Poling Behavior of Functionally Gradient Material Bending Devices.

This paper reports about investigations of the poling behavior of Functionally Gradient Materials (FGM). A model was developed to calculate the virgin loop P(E) of a layered system from measured virgin loops of its components. For the modeling, electrical conductivity is neglected and consequently the polarization is assumed to be constant in the FGM. The modeling allows to calculate the electric field strength and to estimate the poling degree of each layer. The results were compared with experimental data of monolithic BaTi 1-x Sn x O 3 - bending actuators consisting of layers with different amount of tin. Virgin loops of monolithic and conventional devices with 2, 3 and 4 layers were measured. A good agreement between modeling and experiment was obtained for the maximum value of polarization. Differences between the values of the remanent polarization were found and discussed. [ABSTRACT FROM AUTHOR]