Piezoelectric ceramics with a high Curie temperature (T_c) are critical materials for various piezoelectric sensors and actuators working at elevated temperatures, particularly those for aerospace and automotive industries. And the perovskitetype ceramic systems with the general form BiMeO₃–PbTiO₃ (BMePT), where Me can be a single or mixture of cations with an average valence of +3, show both a high T_c and a high piezoelectric coefficient d₃₃.

However, because of the low mechanical quality factor (Q_m) of BMePT, complex perovskite high temperature ceramics with improved Q_m(and hence a low dissipated energy) are highly desirable. Although BiYbO₃–PbTiO₃ (BYPT) has a very high T_c up to 630 °C, its d₃₃ is very low, and the large difference in tolerance factor of BY and PT causes difficulties in fabrication.

To improve the material stability and the piezoelectric properties, PZN (a typical relaxor with a moderate tolerance factor of 0.986) is added to BYPT and a new high temperature (1？x)(0.1BiYbO₃–0.9PbTiO₃)–xPb(Zn_1/3Nb_2/3)O₃ [(1？x)BYPT–xPZN] ternary system with a much higher Q_m is fabricated. In this research, the microstructure and electrical properties of this new system were reported.

The ternary system had a perovskite main phase with a tetragonal symmetry. With increasing PZN content (Fig. 1), the tetragonality decreased, and interestingly, both the piezoelectric properties and Q_m of the samples were largely improved. Microstructural characteristics indicated that the improved piezoelectric performance was also due to the improved density, structural stability and homogeneity. More importantly, the depolarization temperature of this new system was found to be higher than 350 °C, although the T_c is around 400 °C.

Fig.1 Some electric parameters and density data of various (1？x)BYPT–xPZN ceramic samples. (a)x dependence of piezoelectric coefficient d₃₃ and the planar electromechanical coupling factor (b) x dependence of Q_m and density (Image by GUO).

This research was supported by the National Key Basic Research Program of China (973 Program) (Grant No. 2013CB63 2900) and the National Science Foundation of China (NSFC No. 11074277). 

The research “Structure and Electrical Properties of (1？x)(0.1BiYbO3–0.9PbTiO3)–xPb(Zn1/3Nb2/3)O3 High-temperature Ternary Piezoelectric Ceramics” has been published in the journal of Materials Letters (Volume 114, 1 January 2014, Pages 100–102).

Corresponding author:

GUO Dong

Institute of Acoustics, Chinese Academy of Sciences, Beijing, 100190, China

Email: dong.guo@mail.ioa.ac.cn