USA As Represented by Secretary of the Navy

The Penn State Research Foundation

The Pennsylvania Research Corporation

Hoechst Celanese Corporation

Celanese Gmbh

Leco Corporation

Robert E Newnham

Leslie E Cross

Jindong Zhang

Ahmad Safari

James V Biggers

Michael J Haun

Kenneth A Klicker

Qichang C Xu

Basavaraj V Hiremath

Shoko Yoshikawa

Jayne R Giniewicz

Leslie J Bowen

Walter A Schulze, Jr

Joe Kennedy Cochran, Jr

Sei-Joo Jang

Doyle P Skinner

Raymond J Kunz

Walter A Schulze

Geon Sagong

Sedat Alkoy

Michael Blaszkiewicz

Qi C Xu

Aydin Dogan

A process for fabricating a ceramic electroactive transducer of a predetermined shape is disclosed. The process comprises the steps of providing a suitably shaped core having an outer surface, attaching a first conductor to the outer surface of the core, coating an inner conductive electrode on the outer surface of the core such that the inner conductive electrode is in electrical communication with the first conductor, coating a ceramic layer onto the inner electrode, thereafter sintering the ceramic layer, coating an outer electrode onto the sintered ceramic layer to produce an outer electrode that is not in electrical communication with the first conductor, and then poling the sintered ceramic layer across the inner electrode and the outer electrode to produce the ceramic electrode.

Process for fabricating hollow electroactive devices

A process for fabricating a ceramic electroactive transducer of a predetermined shape is disclosed. The process comprises the steps of providing a suitably shaped core having an outer surface, attaching a first conductor to the outer surface of the core, coating an inner conductive electrode on the the outer surface of the core such that the inner conductive electrode is in electrical communication with the first conductor, coating a ceramic layer onto the inner electrode, thereafter sintering the ceramic layer, coating an outer electrode onto the sintered ceramic layer to produce an outer electrode that is not in electrical communication with the first conductor, and then poling the sintered ceramic layer across the inner electrode and the outer electrode to produce the ceramic electrode.

An electro active device for generating a directional beam includes first and second electro active substrates each having first and second opposed continuous planar surfaces wherein each of the first opposed surfaces have a polarity and each of the second opposed surfaces have an opposite polarity. The first opposed surfaces of the first and second electro active substrates are in close contact. A first electrode is coupled to a junction formed by the first opposed surfaces having the same polarity, a second electrode is coupled to the second opposed surface of the first electro active substrate, and a third electrode is coupled to the second opposed surface of the second electro active substrate. A first endcap is joined to the second opposed surface of the first electro active substrate and a second endcap is joined to the second opposed surface of the second electro active substrate.

Class V flextensional transducer with directional beam patterns

An electroactive device incorporating the invention includes an electroactive ceramic annular substrate having a pair of opposed planar annular surfaces, a hollowed interior region and a thickness aspect. A first cap having a concave shape that extends into the hollowed interior region includes a rim portion, bounding the hollowed interior region, and joined to a first one of the planar surfaces. A second cap having a concave shape that extends into the hollowed interior region includes a rim portion, bounding the hollowed interior region, and joined to a second one of the planar surfaces. A potential measured across the ceramic substrate enables a field change in the ceramic substrate to be sensed, the field change caused by flexure of the ceramic substrate as a result of a pressure applied to the first and second caps.

Flextensional metal-ceramic composite transducer

An electroactive device incorporating the invention is configured from an electroactive ceramic hollow sphere having an inner surface, an outer surface, a wall thickness aspect and a radius aspect. Conductive electrodes are positioned on opposed surfaces of said sphere and conductors enable application of an electrical potential between the conductive electrodes to enable a field to be applied to said sphere that causes a dimension change in the radius aspect and thickness aspect thereof. In one embodiment the sphere has a d,direction parallel to the thickness aspect, and d,& d,directions parallel to the sphere surfaces and in another embodiment the d,direction is perpendicular to the thickness aspect, and d,& d,directions are respectively parallel and perpendicular to the sphere surfaces. The sphere is preferably supported by a rod that either passes throng one opening in the sphere or through two opposed openings. Further, the rod may include a pathway for other instrumentality's. Arrays of such devices are also disclosed.

Hollow sphere transducers

A metal-ceramic device includes an electroactive ceramic substrate having a pair of opposed planar surfaces and a thickness aspect. Conductive electrodes sandwich the ceramic substrate and a first sheet metal cap having a concave shape, a substantially unchanging thickness and a rim is joined to a first planar surface of the ceramic substrate. A second sheet metal cap having a concave shape, a substantially unchanging thickness and a rim is bonded to a second planar surface of the ceramic substrate, the second planar surface opposed to the first planar surface. In an actuator embodiment, a potential is applied across the conductive electrodes to cause an expansion of the ceramic substrate in the thickness dimension and a concomitant contraction in its planar dimensions. The contraction causes a flexure of the sheet metal caps, which flexures are used for actuation purposes. In a sensor embodiment, the sheet metal caps are subjected to a displacement by an instrumentality, and a resulting change in voltage across the ceramic substrate is sensed.

Metal-electroactive ceramic composite transducer

The metal-ceramic actuator includes an electroactive substrate having at least a pair of opposed planar surfaces and a determined thickness, with the ceramic substrate being poled in its thickness dimension. Conductive electrodes sandwich the ceramic substrate and are bonded to its planar surfaces. Metal caps, each having a concave cavity bounded by a rim, are bonded to both planar surfaces of the ceramic substrate. A potential is applied to the conductive electrodes to cause an expansion of the ceramic substrate in its thickness dimension and a concomitant contraction in its planar dimensions. The contraction creates a flexure of the metal caps, which flexures are used to actuate another instrumentality.

Metal-electroactive ceramic composite actuators

A solid-state tunable transducer has been developed by incorporating an elastically nonlinear material, silicone rubber, into an electroacoustic transducer made from piezoelectric ceramics. The resonant frequency and mechanical Q of the transducer are tuned mechanically by applying a uniaxial compressive stress to the composite. The resonant frequency is tuned electrically by placing a piezoelectric actuator into the composite and varying the magnitude of the d.c. bias.

Frequency agile sonic transducer

This invention describes an acoustic transducer assembly wherein an extremely high figure of merit (d.sub.h g.sub.h) is obtained as a result of converting incoming acoustic axial stress into radial extensional stress thereby multiplying its effect. The piezoelectric active element is encased in a metal sandwich enclosing two semilunar air spaces which allow the device to withstand extremely high hydrostatic pressure yet still respond to low level sound waves when acting as a hydrophone. The mechanical prestress induced by the differential coefficients of expansion between the metal case and the piezoelectric ceramic element also serves to prevent depolarization aging.

Transformed stress direction acoustic transducer

A hydrophone device is provided with a piezoelectric ceramic-polymer composite of 0-3 connectivity in which the piezoelectric filler comprises a solid solution of PBTiO.sub.3 -BiFeO.sub.3 wherein the solid solution contains 50-80 wt. % of the BiFeO.sub.3. The piezoelectric ceramic-polymer composite has large hydrostatic piezoelectric charge and voltage coefficients which are desirable in hydrophone devices.

Method of detecting sound in water using piezoelectric-polymer

A PZT-polymer composite of 0-3 connectivity further includes a third phase particulate additive of conductive or semiconductive material to increase the electrical conductivity of the polymer matrix.

Easily poled 0-3 piezoelectric composites for transducer applications

A barrier layer ceramic capacitor and a method of making the same, using barium plumbate or modified barium plumbate as the base material. The fabricating process is a one step process requiring a maximum sintering temperature of 1000.degree. C.

Barrier layer ceramic dielectric capacitor containing barium plumbate

A composite of PZT (lead zirconate titanate) and a compliant polymer having 1-3-0 connectivity is described. A polymer self-connected in all three mutually perpendicular directions with a void in the center has an array of parallel PZT rod elements embedded therein and extending through the void. The void isolates a region of the PZT rods from the polymer. The axes of the PZT rods are along the direction of the poling electric field. Such an arrangement significantly enhances the hydrostatic piezoelectric charge and voltage coefficients d.sub.h and g.sub.h.

1-3-0 Connectivity piezoelectric composite with void

A multilayer thermistor and a method of making it are disclosed. The thertor has a positive temperature coefficient of resistance (PTCR) and a room temperature resistance lower than prior art thermistors of the same size. The thermistor is comprised of a plurality of layers of material having the PTCR characteristic laminated in alternation with layers of electrodes, the outer two layers of the thermistor being PTCR layers. Alternate electrodes are electrically connected in common to a pair of conductors forming thereby parallel resistance paths across each layer. The more resistance paths the thermistor has, the lower the overall resistance of the device.

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State College, PA, United States of America

Robert E Newnham