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Piezoelectric Strontium Niobate and Calcium Niobate Ceramics with Super‐High Curie Points
Author(s) -
Ning Huanpo,
Yan Haixue,
Reece Michael J.
Publication year - 2010
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.1551-2916.2009.03587.x
Subject(s) - curie temperature , materials science , piezoelectricity , strontium , microstructure , mineralogy , dielectric , ceramic , ferroelectricity , lithium niobate , perovskite (structure) , strontium barium niobate , strontium titanate , spark plasma sintering , niobium , sintering , analytical chemistry (journal) , composite material , condensed matter physics , crystallography , metallurgy , optoelectronics , chemistry , physics , chromatography , organic chemistry , ferromagnetism
The perovskite‐like layer structured strontium niobate (Sr 2 Nb 2 O 7 ) and calcium niobate (Ca 2 Nb 2 O 7 ) are good candidates for high‐temperature piezoelectric applications because of their high Curie points. Single‐phase dense Sr 2 Nb 2 O 7 and Ca 2 Nb 2 O 7 ceramics with grain‐oriented microstructures were prepared by spark plasma sintering using a two‐step method. The Lotgering orientation factors were 0.86 and 0.70 for Sr 2 Nb 2 O 7 and Ca 2 Nb 2 O 7 , respectively. The T c of Sr 2 Nb 2 O 7 and Ca 2 Nb 2 O 7 were measured as 1327±5°C and above 1525°C, respectively. The dielectric, piezoelectric, ferroelectric properties, and direct‐current electrical conductivity are higher along the directions perpendicular to the pressing direction compared with parallel. The piezoelectric constant d 33 for Sr 2 Nb 2 O 7 was 2.8±0.2 pC/N.