摘要:
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;
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
The application is directed to piezoelectric single crystals having shear piezoelectric coefficients with enhanced temperature and/or electric field stability. These piezoelectric single crystal may be used, among other things, for vibration sensors as well as low frequency, compact sonar transducers with improved and/or enhanced performance.
摘要:
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.
摘要:
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. The print head is operated at a temperature beyond the peak where the PMN:PT actuator "d" coefficient decreases as the temperature increases such that an increase in ink-jet drop ejection velocity caused by reduced ink viscosity is compensated for by a corresponding reduction in mechanical activity. The PMN:PT actuator thereby relaxes the temperature regulation and heat spreading requirements of the phase-change ink-jet print head.
摘要:
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.