Abstract: Piezoelectric devices with excellent high temperature operation capabilities are described, including piezoelectric sensors and actuators that use a rare earth calcium oxyborate or langanite as the piezoelectric material.

Abstract: The present invention is directed to a new family of high Curie temperature, morphotropic phase boundary systems, based on the perovskite solid solution having the general formula (1−x)BiMeO3-xPbTiO3, where Me is a suitably sized cation or combination of cations and x is a molar fraction. The perovskite systems of the present invention offer room temperature properties analogous to, and high temperature properties superior to, commercially available PZT compositions. The perovskite of this invention exhibits a MPB between the rhombohedral and tetragonal phases. Further dopant strategies may be used for property optimization of the perovskite systems.

Abstract: The present invention discloses a method and apparatus for ultrasound imaging with improved spatial sampling. The device includes a plurality of ultrasound imaging elements each having a pitch defined by the center to center spacing of the ultrasound imaging elements; and a motion mechanism operatively connected to the plurality of ultrasound imaging elements and adapted to move the plurality of ultrasound imaging elements over a distance to increase the spatial sampling of the plurality of ultrasound imaging elements. The method of the present invention includes transducing a signal from one or multiple ultrasound imaging elements within an array of ultrasound imaging elements; moving the array of ultrasound imaging elements a distance less than the pitch; and transducing at least one additional signal from the ultrasound imaging element.

Abstract: The disclosed invention relates to Bi2O3—ZnO—Ta2O5 dielectric compounds and compositions, and to their manufacture. The compounds of the invention have outstanding K, Q, TCF, and TCC. Examples of these properties include a K of between 58 and 80, a low dielectric loss (tan &dgr;<0.003), and a TCC<30 ppm/° C. Ceramic compositions produced include those represented by Bi2(ZnTa2)xO6x+3 where 0.57≦x≦1.0, Bi2(ZnTay)2/3O((5y+11)/3) where 1.0≦y≦3.0, as well as by Bi2(ZnTay)2/3O((5y+11)/3) where 1.0≦y≦3.0 with the proviso that y is not=2.0. Solid solutions of compounds defined by the formula r(Bi2(Zn1/3Ta2/3)2O7)-(1−r)(Bi3/2Zn2/3)(Zn1/2Ta3/2)O7)) where 0<r<1 also are produced.

Abstract: Certain embodiments relate to a process for forming a multilayer electrical device. The process includes providing a multilayer structure including layers of a dielectric material and an electrode material. The electrode material may include at least one material selected from the group consisting of nickel and copper. A variety of dielectric materials may be used, such as barium titanate. The method also includes sintering the dielectric material by heating the structure using microwaves in an industrial nitrogen atmosphere, which contains an oxygen partial pressure of 10−2 to 10−12 atm.

Abstract: The present invention is directed to a new family of high Curie temperature, morphotropic phase boundary systems, based on the perovskite solid solution having the general formula (1−x)BiMeO3-xPbTiO3, where Me is a suitably sized cation or combination of cations and x is a molar fraction. The perovskite systems of the present invention offer room temperature properties analogous to, and high temperature properties superior to, commercially available PZT compositions. The perovskite of this invention exhibits a MPB between the rhombohedral and tetragonal phases. Further dopant strategies may be used for property optimization of the perovskite systems.

Abstract: A thin film comprising a pyrochlore represented by the formula: (Bi3xZn2−3x)(ZnxNb2−x)O7 wherein x is from about 0.45 to about 0.73 and an article comprising a substrate and, coated on the substrate, a thin film of the pyrochlore are provided. Also provided is a process for depositing on a substrate the above pyrochlore thin film. The process includes the steps of coating the substrate with a composition comprising bismuth carboxylate, zinc carboxylate, niobium alkoxide, an organic solvent, an organic acid and an organic base, heating to remove organic components and annealing at a temperature and for a length of time sufficient to produce the pyrochlore thin film on the substrate.

Abstract: Certain embodiments relate to a process for forming a multilayer electrical device. The process includes providing a multilayer structure including layers of a dielectric material and an electrode material. The electrode material may include at least one material selected from the group consisting of nickel and copper. A variety of dielectric materials may be used, such as barium titanate. The method also includes sintering the dielectric material by heating the structure using microwaves in an industrial nitrogen atmosphere, which contains an oxygen partial pressure of 10−2 to 10−12 atm.

Abstract: Chemically aided milling of ceramic powders is disclosed. Carrier suspension, usually aqueous, of the ceramic powder may have added to it a dispersing agent and a passivating agent, followed by milling the aqueous suspension while continuously monitoring the pH, and as necessary, adding acid or a base to keep the pH within a desired range during milling. Real time monitoring allows milling with lower energy consumption, and enhances the desirable particle surfaces of the ceramic powder. The passivating agent can also be real time monitored and adjusted as necessary.

Abstract: The present invention discloses a method and apparatus for ultrasound imaging with improved spatial sampling. The device includes a plurality of ultrasound imaging elements each having a pitch defined by the center to center spacing of the ultrasound imaging elements; and a motion mechanism operatively connected to the plurality of ultrasound imaging elements and adapted to move the plurality of ultrasound imaging elements over a distance to increase the spatial sampling of the plurality of ultrasound imaging elements. The method of the present invention includes transducing a signal from one or multiple ultrasound imaging elements within an array of ultrasound imaging elements; moving the array of ultrasound imaging elements a distance less than the pitch; and transducing at least one additional signal from the ultrasound imaging element.

Abstract: The disclosed invention relates to Bi2O3—ZnO—Ta2O5 dielectric compounds and compositions, and to their manufacture. The compounds of the invention have outstanding K, Q, TCF, and TCC. Examples of these properties include a K of between 58 and 80, a low dielectric loss (tan &dgr;<0.003), and a TCC<30 ppm/° C. Ceramic compositions produced include those represented by Bi2(ZnTa2)xO6x+3 where 0.57≦x≦1.0, Bi2(ZnTay)⅔O((5y+11)/3) where 1.0≦y≦3.0, as well as by Bi2(ZnTay)⅔O((5y+11)/3) where 1.0≦y≦3.0 with the proviso that y is not=2.0. Solid solutions of compounds defined by the formula r(Bi2(Zn⅓Ta⅔)2O7)-(1−r)(Bi{fraction (3/2)}Zn⅔)(Zn½Ta{fraction (3/2)})O7))where 0<r<1 also are produced.

Abstract: A method for assembling an ultrasonic transducer, first produces a plurality of plates of piezoelectric material. Then the plates are bonded together through use of a polymeric matrix comprising a polymer and intermixed particles having determined dimensional parameters, the particles acting to separate the plates by predetermined distances that are dependent upon the determined dimensional parameters. Preferred particles are polystyrene spheres. A second embodiment produces a plurality of strips of green piezoelectric ceramic material, each strip including a layer of a fugitive material. The strips are then placed in a stack and the stack is fired to convert the green piezoelectric ceramic material into densified ceramic plates. The firing acts to drive off said second fugitive material and to leave voids. The voids are then backfilled with a polymeric material to create a unified structure.

Abstract: <001>oriented crystals of lead zinc niobate--lead titanate solid solution (0 to 5 mole % lead titanate) have high electromechanical coupling>85% and exhibit electric field induced phase transition at electric field levels>10.times.Ec (where Ec is the coercive field), resulting in increased transducer driving voltages, decreased fabrication degradation, and high sensitivity/large bandwidth transducer characteristics due to high electromechanical couplings, up to 92%. <001>oriented crystals of lead magnesium niobate--lead titanate solid solution (20 to 50 mole % lead titanate) also exhibit high electromechanical couplings>85% and up to 94%, and thereby can be formed into transducers which exhibit both high sensitivity and large bandwidth.

Abstract: An actuator incorporating the invention includes a body of a ferroelectric material. The material is single crystalline and incorporates solid solutions of lead zinc niobate-lead titanate or lead magnesium niobate-lead titanate, described by the formulae: Pb(Zn.sub.1/3 Nb.sub.2/3).sub.1-x Ti.sub.x O.sub.3 and Pb(Mg.sub.1/3 Nb.sub.2/3).sub.l-y Ti.sub.y O.sub.3 l where x and y are defined as 0.ltoreq.x<0.10, and 0.ltoreq.y<0.40. Electrodes enable application of an electric field across the body in a direction that is generally aligned with a <001> crystallographic axis of the ferroelectric material.

Abstract: A ferroelectric relaxor ceramic actuator material, such as lead magnesium niobate ("PMN"), has high electromechanical conversion efficiency, exhibits wide operating and manufacturing temperature ranges, does not require permanent polarization, and provides useful mechanical activity with reduced electrical drive voltages. A PMN actuator (66) may be bonded to an actuator diaphragm (64) with a high temperature soldering or brazing process. PMN material also has a diffuse Curie point range in which the dielectric constant (40), "d" coefficient (32), and dielectric loss (42) characteristics all rise to a peak and then fall as the temperature increases. A phase-change ink-jet print head (50) employs a PMN actuator that is compounded with lead titanate ("PT") to increase the temperature (T.sub.M) at which the peak dielectric constant occurs.

Abstract: A cardiac defibrillator includes a multilayer capacitor with a plurality of conductive electrodes and interspersed dielectric layers, each dielectric layer composed of constituents which cause it to exhibit an antiferroelectric phase. The constituents of each dielectric layer are such as to cause each layer to exhibit plural ferroelectric phases. The defibrillator includes a charging circuit for applying to the capacitor an electric field across each dielectric layer which causes a transition thereof through the plural ferroelectric phases. PLZT is the preferred dielectric material, at constituent values which cause the material to lie within the antiferroelectric phase and to exhibit plural ferroelectric phases.

Abstract: A dielectric ceramic composition comprising a sintered mixture represented by the formula:Bi.sub.2-x (Zn.sub.(2+y)/3 Nb.sub.4/3)O.sub.7-3x/2+y/3where: 0.240.ltoreq.x.ltoreq.0.333, and 0.120.ltoreq.y.ltoreq.0.300; and a dielectric composition given by the formula:(Bi.sub.1-z Ca.sub.z).sub.2-x (Zn.sub.(2+y)/3 Nb.sub.4/3)O.sub.7-3x/2+y/3+xz/2-zwhere: 0.ltoreq.x.ltoreq.0.667, 0.ltoreq.y.ltoreq.0.300, and 0<z.ltoreq.0.200; substitutions for Bi can be selected from the group consisting of Ca, Sr, Ba, Y, Pb, Cd, La and other rare earth oxides having atomic numbers 58-71 of the periodic table; substitutions for Zn can be selected from the group consisting of Mg, Ca, Co, Mn, Ni, and Cu; and substitutions for Nb can be selected from the group consisting of Ti, Zr, Hf, and Ta; wherein the substitutions comprise less than 20 mol % based on the Bi, Zn, and Nb content respectively.Typically, BZN and calcium-modified BZN ceramics are prepared by the initial preparation of a ZnNb.sub.2 O.sub.6 precursor; mixing of ZnNb.

Abstract: An ultrasonic electrostrictive transducer for transmitting and receiving ultrasonic energy and having an expanded operating temperature range, preferably about room temperature. The transducers may be made from PMN-PT solid solutions having select mole percentages of PT and being doped with La, whereby the operating temperature range about a given operating temperature may be effectively doubled.

Abstract: PZT/polymer composites and a simplified method of their fabrication are dribed. Commercially available PZT Pb(Zr, Ti)O.sub.3 powder is thoroughly mixed with a binder such as polyvinylalcohol and polymethyl methacrylate (PMM) spheres and pressed into pellets. The binder and PMM spheres are burnt out by heating pellets slowly and the porous pellets so obtained are sintered by heating them in closed high-purity alumina crucibles and lead zirconate as a source of lead is added thereto. The highly porous pellets thus obtained are impregnated with a suitable polymer such as silicone rubber elastomer or vinylcyclohexene dioxide epoxy.