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Processing and Characterization of BaTi 4 O 9
Author(s) -
Mhaisalkar S. G.,
Lee W. E.,
Readey D. W.
Publication year - 1989
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.1151-2916.1989.tb06048.x
Subject(s) - hollandite , impurity , materials science , calcination , dielectric , analytical chemistry (journal) , mineralogy , phase (matter) , chemistry , chromatography , organic chemistry , biochemistry , optoelectronics , catalysis
BaTi 4 O 9 powder prepared by calcining BaCO 3 and TiO 2 powders was sintered to over 97% of theoretical density. Less than 5% Ba 2 Ti 9 O 20 occurred as a second phase in “pure” BaTi 4 O 9 , and Al 2 O 3 impurities from processing formed isolated hollandite (∼BaAl 2 Ti 6 O 16 ) grains, which were identified by fringes in bright‐field TEM images. For pure BaTi 4 O 9 at 1 MHz, a dielectric loss (tan δ) of 5 × 10 −4 and dielectric constant of 39 were recorded. Hollandite impurities were found to increase tan δ by 2 orders of magnitude, whereas firing in oxygen decreased tan δ by an order of magnitude.