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Spark Plasma Sintering of Tungsten Bronze Sr 2− x Ca x NaNb 5 O 15 ( x = 0.1) Piezoelectric Ceramics: II, Electrical Properties
Author(s) -
Xie RongJun,
Akimune Yoshio,
Wang RuiPing,
Hirosaki Naoto
Publication year - 2002
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.1151-2916.2002.tb00521.x
Subject(s) - materials science , spark plasma sintering , tetragonal crystal system , dielectric , piezoelectricity , ceramic , sintering , tungsten , phase (matter) , ferroelectricity , composite material , metallurgy , optoelectronics , chemistry , organic chemistry
Sr 2− x Ca x NaNb 5 O 15 (SCNN, x = 0.1) piezoelectric ceramics with tetragonal tungsten bonze structure were successfully produced by spark plasma sintering. Part I of this study presented the sintering of these highly dense ceramics. The current work investigates their electrical (dielectric, ferroelectric, and piezoelectric) properties and relates them to the sintering parameters (temperature, heating rate, and soaking time) and crystallographic orientation. The results show that the electrical properties of SCNN are enhanced with increasing heating rate and soaking time. Dielectric study reveals a less pronounced diffuse phase transition of SCNN. Anisotropic electrical properties were observed as a result of the preferred crystallographic orientation in the sintered ceramics. The samples sintered at 1200°C for 30 min exhibited the highest electrical properties, and showed the following piezoelectric properties when poled across the direction perpendicular to the pressing direction: electromechanical planar and thickness coupling coefficients of k p = 9.5% and k t = 39.6%, and piezoelectric constant of d 33 = 121 pC/N (∼45% of the single‐crystal value).