TITLE:
Salt-Assisted SHS Synthesis of Aluminium Nitride Powders for Refractory Applications
AUTHORS:
Alan Wilmański, Mirosław M. Bućko, Zbigniew Pędzich, Jacek Szczerba
KEYWORDS:
Aluminum Nitride, Self-Sustain High-Temperature Synthesis, Salt Assisted Synthesis, Refractory Materials
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.2 No.10,
October
28,
2014
ABSTRACT:
Powders of aluminum nitride can be prepared
by self-sustain high-temperature synthesis (SHS) between aluminum and nitrogen
but its high exothermic effect causes melting and evaporation of aluminum and
low efficiency of such reaction. A presence of inorganic salt in the starting
powder mixture can decrease a heat evolved in the SHS reaction, hinders melting
and coalescence of aluminum, and facilitates penetration of nitrogen into
interior of a powder bed. Mixtures of alumina powders with different grain
sizes and different amounts of aluminum carbonate were subjected to the SHS
reaction under 0.05, 0.1 or 1 MPa nitrogen. The powders were composed of
aluminum nitride, unreacted aluminum, aluminum oxynitride and in some cases
corundum and aluminum oxycarbonate. The finale effects are strongly dependent
on the amount of the salt, a grain size of aluminum and a nitrogen pressure.