Transactions of the INDIAN CERAMIC SOCIETY Vol. 60 2001
Crystallization of Chromium Oxide Prepared
by Sol-Gel Route
J. Radhakrishna, J. V. Dehadraya, S. K. Mukerjee, V. N. Vaidya and V. Venugopal
Pages : 71-73
DOI : 10.1080/0371750X.2001.10799970
Abstract
Chromia finds large applications as a catalyst base. The aim of
the present investigation was to prepare chemically, mechanically
and thermally stable porous Cr20 3 microspheres. Chromia
microspheres (500-700 IJm} were prepared by internal gelation
technique of the sol-gel process. These microspheres were dried
in air at various temperatures between room temperature and
aoo•c for further thermal studies in air I oxygen I argon. These
gel microspheres were subjected to X-ray diffraction analysis
(XRD) and thermal analysis. Crystallization of chromia takes place
at 44o•c in air and at 11o•c in argon. It is reported that in air
amorphous Cr(lll} oxide partially gets oxidized to Cr(VI) below
aso•c and reduces back to Cr(lll} during crystallization. Maximum
oxidation of about 30% could be achieved by heating chromia
microspheres in pure oxygen at aoo•c. The present study deals
with a probable mechanism for the crystallization of chromia in
presence of Cr(VI).