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Sintering behavior of niobium carbide
Soviet Powder Metallurgy and Metal Ceramics, 19741. 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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Crystal growth of niobium nitride and niobium carbide nitride
Journal of Crystal Growth, 1978Abstract 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, 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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Vaporization behavior of niobium carbide
Vacuum, 1962The vaporization behavior of niobium carbide was studied over the temperature range from 2260° to 2940°K utilizing the Langmuir method. NbC was observed to lose carbon preferentially down to a composition of NbC0.75, at which composition the vaporization proceeds congruently at a temperature of 2940°K.
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Activated sintering of niobium carbide
Soviet Powder Metallurgy and Metal Ceramics, 19631. 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 +2 more
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Carbon diffusion in the carbides of niobium
Journal of Nuclear Materials, 1966Abstract 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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Solubility of niobium carbide and niobium carbonitride in alloyed austenite and ferrite
Metallurgical Transactions A, 1984The available data on the solubility of niobium carbide and niobium carbonitride in plain carbon and alloyed austenite has been analyzedvia dilute solution thermodynamics with a view to establishing a consistent set of interaction parameters for predicting austenite + niobium carbonitride equilibria. The computation algorithm includes the prediction of
R. C. Sharma +2 more
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Synchrotron radiation studies of the formation of niobium carbide layers on niobium
Physical Review B, 1984The formation of a NbC overlayer on Nb has been observed with the use of valence-band photoemission, near-edge absorption at the C K edge, and photon- and electron-stimulated Auger decay. The sample was produced by depositing an amorphous C layer on a Nb substrate either by dc glow discharge in a hydrocarbon ambient or by sputtering from a graphite ...
D. Wesner +6 more
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Elastic moduli of niobium carbide and tantalum carbide at high temperature
Journal of the Less Common Metals, 1971Abstract The Young's, shear and bulk moduli of polycrystalline NbC 0.95 and TaC 0.99 were determined from room temperature to 1500°K by the sonic resonance technique. The Young's and shear moduli decrease linearly with increasing porosity, and also decrease with increasing temperature, in agreement with the Wachtman's empirical equation.
C.K. Jun, P.T.B. Shaffer
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Gas evolution from zirconium carbide, niobium carbide, and tantalum carbide powders
Soviet Powder Metallurgy and Metal Ceramics, 1986This work was undertaken with the aim of determining the gas contents of zirconium carbide, niobium carbide, and tantalum carbide powders as functions of their processing history. A high-vacuum, high-temperature apparatus was used, connected to an oilless evacuation system and instruments for the mass-spectrometric measurement of amounts and ...
A. V. Makeev +3 more
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