Synthesis of niobium carbide and nitride in air from mechanically activated Nb-C powder mixtures

Powders of Nb and C mixed in various mole fractions (C=10-80 mol%) have been ground in a planetary ball mill. When thus mechanically activated mixtures were transferred into a graphite crucible and exposed to air, they ignited spontanteously and self-propagating high-temperature synthesis (SHS) took...

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Bibliographic Details
Published in:Journal of materials chemistry 1997, Vol.7 (11), p.2265-2268
Main Authors: TSUCHIDA, T, AZUMA, Y
Format: Article
Language:English
Subjects:
Chemistry
Elements and non-metal compounds (oxides, hydroxides, hydrides, sulfides, carbides, ...)
Exact sciences and technology
Inorganic chemistry and origins of life
Preparations and properties
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Summary:Powders of Nb and C mixed in various mole fractions (C=10-80 mol%) have been ground in a planetary ball mill. When thus mechanically activated mixtures were transferred into a graphite crucible and exposed to air, they ignited spontanteously and self-propagating high-temperature synthesis (SHS) took place. NbC, Nb sub 2 C and Nb sub 2 N were obtained as the main products in the samples with C=40, 30 and 10 mol%, respectively. From measurement of the lattice constant and XPS spectra, the dissolution of nitrogen into NbC obtained from the mixtures with below C=50 mol% was observed, while almost stoichiometric NbC formed for the mixtures with C=50-80 mol%. A possible reaction mechanism for the formation of niobium carbides and nitrides is discussed.
ISSN:0959-9428
1364-5501
DOI:10.1039/a704235c