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Electromechanical Properties of Lead Titanate Zirconate Ceramics Modified with Certain Three‐or Five‐Valent Additions
Author(s) -
KULCSAR FRANK
Publication year - 1959
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.1151-2916.1959.tb14321.x
Subject(s) - materials science , phase boundary , dielectric , lead zirconate titanate , tetragonal crystal system , ceramic , piezoelectricity , curie temperature , titanate , mineralogy , phase (matter) , zirconate , lead titanate , ferroelectricity , grain boundary , composite material , condensed matter physics , microstructure , chemistry , optoelectronics , physics , organic chemistry , ferromagnetism
When small amounts of lanthana, neodymia, niobia, or tantala are added to lead titanate zirconate compositions near the morphotropic (rhombohedral‐tetragonal) phase boundary, the modified ceramics show piezoelectric planar coupling coefficients of about 0.50 and substantially increased dielectric constants of up to 1545. The mechanical Q factor is decreased to about 70, and there is a marked increase in volume resistivity at temperatures up to 500°C. Other effects noted are better shelf‐aging characteristics, improved stability with respect to temperature dependence of resonant frequency, and a lowering of the Curie temperature. Except with neodymia, a definite refinement of the grain structure is also observed. By similar modification of Pb 0.95 Sr 0.05 (Zr. 0.54 Ti 0.45 )O 3 dielectric constants up to 1792 are obtained along with planar couplings of at least 0.49.