Abstract: A piezoelectric device, comprising a number of polarizable ceramic plates 1 which are stacked with intermediate metal plates which serve as electrodes. The stack is subjected to a large amount of preload by a preloading element having a relatively flat spring-force characteristic over the piezoelectric operating range of the device which is formed by a cylindrical housing having two sets of parallel pairs of slots 7, 10, rotationally displaced by 90 degrees, the preloading force being applied to the stack by threaded end plugs 4 and 5. The ceramic plates are polarized only after assembly and preloading.

Abstract: The method utilizes two plates of piezoelectric material. In a first major surface of the first plate there are formed mutually parallel channels which extend from one edge of the major surface to the opposite edge. On both major surfaces of both plates there are provided metal layers and both plates are polarized by application of an electric voltage between these metal layers. The first major surface of the first plate and the first major surface of the second plate are covered with a layer of adhesive. In each channel a tube is arranged and the two plates are arranged one on the other in a registering manner so that the surfaces provided with adhesive face one another. Finally, the adhesive is subjected to a curing process.

Abstract: Electromechanical transducer comprising a piezoelectric body consisting of Pb.sub.1--a M.sub.a (Mg.sub.(1--b) /.sub.3 Mn.sub.b/3 Sb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3, wherein M is one or more of the alkaline earth metals Ca, Sr and Ba, and wherein0.ltoreq.a.ltoreq.0.15,0.ltoreq.b.ltoreq.0.20,0.01.ltoreq.x.ltoreq.0.25,0.40.ltoreq.y.ltoreq.0.55,0.20.ltoreq.z.ltoreq.0.59 and(x+y+z)=1.This material has the advantage that polarization is effected in a very short period of time at room temperature.

Abstract: Piezoelectric body for an electromechanical transducer consisting of Pb.sub.1-a M.sub.a (Mg.sub.(1-b)/3 Mn.sub.b/3 Sb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3, wherein M is one or more of the alkaline earth metals Ca, Sr and Ba,0.ltoreq.a.ltoreq.0.15,0.ltoreq.b.ltoreq.0.20,0.01.ltoreq.x.ltoreq.0.25,0.40.ltoreq.y.ltoreq.0.55,0.20.ltoreq.z.ltoreq.0.59,(x+y+z)=1.This material has the advantage that polarization is effected in a very short period of time at room temperature.