340 results about "Bismuth titanate" patented technology

The present invention belongs to the field of environmental science and engineering technology, in the concrete, it relates to a preparation method of new-type mesopore bismuth titanate photacatalyst for degrading organic pollutant. Said method includes the following steps: using bismuth nitrate and titanate as main raw material, using block interpolymer surfactant as structure guide agent, adopting acetic acid as hydrolysis catalyst, utilizing solvent thermal synthesis method to prepare titanium-bismuth composite oxide gel, making said gel undergo the processes of filtering, drying, high-temperature calcining and crystallizing so as to obtain the mesopore bismuth titanate material with photocatalytic activity.

This invention relates to a mid-temperature calcined and high temperature stabilized ceramic medium material of capacitors composed of barium titanate main material, a first additive, a second additive and a third additive, in which, the first additive is a microcrystal glass, the second additive includes lead-free piezoelectric material bismuth titanate sodium or boron silicate and the third additive includes: a rare earth oxide, ZnO and Nb2O5, and said rare earth oxide includes Ce or Nd oxide. Advantage: batch production is realized to basic materials and dopants so as to simplify the production process.

The invention relates to a rare-earth doped bismuth titanate up-conversion luminescence nanometer crystal material which relates to a bismuth titanate luminescence nanometer crystal material. The invention solves the problem of low luminous intensity of the rare-earth doped bismuth titanate up-conversion luminescence nanometer crystal material. The rare-earth doped bismuth titanate up-conversion luminescence nanometer crystal material is obtained by doping Er, Er/Yb, Yb/Tm and Er/Yb/Tm to the bismuth titanate matrix by a sol-gel method. The up-conversion luminescence nanometer crystal material can realize up-conversion luminescence of different colours of red, green, yellow, blue and white under the excitation of infrared radiation with the wavelength of 980nm and has high luminous intensity. The rare-earth doped bismuth titanate up-conversion luminescence nanometer crystal material can be widely applied in the fields of infrared radiation detection, anti-counterfeit, bimolecular fluorescent mark, and the like.

The invention discloses an X9R ceramic capacitor dielectric material and a preparation method thereof. The material comprises 95 to 98 molar percent of barium titanate-sodium bismuth titanate complex or barium titanate-potassium bismuth titanate complex serving as a main component, and 2 to 5 molar percent of secondary additive consisting of at least one of Nb2O5, CaZrO3 and SrZrO3. According to the preparation method of the invention, the dielectric ceramic material with high property can be obtained, meeting the electronic industries association (EIA) X9R standard; the process is simple, and intermediate temperature sintering can be performed; and the material has the room temperature dielectric constant of 1,500 to 1,700, the room temperature loss of about 2 percent, the room temperature resistivity of more than or equal to 1,013omega.cm, the breakdown voltage of more than or equal to 5kV/mm, and a good industrial prospect.

The invention relates to bismuth titanate natrium-silver-barium series piezoelectric ceramics with ABO3 structure. The general equation of the compound is [Bi0.5(Na1-xAgx)0.5] _{1-yBayTiO3+aM alpha O beta (wt%), and in the equation, 0 alpha Obeta is one or plural doping oxide. The main constituent is 0-5 of Biw(Na1-x-y-zKxLiyAgz})1-wTiO3, M could be Na, K, Li, Ni, Zn, Cr, Co, Nb, Ta, Al, Cu, Fe, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, In, Y, Sc, La, Ho, Lu, Sn, Sb, Mn, Ca, Ba, Sr, Mg, Si, Bi, Ag, etc. Alpha and beta mean the M element and atomicity corresponding to the relative oxide. The sintering temperature is 1100-1200 degree centigrade, keeping for 1-4 hours. The optimal value of the compound of d33 could be over 160pC/N, kp could be over 31%, dielectric loss could be below 0.03. And the technology is stable, and it would be made from traditional technology and raw material.

The invention provides sodium bismuth titanate-barium titanate-potassium bismuth titanate lead-free piezoelectric texture ceramic and a preparation method thereof. The preparation method comprises the following steps: mixing a template with organic additives such as matrix powder, an organic solvent and a binder to obtain slurry by taking a Bi4Ti3O12 crystal as the template; preparing the slurry into a film sheet with thickness of 30 mu m-60 mu m through a curtain coating process; and sintering the film sheet after laminating, cutting, rubber exhausting and isostatic cool pressing to prepare a BNBK texture ceramic material with high oriented growth, wherein original components of the materials are not changed due to precise control in the process. The prepared sodium bismuth titanate-barium titanate-potassium bismuth titanate lead-free piezoelectric texture ceramic constitutes a (1-x-y)Na0.5Bi0.5TiO3-xBaTiO3-Yk0.5Bi0.5TiO3 ternary system, has good crystalline grain orientation effect, excellent performances in the lead-free piezoelectric field, a piezoelectric constant of over 210 pC/N and a Curie temperature of over 320 DEG C.

The invention discloses a method for preparing lanthanum-doped bismuth titanate nano powder by a sol-gel hydrothermal method, which comprises the following steps of: dissolving Bi (NO3) 3.5H2O and La (NO3) 3.6H2O into glacial acetic acid solution to obtain solution A; dropwise adding Ti (OC4H9) 4 into organic solvent to obtain solution B; dropwise adding the solution B into the solution A, and preparing even sol by magnetic stirring; putting the sol into a drying oven, and drying to obtain xerogel; grinding to obtain powdered hydrothermal reaction precursor; putting the hydrothermal reaction precursor into a hydrothermal kettle, and adding pure water taken as solvent and NaOH taken as mineralizer into the hydrothermal kettle; sealing the reaction kettle, and putting the reaction kettle into the drying oven at 160-170 DEG C; taking out products after reaction, and filtering to obtain precipitate; and finally, washing and drying the precipitate to obtain the lanthanum-doped bismuth titanate nano powder. The method can be used for preparing the lanthanum-doped bismuth titanate nano powder under the condition of low temperature, so that the energy is saved, and lanthanum-doped bismuth titanate is perfect in crystallization.

This invention relates to a BFO/BXT laminated capacitor and its preparing method, in which, the capacitor includes: a substrate made of silicon and orderly combined with an oxidation layer, a lower electrode metal layer, a BFO film and an upper metal layer, in which, a BXT induction film is set between the lower electrode metal layer and the BFO film. The method includes: preparation of sol of RFO and BXT precursors and preparation of the capacitor of its laminated structure and the ferroelectric capacitor prepared with this method includes excellent property of anti-fatigue, high residual polarized intensity, low operational voltage and better dielectric property.

The invention discloses a method for preparing bismuth titanate as a visible light response semiconductor photochemical catalyst, which comprises the steps of: dissolving bismuth salts in nitric acid at room temperature, dissolving vanadate or metavanadate same mol with the bismuth salts in 60-90 DEG C hot water, and respectively adding benzene or polyethylene glycol or a mixed solution of the benzene and the polyethylene glycol in two solutions obtained from the steps; and dropping vanadium-containing liquid into bismuth-containing liquid under the stirring state, stirring, ageing, filtering, washing and drying to prepare the bismuth titanate BiVO4 as a visible light response semiconductor photochemical catalyst. The BiVO4 prepared by the steps has the advantages of strong response of visual light, high photocatalytic oxidation degrading capability, simple preparation method, short reaction time and easy industrialized production.

The invention discloses a potassium-bismuth titanate-based solid solution lead-free piezoelectric ceramic and a manufacturing method thereof. The components are represented by the general formula of (1-n){(1-u)(Bi0.5K0.5)TiO3+u[(1-z)Bi(CxDy)O3+zBiEO3]}+nM. The ceramic components of the invention have a morphotropic phase boundary of the rhombic ferroelectric phase and the cubic ferroelectric phase, good piezoelectric performance and higher Curie temperature. The ceramic components have the characteristic of environmental protection, can realize the replacement of a part of the traditional lead-containing piezoelectric ceramics, and can be manufactured by using the manufacturing method of the traditional piezoelectric ceramic and the industrial materials, thereby having practical application.

The invention discloses a bismuth titanate photocatalytic material with visible light response, which is a pure phase material with a chemical formula of Bi20TiO32 and prepared by the steps of preparation of raw materials, heating reaction, and quenching and cooling. The material has the advantages of good photocatalytic activity, low cost, capability of recycling catalyst, simple method, easy large-scale production, and the like.

The invention discloses a preparation method of two-phase low-temperature co-sintered temperature stable dielectric ceramic material. The preparation method comprises the steps of: (1) calcining BaCO3 and TiO2 through at a high temperature of 1250 DEG C which is close to the sintering temperature of BaTiO3 ceramic, so as to synthesize BaTiO3; (2) calcinating Na2CO3, Bi2O3 and TiO2 at 800 DEG C to synthesize Na0.5Bi0.5TiO3; (3) evenly mixing (1-x)BaTiO3 and xNa0.5Bi0.5TiO3 together by weight percentage, wherein x is greater than 0.05 and less than 0.2, and the mixer is used as a substrate material; (4) adding y wt% of Y2O3 by weight of the substrate material in the mixing process, wherein y is greater than 0.1 and less than 0.5; and (5) performing washing-out, drying and compression moulding operations on the powder, and sintering at a temperature of 1100-1150 DEG C, so as to obtain a two-phase low-temperature co-sintered ceramic sample piece. According to the preparation method, different from a BT-BNT composite material, a BT-BNT (Bismuth Titanate-Bismuth Na Titanate) mixed two-phase coexistence dielectric material is prepared by a step-by-step solid phase method. The two-phase low-temperature co-sintered temperature stable dielectric ceramic material has the characteristics of low loss and high dielectric constant of BT at a temperature lower than 120 DEG C and BNT at a temperature higher than 120 DEG C. The preparation method is capable of realizing multiphase medium coexistence and co-sintering without adding any sintering aid, and also capable of realizing co-sintering with a metal internal electrode; therefore, a new preparation method of the temperature stable ceramic is realized; and the preparation method has great application value.

The invention provides a preparation method of a acidic bismuth titanate photocatalyst with photocatalytic activity under sunlight. The invention adopts a chemical solution decomposition method (CSD), and uses bismuth nitrate and P25 as the main raw materials to prepare bismuth titanate (Bi4Ti3Oi2), which is then subjected to acid treatment to obtain the bismuth titanate photocatalyst with sunlight photocatalytic activity. The photocatalyst has excellent methyl orange (MO) degradation performance in the sunlight irradiation. The production process involved in the invention is simple and has cheap and easily available raw materials; the obtained powder has efficient light response degree, and widens the application range of bismuth titanate in photocatalysis field.

It is an object to provide fine particles of bismuth titanate having excellent dielectric characteristics, high crystallinity and a small particle diameter, and a process for their production. The object is accomplished by a process which comprises a step of obtaining a melt comprising, as represented by mol % based on oxides, from 23 to 72% of Bi₂O₃, from 4 to 64% of TiO₂ and from 6 to 50% of B₂O₃, a step of quickly quenching this melt to obtain an amorphous material, a step of crystallization of bismuth titanate crystals from the above amorphous material, and a step of separating the bismuth titanate crystals from the obtained crystallized material, in this order.

The invention relates to bismuth titanate natrium-potassium-lithium-silver series leadless piezoelectric ceramics. The general equation of the compound is Bi0.5(Na1-x-y-zKxLiyAgz)0.5TiO3+aM alpha O beta(wt%), and in the equation, 0 alpha Obeta is one or plural doping oxide. The main constituent is 0-5 of Bi0.5(Na1-x-y-zKxLiyAgz)SUB>0.5TiO3, M could be Na, K, Li, Ni, Zn, Cr, Co, Nb, Ta, Al, Cu, Fe, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, In, Y, Sc, La, Ho, Lu, Sn, Sb, Mn, Ca, Ba, Sr, Mg, Si, Bi, Ag, etc. Alpha and beta mean the M element and atomicity corresponding to the relative oxide. The optimal value of the compound of d33 could be over 210pC/N, kp could be over 40%. And the technology is stable, and it would be made from traditional technology and raw material.

The invention discloses a transparent rare earth doping bismuth titanate luminous ferroelectric film and the preparation method thereof. The film provided by the invention contains (Bi4 minus xLnx) Ti3O12, wherein, the x is larger than or equal to 0 and smaller than or equal to 0.85; and the Ln is rare earth elements Pr, Dy, Ho, Er, Eu, Tm or Yb. The invention further provides a preparation method of the luminous ferroelectric film, which comprises the following step of preparing the solution of a front drive body; coating; baking; and annealing. The luminous ferroelectric film provided by the invention has the advantages of not only good ferroelectricity, dielectric performance and optical transmissibility performance, but also photo luminescent performance discovered. The method for preparing the transparent rare earth doping bismuth titanate luminous ferroelectric film has the advantages that easy control of the components of the film, and good uniformity, as well as low preparation cost, gentle condition, easy large-sized film formation, and uniformity, compactness and non-crack of the film prepared. The technical proposal provided by the transparent rare earth doping bismuth titanate luminous ferroelectric film, and the method thereof ensures that the materials have wider application foreground in the photoelectric material field.

The present invention provides partially crystallizing lead-free and cadmium-free glass enamel composition that fuse at low temperatures. Glass enamel compositions according to the present invention form predominantly bismuth titanate and optionally zinc titanate crystals upon firing. Preferably, glass enamel compositions according to the invention include a glass component that includes by weight from about 11% to about 52% SiO2, from 10.2% to about 40% TiO2, from about 5% to about 75% Bi2O3, up to about 8% B2O3, up to about 14% BaO+SrO, and up to about 45% by weight ZnO, where the sum of Bi2O3 and ZnO comprises from about 30% to about 85% of the glass component by weight.

A lead-free piezoelectric sodium bismuth titanate-potassium bismuth titanate texture ceramics is prepared from the microcrystalline template (bismuth titanate) prepared from TiO2, bismuth oxide, sodium chloride and potassium chloride, the raw powder of sodium carbonate, potassium carbonate, TiO2 and bismuth oxide, organic solvent, and adhesive through mixing, ball grinding, doctor blading, laminating, isostatic pressing in hot water, cutting pre-calcining, and coating Ag.

The invention provides a bismuth oxychloride-iron bismuth titanate composite photocatalyst and a preparation method thereof. The method comprises the steps: a hydrothermal synthesis step comprising at room temperature, dissolving a bismuth source substance, an iron source substance and a titanium source substance in a dilute nitric acid solution to obtain a mixed solution, adjusting the pH value of the mixed solution to 12-14 to obtain a precipitate-containing suspension, under a condition of the temperature of 160-220 DEG C, heating and carrying out heat preservation for 24-72 h, and cleaning and drying the precipitate in the suspension to obtain a powdery iron bismuth titanate photocatalyst; and a hydrochloric acid treatment step comprising under a condition of room temperature or heating, putting the prepared iron bismuth titanate photocatalyst into a dilute hydrochloric acid solution with the molar concentration of 0.5-2 M, carrying out magnetic stirring for 1-24 h, and carrying out centrifugation cleaning and drying on the mixed solution, to obtain the bismuth oxychloride-iron bismuth titanate composite photocatalyst.