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Synthesis and Mechanism of Nanosized AlN from an Aluminum Oleic Emulsion Using Carbothermal Reduction at Low Temperatures
Author(s) -
Paseuth Agsack,
Shimada Shiro
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02267.x
Subject(s) - carbothermic reaction , materials science , graphite , nitride , decomposition , amorphous solid , chemical engineering , carbon fibers , transmission electron microscopy , amorphous carbon , aluminium , analytical chemistry (journal) , metallurgy , crystallography , chemistry , nanotechnology , composite material , carbide , composite number , organic chemistry , layer (electronics) , engineering
Nanosized Al 2 O 3 particles homogeneously dispersed in a matrix of amorphous carbon (a‐C) were prepared by decomposition of an aluminum oleic emulsion at 600°C in Ar. Nanosized aluminum nitride (AlN) grains were prepared by carbothermal reduction and nitridation (CRN) of this Al 2 O 3 –a‐C mixture in NH 3 using graphite, BN, and alumina crucibles or boats. The phases formed by CRN were identified by X‐ray diffraction analysis. The morphology and grain size of the AlN were determined by transmission electron microscopy. The formation of single‐phase AlN was achieved at temperatures as low as 1150°–1200°C in NH 3 using a cylindrical graphite crucible with holes in its two flat faces. Mass spectroscopy (MS) showed that a significant amount of HCN and a minor amount of C 2 H 2 are formed at 500°C by reaction of NH 3 with carbon at the decomposition temperature of NH 3 . A most probable formation mechanism of the AlN from nanosized Al 2 O 3 and a‐C in NH 3 is discussed on the basis of MS results and thermodynamic considerations.