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Atmospheric Pressure Synthesis of Heavy Rare Earth Sesquioxides Nanoparticles of the Uncommon Monoclinic Phase
Author(s) -
Guo Bing,
Harvey Ashley S.,
Neil John,
Kennedy Ian M.,
Navrotsky Alexandra,
Risbud Subhash H.
Publication year - 2007
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.1551-2916.2007.01961.x
Subject(s) - monoclinic crystal system , nanoparticle , transmission electron microscopy , phase (matter) , atmospheric pressure , materials science , chemical engineering , analytical chemistry (journal) , crystallography , chemistry , nanotechnology , crystal structure , organic chemistry , geology , oceanography , engineering
We report, for the first time, the atmospheric pressure synthesis of nonagglomerated nanoparticles (20–60 nm in diameter) of the uncommon monoclinic phase of some heavy rare earth sesquioxides RE 2 O 3 (RE=Dy, Ho, Er, Tm, and Yb). The RE 2 O 3 nanoparticles, prepared by a flame synthesis process, were characterized by X‐ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. Monoclinic nanoparticles were formed when the flame temperature was sufficiently high; lower temperatures led to the formation of the normal cubic (C‐type) phase. We explain the formation of the uncommon monoclinic phase on the basis of pressure–temperature phase equilibria, and the extra internal pressure induced by surface curvature of the nanoparticles.