Abstract
Monolithic ceramics with an uniaxial gradient of piezoelectric and/or dielectric coefficients (functionally graded materials—FGM) are suitable for bending actuators with strongly reduced internal mechanical stresses.
We prepared BaTi1—xSnxO3 ceramics with a Sn-content of 7.5 mol% (BTS7.5) at the upper side and 15 mol% (BTS15) at the lower side. Two sheets of powder with different stoichiometry were pressed and sintered. The gradient of stoichiometry was modified by additional layers of powder with 10 and 12.5 mol% Sn, respectively. The Sn content after sintering across the thickness was investigated by Electron Probe Micro-Analysis (EPMA).
The gradient of the chemical composition was transformed into a functionally gradient of the electromechanical properties by a poling process. An increasing of the bending deflection was obtained by cycling with an unipolar AC-voltage. In this work we studied two effects which can explain this behavior.
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ACKNOWLEDGEMENT
This work was supported by the Deutsche Forschungsgemeinschaft.