822 results about "Barium titanate" patented technology

The invention discloses a high-temperature-resistant, high-voltage-resistant and anti-breakdown capacitor base film and a preparation method thereof. The high-temperature-resistant, high-voltage-resistant and anti-breakdown capacitor base film is prepared from the following raw materials in parts by weight: 100 parts of polypropylene; 17 to 36 parts of polyvinylidene fluoride; 3-12 parts of enhanced and improved talcum powder; 1-6.5 parts of modified barium titanate; 1-6 parts of a cross-linking agent; 2-10 parts of a compatilizer; and 0.05-2 parts of an initiator. The capacitor base film is high in mechanical strength, and has excellent high temperature resistance, thermo-oxidative aging resistance, high voltage resistance and anti-breakdown performance; the enhanced and improved talcum powder is constructed by taking expanded layer modified talc as a carrier and titanium dioxide-carbon dot composite particles as a loading component and grafting and coating the organic matter, so that the defects of the talcum powder can be overcome, and the improvement effect of the talcum powder on heat resistance, high-voltage resistance and breakdown resistance can be fully exerted; meanwhile, the system can be endowed with excellent thermo-oxidative aging resistance.

The invention discloses a method for preparing nano barium titanate based on sol-gel synergistic hydrothermal reaction, which comprises the following steps: (1) dissolving barium acetate in an acetic acid aqueous solution to obtain a barium source solution; weighing tetrabutyl titanate according to the molar ratio of barium to titanium being greater than 1.25, and dissolving the tetrabutyl titanate in alcohol to obtain a titanium source solution; (2) uniformly mixing the barium source solution and the titanium source solution, preserving heat at 20-80 DEG C to obtain gel, drying and grinding to obtain white powder of the barium titanate precursor: (3) preparing a 2-4mol / L inorganic strong alkali aqueous solution, adding the white powder and a dispersing agent into the inorganic strong alkali aqueous solution, and fully stirring to obtain a barium titanate precursor suspension; and (4) transferring the barium titanate precursor suspension into a reaction kettle for hydrothermal reaction, and after the reaction is completed, washing, drying and grinding to obtain the nano barium titanate powder. The preparation method is low in cost, and the prepared nano barium titanate powder is uniform in distribution, spherical or sphere-like in morphology, small in particle size, 80-150nm in average particle size and good in particle crystallinity.

The invention discloses a high-refractive-index nano-composite optical adhesive and a preparation method thereof, and belongs to the technical field of optical transparent adhesives. The optical adhesive is prepared by taking a polyurethane acrylate oligomer with a specific structure as matrix resin, introducing surface-modified barium titanate and zirconium oxide core-shell nanoparticles as a functional filler, and matching with an active diluent, a photoinitiator and a silane coupling agent in a specific proportion. Through the design of the core-shell structure, the core problems that the high-refractive-index nanoparticles are easy to agglomerate in an organic resin matrix, the dispersion stability is poor and the bonding force with a matrix interface is weak are effectively solved. The prepared optical adhesive has a refractive index of more than 1.65, a light transmittance of more than 99% and a haze of less than 0.3% after being cured, has excellent bonding strength, weather resistance and long-term use stability, and is especially suitable for precise lamination of high-end display devices (such as OLEDs (Organic Light Emitting Diodes) and micro-lens arrays).

The invention relates to a self-generating interbody fusion cage and a preparation method thereof, the interbody fusion cage comprises a porous tantalum support and bioactive piezoelectric ceramic arranged on the porous tantalum support, and the bioactive piezoelectric ceramic comprises hydroxyapatite and barium titanate; the preparation method comprises the following steps that the porous tantalum support is obtained through 3D printing, assembling positions of the bioactive piezoelectric ceramics are reserved on the upper surface and the lower surface of the porous tantalum support, the bioactive piezoelectric ceramics are embedded into the assembling positions of the upper surface and the lower surface of the porous tantalum support, and the weight ratio of barium titanate to hydroxyapatite is (92-98): (2-8). Compared with the prior art, the vertebral fusion cage has the advantages of promoting vertebral fusion by utilizing mechanical force in a human body to generate electricity, matching mechanical properties of a contact surface of the fusion cage, providing osteogenesis related ions, being relatively good in interface combination and the like.

The invention relates to the technical field of dielectric materials, and discloses a composite dielectric material and a preparation method and application thereof.The composite dielectric material comprises filler and a base material, the filler is modified barium titanate, and the base material is cyanoethyl cellulose; the modified barium titanate comprises a barium titanate core and a shell, the shell comprises a polymer containing an epoxy group, the core and the shell are connected through a covalent bond, and an infrared spectrum test shows that in an infrared spectrogram of the modified barium titanate, characteristic peaks of the epoxy group and carbonyl respectively exist at 910 + / -10 cm <-1 > and 1720 + / -10 cm <-1 >. Epoxy groups in the modified barium titanate filler can react with hydroxyl groups in a cyanoethyl cellulose matrix material to form covalent linkage, compatibility of the filler and a matrix is improved, meanwhile, a potential well is formed, migration of carriers can be limited, and the composite material has good dielectric performance and energy storage performance.

The invention provides a Joule heat ultrafast sintering preparation method of barium titanate ceramic with ultrahigh dielectric constant and low loss, which comprises the following steps: ball-milling and mixing barium titanate powder and copper oxide powder, drying, pressing into a cake-shaped sample, carrying out cold isostatic pressing to obtain a sample piece, and carrying out vacuum treatment on Joule heat ultrafast sintering equipment to obtain the barium titanate ceramic with ultrahigh dielectric constant and low loss. Putting the sample preparation sheet between two layers of graphite felts, and starting Joule heat ultrafast sintering equipment to enable the graphite felts to generate Joule heat, so as to realize short-time sintering of the barium titanate ceramic. According to the invention, a Joule heat ultrafast sintering technology is adopted, and Joule heat is generated by directly applying voltage and current to the graphite felt, so that the sintering time is greatly shortened, and environmental pollution is avoided; meanwhile, the dielectric constant of the barium titanate ceramic is greatly improved by adding copper oxide, and the energy consumption is remarkably reduced.

The invention relates to the technical field of polymer composite materials, and discloses a nano-ceramic-based composite insulating coating and a preparation method thereof, and the coating is prepared from a composite resin matrix, a composite functional ceramic filler, a double-reactivity organosilicon linker and an initiator. Wherein the composite resin matrix is composed of vinyl-terminated polydimethylsiloxane and a vinyl ether functionalized fluorocarbon copolymer, and a soft and rigid interpenetrating network structure is formed. The composite functional ceramic filler is prepared from needle-shaped silicon nitride, flaky hexagonal boron nitride, nano silicon dioxide, nano cerium oxide and nano barium titanate. According to the invention, a chemical bonding interface is constructed between the inorganic filler and the organic resin, and the synergistic effect of the composite matrix and the multifunctional filler is optimized, so that the coating has excellent adhesive force, flexibility and thermal shock resistance, obtains high volume resistivity and breakdown strength, and meets the insulation protection requirements under harsh working conditions.

The invention provides a high-dielectric low-loss X7P type dielectric ceramic material and a preparation method and application thereof, and relates to the technical field of functional ceramic materials, the dielectric ceramic material is composed of a perovskite type compound as a main component and an auxiliary component; wherein the perovskite type compound contains a Ba element and a Ti element, and the auxiliary components comprise a first auxiliary component containing an Mg element, a second auxiliary component containing SiO2, a third auxiliary component containing an Mn element and a fourth auxiliary component containing a rare earth element R. According to the invention, barium titanate is doped and modified, so that the excellent performance of combining different compounds is realized, the dielectric constant and temperature stability of the dielectric ceramic material are improved, and the dielectric loss is reduced.

The invention provides a high-voltage low-loss dielectric material and a preparation method thereof, and relates to the technical field of high-voltage ceramic capacitors, and the high-voltage low-loss dielectric material comprises the following raw materials in parts by mass: 35-38 parts of barium titanate, 20-29.5 parts of strontium titanate, 15-17.5 parts of titanium dioxide, 9-12 parts of bismuth oxide, 3-4 parts of zirconium oxide, 0.8-1.0 part of X, 1.2-1.4 parts of antimony oxide, 1-1.2 parts of calcium carbonate and the like. The preparation method of the dielectric material comprises the following steps: 1, preparing the dielectric material; melting calcium carbonate, magnesium oxide, zinc oxide and the like, performing water quenching, and performing ball-milling granulation to obtain zinc borosilicate glass powder; uniformly mixing the zinc borosilicate glass powder with barium titanate, strontium titanate, titanium dioxide and the like, and granulating to obtain oxide powder; and tabletting and sintering the oxide powder to obtain the high-pressure low-loss dielectric material. The high-voltage low-loss dielectric material is high in dielectric constant, small in dielectric loss, high in compression strength and good in high-temperature stability, and the preparation method is simple.

The invention belongs to the technical field of ceramic materials, and particularly relates to a ceramic dielectric material and a preparation method and application thereof. The ceramic dielectric material provided by the invention is prepared from the following raw materials: barium titanate, calcium zirconate, a sintering aid and a modifier, the sintering aid is a Li-Zn-B-Si glass material; and the modifier comprises one or more of Nb2O5, MnCO3, MgO and RE2O3 (rare earth oxide). The ceramic dielectric material has the advantages of high-temperature stability, high dielectric constant, low loss and high insulating property.

The invention belongs to the crossing field of biomedical engineering and additive manufacturing, and particularly relates to a 3D printing metamaterial piezoelectric bone defect repair scaffold, and the pore structure of the scaffold is formed by compounding three extremely small curved surface units, namely Gyandroid, SchwarzP and Diamond, which are defined by mathematical expressions; the porosity of the stent is 30%-70%, and the pore diameter range is 0.1-1 mm; the stent is made of a piezoelectric composite material composed of polyvinylidene fluoride (PVDF), polylactic acid and barium titanate, the piezoelectric composite material comprises the following components in percentage by mass: 30%-55% of polyvinylidene fluoride (PVDF), 20%-45% of polylactic acid (PLA) and 10%-25% of barium titanate (BaTiO3), and the sum of the mass percentages of all the components is 100%. Precise regulation and control of a macrostructure and a microstructure are achieved through a multi-material 3D printing technology, and the system has the mechanical adaptability, degradation controllability and the function of actively promoting bone regeneration and is suitable for large-section bone defect repair scenes such as craniomaxillofacial and long bones of four limbs.

The invention relates to the technical field of composite materials, in particular to a high-conductivity thermosetting resin-based composite material and a preparation method thereof.The high-conductivity thermosetting resin-based composite material is prepared from, by weight, 50-80 parts of epoxy resin, 10-30 parts of conductive carbon nanotubes, 20-40 parts of nano-silver particles, 10-20 parts of functionalized polyurethane prepolymer, 5-15 parts of polyamine curing agent and 2-8 parts of organosilane coupling agent. 5-15 parts of graphene nanosheets, 5-15 parts of aluminum borate whiskers and 5-15 parts of barium titanate nanoparticles; 2-10 parts of conductive polymer microspheres; 1 to 5 parts of nano zinc oxide; wherein the conductive polymer microsphere comprises a core formed by polyaniline or polypyrrole, and a polyurethane polymer or a polyacrylate polymer wrapping the outer layer of the core; the surface of the core is modified by adopting nano silver particles and gamma-aminopropyltriethoxysilane; the conductive polymer microspheres are used for providing a long-range conductive path, the nano-silver particles are used for providing short-range conductive connection, and the conductive polymer microspheres and the nano-silver particles form a multi-layer conductive network.

The invention discloses a self-cleaning composite piezoelectric ceramic membrane as well as a preparation method and application thereof, and belongs to the field of composite ceramic membranes. The technical problem that an existing ceramic membrane separation technology is poor in biomembrane pollution resisting effect is solved. According to the preparation method, the barium titanate ceramic membrane is firstly prepared to serve as the base membrane, then the copper oxide one-dimensional nanostructure is loaded on the piezoelectric ceramic substrate, and the base membrane has a large membrane surface area and can be combined with more catalysts, so that more active sites are provided for catalytic reaction; according to the composite membrane, the hydrophilicity, the anti-pollution performance and the piezoelectric catalysis self-cleaning performance of the membrane are remarkably improved, and pollutants in water can be quickly and effectively separated, so that the flux and the anti-pollution performance of the membrane are improved.

The invention discloses an A and B site doped BaTiO3-based dielectric ceramic, which is characterized in that the chemical formula of the A and B site doped BaTiO3-based dielectric ceramic is (Bax1Cax2Sr1-x1-x2) (Ti0. 4La0. 2Ce0. 2Ta. 2) O3, 0 < = x1 < = 1, 0 < = x2 < = 1, and x1 + x2 < = 1. The invention also discloses a preparation method of the composition. Other elements are simultaneously introduced into A and B of the barium titanate ceramic dielectric material, so that the high-temperature stability of the barium titanate ceramic dielectric material is improved, the energy storage performance of the barium titanate ceramic dielectric material is also improved, and the defects that an existing barium titanate ceramic dielectric material is poor in dielectric property temperature stability and low in energy storage efficiency are overcome.

The invention relates to the technical field of flexible electronics and sensing, in particular to a capacitive flexible pressure sensor based on a barium titanate composite dielectric layer, which sequentially comprises a lower electrode layer, an upper electrode layer, a lower electrode layer and an upper electrode layer from bottom to top, the composite dielectric layer is arranged on the lower electrode layer and is formed by compounding an elastic polymer matrix and a high-dielectric-constant barium titanate (BaTiO3) filler; the upper electrode layer is made of a flexible conductive material and is arranged on the composite dielectric layer; the lower electrode layer and the upper electrode layer are connected with an external capacitance measuring circuit through wires. According to the sensor disclosed by the invention, the comprehensive performance of high sensitivity, wide detection range, low hysteresis and excellent cycle stability is realized by optimizing the shape of the barium titanate filler, surface modification and composite structure design.

The invention relates to a thin film electro-optical crystal-silicon nitride heterogeneous integrated N * N high-speed optical switch array and a preparation method thereof. The thin film electro-optical crystal-silicon nitride heterogeneous integrated N * N high-speed optical switch array is formed by connecting 1 * 2 or 2 * 2 Mach-Zehnder high-speed optical switch units according to a certain topological structure. Wherein the high-speed optical switch unit is composed of a silicon nitride passive waveguide and a thin-film electro-optical crystal / silicon nitride heterogeneous integrated phase shift region. Comprising but not limited to thin-film lithium niobate, thin-film lithium tantalate, barium titanate and lead zirconate titanate is integrated above the silicon nitride phase shifting arm through a micro transfer printing method to form a heterogeneous integrated phase shifting region. The large-scale high-speed optical switch array with excellent performance is realized by combining the characteristics of ultra-low loss, CMOS compatibility, thermal stability and the like of a silicon nitride material, the characteristics of low power consumption, low loss, high-speed modulation and the like of a thin film electro-optical crystal and the advantages of high flexibility, parallel integration, low cost, low loss and the like of a micro transfer printing method.

The invention belongs to the technical field of lithium ion solid-state batteries, and relates to a composite polymer electrolyte membrane as well as a preparation method and application thereof. The preparation method of the composite polymer electrolyte membrane comprises the following steps: generating a precursor salt containing Ba and Ti on the surface of an inorganic solid electrolyte through a wet chemical method, and forming a compact barium titanate coating layer on the surface of the electrolyte in a high-temperature calcination process to obtain the barium titanate surface modified inorganic solid electrolyte; uniformly dissolving a high-molecular polymer material, the barium titanate surface modified inorganic solid electrolyte and a lithium salt in a solvent, heating and stirring to prepare a uniform solution; and drying to form a membrane to obtain the polymer composite electrolyte membrane. Barium titanate has a special piezoelectric property and can be spontaneously polarized in a crystal structure to generate a polarization field, and the polarization field can sensitively sense the nonuniformity of lithium ion transmission dynamics and interact with the nonuniformity to balance the transmission process of lithium ions in the solid electrolyte, so that the bottleneck problem of ion migration in the traditional electrolyte is solved.

The invention discloses an acoustic response light-emitting composite nanomaterial as well as a preparation method and application thereof, and belongs to the technical field of light-emitting composite nanomaterials. The acoustic response luminescent composite nano material provided by the invention comprises hollow mesoporous silica nano particles and europium-doped barium titanate nano particles loaded on the surfaces of the hollow mesoporous silica nano particles and in mesopores; the chemical formula of the europium-doped barium titanate nanoparticles is BaTiO3: Eu < 3 + >; the mass ratio of the hollow mesoporous silica nanoparticles to the europium-doped barium titanate nanoparticles is 1: (0.8-1.5). The sound response luminescent composite nano material provided by the invention can realize detection of sound intensity, and has good temperature stability, and meanwhile, the preparation method is simple and low in cost.

The invention relates to the field of ceramic materials, provides a high-voltage-resistant PTC (Positive Temperature Coefficient) thermal sensitive ceramic material as well as a preparation method and application thereof, and aims to improve the voltage resistance and PTC effect stability of thermal sensitive ceramic. The material is composed of aluminum oxide-coated manganese-doped barium titanate nanorods, hollow-core silicon dioxide microspheres and a glass phase sintering aid, and the electric heating performance and the microstructure stability are optimized by constructing a core-shell structure and a three-dimensional composite system. A hydrothermal method and a sol-gel method are adopted to precisely control a raw material structure, and alcohol dispersion, tape casting and weak oxidizing atmosphere sintering are combined, so that the compactness and consistency of the ceramic are ensured. The material is suitable for high-voltage temperature control elements and over-current protection devices, and is widely applied to the fields of new energy automobile battery pack over-temperature protection, high-voltage power equipment current limiting elements, industrial automatic temperature control switches and the like.

A multilayer ceramic capacitor includes: a capacitor body comprising a dielectric layer and an internal electrode layer; and an external electrode disposed on an outside surface of the capacitor body, wherein the capacitor body includes an active portion where the dielectric layer and the internal electrode layer are alternately disposed, side margin portions disposed at both side end portions of the active portion facing each other, and bonding portions disposed between the active portion and the side margin portions, and at least one of the active portion or the side margin portions includes a barium titanate-based main ingredient including barium (Ba) and titanium (Ti), and gallium (Ga).

The invention relates to a method and a device for preparing piezoelectric catalytic degradation PFAS nano barium titanate from sludge graded extracts, and belongs to the technical field of sludge utilization environments. The method comprises the following steps: uniformly mixing fresh sludge and modified cation resin, and extracting a cation resin extracting solution to obtain the cation resin extracting solution and cation sludge; uniformly mixing the cation mud and the modified anion resin, and extracting an anion resin extracting solution to obtain the anion resin extracting solution and the cation mud; mixing the sludge and alkali for reaction to obtain an alkali extracting solution and extraction residues; mixing barium salt with the cation resin extracting solution to obtain a barium complexing solution, and mixing titanium salt with the anion resin extracting solution to obtain a titanium complexing solution; and mixing the barium complexing solution with the same volume of the alkali extracting solution, then adding the titanium complexing solution with the same molar ratio, heating, drying and calcining to obtain the piezoelectric catalytic degradation PFAS nano barium titanate. According to the method, multi-stage extraction can be carried out according to application property requirements, extraction is sufficient, the comprehensive utilization rate of sludge is high, dispersity is good, the particle size is small, piezoelectric catalysis performance is high, and synthesis cost is low.

The invention belongs to the technical field of preparation of barium titanate, and particularly relates to nanoscale tetragonal-phase barium titanate and a confinement preparation method thereof. The preparation method comprises the following steps: pumping a solution of barium titanium salt and a solution of a precipitator into a mixing reactor of a microchannel reactor for confinement mixing, and aging the obtained mixed slurry to obtain a barium titanate precursor; the flow velocity of the solution of the barium titanium salt and the flow velocity of the solution of the precipitant are independently 20-70 mL / min; and mixing the barium titanate precursor, a barium source and water for hydrothermal reaction to obtain the nanoscale tetragonal-phase barium titanate. The method can be used for efficiently and stably preparing the nanoscale tetragonal barium titanate which is small in size, high in crystallinity, high in particle size uniformity, narrow in particle size distribution and high in tetragonal phase purity.

The invention discloses a full-spectrum protective anti-fingerprint resin lens and a preparation method thereof. The full-spectrum protective anti-fingerprint resin lens comprises a functionalized resin base material and a gradient composite functional coating. The base material takes polyurethane acrylate as a matrix, and nano cerium oxide, nano barium titanate and nano tungsten oxide functional particles are uniformly dispersed through in-situ polymerization, so that base material intrinsic protection on ultraviolet rays, harmful blue light and near-infrared light is realized. The gradient coating comprises an adhesion promoting layer, a full-spectrum repairing and protecting layer and an anti-fingerprint layer from inside to outside, a stable composite system is formed through chemical bonding, protection is further reinforced, and the lens is endowed with super-hydrophobic and oleophobic anti-fingerprint characteristics. Through the integrated design of base material modification and coating compounding, the technical problems that an existing lens is single in protection wave band, not lasting in performance and prone to being stained with fingerprints are solved, and meanwhile the lens has high light transmittance, low reflection, excellent wear resistance and impact resistance and excellent comprehensive performance.

The invention belongs to the field of wave-absorbing materials, and particularly relates to a fiber-reinforced barium titanate-polymer conversion ceramic-based composite wave-absorbing material and a preparation method thereof. The composite wave-absorbing material provided by the invention comprises a ceramic matrix and a fiber reinforcement embedded in the ceramic matrix, the ceramic matrix comprises a barium titanate ceramic phase and a polymer conversion ceramic phase; the fiber reinforcement body is formed by stacking a plurality of layers of fiber cloth, and an interface layer is deposited on the surface of each layer of fiber cloth; fibers in the multi-layer fiber cloth comprise multiple of carbon fibers, silicon dioxide fibers, silicon carbide fibers, glass fibers, aluminum oxide fibers and zirconium oxide fibers, and the interface layer is one or more of a PyC interface, a BN interface and a SiC interface. The composite wave-absorbing material provided by the invention takes various fibers as reinforcements and barium titanate-polymer converted ceramic as a matrix, and has excellent mechanical properties and wave-absorbing properties.

The invention discloses a barium titanate coated Ni particle material synthesized under the assistance of a spray drying technology and a method thereof, and belongs to the technical field of metal powder material preparation. The method comprises the following steps: firstly, taking metatitanic acid and barium hydroxide as raw materials, and mixing the metatitanic acid and the barium hydroxide with nano and submicron Ni powder to prepare a mixed solution; secondly, synthesizing a Ni-based composite material intermediate by adopting a spray drying method; and finally, sintering in a tubular furnace to form the barium titanate coated Ni powder. The barium titanate coated Ni inner electrode material is Ni coated BaTiO3 spherical particles with a core-shell structure, the particles are of a core / shell microstructure, a shell layer is a barium titanate coating layer with the thickness of 10-15 nm, and the particle size of the particles is 100-150 nm. According to the method, required equipment can be scaled, components and microstructures are easy to regulate and control, and the method has high sphericity and dispersity, high compactness and good repeatability; the particle size and distribution can be changed by adjusting process parameters; meanwhile, good interface bonding with a ceramic dielectric layer is realized, and the key problems of mismatching of interlayer interface volume shrinkage, easy cracking and the like in the sintering process are relieved.

The invention relates to the technical field of high polymer materials, and discloses a preparation method of high-dielectric-constant epoxy resin. The method comprises the following steps: (1) carrying out copolymerization reaction on bisphenol A epoxy resin and polytetrafluoroethylene at 80-100 DEG C for 2-3 hours; (2) adding a dicyandiamide curing agent into the reaction product obtained in the step (1), and carrying out gradient heating for curing; and (3) adding surface-modified barium titanate nanoparticles into the product obtained in the step (2), performing ultrasonic treatment, performing casting molding, and performing annealing treatment. According to the method, through molecular level design, the dielectric constant is remarkably improved while the excellent mechanical property of the epoxy resin is maintained, the dielectric loss (tan delta) and the thermal stability are optimized, and a high-performance base material is provided for electronic devices.

The invention discloses an ultrasonic activation type piezoelectric gel dressing and a preparation method and application thereof.The surface of a system is an antibacterial hydrogel layer, the antibacterial hydrogel layer is composed of polyethyleneimine (PEI) and polyvinyl alcohol (PVA) cross-linked hydrogel, and ultrasound and current can be transmitted to a deep area; bT-dNO piezoelectric nanoparticles are packaged inside, and BT-dNO is prepared by coating a nitric oxide (NO) donor on the surface of piezoelectric barium titanate (BT) subjected to hydroxylation and dopamine modification. Under the stimulation of low intensity focused ultrasound (LIFU), the donor can release NO as required, and the BT nanoparticles can generate reactive oxygen species (ROS) and output piezoelectric current. The dressing system has an effective combined repair effect, excellent biocompatibility and good anti-inflammatory ability.

The invention relates to the technical field of dielectric ceramic powder preparation processes, in particular to a multilayer ceramic capacitor, high-activity nano barium titanate powder for the multilayer ceramic capacitor and a preparation method of the high-activity nano barium titanate powder, and the method comprises the following steps: (1) reacting soluble barium salt with a precipitator to obtain barium carbonate precursor particles with high specific surface area; (2) uniformly coating the surfaces of the barium carbonate precursor particles with nano titanium dioxide particles by using a supercritical fluid flash evaporation technology to form a composite precursor; and (3) carrying out solid-phase synthesis reaction on the composite precursor, and sintering to obtain the nano barium titanate powder. Through the synergistic effect of two means of high-activity precursor preparation and nanoscale uniform coating, the composite precursor with extremely high specific surface area, surface energy and microcosmic uniformity is prepared, the thermal sintering temperature is effectively reduced, abnormal growth of crystal grains and lattice distortion are restrained, and the preparation method has the advantages that the preparation process is simple, and the preparation cost is low. The tetragonality of the nano barium titanate powder is obviously improved.

The present application relates to the technical field of dielectric ceramic powder preparation, and particularly relates to a multilayer ceramic capacitor, a high-activity nano-barium titanate powder for the multilayer ceramic capacitor and a preparation method of the high-activity nano-barium titanate powder, the method comprising the following steps: (1) reacting a soluble barium salt with a precipitator to obtain barium carbonate precursor particles with high specific surface area; (2) uniformly coating nano-titanium dioxide particles on the surface of the barium carbonate precursor particles by using a supercritical fluid flash technology to form a composite precursor; and (3) performing a solid-phase synthesis reaction on the composite precursor and sintering to obtain nano-barium titanate powder. The present application, through the synergistic effect of the two means of "high-activity precursor preparation" and "nano-level uniform coating", prepares a composite precursor with extremely high specific surface area, surface energy and micro-uniformity, effectively reduces the heat sintering temperature, suppresses abnormal grain growth and lattice distortion, and significantly improves the tetragonality of the nano-barium titanate powder.

The invention discloses a sintering aid coated lead barium titanate-based thermal sensitive ceramic and a preparation method thereof, and relates to the technical field of material science, the raw materials of the core layer comprise barium carbonate, lead tetraoxide, calcium carbonate, strontium carbonate, zirconium oxide, tin oxide, titanium dioxide, manganese oxide and niobium pentoxide; the raw materials of the shell layer comprise silica sol, an aluminum compound, a calcium compound, a sodium compound, a potassium compound, a magnesium compound and boric acid; the preparation method comprises the following steps: mixing the raw materials of the core layer, calcining at 950-1050 DEG C, adding a deionized water solution of the raw materials of the shell layer, mixing, calcining at 1000-1100 DEG C, adding a polyvinyl alcohol water solution, granulating, forming, degumming and sintering to obtain the sintering aid coated lead barium titanate based thermal sensitive ceramic. According to the invention, the sintering aid is used for coating the lead barium titanate-based thermal sensitive ceramic, so that the densification of the ceramic is promoted while grains are refined, and the ceramic has high voltage resistance and excellent PTC (Positive Temperature Coefficient) effect.