Results 191 to 200 of about 128,309 (243)

Optical and electrical properties of niobium carbide

Physical Review B, 1987
The optical and electrical properties were measured for single crystals of ${\mathrm{NbC}}_{\mathrm{x}}$ for x=0.98, 0.87, and 0.76, and for one hot-isostatically-pressed sample of ${\mathrm{NbC}}_{0.88}$. Specular reflectance was measured between 0.025 and 11 eV, and ellipsometry measurements were made at 1.96 eV.
, Allison, , Modine, , French
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Recrystallization of niobium and zirconium carbides

Soviet Powder Metallurgy and Metal Ceramics, 1977
The temperature level at the beginning of recrystallization of transition metal carbides depends on the degree of their homogeneity, their reaction with oxygen in the course of deformation and annealing, and the stability of the resultant oxide phases.
A. E. Kravchik, G. A. Savel'ev, V. S. Neshpor, S. S. Ordan'yan   +3 more
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Hardness anisotropy in niobium carbide

Journal of Materials Science, 1974
Measurements of hardness anisotropy by Knoop diamond indentation on the {100} surfaces of Nb6C5 crystals show that the hardness is determined by crystallographic slip on {111} 〈1¯10〉 and {110} 〈1¯10〉 systems. {111} is the preferred slip plane for Nb6C5 and crystals with higher carbon content which show a marked decrease in Knoop hardness.
G. Morgan, M. H. Lewis
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Crystal growth of niobium nitride and niobium carbide nitride

Journal of Crystal Growth, 1978
Abstract Single crystals of niobium carbide nitride were obtained by zone melting growth in ambient nitrogen gas pressures of up to 9.0 MPa. Single crystals of δ-NbN or γ-NbN could not be obtained by this method, but single crystals of γ-NbN were obtained by annealing of NbN in nitrogen gas pressures of up to 2.0 MPa.
A.Nørlund Christensen, C. Rusche
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Synthesis of Niobium Carbide from Niobium Oxide Aerogels

Chemistry of Materials, 1995
Niobium 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, E. I. Ko, M. Schmal, S. T. Oyama   +3 more
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THE NIOBIUM—NIOBIUM CARBIDE SYSTEM¹

The Journal of Physical Chemistry, 1960
The solid pontion of the Nb--NbC phase diagram was determined. The following characteristic temperatures were measured: a eutectic temperature between NbC/sub 0.08/ and NbC/sub 0.39/ of 2335 plus or minus 20 deg C, a peritectic temperature between NbC/sub 0.52/ and NbC/sub 0.56/ of 3090 deg 50 deg C and a melting point maximum at about NbC/sub 0.86/ of
E. K. Storms, N. H. Krikorian
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The use of niobium carbide as grain growth inhibitor in WC-10Co cemented carbides [PDF]

Journal of the European Ceramic Society
peer reviewedA key parameter in the processing of tungsten carbide materials is the control of the grain growth during the sintering stage. To limit the grain coarsening, grain growth inhibitors are added during the mixing of the powders.
Fabienne Delaunois, Alexandre Mégret, Véronique Vitry   +2 more
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Carbon diffusion in the carbides of niobium

Journal of Nuclear Materials, 1966
Abstract The reaction between niobium and graphite has been investigated over the temperature range 1700°–2300° C. Parabolic growth behaviour was observed for the Nb2C and NbC phases. The rate constants for layer growth can be expressed as KNb2C = 0.3exp (−80.7 kcal/mole/RT) cm2/sec and KNbC = 17.6exp (−96.2 kcal/mole/RT) cm2/sec.
Wm.F. Brizes, L.H. Cadoff, J.M. Tobin
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Sintering behavior of niobium carbide

Soviet Powder Metallurgy and Metal Ceramics, 1974
1. The kinetics of the sintering of niobium carbide is largely determined by the presence in the latter of iron, which is picked up during milling in units with steel balls. Activated sintering was found to be exhibited by powder containing, in the starting condition, as little as 0.3 wt.% of iron. No upper limit of the activating action of iron has
V. S. Kindysheva, P. S. Kislyi
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Activated sintering of niobium carbide

Soviet Powder Metallurgy and Metal Ceramics, 1963
1. A process has been proposed for the activated sintering of niobium carbide with additions of Fe and CoCl2; other conditions being equal, this process permits a three-fold increase in the packing of sintered components. 2. We have discussed processes occurring during activated sintering, on the basis of Dawihl's ideas [4] on packing ...
P. S. Kislyi, A. D. Panasyuk, G. V. Samsonov   +2 more
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