72 results about "Batio3 ceramics" patented technology

An enhanced piezoelectric wire structure includes an elongated portion of piezoelectric material, a metallic core, and an outer conductive sheath. The metallic core is substantially surrounded by the elongated portion of piezoelectric material and configured to function as a first electrode for the piezoelectric structure. The conductive outer sheath preferably covers selected areas of the elongated portion of piezoelectric material and functions as a second electrode for the structure. The piezoelectric material may correspond to barium titanate ceramic fibers, such that a lead-free structure is effected, however other piezoelectric materials may also be utilized. The disclosed structure can be poled with a reduced poling voltage and lower temperature level, and also requires a reduced voltage potential level required for mechanical actuation. A collection of such piezoelectric structures can be provided together in a modular patch assembly that may be formed in a variety of customized configurations for integration with various environments, and can function as a mechanical actuator device, a condition-responsive device (e.g., a sensor) and/or as a power generation device. When utilized as a power generation device, the subject piezoelectric assembly can power tire electronics components such as a revolution counter, a sensor, a rechargeable battery, a flashing light assembly, a microcontroller, a global positioning system (GPS), and a radio frequency (RF) device.

An electrical-energy-storage unit (EESU) has as a basis material a high-permittivity composition-modified barium titanate ceramic powder. This powder is double coated with the first coating being aluminum oxide and the second coating calcium magnesium aluminosilicate glass. The components of the EESU are manufactured with the use of classical ceramic fabrication techniques which include screen printing alternating multilayers of nickel electrodes and high-permittivitiy composition-modified barium titanate powder, sintering to a closed-pore porous body, followed by hot-isostatic pressing to a void-free body. The components are configured into a multilayer array with the use of a solder-bump technique as the enabling technology so as to provide a parallel configuration of components that has the capability to store electrical energy in the range of 52 kW·h. The total weight of an EESU with this range of electrical energy storage is about 336 pounds.

The invention provides a barium titanate/polyvinylidene fluoride composite dielectric film and a preparation method thereof. The film comprises barium titanate and polyvinylidene fluoride with the weight ratio of 1.5-5.0:1, and the thickness of the film is less than 50 mu m. In the frequency range of 100 Hz-1 MHz, the relative dielectric constant of the film can reach more than 70, and the dielectric loss is lower than 5*10<-2>. By compounding BaTiO3 ceramic and PVDF polymer, the dielectric film material with high dielectric constant and low dielectric loss is prepared. According to the invention, the barium titanate/polyvinylidene fluoride composite dielectric film with uniform distribution of ceramic particles, controllable thickness, high dielectric constant and low dielectric loss is prepared by preparing barium titanate ceramic powder through solid phase reaction or chemical coprecipitation and then using high temperature drying gel method or solvent induced phase separation gel method. The dielectric film is especially suitable for capacitor, ferroelectric memory, and other electronic devices.

Textured ceramic compositions having improved piezoelectric characteristics as compared with their random counterparts are provided. Methods of making the compositions and devices using them are also included. More particularly, compositions comprising textured ceramic Na_0.5Bi_0.5TiO₃—BaTiO₃(NBT-BT) materials synthesized from high aspect ratio NBT seeds exhibit improved characteristics, including an increased longitudinal piezoelectric constant (d₃₃) and magnetoelectric coupling coefficient over randomly oriented NBT-BT. Additionally provided are compositions comprising of nanostructured Na_0.5B_0.5TiO₃—BaTiO₃ ferroelectric whiskers having a high aspect ratio. Nanostructured whiskers can be used to improve the piezoelectric properties of the bulk ceramics. The inventive materials are useful in microelectronic devices, with some finding particular application as multilayer actuators and transducers.

A method of forming composition-modified barium titanate ceramic particulate includes mixing a plurality of precursor materials and a precipitant solution to form an aqueous suspension. The plurality of precursors include barium nitrate, titanium chelate, and a metal or oxometal chelate. The precipitant solution includes tetraalkylammonium hydroxide and tetraalkylammonium oxalate. The method further includes treating the aqueous suspension at a temperature of at least 150° C. and a pressure of at least 200 psi, and separating particulate from the aqueous suspension after treating.

The invention relates to a preparation method of giant-dielectric-constant barium titanate ceramic, belonging to the technical field of ceramic materials. The giant-dielectric-constant barium titanate ceramic is sintered by using a self-propagating high-temperature quick pressurizing technology, wherein a self-propagating high-temperature system adopts a thermit system. The method comprises the following steps of: performing compression molding on barium titanate powder under the pressure of 200 MPa; placing into a self-propagating system; and after a self-propagating reaction is finished, applying axial pressure of 100 to 200 MPa, so that the barium titanate ceramic is compact. The barium titanate ceramic prepared by the method has the advantages of high dielectric constant, low dielectric loss and high heat stability. The self-propagating high-temperature quick pressurizing technology is low in energy consumption; the process is simple; the required materials are low in price; the sintering time is extremely short; and great value is achieved on industrial application.

The invention relates to a (Na1/2Bi1/2) TiO3/BaTiO3 ceramic dielectric material and a preparation of a capacitor thereof. The ceramic dielectric material contains the following components of BaCO3, SrCO3, Bi2O3, SnO2, TiO2, (Na1/2Bi1/2) TiO3, Y2O3, ZnO and MnO2, and the sum of the mole percents of the components is 100%. The method for preparing the capacitor by using the material comprises the following steps of synthesizing the (Na1/2Bi1/2) TiO3; preparing a pre-synthesizing material by using the BaCO3, the SrCO3, the Bi2O3, the SnO2 and the TiO2, (Na1/2Bi1/2) TiO3; preparing a dry grinding material by using the Y2O3, the ZnO, MnO2and the pre-synthesizing material; adding a polyvinyl alcohol solution in the dry grinding material, and then pelleting, screening, pressing and sintering and preparing a silver electrode to obtain the capacitor. The ceramic dielectric material has the characteristics of high dielectric constant, low dielectric loss and low temperature change rate of the dielectric constant. The prepared capacitor has good performance parameters.

The invention provides a low-temperature cold sintering preparation method of barium titanate ferroelectric ceramic. The preparation method comprises the following steps: 1, dissolving Ba(OH)2 and TiO2 into deionized water; 2, adding BaTiO3 nano-level powder and BaTiO3 submicron-level powder into 25 percent of Ba(OH)2/TiO2 suspension by weight prepared in the step 1 according to the mass ratio of 1 to 1, and carrying out grinding in a grinding bowl for 0.5 to 1 hour; 3, pouring BaTiO3 mixed slurry into a mold, carrying out cold pressing on an electric heating press in an environment with room temperature till the pressure is 450 to 500 MPa, preserving the pressure for 10 to 20 min, then under a condition of not changing the pressure, heating to 180 to 200 DEG C at the heating rate of 5 to 10 DEG C per minute, and preserving the temperature for 3 hours; 4, drying a BaTiO3 ceramic prefabricated blank at 200 DEG C for 12 to 18 hours; and 5, sintering the dried BaTiO3 ceramic prefabricated blank at 850 to 950 DEG C. The process is simple, environment-friendly and extremely low in energy consumption; the preparation method can be an ideal preparation method of the BaTiO3 ferroelectric ceramic for an underwater acoustic transducer, and has a wide industrial application prospect.

The invention provides a graphite paper and barium titanate ceramic film capacitor. The graphite paper and barium titanate ceramic film capacitor comprises one or more layers of inner electrodes, ceramic dielectric layers among the inner electrodes, insulating layers between the dielectric layers and the inner electrodes, and end electrodes at the two ends. The graphite paper and barium titanate ceramic film capacitor is characterized in that the inner electrodes are made of graphite paper materials, the dielectric layers are barium titanate ceramic film, the end electrodes are formed by coating conductive aquadag in a dried mode, the insulating layers are aluminum oxide ceramic film, and the outermost layer of the graphite paper and barium titanate ceramic film capacitor is wrapped and packaged by barium titanate ceramic. A preparation method for the graphite paper and barium titanate ceramic film capacitor comprises the steps of (1) using graphite paper as the inner electrodes, (2) carrying out film pulling forming in aluminum oxide ethanol dispersion liquid, (3) carrying out film pulling forming and lamination in barium titanate ethanol dispersion liquid after drying, (4) using barium titanate powder to carry out packaging, and (5) carrying out integral pressure forming and vacuum hot pressing sintering to form the graphite paper and barium titanate ceramic film capacitor. The graphite paper and barium titanate ceramic film capacitor prepared through the preparation method has the advantages of being excellent in performance, high in dielectric constant, low in cost, simple in production technology and controllable in structure, and facilitating commercial production.

The invention belongs to the technical field of capacitor dielectric materials, and particularly relates to nanocrystalline barium titanate ceramic and a preparation method thereof. The preparation method of the nanocrystalline barium titanate ceramic comprises the following steps of: mixing barium carbonate and titanium dioxide, and carrying out ball milling, sanding, drying, sieving and calcining to obtain the barium titanate ceramic. The preparation method of the nanocrystalline barium titanate ceramic comprises the following steps of: mixing and ball-milling barium carbonate and titanium dioxide to increase the sintering activity of barium carbonate and titanium dioxide; carrying out solid-phase synthesis by using a sanding method to obtain barium titanate nano-powder with relatively small particle size and high tetragonality; the barium titanate nano-powder is subjected to calcination treatment, and the obtained nanocrystalline barium titanate ceramic has a small grain size and ahigh dielectric constant and can meet the requirement that a capacitor contains 5-6 ceramic grains in each single dielectric medium when being used as a ceramic capacitor material.

The invention discloses a samarium-doped bismuth ferrite-barium titanate ceramic film as well as a preparation method and application thereof, and belongs to the technical field of dielectric materials. The chemical general formula of the film is x (Bi1-yScy) FeO3-(1-x) (Ba1-yScy) TiO3, wherein x and y are mole fractions, x is more than 0 and less than 1, and y is more than 0 and less than 1. The preparation method comprises the following steps of: mixing Bi2O3, Fe2O3, BaCO3, TiO2 and Sm2O3 according to a selected stoichiometric ratio to obtain raw material powder; pre-sintering the raw material powder to obtain a ceramic blank; carrying out buried sintering to obtain a ceramic target material; and bombarding the target material by using pulse laser, and carrying out annealing treatment to obtain the ceramic film. Experiments prove that the breakdown field strength of the film can reach 4-5.3 MV/cm, the energy storage density can reach 152 J/cm < 3 >, and the energy storage efficiency is about 78%; and the film is a novel dielectric material which has high breakdown field strength and high energy storage density and is environment-friendly.

The present invention is laser preparation process of hexagonal barium titanate ceramic and belongs to the field of ceramic preparing technology. The preparation process includes the following steps: preparing barium titanate ceramic biscuit via traditional solid reaction process; irradiating the ceramic biscuit directly with great power laser in scanning mode through raising the laser power density from 0 to 466-777 W/sq cm in 10-60 sec, sintering for 20-60 sec and lowering laser power density continuously in 10-60 sec; and cooling to form the hexagonal barium titanate ceramic. The preparation process has short time and easy control, and can realize no-contamination sintering.

The invention discloses a surface treatment method of a BaTiO3 ceramic substrate used for a single-layer capacitor. The surface treatment method comprises the steps of: (1) selecting a grinding disc; (2) selecting a grinding liquid; (3) selecting a planetary frame; (4) polishing the substrate after grinding, wherein a grinding rate is controlled to range from 8 to 10mu m/min, a polishing rate is controlled to range from 3 to 4mu m/min, is controlled to range from 3 to 5 kg, and the grinding time is controlled to be within 30min; (5) mixing one or more of deionized water, alcohol, acetone and a cleaning agent evenly, and carrying out ultrasonic cleaning for 30 min at the temperature ranging from 40 to 50 DEG C within a power range from 250 to 300W; (6) and carrying out thermal treatment on the substrate after surface treatment under the conditions of temperature ranging from 500 to 600 DEG C and heat preservation time of 2 hr. By adopting the surface treatment method, the recycling type cutting machine can protect the factory environment, and prevents cutting fluid from contaminating the field.

The invention relates to the technical field of piezoelectric ceramics, in particular to barium hafnium titanate leadless piezoelectric ceramic with a high piezoelectric coefficient and a preparation method of the leadless piezoelectric ceramic. The preparation method of the barium hafnium titanate leadless piezoelectric ceramic with the high piezoelectric coefficient comprises the steps of uniformly mixing BaCO3, TiO2 and HfO2 at a ratio of 1:(1-x):x into a mixed material. Compared with barium titanate ceramic, under the condition that the sintering temperature of the barium hafnium titanate leadless piezoelectric ceramic is slightly lower than that of the barium titanate ceramic, the piezoelectric coefficient of the barium hafnium titanate leadless piezoelectric ceramic is 2-3 times that of the barium titanate ceramic; compared with zircon barium titanate ceramic, under the condition that the sintering temperature of the barium hafnium titanate leadless piezoelectric ceramic is much lower than that of the zircon barium titanate ceramic, the piezoelectric coefficient of the barium hafnium titanate leadless piezoelectric ceramic is much higher than that of the zircon barium titanate ceramic; the sintering temperature of a material is reduced on the basis of increasing the piezoelectric coefficient of the material; the production cost is saved; and in addition, the preparation technology is simple and is applicable to industrial production and popularization.

The invention relates to barium titanate-based high-energy-storage-density electronic ceramic and a preparation method thereof. The preparation method comprises the following steps: doping Sr<2+>, Bi<3+>, Mg<2+> and Nb<5+> ions into barium titanate ceramic to form a chemical composition of (1-x)Ba(1-y)SryTiO3-xBi(Mg2/3Nb1/3)03, and enabling the chemical composition to be in a crossed region; and 2, calculating the chemical proportion of the formula components obtained in the step 1, weighing high-purity BaCO3, SrCO3, Bi2O3, MgO, TiO2 and Nb2O5 powder, and carrying out ball-milling drying, presintering, tabletting and sintering to obtain the barium titanate-based high-energy-storage-density electronic ceramic. According to the method, electric domain engineering, Rankine free energy calculation and the like are introduced in the component design process; compared with an existing product, the energy storage performance of the ceramic prepared through a solid-phase method is greatly improved, the technological process is simple, prepared samples are uniform in grain size and high in chemical uniformity and electrical uniformity, and high energy storage density and efficiency are shown.

The invention discloses application of a pyroelectric material. The pyroelectric material is used for collecting heat energy, the heat energy is converted into electric energy by utilizing temperaturechange, and the pyroelectric material is a porous zirconium calcium barium titanate ceramic material; the temperature change is greater than or equal to 1 DEG C; and the porosity of the porous bariumcalcium zirconate titanate ceramic material is 10-60%. The porous zirconium-calcium-barium titanate ceramic material is applied to heat energy collection for the first time, the inventor finds that the porous barium calcium zirconate titanate can be used as the pyroelectric material, and the working principle is as follows: when the environment temperature changes, the pyroelectric material has apyroelectric effect and generates voltage on the upper and lower surfaces of the material, and the heat energy is converted into the electric energy. The porous barium calcium zirconate titanate serves as the pyroelectric material to be used for heat energy collection, the condition for converting the heat energy into the electric energy is that the temperature fluctuation is larger than or equalto 1 DEG C, that is, heat energy collection can be achieved only through temperature fluctuation of 1 DEG C, and the heat energy collection efficiency is greatly improved compared with a thermoelectric material in the prior art.

The invention relates to a high-dielectric-constant ultrahigh-field animal magnetic resonance radio frequency probe which comprises a coil unit, the coil unit comprises a cylindrical coil circuit substrate and a cylindrical inner wall substrate, and the inner wall substrate is arranged in the coil circuit substrate. The two ends of a high-dielectric-constant ceramic unit are fixed between the coilcircuit substrate and the coil inner wall substrate through a ceramic unit support. All the units are independent of one another, assembling is flexible, and the sensitivity of the radio frequency probe can be effectively improved. The plurality of high-dielectric-constant ceramic blocks can greatly improve the B1 field emission efficiency in the central region, and avoids the adverse effects ofcoil mode increase and disorder caused by complete cylindrical barium titanate ceramic.

The invention discloses a preparation method of a BaTiO3 ceramic sheet, and belongs to electronic component preparation technologies. Components prepared by means of an existing BaTiO3-grouped ceramicsheet preparation method is higher in power attenuation and poorer in temperature coefficient and pressure resistance stability. Barium titanate ceramic is taken as a main body, complementary dopingof Nb5+ in lead titanate and barium titanate groups is achieved through multi-donor doping of Y3+ and Nb5+, and the total amount of doping is certain; the multi-donor doping of Y3+ and Nb5+ in the barium titanate group is achieved, and graphene is added to improve the heating uniformity and the heating rate of the ceramic sheet. The BaTiO3 ceramic sheet prepared by means of the method has the advantages that the heating efficiency is high, and higher voltage and temperature coefficient and lower power attenuation can be withstood under a static state. The convenience of BaTiO3 ceramic sheet production can be improved, and a prepared PTC ceramic sheet is more suitable for using in residential heating equipment.

The invention provides a ceramic dielectric material as well as a preparation method and application thereof. A main body material of the material is BaTiO3, and doping materials comprise SiO2, CaO, V2O5, ZrO2 and oxides of rare earth elements; the oxides of the rare earth elements comprise at least two of Sc2O3, Sm2O3, Dy2O3 and Ho2O3; the addition amount of the BaTiO3 is 93.5 to 95 mol% in terms of molar percentage; the total addition amount of the doping material is 4.6-7 mol%. BaTiO3 is used as a main body material, a sintering aid, a metal oxide and a rare earth element are used as a composite doping agent, a barium titanate ceramic matrix is modified, the sintering aid and the doping material are added to refine particles, defects are controlled, and the grain size uniformity is improved, so that the high-reliability and high-performance barium titanate ceramic is prepared. The invention relates to a fine-grain ceramic and multilayer ceramic capacitor which has stable capacitance characteristics and is easier to stack.

The invention discloses a barium titanate single crystal epitaxial film threshold switching device and a preparation method thereof. The invention belongs to the technical field of physical chemistrysynthesis and electronic information. The preparation method comprises the following steps: (1) taking NSTO as a substrate, putting the cleaned NSTO substrate into a pulse laser deposition system, taking barium titanate ceramic as a target material, carrying out barium titanate film growth, carrying out in-situ annealing after the growth is finished, cooling to room temperature under the protection of an oxygen atmosphere, and taking out a sample; (2) covering the surface of the barium titanate film with a mask, and evaporating a chromium film; (3) thermally evaporating a metal Au film on thechromium film; and (4) pressing a metal indium wire or indium particles on the back surface of the substrate to serve as a lower electrode to obtain the single crystal epitaxial barium titanate thin film threshold switching device, wherein the structure of the device is Au/Cr/BTO/NSTO/In.