Title :
Large anisotropy on electromechanical properties of rare-earth and alkaline-earth oxides complex modified PbTiO3 ceramics
Author :
Wang, H. ; Xue, W.R. ; Lu, P.N. ; Shen, D.W. ; Zhang, Q.T. ; Zhao, M.Y.
Author_Institution :
Dept. of Silicate Eng., Nanjing Inst. of Chem. Technol., China
fDate :
30 Aug-2 Sep 1992
Abstract :
The dielectric and piezoelectric properties, the microstructural development and the crystal structures of (Pb0.88-xGd0.08Mex(Ti0.98Mn 0.02) O3+y(Sb2O3+Nb2 O5)wt.% (x=0-20 mol.%., 0<y<1.5, Me=Ca, Ba or Sr)) were investigated. It was found that the content of the alkaline-earth ions strongly influenced the electromechanical properties of the samples. When Me=15 mol.%, the optimum properties were Kt =55%, Kp=0, Kt/Kp→Ω, Q m=60, ε33T/ε0<250, tan δ<1.5%, and d33=70×10-12 c/N. The effects of the poling electric field on those properties were studied. SEM (scanning electron microscopy) and XRD (X-ray diffraction) revealed that the ceramic microstructure clearly changed and that tetragonality (c/a) decreased due to the Me ion doping. It is suggested that both the microstructure and crystal structure are responsible for this behavior. The lower c/a ratio and the microstructure with wide grain boundaries and greater porosity can lead to an increase of the domains parallel to the poling electric field, and hence improve the electromechanical properties
Keywords :
X-ray diffraction examination of materials; antimony compounds; ceramics; dielectric losses; dielectric polarisation; grain boundaries; infrared spectra of inorganic solids; lead compounds; niobium compounds; permittivity; piezoelectric materials; porosity; scanning electron microscope examination of materials; IR spectra; PbGdBaTiO3MnO3-Sb2O3 -Nb2O5; PbGdCaTiO3MnO3-Sb2O3 -Nb2O5; PbGdSrTiO3MnO3-Sb2O3 -Nb2O5; SEM; X-ray diffraction; XRD; alkaline-earth oxides; ceramic microstructure; crystal structures; dielectric constant; dielectric loss; dielectric properties; electromechanical anisotropy; electromechanical properties; grain boundaries; piezoelectric properties; piezoelectricity; polarisation; poling electric field; porosity; rare-earth oxides; scanning electron microscopy; tetragonality; Anisotropic magnetoresistance; Ceramics; Crystal microstructure; Dielectrics; Doping; Grain boundaries; Scanning electron microscopy; Strontium; X-ray diffraction; X-ray scattering;
Conference_Titel :
Applications of Ferroelectrics, 1992. ISAF '92., Proceedings of the Eighth IEEE International Symposium on
Conference_Location :
Greenville, SC
Print_ISBN :
0-7803-0465-9
DOI :
10.1109/ISAF.1992.300569
