C. He et Gc. Stangle, THE MECHANISM AND KINETICS OF THE NIOBIUM-CARBON REACTION UNDER SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS-LIKE CONDITIONS, Journal of materials research, 10(11), 1995, pp. 2829-2841
The mechanism and kinetics of the chemical reaction between Nb(s) and
C(s) under self-propagating high-temperature synthesis (SHS)-like (or
combustion synthesis-like) conditions have been studied. Experiments w
ere designed and conducted in order to produce a transport-resistance-
free reaction between Nb and C under time-temperature conditions that
are characteristic of the combustion synthesis process. To do so, a re
action couple, consisting of carbon and either a thin niobium foil or
a fine niobium wire, was used. The effects of the temperature history
and the formation of a liquid phase on the reaction were studied. In a
ddition, theoretical experiments of the reaction were also conducted.
The results showed that at high temperatures, layered niobium carbide
phases formed in a direction that was parallel to the original carbon-
niobium interface. As might be expected, local melting played a very s
ignificant role in the reactions. The mechanism and kinetics of these
reactions provide a fundamental understanding of the manner and rate b
y which a powder-based Nb/C SHS process takes place, and, by extension
, to a large, general class of solid-solid material synthesis processe
s that are based on the SHS (or combustion synthesis) process.