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Bismuth Titanate from Mechanical Activation of a Chemically Coprecipitated Precursor
Author(s) -
Ng Szu Hwee,
Xue Junmin,
Wang John
Publication year - 2002
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.1151-2916.2002.tb00512.x
Subject(s) - crystallite , nanocrystalline material , calcination , materials science , nucleation , amorphous solid , bismuth titanate , bismuth , chemical engineering , ceramic , hydroxide , titanate , perovskite (structure) , sintering , mineralogy , dielectric , nanotechnology , composite material , chemistry , crystallography , ferroelectricity , metallurgy , catalysis , organic chemistry , optoelectronics , engineering
Most of the chemistry‐based preparation routes for bismuth titanate (BIT) involve calcination at elevated temperatures in order to realize precursor‐to‐ceramic conversion. In a completely different approach using an amorphous BIT hydroxide precursor, nanocrystalline particles of layered perovskite BIT are synthesized by mechanical activation, skipping the detrimental crystallite coarsening and particle aggregation encountered at high temperatures. Mechanical activation leads to nucleation and steady growth of BIT crystallites in the amorphous precursor matrix, while Bi 2 O 3 is involved as an intermediate transitional phase. The activation‐derived BIT particles demonstrate a rounded morphology of ∼50 nm in size. This is in contrast to the BIT derived from calcination of the coprecipitated precursor at 600°C that is dominated by coarsened platelike particles. The former is sintered to a density of >95% theoretical at 875°C for 2 h, leading to a dielectric constant of ∼1260 when measured at 1 MHz and the Curie temperature of 646°C.