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Phase Transformation of Hydrous‐Zirconia Fine Particles Containing Cerium Hydroxide
Author(s) -
Matsui Koji,
Ohgai Michiharu
Publication year - 1999
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.1151-2916.1999.tb02196.x
Subject(s) - monoclinic crystal system , tetragonal crystal system , cubic zirconia , cerium , materials science , phase (matter) , aqueous solution , hydroxide , ammonium hydroxide , crystallography , particle size , mineralogy , inorganic chemistry , crystal structure , chemistry , metallurgy , ceramic , organic chemistry
Monoclinic hydrous‐zirconia fine particles that contained cerium(IV) hydroxide (Ce(OH) 4 ) were heated from 200°C to 600°C, to investigate the phase transformation to CeO 2 ‐doped tetragonal ZrO 2 . Both ZrOCl 2 ·8H 2 O and CeCl 3 ·7H 2 O were dissolved in aqueous solutions and then boiled to prepare the hydrous‐zirconia particles. The Ce(OH) 4 ‐containing hydrous‐zirconia particles were prepared by adding aqueous ammonia into the boiled solutions. The monoclinic‐to‐tetragonal ( m right arrow t ) phase transformation of the Ce(OH) 4 ‐containing hydrous zirconias was observed at 300°C using X‐ray diffraction (XRD). XRD and Brunauer‐Emmett‐Teller (BET) specific surface area measurements revealed that the Ce(OH) 4 ‐containing hydrous zirconias had a tendency to transform from the monoclinic phase to the tetragonal phase at lower temperatures as the primary particle size of the hydrous zirconia decreased and the Ce(OH) 4 content increased. These tendencies for the m right arrow t phase transformation agree with the conclusions that have been derived from thermodynamic and kinetic considerations.