Effects of sintering temperature on structure and properties of BY-PT-PMN ternary piezoelectric ceramics
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0.7(0.1BiYbO3-0.9PbTiO3)-0.3 Pb(Mg1/3Nb2/3)O3 (0.7BYPT-0.3PMN) ternary piezoelectric ceramics were prepared by a columbite precursor method. The effects of sintering temperature on the crystalline phase, microstructure, and electrical properties of the ceramics were systematically investigated. There were two phases coexisting in the 0.7BYPT-0.3PMN ceramics sintered at 1100–1250 °C, one is the perovskite host phase with tetragonal symmetry and the other is Yb2Ti2O7 impurity phase. It was observed that, with increasing sintering temperature, the piezoelectric constant d33, dielectric constant er, planar electromechanical coupling coefficient kp, and Curie temperature TC increased initially and then decreased. An apparent structure distortion could also be observed in samples synthesized at high sintering temperature due to the severe volatilization of Pb and Bi. The optimum performances of the material were obtained for samples sintered at 1150 °C with d33 5 100 pC/N, er 5 494, kp 5 25.4%, and TC 5 380 °C, respectively. It can be ascribed to the combined effect of a higher density, structural homogeneity with decreased tetragonality as well as a small amount of pyrochlore phase.
I. INTRODUCTION
Piezoelectric ceramics based on Pb(Zr 1xTix)O3 (abbreviated as PZT) system are widely used as sensors and actuators because of their excellent dielectric, piezoelectric, and electrostrictive properties.1–6 However, the major disadvantage of PZT-based ceramics is the relatively low Curie temperatures TC (300–380 °C). This low TC comes with the disadvantages of more temperaturedependent properties and less polarization stability, which in turn restricts the operating temperature range (;1/2 TC) to less than 180 °C. Further limitation for high-temperature applications is also partially ascribed to the increased electrical conductivity at high usage temperature. Searching for piezoelectric ceramics with high TC has been a continuous work in the field of electroceramics due to the expanding demand from high temperature piezoelectric applications.7,8 However, piezoelectric materials with a higher TC usually show a worse piezoelectric response.7 Excitingly, a new binary Bi-based system has been found to have a morphotropic phase boundary (MPB) with high transition temperatures and high electromechanical properties, such as BiScO3-PbTiO3 (BS-PT), which may be used as piezoelectric sensors and actuators for these high-temperature environments.8–19 Among these binary systems, many intensive studies were focused on BS-PT ceramics due Contributing Editor: Ian M. Reaney a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2015.51 782
J. Mater. Res., Vol. 30, No. 6, Mar 28, 2015
http://journals.cambridge.org
Downloaded: 15 Apr 2015
to their excellent piezoelectric property d33 (460 pC/N) and high TC (450 °C), showing an increasing prospect for some of the applications, comparable to PZT-based ceramics.8,9 However, one of the disadvantages of this material is the high cost of Sc2O3, which means tha
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