Title
Novel high pressure hexagonal OsB2 by mechanochemistry
Abbreviated Journal Title
J. Solid State Chem.
Keywords
Osmium; Boron; Mechanochemistry; Ceramic; OSMIUM DIBORIDE; SUPERHARD MATERIAL; CRYSTAL STRUCTURE; RHENIUM; DIBORIDE; HARD MATERIAL; BORIDES; PHASE; RUB2; TRANSITION; IRIDIUM; Chemistry, Inorganic & Nuclear; Chemistry, Physical
Abstract
Hexagonal OsB2, a theoretically predicted high-pressure phase, has been synthesized for the first time by a mechanochemical method, i.e., high energy ball milling. X-ray diffraction indicated that formation of hexagonal OsB2 begins after 2.5 h of milling, and the reaction reaches equilibrium after 18 h of milling. Rietveld refinement of the powder data indicated that hexagonal OsB2 crystallizes in the P63/mmc space group (No. 194) with lattice parameters of a=2.916 angstrom and c=7.376 angstrom. Transmission electron microscopy confirmed the appearance of the hexagonal OsB2 phase after high energy ball milling, in situ X-ray diffraction experiments showed that the phase is stable from 225 degrees C to 1050 degrees C. The hexagonal OsB2 powder was annealed at 1050 degrees C for 6 days in vacua to improve crystallinity and remove strain induced during the mechanochemical synthesis. The structure partially converted to the orthorhombic phase (20 wt%) after fast current assisted sintering of hexagonal OsB2 at 1500 degrees C for 5 min. Mechanochemical approaches to the synthesis of hard boride materials allow new phases to be produced that cannot be prepared using conventional methods. (C) 2014 Elsevier Inc. All rights reserved.
Journal Title
Journal of Solid State Chemistry
Volume
215
Publication Date
1-1-2014
Document Type
Article
Language
English
First Page
16
Last Page
21
WOS Identifier
ISSN
0022-4596
Recommended Citation
"Novel high pressure hexagonal OsB2 by mechanochemistry" (2014). Faculty Bibliography 2010s. 6307.
https://stars.library.ucf.edu/facultybib2010/6307
Comments
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