Characterization of the Electro-Mechanical Behavior of Zirconia-Rich PZT Ceramics G. R. Burns 1 , M. R. Winter 1 , c. B. DiAntonio 1 , M. A. Rodriguez 1 , P. Yang 1 , T. P. Chavez 1 , and A. L. Blea 1 lSandia National Laboratories, 1515 Eubank Blvd. SE, Albuquerque, NM 87123, USA METHODOLGY a e : Lyslca Imenslons 0 es specImens. Length Width/Diameter Thickness Geometry (mm) (mm) (mm) Rod - 3.28 0.987 Plate 15.23 3.00 0.939 Disk - 15.16 0.94 Resonance Measurements Resonance measurements were performed using an Agilent Industries 4294A Impedance Analyzer, a Sun Systems Model lA Environmental Chamber, and a PC running Lab View for acquisition of the impedance, phase, and temperature. The impedance and phase spectra were collected at 2°C intervals over the range of RT to 130°C. The resonant (f r ) and anti-resonant (fa) frequencies were determined automatically by the analyzer's search function, when possible. Sometimes, post analysis of the impedance and phase spectra was conducted to extract the correct frequencies. This is particularly necessary for temperatures close to the The methodology for measuring the piezoelectric and electromechanical properties of poled ferroelectrics are detailed elsewhere 1 ,2 and are not discussed here. We have used the equations and methods presentd in the following two standards: IEEE Std 176- 1987 1 and CENELEC EN 50231-2:2002 2 . Sample Preparation Two zirconia-rich compositions were studied, including Pbo.991(ZrO.958 Tio.042)o.982Nbo.01803 (PZT 95/5) and Pbo.99(Sno.13Zro.82Tio.os)o.98Nbo.o203 (PSZT), the former was synthesized by co-precipitation method and the later was prepared by mixed oxides. The powders were pressed into pellets and sintered at 1350°C for 6 hours, using a double crucible technique to prevent lead loss at high temperatures. Electrical testing samples were fabricated from these billets to correspond with the dimensional ratios established by the available standards. 1 ,2 The average sample dimensions are given in Table I. The samples were then ground and polished to a surface finish of <1 f.tm. After polishing, the samples were cleaned with acetone, isopropanol and deionized water, then thermally cleaned at 600°C for 1 hour. Platinum electrodes were sputtered onto ceramics with a thickness "'0.15 f.tm. Finally, the samples were electrically poled (E > 30 kVfcm) at room temperature (RT) in a Fluorinert bath (FC-43) to prevent electrical breakdown. T bl I Ph . I d· f t t The piezoelectric nature of electrically poled PZT ceramics permits energy to be applied to a piezoelectric body either mechanically by stressing it, or electrically by poling it. Upon these excitations, the elastic body will show numerous resonances. Using the converse piezoelectric effect, it is convenient to excite elastic waves and observe the interaction of mechanical resonance with the electric behavior. By measuring the resonance and anti-resonance characteristics, corresponding to the mechanical resonance under zero- field and open-circuit conditions, one can determine the electromechanical coupling factors Le., the square root of the fraction of electrical energy converted to mechanical energy in each cycle or vice versa. These electromechanical coupling factors are extremely useful as a figure of merit for piezoelectric applications. The electromechanical coupling behavior depends on the spontaneous polarization and the degree of poling, which are strongly dependent on temperature. In this investigation, we studied the electromechanical responses as a function of temperature for these materials and illustrated the importance of elastic properties to these coefficients. INTRODUCTION Abstract - Lead zirconate titanate (PZT) ceramics near the morphotropic phase boundary have been the backbone materials for piezoelectric applications for more than 50 years. The electro-mechanical responses for these materials have been well studied. In this study, we investigated the electro-mechanical behavior of two zirconia-rich PZT compositions, with and without tin (Sn) modification. These materials, close to the antiferroelectric phase region, have been used for power supply and actuator applications due to their unique ferroelectric(FE)-antiferroelectric(AFE) phase transformation behavior. However, limited information is available characterizing their electromechanical responses, especially outside of room temperature. In this work, we present the electromechanical properties of these compositions as a function of temperature. Special attention has been placed on the electromechanical responses near the FE-FE phase transformation. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energg's National Nuclear Security Administration under contract DE-AC04- 94AL85000.