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Synthesis of Niobium Carbide from Niobium Oxide Aerogels
Chemistry of Materials, 1995Niobium carbide (NbC) synthesis was studied by the temperature-programmed reaction (TPR) between niobium oxide precursors of different textural properties and a 20% (v/v) CH{sub 4}-H{sub 2} mixture. Surface areas ranging between 13 and 74 m{sup 2}/g were obtained depending on the temperature and on the nature of the precursor (Nb{sub 2}O{sub 5} or an ...
V. L. S. Teixeira da Silva +3 more
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Delayed Ionization of Photoexcited Niobium and Niobium Oxide Clusters
Berichte der Bunsengesellschaft für physikalische Chemie, 1992AbstractThe delayed emission of electrons from hot refractory metal clusters can be regarded as the molecular equivalent of “thermionic emission”, which is well‐known for metal surfaces. Niobium clusters – generated via pulsed laser vaporization technique – were exposed to a 10 ns laser pulse, and the delayed emission of electrons from the clusters was
K. Athanassenas +3 more
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On the oxidation and on the superconductivity of niobium
Applied Physics A Solids and Surfaces, 1987Most superconducting rf cavities consist on Nb and most Josephson tunnel junctions are Nb based. Due to the very small dissipation in these superconducting cavities and tunnel junctions quantitative and qualitative new surface effects emerge, which are related to the oxidation of Nb.
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Electrical conduction in niobium-niobium oxide-gold diodes
Thin Solid Films, 1970It is shown that for voltages between 0.2 V and 1 V (Nb-) a linear relationship is obtained between ln J and √V for diodes with relatively thick oxides (1700 A). The effects of heat treatment under vacuum conditions upon the conduction characteristics is reported.
R.J. Schwartz, Y.L. Chiou, H.W. Thompson
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EELS Investigations of Different Niobium Oxide Phases
Microscopy and Microanalysis, 2006Electron energy loss spectra in conjunction with near-edge fine structures of purely stoichiometric niobium monoxide (NbO) and niobium pentoxide (Nb2O5) reference materials were recorded. The structures of the niobium oxide reference materials were checked by selected area electron diffraction to ensure a proper assignment of the fine structures ...
Bach, D. +4 more
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Journal of Nuclear Science and Technology, 2015
The change of chemical states of niobium with oxide growth was examined in the oxide layers of Zr–2.5Nb around the first kinetic transition by the conversion electron yield – X-ray absorption near-edge structure measurements. The detailed depth profiles of niobium chemical states were obtained in both the pre- and the post-transition oxide layers of Zr–
Kan Sakamoto +4 more
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The change of chemical states of niobium with oxide growth was examined in the oxide layers of Zr–2.5Nb around the first kinetic transition by the conversion electron yield – X-ray absorption near-edge structure measurements. The detailed depth profiles of niobium chemical states were obtained in both the pre- and the post-transition oxide layers of Zr–
Kan Sakamoto +4 more
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Niobium oxide solution chemistry
Journal of Raman Spectroscopy, 1991AbstractThe solution chemistry of niobium oxide in alkaline and acidic oxalate solutions was investigated by Raman spectroscopy in order to determine the molecular structures of the various aqueous niobium oxide species. The aqueous potassium niobate species were studied as a function of pH from 14.5 to 0.55.
Jih‐Mirn Jehng, Israel E. Wachs
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Oxidation of Polycrystalline Niobium Nitride
Israel Journal of Chemistry, 1982AbstractIsothermal and dynamic TG were used to follow the oxidation of a sieved fraction, 177–250 μm, of niobium nitride powder in a flow of dry 0.1% O2 in Ar. The material underwent enormous expansion during the oxidation. The isothermal weight gain was measured in the temperature range from 817 to 897 K. It followed a pseudo‐first order reaction rate
P. K. Gallagher, W. R. Sinclair
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1991
Publisher Summary This chapter examines the properties and applications of niobium oxide (Nb2O5) and niobates. Nb2O5is extensively used for the preparation of niobates and for the modification of the properties of ferroelectric ceramics. It can be extracted from niobium-rich ores, which usually contain some tantalum, iron, titanium and tin, by either
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Publisher Summary This chapter examines the properties and applications of niobium oxide (Nb2O5) and niobates. Nb2O5is extensively used for the preparation of niobates and for the modification of the properties of ferroelectric ceramics. It can be extracted from niobium-rich ores, which usually contain some tantalum, iron, titanium and tin, by either
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Binary oxide systems of niobium pentoxide with oxides of common niobium alloying elements
Journal of the Less Common Metals, 1965Abstract A review of the reported work of binary oxide systems of Nb 2 O 5 with Al 2 O 3 , Cr 2 O 3 , TiO 2 , V 2 O 5 , Ta 2 O 5 , WO 3 ,and MoO 3 has been presented. Some of the systems have been characterized fairly completely; for example, the Al 2 O 3 , Cr 2 O 3 , TiO 2 , and Ta 2 O 5 systems.
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