FABRICATION AND PROPERTIES OF PSZT ANTIFERROELECTRIC RAINBOW ACTUATORS

A new type of high-displacement actuator called Rainbow (Reduced And INternally Biased Oxide Wafer) was recently developed, and it shows promising characteristics in a variety of potential applications. The fabrication and properties of Rainbow actuators from PSZT antiferroelectric ceramics with compositions near the antiferroelectric-ferroelectric (AFE-FE) phase boundary were investigated. It was found that the chemical reduction reaction proceeded much more rapidly in PSZT than in PLZT ceramics. The optimum conditions for the processing of PSZT Rainbows were determined to be 850 degrees C for 2-3 hours. Large axial displacements ranging from 102 to 273 mu m were obtained from the PSZT Rainbow samples by application of electric fields greater than the AFE-to-FE phase switching levels. The characteristics of the field-induced displacements of the Rainbow samples were dependent on the manner of applying mechanical load on the samples. At room temperature, the antiferroelectric PSZT Rainbows exhibited a concave curvature with respect to the oxide side, which was attributed to the cubic-to-antiferroelectric phase transition in the oxide layer during cooling. The dielectric and AFE-FFZ phase transition properties of the Rainbow samples were compared with those of the normal ceramics.