99 results about "Relaxor ferroelectric" patented technology

A MEMS hierarchically-dimensioned deformable minor comprising a substrate, a plurality of spacers disposed on the substrate, a plurality of piezoelectric cantilever microactuators disposed on the plurality of spacers, and a continuous deformable membrane disposed on the plurality of the cantilever assemblies, has significantly improved overall device performances owing to the use of the cantilever microactuators based on relaxor ferroelectric single crystal materials or other piezoelectric materials.

Systems and methods are provided for preparing multi-component ferroelectric crystals (e.g., PMN-PT, amongst others) having piezoelectric properties. The crystals are fabricated using a system that employs multiple heaters and sensors that are located along the length of a crystal growth chamber. The heaters are controlled in concert, via a feedback system, to produce a temperature profile having a gradient that effectively moves along the length of the chamber, to suitably effectuate crystallization throughout the chamber, without need for the chamber to translate relative to the heater(s). During the crystallization process, the contents of the chamber may be mixed and/or homogenized via suitable agitation thereof, resulting in a multi-component ferroelectric crystal of desirable quality.

The invention relates to a reading circuit based on relaxor ferroelectric monocrystal pyroelectricity, which can realize the outputting of a relaxor ferroelectric monocrystal pyroelectric signal. The output current signal of the relaxor ferroelectric detector is converted into a voltage signal through an CTIA input-stage circuit module, the voltage signal is output after amplification, a double sampling hold circuit samples the signal twice, and a multichannel transmission circuit outputs the signals in each channel after conduction. The circuit modules are integrated on an integrated circuit chip and connected with a detector chip, and the control signal of the circuit modules is provided by an external drive circuit, thus the integrated circuit chip can effectively read the signal of the relaxor ferroelectric detector.

The invention discloses an all-solid-state electrocaloric refrigerator. A third electrode layer serves as a center layer. An electrocaloric refrigeration unit cold end formed by sequentially attaching a second electrocaloric material layer and a second electrode layer to one side is connected with a refrigeration sheet. An electrocaloric refrigeration unit heat end formed by sequentially attaching a first electrocaloric material layer and a first electrode layer to the other side is connected with a cooling sheet. The all-solid-state electrocaloric refrigerator further comprises a first power source and a second power source, wherein the first power source is connected with the cold end so as to provide pulse voltages, and the second power source is connected with the heat end so as to provide pulse voltages. The electrocaloric material layers are made of ferroelectric materials or relaxor ferroelectric materials with an electrocaloric effect. Film materials with excellent heat conduction but without electric conduction are sputtered on the surfaces of the first electrode layer and the third electrode layer which make contact with the refrigeration sheet and the cooling sheet, and the film materials can be BeO or AlN.

The invention relates to a preparation method of perovskite-structure relaxor ferroelectric single crystal lead indium niobate-lead magnesium niobate-lead titanate. The chemical composition of the perovskite-structure relaxor ferroelectric single crystal lead indium niobate-lead magnesium niobate-lead titanate is (1-x-y)Pb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-xPbTiO3, wherein x is equal to 0.20-0.45 and y is equal to 0.15-0.70. The preparation method comprises the following steps: (1) preparing a primary crystal growth raw material; (2) primarily growing crystals; (3) preparing secondary crystal growth raw material; and (4) secondarily growing the crystals. According to the preparation method disclosed by the invention, a crucible descending multi-growth method is adopted, the component segregation of wafers can be obviously suppressed, the high-performance areas of the crystals can be expanded, and relaxor ferroelectric single crystal material PIMNT with large dimensions, large high-performance intervals and high quality can be grown effectively with regard to the optimally-orientated wafers for different applications, thus the utilization rate of the crystals is increased, and the difficulties of batch growth and applications of single crystals can be overcome.

The invention provides a piezoelectric principle-based omnidirectional horizontal shear guided wave transducer. The piezoelectric principle-based omnidirectional horizontal shear guided wave transducer comprises a plurality of piezoelectric sensing elements and a temporary adhesive tape substrate, the piezoelectric sensing elements are annularly arranged to form an axisymmetric sensor array, each of the piezoelectric sensing elements has two electrodes, and all positive electrodes of the piezoelectric sensing elements are connected in series by a lead; and the piezoelectric sensing elements are cut from a relaxor ferroelectric monocrystalline material according to a certain angle to make the d36 piezoelectric coefficient not 0. The piezoelectric principle-based omnidirectional horizontal shear guided wave transducer can generate uniform and continuous shear guided waves in 360 degrees, and can sense horizontal shear guided waves propagated from any direction. Compared with present omnidirectional horizontal shear guided wave transducers, the piezoelectric principle-based omnidirectional horizontal shear guided wave transducer has the advantages of minimal size, generation of omnidirectional horizontal shear guided waves, and permanent fixation to the surface of a structure or embedding into the inside of the structure.

The invention discloses a microwave sintered lead-free high energy density ST/NBT (nitroblue tetrazolium) ceramic material and a preparation method thereof. The preparation method comprises the following steps: firstly, respectively weighing the following materials at a molar ratio: Na2CO3, Bi2O3, SrCO3 and TiO2, so as to obtain a mixture, ball-milling, drying and briquetting the mixture to form a full ingredient and sequentially granulating and sieving the full ingredient, so as to form a granulated resin; next, pressing the granulated resin into a sample and sintering the prepared sample, so as to obtain a sintered sample; finally, polishing and washing the sintered sample, uniformly coating silver electrode slurry on the front surface and the back surface of the sintered sample after being polished and washed and sintering the sample coated with the silver electrode, so as to obtain ST/NBT system ceramics. The ST/NBT lead-free relaxor ferroelectrics ceramic material obtained according to the method has high dielectric constant and obvious relaxation behavior and is suitable for wider temperature range; in addition, the preparation process is simple, the cost of the material is low, and the material is environmentally friendly. Therefore, the material becomes an important candidate material excellent both in technology and economic, which can be used as a high-end industrial application material instead of a lead-based ceramic material.

The present application is directed towards, among other things, systems and methods for modulating the intensity of laser light at high frequencies for use in projection systems. A laser is modulated by an electro-optical device, such as an intensity modulator, that can change its reflective or transmissive behavior at rates exceeding tens of megahertz under the application of an electric field. In some embodiments, the intensity modulator may be configured as a Fabry-Pérot interferometer or etalon, or a Gires-Tournois etalon. In many embodiments, the intensity modulator may include a transparent relaxor-ferroelectric-type material between the modulator's reflective plates. By applying a voltage to the ferroelectric material, its refractive index may be varied to dynamically change the resonance of the modulator, modulating the intensity of the light transmitted through or reflected from the modulator. The intensity modulator may be placed in various configurations to modulate the laser through transmission, reflection, or phase delay and recombination.

The invention discloses a preparation method of (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics. The method comprises the steps of firstly weighing corresponding masses of Na2CO3, Bi2O3, SrCO3 and TiO2 according to the molar ratio to obtain a mixture; carrying out ball milling, drying and briquetting on the mixture to form a whole ingredient, sequentially carrying out pelleting and sieving on the whole ingredient to form a granulated material; pressing the granulated material to prepare a sample and sintering the prepared sample to obtain a sintered sample; and finally polishing and cleaning the sintered sample, evenly coating the front surface and the back surface of the polished and cleaned sintered sample with electrode slurry, and sintering the sample coated with a silver electrode to obtain the (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics. The (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics obtained by the method has a high dielectric constant and obvious relaxation characteristics, is suitable for a wider temperature range, adopts a simple preparation process, is low in material cost, environmentally friendly, and becomes an excellent important candidate material used as a high-end industrial application material instead of a lead-based ceramic material in technology and economy.

The invention relates to a pyroelectric detector based on current type relaxor ferroelectric single crystal. The pyroelectric detector comprises a hollow packaging tube shell, an optical filter, a sensitive element chip Up and a line substrate. The packaging tube shell comprises a tube cap and a base, the optical filter is embedded in a window formed in the upper surface of the tube cap, the lower end of the tube cap is fixedly connected with the base and forms a hollow seal structure with the base, the line substrate is arranged on the base and located in the seal structure, a suspension supporting frame is arranged on the line substrate, and the sensitive element chip Up is arranged on the upper surface of the suspension supporting frame and located under the optical filter; a feedback amplifying circuit is arranged on the line substrate, and the sensitive element chip Up is connected between the two input ends of the feedback amplifying circuit through the suspension supporting frame. The current type circuit is adopted, pyroelectric detector is high in capacity for resisting outside noise interference and capable of fast responding outside infrared radiation, and the time of startup preheating and signal stabilizing is shortened.

A piezoelectric transformer includes a single crystal relaxor ferroelectric element poled along a [0 11] direction and selected from the group consisting of PZN-PT, PMN-PZT, PZN-PT and PMN-PT. The element has two opposed surfaces substantially perpendicular to the [0 11] direction with an input electrode and an output electrode positioned on one surface. The output electrode is isolated from electrical communication with the input electrode. A ground electrode is positioned on the second, opposed surface. Input electrical energy results in piezoelectric change in the element that is mechanically coupled through the element to generate piezoelectric output energy.

The invention discloses zinc-bismuth based perovskite-lead titanate-lead based relaxor ferroelectric ternary system piezoceramics and a preparation method thereof. The piezoceramics is shown by of general formula of (1-n)[(1-u-v)PbTiO3+uBi(ZnxDy)O3+vPb(EzFw)O3]+nM. The preparation method comprises the steps of mixed ball milling, presintering, blank material preparation, sintering, silver-layer coating and polarization. The piezoceramics composition has the morphotropic phase boundary of rhombic ferroelectric phases and square ferroelectric phases and has excellent piezoelectric performance and higher Curie temperature, the lead content is reduced, the lower sintering temperature is realized, the replacement of partial traditional lead-containing piezoceramics can be realized, the piezoceramics can be obtained through the traditional piezoceramics preparation technology and industrial raw materials, and the practicability is realized.

The invention relates to a morphotropic phase boundary potassium-bismuth titanate-based leadless relaxor ferroelectric ceramic preparation method. The method comprises the following steps: selecting raw materials and performing two-time ball milling, discharging materials, drying the materials, and calcining the materials to obtain ceramic powder, dumping the material in a muffle furnace and performing sintering, and using sand paper with different granularity for grinding sintered ceramic chip to obtain the thin ceramic chip with a flat and bright surface. Compared with the prior art, the ceramic phase structure constitutes rhombohedral phase and tetragonal phase, under effect of an electrical field, a ferroelectric domain is easily overturned, large electrocaloric effect can be obtained,the ceramic can be obtained through a common sintering method, cost is low, and pollution is not generated, the prepared material has electrocaloric effect in a wide temperature area, and has a largeapplication prospect on a solid refrigeration aspect.

The invention discloses a preparation method of rare earth element-doped PMN-PT relaxor ferroelectric powder, and relates to the field of chemical preparation of physical materials. The preparation method can overcome the defect nonuniform components through a solid-phase reaction method, and has advantages of economic and practical raw materials, uniform components and simple process. According to a sol-gel process adopted in the method, glacial acetic acid is used as a solvent and citric acid is used as a chelating agent, oxides of required raw materials are dissolved by using an organic acid to obtain a RE-Pb-Mg-Nb-Ti uniform transparent composite precursor solution, and then the composite precursor solution is put into a drying oven for gelatinization to obtain a dry gel, and finally,the dry gel is calcined at a high temperature to prepare the rare earth element-doped PMN-PT superfine relaxor ferroelectric powder. The preparation method has the advantages that the required raw materials are economical and practical and the operation is simple and feasible, and has a wide application prospect.

Domain engineered Pb(In_1/2Nb_1/2)O₃—Pb(Mg_1/3Nb_2/3)O₃—PbTiO₃ (PIN-PMN-PT) single crystals show an induced rhombohedral (FR)—orthorhombic (FO) phase transition under uniaxial stress or/and applied electric field. A blast sensor includes a fixture holding a single crystal of PIN-PMN-PT; a diaphragm exposed to an exterior environment; a strain transfer rod configured to transfer pressure from the diaphragm to the crystal; and an analog/digital converter (ADC) configured to receive electrical output from the crystal when the crystal is subjected to pressure.

The invention discloses a high energy-storage density (Na0.5Bi0.5)(1-x)BaxTi(1-x)SnxO3 relaxor ferroelectrics ceramic material and a preparing method thereof. Na0.5Bi0.5TiO3 powder is mixed with BaSnO3 powder to be subjected to ball milling, dried and briquetted, and a full component is formed and sieved to form a sieving material; isostatic cool pressing is utilized to obtain an isotropic compactgreen body. The prepared green body is subjected to microwave sintering to obtain a sintering sample. The invention further discloses a lead-free high energy-storage-density ceramic material preparedthrough the ceramic material and a preparing method of the lead-free high energy-storage-density ceramic material. The provided (Na0.5Bi0.5)(1-x)BaxTi(1-x)SnxO3 lead-free high energy-storage-densityceramic material has high energy-storage density, and is simple in preparing technology, low in material cost, and environmentally friendly.

Provided is a high energy density ceramic material and a preparation method. BCTZ ceramic powder and NBT ceramic powder are blended according to a chemical formula (1-x)NBT-xBCTZ; after being mixed uniformly and undergoing granulation and forming, the BCTZ ceramic powder and the NBT ceramic powder undergo heat preservation for 2-4 hours at 1150-1200 DEG C to be sintered to obtain porcelain, so as to obtain the high energy density ceramic material, wherein the value range of x is 0.45-0.55. According to the high energy density ceramic material, the (1-x)NBT-xBCTZ prepared by utilizing a conventional solid state method is adopted, the energy density of a relaxor ferroelectric ceramic material reaches 0.66 J/cm3 and is much higher than the energy density of the ceramic material of Ba0.4Sr0.6TiO3. The method for preparing the high energy density ceramic material is simple in device, simple to operate, low in cost and capable of being produced on a large scale and provides the foundation for the preparation of the high energy density ceramic material on a large scale at low cost.

The invention relates to a lead-free compound ferroelectric ceramic composed of potassium-bismuth titanate and zinc oxide and preparation thereof, and belongs to the technical field of ferroelectric ceramics. The invention aims at inhibiting the depolarization phenomenon of K0.5Bi0.5TiO3 and promoting the ferroelectric property. K2CO3, TiO2, Bi2O3 and ZnO are taken as raw materials and are compounded to prepare the lead-free compound ferroelectric ceramic K0.5Bi0.5TiO3:ZnO by a two-step solid phase method. Through X-ray diffraction, scanning electron microscope and a dielectric test, the microcosmic structure and dielectric behavior of the compound ceramic are analyzed. The results show that three-phase Zn2TiO4 is generated in the compound ceramic after ZnO is added into K0.5Bi0.5TiO3, the introduction of ZnO can inhibit the phase transformation of K0.5Bi0.5TiO3 from normal ferroelectrics to relaxation ferroelectrics, and the introduction of ZnO has significance in applying and researching K0.5Bi0.5TiO3.

The present invention relates to a ferroelectric ceramic compound having the composition of the following formula: s[L]-x[P]y[M]z[N]p[T], a ferroelectric ceramic single crystal, and preparation processes thereof. The ferroelectric ceramic compound and the single crystal according to the present invention are relaxor ferroelectrics having high piezoelectricity, a high electromechanical coefficient and a high electrooptical coefficient, and are useful for manufacturing tunable filters for radio communication, optical communication devices, surface acoustic wave devices, and the like. Particularly, the process of preparing the single crystal according to the present invention enables preparation of a single crystal having a diameter of 5 cm or greater and a single crystal wafer with uniform composition. In the formula, [P] is lead oxide, [M] is magnesium oxide or zinc oxide, [N] is niobium oxide, [T] is titanium oxide, [L] is one selected from the group consisting of lithium tantalate or lithium niobate, lithium, lithium oxide, platinum, indium, palladium, rhodium, nickel, cobalt, iron, strontium, scandium, ruthenium, copper, yttrium, and ytterbium or mixtures thereof, and x, y, z, p and s are defined as 0.55<x<0.60, 0.09<y<0.20, 0.09<z<0.20, 0.01<p<0.27 and 0.01<s<0.1, respectively.

The invention relates to a sodium bismuth titanate-based relaxor ferroelectric ceramic material with wide temperature range, high electrocaloric effect and high electrocaloric strength and a preparation method of the sodium bismuth titanate-based relaxor ferroelectric ceramic material, wherein the ceramic material conforms to a chemical general formula (Bi0.5Na0.44-xK0.06+x)0.92Sr0.08Ti0.99Nb0.01O3. The preparation method comprises the following steps: according to the chemical general formula,mixing the raw materials, and sequentially carrying out primary ball milling, discharging, drying, presintering, secondary ball milling, granulation, compression molding, rubber discharging and sintering to obtain the ceramic material. Compared with the prior art, the novel sodium bismuth titanate-based relaxor ferroelectric ceramic material provided by the invention is used as a lead-free material, and the ceramic electrocaloric refrigeration material meets the requirements of environmental protection and has the advantages of low preparation cost and good stability; and the high electrocaloric effect and the wide-temperature-range high electrocaloric effect under the low electric field have huge application prospects in the aspect of solid refrigeration.