Abstract: Disclosed herein is an electroviscous fluid comprising an electrical insulating liquid and particles dispersed therein, said particles being composed of semiconducting particles having a weight average particle size of 1 to 100 .mu.m and dielectric particles having a weight average particle size of 1 to 3 .mu.m, the weight average particle size of the dielectric particles being not more than 30% of that of the semiconducting particles, the amount of the dielectric particles being 5 to 40 vol % based on the total particles, and the amount of the particles in the whole fluid being 10 to 60 vol %.

Abstract: The present invention relates to a piezoelectric ceramic composition for actuator which is a composition comprising a basic composition containing lead, lanthanum, alkali earth metals, zirconium, titanium and oxygen in the formulation represented by the following general formula (I): ##EQU1## where A represents one or more element(s) selected from the group consisting of Ba, Ca and Sr; 0<x.ltoreq.0.07; 0.40.ltoreq.y.ltoreq.0.65; and 0<m.ltoreq.0.15, wherein the ceramic composition containing, relative to the basic composition, one or more element(s) selected from the group consisting of iron, aluminum, manganese, indium and tellurium in an amount of 0.02 to 0.3% by weight in terms of Fe.sub.2 O.sub.3 or Al.sub.2 O.sub.3, 0.02 to 0.2% by weight in terms of MnO.sub.2 and 0.02 to 0.5% by weight in terms of In.sub.2 O.sub.3 or TeO.sub.2.

Abstract: A piezoelectric ceramic composition for actuators, composed of lead, lanthanum, zirconium, titanium, magnesium, zinc, niobium, manganese, chromium and oxygen atoms, which contains manganese in an amount of at most 1.5% by weight as calculated as Mn.sub.2 O and chromium in an amount of at most 0.5% by weight as calculated as Cr.sub.2 O.sub.3, relative to a main component composition of the formula (I):Pb.sub.(1-x) La.sub.x [(1-z)(Zr.sub.y Ti.sub.(1-y))+z{Mg.sub.q Zn.sub.(1-q)).sub.1/3 Nb.sub.2/3 }].sub.(1-x/4) O.sub.3 (I)wherein 0<x.ltoreq.0.07, 0.40.ltoreq.y.ltoreq.0.65, 0.ltoreq.q.ltoreq.1, and 0<z.ltoreq.0.40.

Abstract: The present invention relates to a piezoelectric ceramic composition for an actuator which is a ceramic composition comprising a main component represented by the formula: Pb.sub.(1-x) La.sub.x [Zr.sub.y Ti.sub.(1-y) ].sub.(1-x/4) O.sub.3 and, as a sub component, antinomy in an amount of more than 0.05% by weight and less than 3.0% by weight in terms of anitmony pentoxide relative to the main component. The piezoelectric ceramic composition of the present invention has a high electromechanical coupling factor, a high piezoelectric strain constant and a high Curie point, and is particularly excellent as a material for a piezoelectric actuator.

Abstract: A process for preparing a slender or thin ceramic green body, which comprises discharging a raw material slurry comprising a ceramic powder raw material, a binder and a solvent from a discharge outlet in a slender or thin shape, and then contacting it with a solidifying liquid composed of a liquid in which the solvent is soluble and the ceramic powder raw material and the binder are insoluble or hardly soluble so that the solvent in the slurry is dissolved and removed to form the green body.

Abstract: A piezoelectric actuator comprising a longitudinal effect-type laminated piezoelectric element composed of piezoelectric ceramic sheets laminated in their thickness direction, and a supporting member fixed to one side in the longitudinal direction of the element and being bending and capable of constraining expansion of the element.

Abstract: A piezoelectric element of laminate type comprising a plurality of films or thin sheets of piezoelectric material of the same size, each having an internal electrode formed on its entire surface, said films or sheets being laminated so that the end face of each internal electrode is exposed at the side of the laminate, wherein an insulating layer is formed by a photosensitive composition to electrically connect every second internal electrode.

Abstract: A piezoelectric ceramic composition for actuators, which consists essentially of a composite of perovskite compounds represented by the formulaPb.sub.(1-x) La.sub.x [z{(Zn.sub..alpha. Mg.sub.(1-.alpha.))1/3Nb.sub.2/3 }+(1-z){Zr.sub.y Ti.sub.(1-y) }].sub.(1-x/4) O.sub.3wherein 0.03.ltoreq.x.ltoreq.0.07, 0.50.ltoreq.y.ltoreq.0.65, o<z<0.20, and 0<.alpha.<1.

Abstract: A piezoelectric actuator comprising a longitudinal effect-type laminated piezoelectric element composed of piezoelectric ceramic sheets laminated in their thickness direction, and a supporting member fixed to one side in the longitudinal direction of the element and being bending and capable of constraining expansion of the element.