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Energy-dispersive Spectroscopy (energy-dispersive + spectroscopy)
Selected AbstractsTernary System Al2O3,MgO,CaO: Part II, Phase Relationships in the Subsystem Al2O3,MgAl2O4,CaAl4O7JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2000Antonio H. de Aza Solid-state compatibility and melting relationships in the subsystem Al2O3,MgAl2O4,CaAl4O7 were studied by firing and quenching selected samples located in the isopletal section (CaO·MgO),Al2O3. The samples then were examined using X-ray diffractomtery, optical microscopy, and scanning and transmission electron microscopies with wavelength- and energy-dispersive spectroscopies, respectively. The temperature, composition, and character of the ternary invariant points of the subsystem were established. The existence of two new ternary phases (Ca2Mg2Al28O46 and CaMg2Al16O27) was confirmed, and the composition, temperature, and peritectic character of their melting points were determined. The isothermal sections at 1650°, 1750°, and 1840°C of this subsystem were plotted, and the solid-solution ranges of CaAl4O7, CaAl12O19, MgAl2O4, Ca2Mg2Al28O46, and CaMg2Al16O27 were determined at various temperatures. The experimental data obtained in this investigation, those reported in Part I of this work, and those found in the literature were used to establish the projection of the liquidus surface of the ternary system Al2O3,MgO,CaO. [source] Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?CONTACT DERMATITIS, Issue 2 2010Jacob Pontoppidan Thyssen Background: Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure. Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items. Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). Results: Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin,cobalt plating on these. Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future. Industries may not be fully aware of the potential cobalt allergy problem. [source] Wettability of Bionic Nanopapilla Particles and Their High Electrorheological Activity,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005X. Wang Abstract Inspired by the nano- and microscale structure of biological surfaces, a kind of nanopapilla particle possessing both nano- and microscale structure has been prepared via a hydrothermal method. The nanopapilla particles have been analyzed using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer,Emmett,Teller (BET) methods, energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), etc. The results show that TiO2 nanopapillae are radially distributed on the surface of thin-flake kaolinite. The BET surface area and the wettability of the nanopapilla particles show a marked improvement compared to kaolinite. Moreover, the oleophilic ability of the kaolinite/TiO2 nanopapilla particles spurs a very high electrorheological activity, which is about fifty times that of pure kaolinite. It is suggested that the significant electrorheological improvement can be attributed to the enhanced dielectric properties of the nanopapilla-particle electrorheological fluid. [source] Physical and mechanical characterization and the influence of cyclic loading on the behaviour of nickel-titanium wires employed in the manufacture of rotary endodontic instrumentsINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2005M. G. A. Bahia Abstract Aim, To analyse the influence of cyclic loading on the mechanical behaviour of nickel-titanium (NiTi) wires employed in the manufacture of ProFile rotary endodontic instruments. Methodology, Nickel-titanium wires, 1.2 mm in diameter, taken from the production line of ProFile rotary endodontic instruments before the final machining step, were tensile-tested to rupture in the as-received condition and after 100 load,unload cycles in the superelastic plateau (4% elongation). The wires were characterized by X-ray energy-dispersive spectroscopy, X-ray diffraction and by differential scanning calorimetry and compared with new size 30, .06 taper ProFile instruments. The fracture surfaces of the wires were observed by scanning electron microscopy. Results, The mechanical properties of the as-received wires, their chemical composition, the phases present and their transformation temperatures were consistent with their final application. Only small changes, which decreased after the first few cycles, took place in the mechanical properties of the cycled wires. The stress at maximum load and the plastic strain at breakage remained the same, while the critical stress for inducing the superelastic behaviour, which is related to the restoring force of the endodontic instruments, decreased by approximately 27%. Conclusions, The mechanical behaviour of the NiTi wires was modified slightly by cyclic tensile loading in the superelastic plateau. As the changes tended towards stabilization, the clinical use of rotary NiTi ProFile instruments does not compromise their superelastic properties until they fracture by fatigue or torsional overload, or are otherwise discarded. [source] Synthesis and Dielectric Properties of Niobia Coating on BaTiO3INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2009Jia-Jia Gan Different from conventional powder mixing, this study demonstrates a method of homogeneous coating for niobia (Nb2O5) on ferroelectric barium titanate (BaTiO3) powders. The precipitation of Nb coating with pH has been determined quantitatively by the inductance-coupled plasma method. Crystalline phases were determined by X-ray diffractometry, and the formation of a "core-shell" structure with a Nb concentration gradient was observed by a transmission electron microscope with X-ray energy-dispersive spectroscopy. The dielectric constant (K) of the samples prepared by the nanocoating method showed a more stable temperature coefficient of capacitance and well satisfied the requirements of X7R. [source] Hydrothermal Synthesis and Characterization of KxNa(1,x)NbO3 PowdersINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2007Jun-Hai Lv NaNbO3, KNbO3, and KxNa(1,x)NbO3 powders were successfully prepared by the hydrothermal method. The phase of the products was identified to be orthorhombic structure by X-ray diffraction (XRD) technique, and the XRD results revealed that the x value of the KxNa(1,x)NbO3 gradually increased with the increase in the ratio of K+ to Na+ in alkaline solution. The morphology and the microstructure were investigated by scanning electron microscopy, energy-dispersive spectroscopy, and transmission electron microscopy, and the results indicated that the ratio of K+ to Na+ in the solution had a great effect on the morphology and the size of products. Na0.5K0.5NbO3 with morphotropic phase boundary composition could be synthesized when the molar ratio of K+ to Na+ was between 4:1 and 6:1 in the solution. A possible formation mechanism of the KxNa(1,x)NbO3 crystal was also proposed based on the experimental results. [source] Quantitative X-Ray Spectrum Imaging of Lead Lanthanum Zirconate Titanate PLZT Thin-FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Chad M. Parish The high permittivity of Pb(Zr,Ti)O3 and (Pb,La)(Zr,Ti)O3,PZT and PLZT, respectively,thin films and the flexibility of chemical solution deposition (CSD) make solution-derived P(L)ZT thin films extremely attractive for integrated capacitor applications. However, Pb-loss or cation segregation during processing results in degraded properties of the final film. Here, we have extended the use of multivariate statistical analysis (MSA) of energy-dispersive spectroscopy (EDS) spectrum images (SIs) in scanning transmission electron microscopy (STEM) to allow the two-dimensional (2D) quantitative analysis of cation segregation and depletion in P(L)ZT thin films. Quantified STEM-EDS SIs allow high-resolution (< ,10 nm) quantification of these cation distributions. Surface Pb depletion is found after crystallization and is replenished by a unique post-crystallization PbO overcoat+anneal processes. Zr/Ti and La segregation are found to develop in a decidedly nonplanar fashion during crystallization, especially in PLZT 12/70/30 material, highlighting the need for 2D analysis. Quantitative 2D chemical information is essential for improved processing of homogeneous P(L)ZT films with optimal electrical properties. [source] Microstructural Morphology and Electrical Properties of Copper- and Niobium-Doped Tin Dioxide Polycrystalline VaristorsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2006Chun-Ming Wang The influence of a Nb2O5 additive on the densification, microstructural morphology, and nonlinear electrical properties of the CuO-doped SnO2 -based varistors was investigated. It was found that copper oxide significantly improves the densification of the SnO2 ceramics. The effects of Nb2O5 on tin dioxide varistors were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and capacitance,voltage measurements, as well as impedance spectroscopy. Copper oxide segregates at the grain boundaries and precipitates at triple points, and niobium makes the tin dioxide grain semi-conductive. The copper oxide intergranular insulating layer separates two semi-conductive tin dioxide grains and forms the barriers. The reason for the nonlinearity of SnO2 -based ceramics was explained. [source] Synthesis of Mixed Conducting Ceramic Oxides SrFeCo0.5Oy Powder by Hybrid Microwave HeatingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2002Di Huo Mixed conducting ceramic oxide SrFeCo0.5Oy powders were prepared by a conventional solid-state reaction method and two types of hybrid microwave heating methods. XRD, SEM/EDS (energy-dispersive spectroscopy), and TEM/EDX (energy-dispersive X-ray microanalysis) were used to characterize the products. The conventional heated sample is a three-phase mixture composed of a predominant orthorhombic Sr4(Fe1,xCox)6O13±, phase, a cubic perovskite SrFe1,xCoxO3,, phase, and a CoO phase. Phase components of the direct hybrid heated samples are similar to those of the conventional heated sample, except that its predominant phase is a cubic perovskite SrFe1,xCoxO3,, phase other than the orthorhombic Sr4(Fe1,xCox)6O13±, phase. The indirect hybrid heated sample is mainly composed of a cubic perovskite Sr(Fe,Co)1.5Oy phase, with a trace amount of orthorhombic phase and spinel (Fe,Co) oxides. The cobalt content of the Sr(Fe,Co)1.5Oy phase is much higher than that of the SrFe1,xCoxO3,, phase. Particle size distribution of the conventional heated sample is very wide. The indirect hybrid heated sample has a relatively narrow particle size distribution, with an average particle size of 3,4 ,m, but the particles stick to form agglomerates. The morphology of the direct hybrid heated sample is similar to that of the conventional heated sample, except that submicrometer grade particles were rarely observed. [source] Preliminary Observations on Phase Relations in the "V2O3,FeO" and V2O3,TiO2 Systems from 1400°C to 1600°C in Reducing AtmospheresJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2000Theresa Coetsee Phase relations within the "V2O3,FeO" and V2O3,TiO2 oxide systems were determined using the quench technique. Experimental conditions were as follows: partial oxygen pressures of 3.02 × 10,10, 2.99 × 10,9, and 2.31 × 10,8 atm at 1400°, 1500°, and 1600°C, respectively. Analysis techniques that were used to determine the phase relations within the reacted samples included X-ray diffractometry, electron probe microanalysis (energy-dispersive spectroscopy and wavelength-dispersive spectroscopy), and optical microscopy. The solid-solution phases M2O3, M3O5, and higher Magneli phases (MnO2n,1, where M = V, Ti) were identified in the V2O3,TiO2 system. In the "V2O3,FeO" system, the solid-solution phases M2O3 and M3O4 (where M = V, Ti), as well as liquid, were identified. [source] Effects of copper amine treatment on mechanical properties of PVC/wood-flour compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2004Haihong Jiang Copper amine,treated wood flour was added to PVC [poly(vinyl chloride)] matrix in order to manufacture PVC/wood-flour composites. Effects of copper treatments on the mechanical properties of PVC-wood composites were evaluated. Unnotched impact strength, flexural strength, and flexural toughness of the composites were significantly improved by the wood-flour copper treatment. The optimum copper concentration range was 0.2 to 0.6 wt% of wood flour. Fractured surfaces were examined by using scanning electron microscopy (SEM) combined with energy-dispersive spectroscopy (EDS). PVC/wood interfacial debonding was the main fracture mode of untreated wood-flour composites, whereas wood-particle pullout and breakage dominating the fractured surfaces of copper-treated wood-flour composites. On the fractured surfaces, more PVC could be found on the exposed copper-treated wood particles than on untreated wood, a result suggesting improved PVC-wood interfacial adhesion after copper treatments. J. Vinyl Addit. Technol. 10:70,78, 2004. © 2004 Society of Plastics Engineers. [source] Growing ZnO Crystals on Magnetite NanoparticlesCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2004Rachel Turgeman Abstract We report herein on the oriented growth of ZnO crystals on magnetite nanoparticles. The ZnO crystals were grown by hydrolyzing a supersaturated aqueous solution of zinc nitrate. The seeds for the growth were magnetite nanoparticles with a diameter of 5.7 nm and a narrow size distribution. Hollowed ZnO hexagons of 0.15 ,m width and 0.5 ,m length filled with Fe3O4 particles were obtained. HR-TEM (high-resolution transmission electron microscopy) and selected-area EDS (energy-dispersive spectroscopy) show that the nanoparticles are homogenously spread in the ZnO tubes. Zeta potential measurements were employed to understand the relationship between the nanoparticles and the oriented growth of the ZnO crystals. The results show that the surfactants induced the directional growth of the ZnO crystals. [source] | |||||||||||||||||||||||||