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Crystallographic Properties of Hydrothermal Barium Titanate Crystallites
Author(s) -
Shi ErWei,
Xia ChangTai,
Zhong WeiZhou,
Wang BuGuo,
Feng ChuDe
Publication year - 1997
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.1151-2916.1997.tb03017.x
Subject(s) - crystallite , barium titanate , tetragonal crystal system , materials science , crystallography , hydrothermal circulation , curie temperature , mineralogy , barium , crystal structure , chemical engineering , chemistry , composite material , ceramic , metallurgy , condensed matter physics , physics , ferromagnetism , engineering
The crystallographic properties and defects of hydrothermally grown barium titanate crystallites are reported. When a precursor with a Ba:Ti molar ratio of 1.0 was used, cubic barium titanate crystallites were formed. However, when the precursor Ba:Ti molar ratio was 3.0, the product was tetragonal. The defect concentration (including OH defects and barium vacancies) was higher in cubic crystallites than in tetragonal crystallites. Because of the defects in the crystallites, the displacement of Ba 2+ cations and the deformation of the Ti‐O 6 octahedrons was suppressed; thus, no phase transition from cubic to tetragonal occurred at the Curie point. When the defects were eliminated by thermal treatment, the normal crystallographic properties were obtained. A high reaction temperature and a high Ba:Ti molar ratio in the precursor were beneficial to limiting defect dormation in the crystallites; thus, tetragonal crystallites were obtained.