecole Nat. Sup. de Mecanique, Nantes (France)

    1992-12-31

    Considering the shape of the steady state current-potential curve, we proposed a dissolution-passivation model composed of five determining steps and we calculated the associated elementary rates. Two different compounds of tetravalent zirconium are involved in the formation of the surface film. The influence of temperature on the elementary rates allows us to consider the chemical dissolution as the slowest steps and to involve fluoride in the formation of the film in the vicinity of the corrosion potential.

  20. Ferrier rearrangement promoted by an electrochemically generated zirconium catalyst.

    Science.gov (United States)

    Stevanović, Dragana; Pejović, Anka; Damljanović, Ivan; Minić, Aleksandra; Bogdanović, Goran A; Vukićević, Mirjana; Radulović, Niko S; Vukićević, Rastko D

    2015-04-30

    In situ generated zirconium catalyst from a sacrificial zirconium anode was successfully applied to promote Ferrier rearrangement of 3,4,5-tri-O-acetyl-D-glucal and 6-deoxy-3,4-di-O-acetyl-L-glucal (3,4-di-O-acetyl-L-rhamnal) in the presence of three thiols and eleven thiophenols as nucleophiles. A simple constant current electrolysis (20 mA, 0.4 F mol(-1)) of an acetonitrile solution of lithium perchlorate (0.1 M) containing the corresponding glycal and S-nucleophiles, using a zirconium anode and a platinum cathode resulted in the successful synthesis of the corresponding 2,3-unsaturated peracetylated thioglycosides (with an average anomer ratio α/β=4.129 in the case of peracetylated D-glucal and 8.740 in the case of L-rhamnal). The same procedure proved to be appropriate in synthesizing dihydropyran derivatives ('C-glycosides') using allyltrimethylsilane as the nucleophile (only 'α-anomers' were obtained). All new compounds were fully characterized by spectral data, whereas single-crystal X-ray analysis was performed for two thioglycosides.

  1. Analysis of hydrogenated zirconium alloys irradiated with gamma - rays

    Directory of Open Access Journals (Sweden)

    Askhatov Askar

    2017-01-01

    Full Text Available The paper represents the investigations concerning the geometrical size effect of hydrogenated zirconium alloys (Zr-1Ni-H during gamma-ray irradiation on the amount of energy absorbed. The results have shown that the less the cross-sectional dimensions of the sample or product is, the less energy is absorbed. The paper provides theoretical calculations. The zirconium sample with a cross-section of 2.8х2.8 cm absorbs 30-35% of the energy of the incident gamma-ray flow. The increase in the cross-section of a product up to 28 cm leads to the increase in the absorbed energy by more than 2 times. At the same time, the thickness of the product is constant. This effect is explained by the multiple scattering of gamma-rays. It leads to the nonuniform distribution of defects which can accumulate hydrogen and should be considered when developing the analysis methods. These edge effects are confirmed by the measurement of the thermal electromotive force for the samples of zirconium alloys before hydrogenation and gamma-ray irradiation, and after irradiation.

  2. [Experimental study of osseointegration of zirconium and titanium dental implants].

    Science.gov (United States)

    Kulakov, O B; Doktorov, A A; D'iakova, S V; Denisov-Nikol'skiĭ, Iu I; Grötz, K A

    2005-01-01

    In an experiment performed on pigs, methods of light and scanning electron microscopy were used to study the interaction of zirconium and titanium dental implants with bone 6 months following their insertion. Distinct features of integration of both implant types with bone structures were detected. Sites of direct contact of bone structures with metal were found to undergo constant remodeling according to biochemical and metabolic conditions in each zone of an implant surface. Statistically the degree of interactive properties of zirconium implants significantly exceeded similar parameter for titanium screws. Along the perimeter of the zones of bone contact with zirconium implants greater numbers of forming and formed bone areas were revealed as compared to the zones of bone contact with titanium implants, where erosion lacunae were more numerous. The complex of research methods used in this study have not revealed distinct changes in the structure of osteocytes, located in immediate proximity to the metal surface in comparison with more distant sites in the bone.

  3. Advances in microstructure and mechanical properties of zirconium diboride based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Monteverde, Frederic; Guicciardi, Stefano; Bellosi, Alida

    2003-04-15

    The use of silicon nitride as a sintering aid (5 vol.%) greatly improves the powder sinterability of zirconium diboride, in comparison to additive free ZrB{sub 2}. Nearly full dense monolithic material is obtained by hot pressing at 1700 deg. C. The microstructure consists of fine regular ZrB{sub 2} grains and of various secondary grain boundary phases (e.g. BN, t-ZrO{sub 2}, BN-rich glassy phase), mainly located at triple points. The addition of 20 vol.% of silicon carbide as a reinforcing particulate phase to the ZrB{sub 2}+5vol.%Si{sub 3}N{sub 4} powder mixture slows down the densification rate of ZrB{sub 2}, therefore a higher hot pressing temperature (i.e. 1870 deg. C) is necessary to achieve nearly full density. Further addition of oxide additives (1vol.%Al{sub 2}O{sub 3}+0.5vol.%Y{sub 2}O{sub 3}) to the ZrB{sub 2}-20vol.%SiC-5vol.%Si{sub 3}N{sub 4} system enables the production of near fully dense composites at lower hot pressing temperature (1760 deg. C). The presence of SiC particles in both the ZrB{sub 2}-based composites effectively improves strength, hardness and toughness, compared to monolithic zirconium diboride. Some mechanical properties are very interesting: flexural strength up to 700 and 600 MPa are measured at room temperature and 1000 deg. C, respectively. The properties are discussed in terms of the microstructural features.

  4. High ramp rate thermogravimetric analysis of zirconium(II) hydride and titanium(II) hydride

    Energy Technology Data Exchange (ETDEWEB)

    Licavoli, Joseph J., E-mail: jjlicavo@mtu.edu; Sanders, Paul G., E-mail: sanders@mtu.edu

    2015-09-20

    Highlights: • A unique arc image device has been proposed for high ramp rate thermogravimetry. • Powder oxidation influences decomposition kinetics at temperatures below 933 K. • Particle size has a negligible effect on TiH{sub 2} decomposition behavior. • Improvements to the device are required to conduct accurate kinetic analysis. - Abstract: Zirconium and titanium hydride are utilized in liquid phase metal foam processing techniques. This application results in immediate exposure to molten metal and almost immediate decomposition at high temperatures. Most decomposition characterization techniques utilize slow heating rates and are unable to capture the decomposition behavior of hydrides under foam processing conditions. In order to address this issue a specialized high ramp rate thermogravimetric analyzer was created from a xenon arc image refiner. In addition to thermogravimetry, complimentary techniques including X-ray diffraction and scanning electron microscopy were used to characterize hydride decomposition and compare the results to literature. Hydrides were partially oxidized and separated into particles size ranges to evaluate the influence of these factors on decomposition. Oxidizing treatments were found to decrease decomposition rate only at temperatures below 933 K (660 °C) while particle size effects appeared to be negligible. Several improvements to the unique TGA apparatus presented in the current work are suggested to allow reliable kinetic modeling and analysis.

  5. Separate-effect tests on zirconium cladding degradation in air ingress situations

    Energy Technology Data Exchange (ETDEWEB)

    Duriez, C. [Institut de Radioprotection et de Surete Nucleaire, IRSN, Direction de Prevention des Accidents Majeurs, Centre de Cadarache, 13115 St Paul Lez Durance (France)], E-mail: christian.duriez@irsn.fr; Steinbrueck, M. [Forschungszentrum Karlsruhe, FZK, Institut fuer Materialforschung, Postfach 3640, 76021 Karlsruhe (Germany); Ohai, D.; Meleg, T. [Institute for Nuclear Research, INR, Nuclear Material and Corrosion Department, Pitesti, 115400 Mioveni Arges (Romania); Birchley, J.; Haste, T. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2009-02-15

    In the event of air ingress during a reactor or spent fuel pond low probability accident, the fuel rods will be exposed to air-containing atmospheres at high temperatures. In comparison with steam, the presence of air is expected to result in a more rapid escalation of the accident. A state-of-the-art review performed before SARNET started showed that the existing data on zirconium alloy oxidation in air were scarce. Moreover, the exact role of zirconium nitride on the cladding degradation process was poorly understood. Regarding the cladding behaviour in air + steam or nitrogen-enriched atmospheres (encountered in oxygen-starved conditions), almost no data were available. New experimental programmes comprising small-scale tests have therefore been launched at FZK, IRSN (MOZART programme in the frame of the International Source Term Program-ISTP) and INR. Zircaloy-4 cladding in PWR (FZK, IRSN) and in CANDU (INR) geometry are investigated. On-line kinetic data are obtained on centimetre size tube segments, by thermogravimetry (FZK, IRSN and INR) or by mass spectrometry (FZK). Plugged tubes 15 cm long (FZK) are also investigated. The samples are air-oxidised either in the 'as-received' state, or after pre-oxidation in steam. 'Analytical' tests at constant temperature and gas composition provide basic kinetic data, while more prototypical temperature transients and sequential gas compositions are also investigated. The temperature domains extend from 600 deg. C up to 1500 deg. C. Systematic post-test metallographic inspections are performed. The paper gives a synthesis of the results obtained, comparing them in terms of kinetics and oxide scale structure and composition. A comparative analysis is performed with results of the QUENCH-10 (Q-10) bundle test, which included an air ingress phase. It is shown how the data contribute to a better understanding of the cladding degradation process, especially regarding the role of nitrogen. For modelling of

  6. Current situation and development trend of zirconium and zirconium alloys%核级锆及锆合金研究状况及发展前景

    Institute of Scientific and Technical Information of China (English)

    王峰; 王快社; 马林生; 张兵; 孔亮; 林兆霞

    2012-01-01

    The nuclear properties of zirconium and zirconium alloys are briefly described. The preparation methods of sponge zirconium are indicated. The current situation of zirconium alloys process technology in smelting, plastic working and welding is introduced. The corrosion resisting property and hydrogen absorption property of zirconium alloys are described in detail. It is pointed that the study of hydrogen absorption and corrosion mechanism is a long-term and concerned problem. The development trend of zirconium and zirconium alloys is narrated.%简要介绍锆及锆合金的核性能,海绵锆的制备方法,并与所述制备方法进行比较;从熔炼、塑性加工和焊接等方面综述锆合金加工技术的现状.详细描述锆合金的耐腐蚀性能和吸氢性能,指出吸氢问题和腐蚀机理的研究是一个长期关注的问题;同时对锆及锆合金的发展趋势进行了展望.

  7. Liquid-liquid extraction and separation of lanthanium(III) from titanium(IV), zirconium(IV), hafnium(IV), thorium(IV) and uranium(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Bhilare, N.G.; Shinde, V.M. [Institute of Science, Bombay (India)

    1995-02-01

    A method for the solvent extraction of lanthanum from salicylate media by using triphenylphosphine oxide is presented. Lanthanum is extracted quantitatively from 2.0 x 10{sup -2}-5.0 x 10{sup -2} mol dm{sup -3} sodium salicylate solution at pH 4.0-5.0 using 1.5% triphenylphosphine oxide dissolved in toluene. The extracted metal ion is stripped using water and estimated spectrophotometrically following complexation with Thoron-I. A possible mechanism of extraction is discussed. The method permits the separation of lanthanum from titanium, zirconium, hafnium, thorium and uranium. (author).

  8. Stability of the monoclinic phase in the ferroelectric perovskite PbZr1-xTixO3

    NARCIS (Netherlands)

    Noheda, B.; Cox, D.E.; Shirane, G.; Guo, R.; Jones, B.; Cross, L.E.

    2000-01-01

    Recent structural studies of ferroelectric PbZr1-xTixO3 (PZT) with x=0.48, have revealed a monoclinic phase in the vicinity of the morphotropic phase boundary (MPB), previously regarded as the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper,

  9. Application of RPR to Monoclinic and Triclinic Symmetries: Initial Results on Elasticity of Single-Crystal Diopside

    Science.gov (United States)

    Isaak, D. G.; Ohno, I.

    2001-12-01

    In past years, the rectangular parallelepiped resonance (RPR) method has been used to measure single-crystal elastic moduli, and their temperature dependences, of several materials important to geophysics. The high-temperature elastic properties of cubic, orthorhombic, tetragonal, and trigonal crystals, in addition to polycrystals, have all been studied with the RPR method. One feature of the RPR method is that, in principle, all the single-crystal elastic moduli (Cij) can be obtained from a single spectral sweep. However, no materials with crystal symmetry lower than orthorhombic symmetry have been reported in RPR studies. We extend the RPR theory to monoclinic and triclinic crystal symmetries. With these developments, we are able to compute single-crystal resonant spectra using a set of assumed Cij for right-rectangular parallelepiped monoclinic specimens cut along the b and c axes, or monoclinic specimens cut along known, but arbitrary, axes. We present initial results showing the comparison of calculated and measured resonance modes for single-crystal monoclinic diopside. Our measured resonance spectrum on chrome diopside is markedly more consistent with the spectrum calculated from the elasticity data of Collins and Brown (PCM, 26, 7-13, 1998) using a specimen that is 72% diopside than the end-member diopside elasticity data reported by Levien et al. (PCM, 4, 105-113, 1979).

  10. Coexistence of different charge states in Ta-doped monoclinic HfO2: Theoretical and experimental approaches

    DEFF Research Database (Denmark)

    Taylor, M.A.; Alonso, R.E.; Errico, L.A.

    2010-01-01

    A combination of experiments and ab initio quantum-mechanical calculations has been applied to examine hyperfine interactions in Ta-doped hafnium dioxide. Although the properties of monoclinic HfO2 have been the subject of several earlier studies, some aspects remain open. In particular, time dif...

  11. Studies in group IV organometallic chemistry XXX. Synthesis of compounds containing tin---titanium and tin---zirconium bonds

    NARCIS (Netherlands)

    Creemers, H.M.J.C.; Verbeek, F.; Noltes, J.G.

    1968-01-01

    Starting from the tetrakis(diethylamino) derivatives of titanium and zirconium and pheyltin hydrides six intermetalic compounds contianing up to nine tin and titanium(or zirconium) atoms have been obtained by hydrostannolysis type reactions.

  12. Studies in group IV organometallic chemistry XXX. Synthesis of compounds containing tin---titanium and tin---zirconium bonds

    NARCIS (Netherlands)

    Creemers, H.M.J.C.; Verbeek, F.; Noltes, J.G.

    Starting from the tetrakis(diethylamino) derivatives of titanium and zirconium and pheyltin hydrides six intermetalic compounds contianing up to nine tin and titanium(or zirconium) atoms have been obtained by hydrostannolysis type reactions.

  13. In situ growth of ZrO{sub 2}–Al{sub 2}O{sub 3} nano-crystalline ceramic coatings via micro arc oxidation of aluminum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Shoaei-Rad, V. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Bayati, M.R., E-mail: mbayati@ncsu.edu [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, North Carolina State University, Raleigh 27695-7907, NC (United States); Zargar, H.R. [Department of Metals and Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Javadpour, J. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Golestani-Fard, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of)

    2012-06-15

    Highlights: ► ZrO{sub 2}–Al{sub 2}O{sub 3} layers were fabricated by MAO process. ► A formation mechanism was also proposed. ► Effect of voltage and electrolyte composition on layers properties was studied. -- Abstract: Micro arc oxidation technique was employed to grow zirconia–alumina porous layers. Considering XPS, XRD, and EDX results, the layers mainly consisted of α-Al{sub 2}O{sub 3}, γ-Al{sub 2}O{sub 3}, monoclinic ZrO{sub 2}, tetragonal ZrO{sub 2}. Fractions of these phases were observed to change based on the fabrication conditions. Zirconia phases formed not only on the surface, but also in the layers depth. Increasing the voltage as well as utilizing thicker electrolytes resulted in higher zirconium concentration. The average crystalline size of the ZrO{sub 2} and the Al{sub 2}O{sub 3} phases was determined as about 57 and 75 nm. AFM studies revealed that the surface roughness increased with voltage and electrolyte concentration. Morphological evaluations, performed by SEM, showed that the microstructure of the layers strongly depended on the synthesis conditions. The layers revealed a porous structure with a pores size of 40–300 nm. Microcracks were observed to appear when the electrolyte concentration and the applied voltage increased. Finally, a formation mechanism was put forward with emphasis on the chemical and the electrochemical foundations.

  14. Single crystalline monoclinic La0.7Sr0.3MnO3 nanowires with high temperature ferromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Carretero-Genevrier, Adrian [ICMAB, Barcelona, Spain; Gazquez Alabart, Jaume [ORNL; Idrobo Tapia, Juan C [ORNL; Oro, Judith [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Ferain, Etienne [Universite catholique de Louvain, Belgium (UCL); Rodriguez-Carvajal, Juan [Institut Laue-Langevin (ILL); Puig, Teresa [ICMAB, Barcelona, Spain; Mestres, Narcis [ICMAB, Barcelona, Spain; Obradors, Xavier [ICMAB, Barcelona, Spain

    2011-01-01

    Porous mixed-valent manganese oxides are a group of multifunctional materials that can be used as molecular sieves, catalysts, battery materials, and gas sensors. However, material properties and thus activity can vary significantly with different synthesis methods or process conditions, such as temperature and time. Here, we report on a new synthesis route for MnO{sub 2} and LaSr-doped molecular sieve single crystalline nanowires based on a solution chemistry methodology combined with the use of nanoporous polymer templates supported on top of single crystalline substrates. Because of the confined nucleation in high aspect ratio nanopores and of the high temperatures attained, new structures with novel physical properties have been produced. During the calcination process, the nucleation and crystallization of {var_epsilon}-MnO{sub 2} nanoparticles with a new hexagonal structure is promoted. These nanoparticles generated up to 30 {mu}m long and flexible hexagonal nanowires at mild growth temperatures (T{sub g} = 700 C) as a consequence of the large crystallographic anisotropy of {var_epsilon}-MnO{sub 2}. The nanocrystallites of MnO{sub 2} formed at low temperatures serve as seeds for the growth of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} nanowires at growth temperatures above 800 C, through the diffusion of La and Sr into the empty 1D-channels of {var_epsilon}-MnO{sub 2}. Our particular growth method has allowed the synthesis of single crystalline molecular sieve (LaSr-2 x 4) monoclinic nanowires with composition La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and with ordered arrangement of La{sup 3+} and Sr{sup 2+} cations inside the 1D-channels. These nanowires exhibit ferromagnetic ordering with strongly enhanced Curie temperature (T{sub c} > 500 K) that probably results from the new crystallographic order and from the mixed valence of manganese.

  15. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Science.gov (United States)

    2010-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... zirconium(4+) salt and silica, acetates (PMN P-07-674) is subject to reporting under this section for...

  16. On the stabilization of niobium(V) solutions by zirconium(IV) and hafnium(IV)

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    Niobium cannot be separated from zirconium or hafnium when these elements occur together in solution with common anions such as chloride and sulphate. This is ascribed to the co-polymerization of niobium(V) and the hydrolysed ionic species of zirconium(IV) and hafnium(IV) to form colloidal...

  17. Bis[2-(hy-droxy-imino-meth-yl)phenolato]nickel(II): a second monoclinic polymorph.

    Science.gov (United States)

    Rusanova, Julia A; Buvaylo, Elena A; Rusanov, Eduard B

    2011-01-15

    The title compound, [Ni(C(7)H(6)NO(2))(2)], (I), is a second monoclinic polymorph of the compound, (II), reported by Srivastava et al. [Acta Cryst. (1967), 22, 922] and Mereiter [Private communication (2002) CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The mol-ecule in both structures lies on a crystallographic inversion center and both have an inter-nal hydrogen bond. The title compound crystallizes in the space group P2(1)/c (Z = 2), whereas compound (II) is in the space group P2(1)/n (Z = 2) with a similar cell volume but different cell parameters. In both polymorphs, mol-ecules are arranged in the layers but in contrast to the previously published compound (II) where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I) is stabilized by strong intra-molecular O-H⋯O hydrogen bonding between the O-H group and the phenolate O atom.

  18. Phonon instability and pressure-induced isostructural semiconductor-semimetal transition of monoclinic V O2

    Science.gov (United States)

    He, Huabing; Gao, Heng; Wu, Wei; Cao, Shixun; Hong, Jiawang; Yu, Dehong; Deng, Guochu; Gao, Yanfeng; Zhang, Peihong; Luo, Hongjie; Ren, Wei

    2016-11-01

    Recent experiments have revealed an intriguing pressure-induced isostructural transition of the low temperature monoclinic V O2 and hinted to the existence of a new metallization mechanism in this system. The physics behind this isostructural phase transition and the metallization remains unresolved. In this work, we show that the isostructural transition is a result of pressure-induced instability of a phonon mode that relates to a CaC l2 -type of rotation of the oxygen octahedra, which alleviates, but does not completely remove, the dimerization and zigzagging arrangement of V atoms in the M1 phase. This phonon mode shows an increasing softening with pressure, ultimately leading to an isostructural phase transition characterized by the degree of the rotation of the oxygen octahedra. We also find that this phase transition is accompanied by an anisotropic compression, in excellent agreement with experiments. More interestingly, in addition to the experimentally identified M1' phase, we find a closely related M1 '' phase, which is nearly degenerate with the M1 ' phase. Unlike the M1 ' phase, which has a nearly pressure-independent electronic band gap, the gap of the M1 '' drops quickly at high pressures and vanishes at a theoretical pressure of about 40 GPa.

  19. Monoclinic BiVO{sub 4} with regular morphologies: Hydrothermal synthesis, characterization and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li Haibin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)], E-mail: coastllee@hotmail.com; Liu Guocong [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Department of Chemistry, Yulin Normal University, Yulin 537000 (China); Duan Xuechen [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2009-05-15

    Monoclinic bismuth vanadate (BiVO{sub 4}) samples with regular morphologies were prepared by a facile hydrothermal process with Bi{sub 2}O{sub 3} and NH{sub 4}VO{sub 3} as starting materials. The physical and photophysical properties of the as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and UV-vis diffuse reflectance spectroscopy (UV-vis). It was found that cuboid-like, square plate-like and flower-like BiVO{sub 4} could be readily obtained by tailoring the pH values of the reaction suspensions in the presence of CTAB. Both pH value and CTAB played crucial roles in the morphology evolution of the as-prepared samples. The bandgaps (E{sub g}) of cuboid-like, square plate-like and flower-like BiVO{sub 4} were 2.39 eV, 2.40 eV and 2.46 eV, respectively. The photocatalytic performance of the as-prepared BiVO{sub 4} was much better than that of P25 for photodegradation of methyl orange under sunlight irradiation. The photocatalytic activities of BiVO{sub 4} samples were highly related to their crystallinities and shapes.

  20. Monoclinic structured BiVO4 nanosheets: hydrothermal preparation, formation mechanism, and coloristic and photocatalytic properties.

    Science.gov (United States)

    Zhang, Li; Chen, Dairong; Jiao, Xiuling

    2006-02-16

    Bismuth vanadate (BiVO(4)) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO(4) nanosheets had a monoclinic structure, were ca. 10-40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N',N'-tetraethylated rhodamine (RB) under solar irradiation.

  1. Vibrational Spectroscopy and Phonon-Related Properties of the L-Aspartic Acid Anhydrous Monoclinic Crystal.

    Science.gov (United States)

    Silva, A M; Costa, S N; Sales, F A M; Freire, V N; Bezerra, E M; Santos, R P; Fulco, U L; Albuquerque, E L; Caetano, E W S

    2015-12-10

    The infrared absorption and Raman scattering spectra of the monoclinic P21 l-aspartic acid anhydrous crystal were recorded and interpreted with the help of density functional theory (DFT) calculations. The effect of dispersive forces was taken into account, and the optimized unit cells allowed us to obtain the vibrational normal modes. The computed data exhibits good agreement with the measurements for low wavenumbers, allowing for a very good assignment of the infrared and Raman spectral features. The vibrational spectra of the two lowest energy conformers of the l-aspartic molecule were also evaluated using the hybrid B3LYP functional for the sake of comparison, showing that the molecular calculations give a limited description of the measured IR and Raman spectra of the l-aspartic acid crystal for wavenumbers below 1000 cm(-1). The results obtained reinforce the need to use solid-state calculations to describe the vibrational properties of molecular crystals instead of calculations for a single isolated molecule picture even for wavenumbers beyond the range usually associated with lattice modes (200 cm(-1) < ω < 1000 cm(-1)).

  2. Switch effect of the nonquantized intrinsic spin Hall conductivity in monolayered monoclinic transition metal dichalcogenides

    Science.gov (United States)

    Lin, Xianqing; Ni, Jun

    2017-07-01

    First-principles calculations have been performed to study the intrinsic spin Hall effect (SHE) and its behavior under vertical electric field in monoclinic transition metal dichalcogenide monolayers (1T‧-MX2 with M  =  Mo, W and X  =  S, Se, Te). We find that the pristine systems exhibit nonquantized intrinsic spin Hall conductivity (SHC) due to the unconserved spin around the direct band gaps though they have nontrivial band topology. The unconserved spin is attributed to the band crossings at Fermi levels for systems without spin-orbit coupling and the distinct composition of the band states around the crossings. Despite the nonquantization of SHC, calculations with the hybrid functional predict SHC approaching the quantized value in W based systems, especially 1T‧-WTe2, which has been realized in experiments. More interesting, a sharp drop of SHC to almost zero in semiconducting systems induced by vertical electric field is observed at the topological phase transition point, suggesting that such systems exhibit a strong switch effect of SHC. In contrast, the switch effect is weak in semi-metallic systems, where the SHC decreases almost continuously with increasing field strength for the chemical potential around the Fermi levels. Our findings suggest potential applications of the pristine 1T‧-MX2 and those under vertical electric field in spintronics devices by utilizing the intrinsic SHE of their bulk states.

  3. Elastic and vibrational properties of monoclinic HfO2 from first-principles study

    Science.gov (United States)

    Wu, Rui; Zhou, Bo; Li, Qian; Jiang, ZhenYi; Wang, WenBo; Ma, WenYan; Zhang, XiaoDong

    2012-03-01

    The elastic and vibrational properties of crystalline monoclinic HfO2 have been investigated using density functional perturbation theory. Using the Voigt and Reuss theory, we estimate the bulk, shear and Young's modulus for polycrystalline HfO2, which agree very well with the available experimental and theoretical data. Additionally, we present a systematic analysis of the elastic properties of HfO2 polymorphs and find the trends in the elastic parameters for the HfO2 structures are consistent with those for the ZrO2 structures. The choice of exchange-correlation functional has an important effect on the results of elastic and vibrational properties. The utilization of Hartwigzen-Goedecker-Hutter type functional is a great improvement on calculation of the zone-centre phonon frequencies, and shows the root-mean-square absolute deviation of 7 cm-1 with experiments. A rigorous assignment of all the Raman modes is achieved by combining symmetry analysis with the first-principles calculations, which helps us to identify the main peak and some other features of Raman spectra. Furthermore, the Raman spectrum of HfO2 powder has been simulated for the first time, providing a theoretical benchmark for the interpretation of the unresolved problems in experimental studies.

  4. EFFECT OF CERIUM ION IMPLANTATION ON THE AQUEOUS CORROSION BEHAVIOR OF ZIRCONIUM

    Institute of Scientific and Technical Information of China (English)

    D.Q. Peng; X.D. Bai; Q.G. Zhou; X.W. Chen; R.H. Yu; X.Y. Liu

    2004-01-01

    In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1 ×1016 to 1 ×1017 ions/cm2 at about 150℃, using MEWA source at an acceler ative voltage of 40kV. The valence of the surface layer was analyzed by X-ray photoelectron spectroscopy (XPS); Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium in a 0.5mol/L H2SO4 solution. It was found that a remarkable decline in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. Finally, the mechanism of the corrosion resistance decline of the cerium-implanted zirconium is discussed.

  5. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    Science.gov (United States)

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (pzirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  6. A simple spectrophotometric method for determination of zirconium or hafnium in selected molybdenum-base alloys

    Science.gov (United States)

    Dupraw, W. A.

    1972-01-01

    A simple analytical procedure is described for accurately and precisely determining the zirconium or hafnium content of molybdenum-base alloys. The procedure is based on the reaction of the reagent Arsenazo III with zirconium or hafnium in strong hydrochloric acid solution. The colored complexes of zirconium or hafnium are formed in the presence of molybdenum. Titanium or rhenium in the alloy have no adverse effect on the zirconium or hafnium complex at the following levels in the selected aliquot: Mo, 10 mg; Re, 10 mg; Ti, 1 mg. The spectrophotometric measurement of the zirconium or hafnium complex is accomplished without prior separation with a relative standard deviation of 1.3 to 2.7 percent.

  7. Stabilized tin-oxide-based oxidation/reduction catalysts

    Science.gov (United States)

    Jordan, Jeffrey D. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Leighty, Bradley D. (Inventor); Watkins, Anthony Neal (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor); Gulati, Suresh T. (Inventor); Summers, Jerry C. (Inventor)

    2008-01-01

    The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

  8. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture

    Directory of Open Access Journals (Sweden)

    T.S. Bhosale

    2014-10-01

    Full Text Available The samples of lithium zirconium silicate were prepared by precipitation, template and sol-gel meth-ods. The samples were prepared with several mol ratios of Li:Zr:Si. The preparation of lithium zirco-nium silicate samples by precipitation method were carried out by using the lithium nitrate, zirconyl nitrate, zirconium(IV oxypropoxide and tetramethylorthosilicate (TEOS as precursors. The samples of lithium zirconium silicate were prepared by using cetyltrimethyl-ammonium bromide (C-TAB and tetramethyl ammonium hydroxide (TMAOH by template method. The samples of lithium zirconium silicate were characterized by XRD, TEM, SEM, 29Si-MAS NMR and FTIR. The surface area, alkalinity / acidity of the samples of lithium zirconium silicate were measured. The TGA analysis of lithium zirco-nium silicate samples was done. The CO2 captured by the samples of lithium zirconium silicate was es-timated. The captured CO2 by the samples of lithium zirconium silicate was found to be in the range 3.3 to 8.6 wt%. © 2014 BCREC UNDIP. All rights reservedReceived: 27th March 2014; Revised: 31st July 2014; Accepted: 2nd August 2014How to Cite: Bhosale, T.S. , Gaikwad, A.G. (2014. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture. Bulletin of Chemical Reaction Engineering & Catalysis, 9(3: 249-262. (doi:10.9767/bcrec.9.3.6646.249-262Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6646.249-262

  9. Recent Advances in the Synthesis of Metal Oxide Nanofibers and Their Environmental Remediation Applications

    OpenAIRE

    Kunal Mondal

    2017-01-01

    Recently, wastewater treatment by photocatalytic oxidation processes with metal oxide nanomaterials and nanocomposites such as zinc oxide, titanium dioxide, zirconium dioxide, etc. using ultraviolet (UV) and visible light or even solar energy has added massive research importance. This waste removal technique using nanostructured photocatalysts is well known because of its effectiveness in disintegrating and mineralizing the unsafe organic pollutants such as organic pesticides, organohalogens...

  10. ENTIRELY AQUEOUS SOLUTION-GEL ROUTE FOR THE PREPARATION OF ZIRCONIUM CARBIDE, HAFNIUM CARBIDE AND THEIR TERNARY CARBIDE POWDERS

    Directory of Open Access Journals (Sweden)

    Zhang Changrui

    2016-07-01

    Full Text Available An entirely aqueous solution-gel route has been developed for the synthesis of zirconium carbide, hafnium carbide and their ternary carbide powders. Zirconium oxychloride (ZrOCl₂.8H₂O, malic acid (MA and ethylene glycol (EG were dissolved in water to form the aqueous zirconium carbide precursor. Afterwards, this aqueous precursor was gelled and transformed into zirconium carbide at a relatively low temperature (1200 °C for achieving an intimate mixing of the intermediate products. Hafnium and the ternary carbide powders were also synthesized via the same aqueous route. All the zirconium, hafnium and ternary carbide powders exhibited a particle size of ∼100 nm.

  11. Titanium-zirconium-phosphonate hybrid film on 6061 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Shuanghong WANG; Lei WANG; Changsheng LIU

    2011-01-01

    Three titanium-zirconium-phosphonate hybrid films were formed on AA6061 aluminum alloy by immersing in fluorotitanic acid and fluorozirconic acid based solution containing different phosphonic acids for protective coatings of aluminium alloy. The corrosion resistance of three hybrid films as the substitute for chromate film were evaluated and compared. The neutral salt spray test was explored,the immersion test was conducted and electrochemical test was also executed. The hybrid films exhibited well-pleasing corrosion resistance and adhesion to epoxy resin paints. It was found out that the hybrid films could efficiently be a substitute for chromate based primer over aluminium alloy.

  12. XPS investigation of DNA binding to zirconium-phosphonate surfaces.

    Science.gov (United States)

    Lane, Sarah M; Monot, Julien; Petit, Marc; Bujoli, Bruno; Talham, Daniel R

    2007-07-01

    The surface coverage of phosphorylated oligonucleotides immobilized on a zirconium-phosphonate surface was analyzed using X-ray photoelectron spectroscopy (XPS). By quantifying the intensity of the N 1s signal originating from the oligonucleotide and the Zr 3d peak from the metal-phosphonate surface, the surface coverage of the oligonucleotide could be calculated with a modified substrate-overlayer model. We found relatively low surface coverages indicating that once covalently bound via the terminal phosphate the polymer chain further physisorbs to the surface limiting the adsorption of additional molecules.

  13. Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hollis, Kendall J [Los Alamos National Laboratory; Pena, Maria I [Los Alamos National Laboratory

    2010-01-01

    Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

  14. Evidence of stress-induced hydrogen ordering in zirconium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Steuwer, A. [FaME38 at the ESRF-ILL, 6 rue J Horowitz, 38042 Grenoble (France); ESS Scandinavia, University of Lund, Stora Algatan 4, 22350 Lund (Sweden)], E-mail: steuwer@ill.fr; Santisteban, J.R. [Centro Atomico Bariloche, CNEA, San Carlos de Bariloche (Argentina); Preuss, M. [University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Peel, M.J.; Buslaps, T. [European Synchrotron Radiation Facility, 6 rue J Horowitz, 38042 Grenoble (France); Harada, M. [R and D Section, Chofu-Kita Plant, Kobe Special Tube Co, Shimonoseki 752-0953 (Japan)

    2009-01-15

    The formation of hydrides in zirconium alloys significantly affects their mechanical properties and is considered to play a critical role in their failure mechanisms, yet relatively little is known about the micromechanical behavior of hydrides in the bulk. This paper presents the result of in situ uniaxial mechanical tensioning experiments on hydrided zircaloy-2 and zircaloy-4 specimens using energy-dispersive synchrotron X-ray diffraction, which suggests that a stress-induced transformation of the {delta}-hydride to {gamma}-hydride via ordering of the hydrogen atoms occurs, akin to a Snoek-type relaxation. Subsequent annealing was found to reverse the ordering phenomenon.

  15. Polarization-dependent angular distribution of the absorption behavior in Ytterbium-doped monoclinic LYB and LGB compounds

    Science.gov (United States)

    Gebremichael, W.; Petit, Y.; Rouzet, S.; Fargues, A.; Veber, P.; Velazquez, M.; Jubera, V.; Canioni, L.; Manek-Hönninger, I.

    2017-02-01

    In this contribution we detail the full characterization of the anisotropy of the absorption properties of two different Yb-doped monoclinic borate compounds under polarized light. The studied crystals are Li6(Gd)0.75Yb0.25(BO3)3 and Li6Y0.75Yb0.25(BO3)3, respectively, grown by the Czochralski method. We focused on the study of their absorption at the zero line transition as a function of the polarization direction of the incident light for two different crystal cuts of each compound. We discuss the different Eigen frames that must be considered in these materials due to their monoclinic character, as well as the optimal crystal orientation for the considered absorption and the potential influences when used as laser materials.

  16. Influence of downsizing of zeolite crystals on the orthorhombic ↔ monoclinic phase transition in pure silica MFI-type

    Science.gov (United States)

    Kabalan, Ihab; Michelin, Laure; Rigolet, Séverinne; Marichal, Claire; Daou, T. Jean; Lebeau, Bénédicte; Paillaud, Jean-Louis

    2016-08-01

    The impact of crystal size on the transition orthorhombic ↔ monoclinic phase in MFI-type purely silica zeolites is investigated between 293 and 473 K using 29Si MAS NMR and powder X-ray diffraction. Three silicalite-1 zeolites are synthesized: a material constituted of micron-sized crystals, pseudospherical nanometer-sized crystals and hierarchical porous zeolites with a mesoporous network created by the use of a gemini-type diquaternary ammonium surfactant giving nanosheet zeolites. Our results show for the first time that the orthorhombic ↔ monoclinic phase transition already known for micron-sized particles also occurs in nanometer-sized zeolite crystals whereas our data suggest that the extreme downsizing of the zeolite crystal to one unit cell in thickness leads to an extinction of the phase transition.

  17. Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

    2004-12-14

    Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for

  18. Protection of zirconium and its alloys by metallic coatings; Protection du zirconium et de ses alliages par des revetements metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Loriers, H.; Lafon, A.; Darras, R.; Baque, P. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    At 600 deg. C in an atmosphere of carbon dioxide, zirconium and its alloys undergo corrosion which presents two aspects simultaneously: - formation of a surface layer of zirconia, - dissolution of oxygen in the alloy sub-layer leading to brittleness. The two phenomena greatly restrict the possibilities of using zirconium alloys as a canning material for fuel elements in CO{sub 2} cooled nuclear reactors. An attempt has thus been made to limit, and perhaps to suppress, the corrosion effects in zirconium under these conditions by protecting it with metallic coatings. A first attempt to obtain a protection using copper-based coatings did not produce the result hoped for. Aluminium coatings produced by vacuum evaporation, followed by a consolidating thermal treatment make it possible to prevent the formation of the zirconia layer, but they do not eliminate the hardening effect produced by oxygen diffusion. On the other hand, electrolytically produced chromium deposits whose adherence is improved by a thermal vacuum treatment, counteract both these phenomena simultaneously. A similar result has been obtained with coatings of molybdenum produced by the technique of high-frequency inductive plasma sputtering. The particular effectiveness of the last two types of coatings is due to their structures characterized by the existence of an adherent film of chromium or molybdenum in the free state. (authors) [French] Le zirconium et ses alliages subissent, en atmosphere de gaz carbonique vers 600 deg. C, une corrosion qui prend deux aspects simultanes: - formation d'une couche de zircone superficielle, - dissolution fragilisante de l'oxygene dans l'alliage sous-jacent. Ces deux phenomenes restreignent fortement les possibilites d'utilisation des alliages de zirconium comme materiaux de gaine d'elements combustibles pour reacteurs nucleaires refroidis par le gaz carbonique. Il a donc ete cherche a limiter, voire supprimer, les effets de la corrosion du

  19. Analysis of tetragonal to monoclinic phase transformation caused by accelerated artificial aging and the effects of microstructure in stabilized zirconia

    Science.gov (United States)

    Lucas, Thomas J.

    This investigation addresses the issue that yttria stabilized zirconia is being used as a dental biomaterial without substantial evidence of its long-term viability. Furthermore, stabilized zirconia (SZ) undergoes low temperature degradation (LTD), which can lead to roughening of the surface. A rougher exterior can lead to increased wear of the antagonist in the oral environment. Despite the LTD concerns, SZ is now widely used in restorative dentistry, including full contour crowns. A comparison of aging methods to determine the role of artificial aging on inducing the transformation has not been extensively studied. Therefore, simulations of the transformation process were investigated by comparing different methods of accelerated aging. The rejected null hypothesis is that the temperature of aging treatment will not affect the time required to cause measurable monoclinic transformation of yttria stabilized zirconia. The transformation of SZ starts at the surface and progresses inward; however, it is unclear whether the progression is constant for different aging conditions. This investigation analyzed the depth of transformation as a function of aging conditions for stabilized zirconia in the top 5-6 mum from the surface. The rejected null hypothesis is that the transformation amount is constant throughout the first six micrometers from the surface. The effects of grain size on the amount of monoclinic transformation were also investigated. This study aimed to determine if the grain size of partially stabilized zirconia affects the amount of monoclinic transformation, surface roughness, and property degradation due to aging. The rejected null hypothesis is that the grain size will not affect the amount of monoclinic transformation, thus have no effect on surface roughening or property degradation. The final part of this study addresses the wear of enamel when opposing zirconia by observing how grain size and aging affected the wear rate of an enamel antagonist

  20. Batteries: encapsulated monoclinic sulfur for stable cycling of li-s rechargeable batteries (adv. Mater. 45/2013).

    Science.gov (United States)

    Moon, San; Jung, Young Hwa; Jung, Wook Ki; Jung, Dae Soo; Choi, Jang Wook; Kim, Do Kyung

    2013-12-03

    On page 6547 Do Kyung Kim, Jang Wook Choi and co-workers describe a highly aligned and carbon-encapsulated sulfur cathode synthesized with an AAO template that exhibits a high and long cycle life, and the best rate capability based on the complete encapsulation of sulfur (physical) and implementation of the monoclinic sulfur phase (chemical). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.