Abstract: A transducer including a ceramic body having a base and an array of tube-shaped piezoelectric or electrostrictive ceramic elements integral with the base. A first electrode contacts the tube wall inner surface, while a second electrode contacts the tube wall outer surface and is electrically isolated from the first electrode and from the lower surface of the transducer. The first electrode extends onto the transducer lower surface for electrical connection to a power source for driving the transducer across the tube walls for d.sub.31 mode vibration of the tube walls. A stiff cover plate may be used to transmit the tube wall vibration to a desired medium. The ceramic base may be removed if an electrically insulating layer is provided between the elements at the lower surface of the transducer. The insulating layer and tube wall upper edges then electrically isolate the second electrode from the first electrode and the transducer lower surface.

Abstract: A net-shape process for fabricating a fully dense ceramic preform for a piezoelectric or electrostrictive composite transducer exhibiting 1-3 or 2-2 connectivity. The process involves preparing a homogeneous, granulated, thermoplastic powder/binder mixture from a strongly piezoelectric or electrostrictive ceramic material powder and a thermoplastic organic binder selected to be nondestructively removed from the mixture by heating. The mixture is injection molded to form a self-supporting green body including a planar ceramic base with parallel ceramic elements extending perpendicularly from the base in a preselected array. Each element has a rod-like or lamellar shape. The body is released from the preform mold, heated to a temperature of 300.degree.-700.degree. C. for a time sufficient to completely remove the binder, and sintered to at least about 95% of theoretical density.