Temperature dependence of piezoelectric, elastic and dielectric coefficients at radial resonance of piezoceramics with an aurivillius-type structure.

Aurivillius-type structure compounds are considered good candidates for piezoelectric materials at high temperature, due to their high ferro-paraelectric phase transition temperature. Despite this fact, very few papers have been published on the study of piezoelectric properties at the expected working temperatures. An iterative automatic method has been used in this work to characterize the piezoelectric, electromechanical, and elastic properties at radial resonance of thin ceramic disks with composition (SrBi2Nb2O9)0.35(Bi3TiNbOg)0.65 [SBN/BTN 35/65], from room temperature up to the ferro-paraelectric phase transition. Ceramics were prepared by sintering or by recrystallization after hot-pressing of mechanically activated precursors. By this new method, ceramics with controlled texture and microstructure are obtained. The influence of the processing route in the properties of the ceramics, over the whole temperature range of piezoelectric activity, is discussed. Values of d31 = 2.1 pC/N and kp = 2.9% at 500 degrees C are achieved.