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Crystallization of Fine, Chemically Prepared Lead Lanthanum Zirconate Titanate Powders at Low Temperature
Author(s) -
Yoshikawa Yoshio,
Tsuzuki Kaoru
Publication year - 1990
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.1151-2916.1990.tb05085.x
Subject(s) - materials science , nucleation , crystallization , calcination , lead zirconate titanate , isothermal process , microstructure , activation energy , chemical engineering , lanthanum , mineralogy , analytical chemistry (journal) , ferroelectricity , inorganic chemistry , chemistry , composite material , chromatography , dielectric , thermodynamics , catalysis , biochemistry , physics , optoelectronics , organic chemistry , engineering
Fine, homogeneous lead lanthanum zirconate titanate (PLZT) powder prepared by the hydrolysis of an aqueous nitrate solution with ammonia gas exhibits high reactivity when calcined. The minimum temperature for crystal formation in PLZT is 400°C. The kinetics of crystallization between 400° and 600°C are studied isothermally by XRD. The isothermal crystallization process is best fitted to a first‐order equation derived for a random, nucleation‐controlled system on a large number of small particles with an activation energy of 297 kJ/mol. Characterization of the powder by XRD line‐broadening and BET surface‐area examination in the range 400° to 500°C shows a microstructure consisting of ∼20‐nm subunits agglomerated into ∼60‐nm particles. Each subunit evidently generates a single nucleus, which grows within that subunit.