Sintering and Dielectric Property of (K 1 − x Na x )Ba 2 Nb 5 O 15 Ceramics

The crystal structure and dielectric property of tetragonal tungsten-bronze (TTB) structured (K 0.5 Na 0.5 )Ba 2 Nb 5 O 15 (KNBN50) ceramics was investigated as a function of extra Na 2 CO 3 content (α) ranging from 0 to 3.0 mol%. All the synthesized ceramics showed relative densities higher than 94...

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Published inFerroelectrics Vol. 368; no. 1; pp. 179 - 184
Main Authors Kakimoto, Ken-Ichi, Kato, Hisato, Yoshifuji, Tomoko, Ohsato, Hitoshi
Format Journal Article
LanguageEnglish
Published Taylor & Francis Group 21.10.2008
Subjects
Alkali barium niobate
Curie temperature
lattice parameter
sodium excess
tetragonal tungsten-bronze structure
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Summary:The crystal structure and dielectric property of tetragonal tungsten-bronze (TTB) structured (K 0.5 Na 0.5 )Ba 2 Nb 5 O 15 (KNBN50) ceramics was investigated as a function of extra Na 2 CO 3 content (α) ranging from 0 to 3.0 mol%. All the synthesized ceramics showed relative densities higher than 94% of theoretical, and the samples with α ranging from 1.5 to 2.5 demonstrated an enhanced √10 c/a ratio in TTB structure and high T c around 450°C which is approximately 70°C higher than that of Na-free KBa 2 Nb 5 O 15 (KBN) piezoceramics. It is also confirmed that extra Na 2 CO 3 could reduce ionic conduction and provide a nomal Curie-Weiss behavior with enhanced dielectric constant maximum.
ISSN:0015-0193
1563-5112
DOI:10.1080/00150190802368446