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65 results about "Lead tungstate" patented technology

Stolzite is a mineral, a lead tungstate; with the formula Pb W O 4. It is similar to, and often associated with, wulfenite which is the same chemical formula except that the tungsten is replaced by molybdenum .

Interposer capacitor built on silicon wafer and joined to a ceramic substrate

An interposer, located between an integrated circuit having power, ground and signal connections and a ceramic substrate having power, ground and signal connections, that includes an oxide layer formed on a polished surface of a silicon substrate, a thin film dielectric capacitor formed on the oxide layer, a plurality of metallized that electrically connect to either of the electrodes of the thin film dielectric capacitor, and vias than conduct power, ground and signals between a the ceramic substrate and the integrated circuit. The interposer connects the metallized vias to the integrated circuit by solder connections and also connects the vias conducting power, ground and signals from the ceramic substrate to the interposer by solder connections. The dielectric of the thin film dielectric capacitor may be selected from the group of high-K titanates, such as, barium zirconate titanate, barium strontium titanate, pure barium titanate, barium titanate modified with Pb, Nb, W, Ca, Mg, and Zn, lead titanate, lead zirconate titanate, and polycrystalline lanthanum-modified lead zirconate titanate, or other high-K dielectrics, such as, lead niobate and its derivatives, and lead tungstate and its derivatives.
Owner:GLOBALFOUNDRIES US INC

Gravity separation and flotation separation combined process for treatment of complex tungsten-molybdenum-copper-lead-zinc polymetallic ores

The invention discloses a gravity separation and flotation separation combined process for treatment of complex tungsten-molybdenum-copper-lead-zinc polymetallic ores. The gravity separation and flotation separation combined process comprises the following steps: (1) performing grinding-gravity separation on raw ores to obtain lead tungstate rough concentrate enriched in wolframite and gelenite and gravity separation tailings; (2) performing lead flotation on the lead tungstate rough concentrate to obtain lead rough concentrate and tungsten concentrate, and further performing lead concentration on the lead rough concentrate to obtain lead concentrate; (3) performing copper-molybdenum mix-floatation on the gravity separation tailings to obtain copper-molybdenum mixed crude concentrate and copper-molybdenum mix-floatation tailings; (4) performing copper-molybdenum mixed concentration on the copper-molybdenum mixed crude concentrate to obtain copper-molybdenum bulk concentrate, and further performing copper-molybdenum separation-rough concentration and copper-molybdenum separation-concentration on the copper-molybdenum bulk concentrate to obtain copper concentrate and molybdenum concentrate; and (5) sequentially performing zinc rough concentration and zinc concentration on the copper-molybdenum mix-floatation tailings to obtain zinc concentrate. With the adoption of the gravity separation and flotation separation combined process provided by the invention, valuable elements in the complex tungsten-molybdenum-copper-lead-zinc polymetallic ores can be fully recycled, and the resource utilization rate of the complex tungsten-molybdenum-copper-lead-zinc polymetallic ores is improved.
Owner:有研资源环境技术研究院(北京)有限公司

Method for preparing fluorinion doped lead tungstate scintillation crystal

The invention discloses a method for preparing fluorinion doped lead tungstate scintillation crystal which comprises, utilizing the characteristics of low melting point and easy-volatilization of the PbF2 and gaseous phase transmission balancing technique, regulating the parameters including batch component proportioning, temperature and time in the high temperature, rich fluorine atmosphere, controlling the diffusion of F- ions. The method provided by the invention can improve the evenness for the F ion doping PWO crystallo-luminescence.
Owner:SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI

Interposer capacitor built on silicon wafer and joined to a ceramic substrate

An interposer, located between an integrated circuit having power, ground and signal connections and a ceramic substrate having power, ground and signal connections, that includes an oxide layer formed on a polished surface of a silicon substrate, a thin film dielectric capacitor formed on the oxide layer, a plurality of metallized that electrically connect to either of the electrodes of the thin film dielectric capacitor, and vias than conduct power, ground and signals between a the ceramic substrate and the integrated circuit. The interposer connects the metallized vias to the integrated circuit by solder connections and also connects the vias conducting power, ground and signals from the ceramic substrate to the interposer by solder connections. The dielectric of the thin film dielectric capacitor may be selected from the group of high-K titanates, such as, barium zirconate titanate, barium strontium titanate, pure barium titanate, barium titanate modified with Pb, Nb, W, Ca, Mg, and Zn, lead titanate, lead zirconate titanate, and polycrystalline lanthanum-modified lead zirconate titanate, or other high-K dielectrics, such as, lead niobate and its derivatives, and lead tungstate and its derivatives.
Owner:GLOBALFOUNDRIES US INC

Process for preparing lead tungstate crystal

The invention discloses a method for preparing lead tungstate crystal, and contains the following steps: pre-treating the raw material PbWO3, pouring into the growing crucible containing crystallon with a space of 0.1-0.6 time of the crystal length at the top, packaging, sealing, vacuumizing, reinjecting oxygen of one atmospheric pressure, placing in a descent furnace for inoculating and growing, keeping the furnace temperature at 1200-1250DEG C, descending at a speed of 1mm / h, cooling to 950DEG C at a speed of 30DEG C / h, annealing for 5h, heating the lead tungstate crystal in an annealing furnace to 1000DEG C at a speed of 30DEG C / h, keeping the temperature for 5h for annealing, cooling to room temperature at a speed of 30DEG C / h, cutting according to the settled specification, and polishing to obtain the final product.
Owner:JIAXING UNIV

Method for preparing Nano material of lead tungstate

This invention relates to a method for synthesizing lead tungstate nanomaterial. The method comprises: placing sodium tungstate and lead salt in a container, adding deionized water and additives, reacting at room temperature for 40-60 min, transferring to a reaction kettle, adding deionized water (60-70 vol. % of the reaction kettle), sealing, reacting at 120-160 deg.C for 3-12 h, naturally cooling to room temperature, taking out the product, washing, centrifuging for separation, drying, and dispersing the product in absolute ethanol. The method has such advantages as abundant raw materials, simple process, simple apparatus, high product purity, convenient post treatment, and no pollution.
Owner:TONGJI UNIV

Combined different valence ions doped crystal of lead tungstate with high light yield, and prepartion method

This invention relates to a method for preparing heterovalent ions-doped high-luminescence-yield lead tungstate crystal and its preparation method. The high-luminescence-yield lead tungstate crystal is doped with F- 100-8000 ppm, Sb3+ 100-5000 ppm, and Mo6+, V5+, Nb5+, Zr4+, and Ti4+ 0-10000 ppm, and is prepared via modified Bridgman method by using platinum crucible. The method can be used for preparing several strands of lead tungstate crystals in one process, and is suitable for mass production. The obtained heterovalent ions-doped high-luminescence-yield lead tungstate crystal has such advantages as rapid attenuation and high luminescence yield.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Preparation method of lead tungstate powder with high scintillation property

The invention discloses a preparation method of a lead tungstate powder with high scintillation property, comprising the following specific steps of: a) dropwise adding a water soluble lead salt solution into a water soluble tungstate solution with a pH value being not less than 7 at the uniform velocity so that the coprecipitation chemical reaction is conducted at 30-80 DEG C; b) filtering, washing and drying the obtained lead tungstate precipitation; and c) carrying out thermal treatment on the obtained lead tungstate crystal grains. By the invention, the luminescence peak of the lead tungstate powder body is within the blue light wave band of 450-500nm and belongs to fast luminescence component; the luminescence strength is high and is remarkably improved by about 15 times in comparison with the luminescence strength of the power obtained by grinding lead tungstate crystal grains which grow by a descending method, can reach the luminescence level of the power obtained by grinding of bismuth germanate crystal grains which grow by a descending method and has excellent scintillation property; in addition, the invention has the advantages of simple operation, short reaction time, low requirements on experimental equipment, high controllability and the like, and is suitable for large-scale production.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Preparation method and application of lead tungstate/cadmium sulfide composite visible-light-driven photocatalyst

The invention specifically relates to a preparation method and application of a lead tungstate / cadmium sulfide composite visible-light-driven photocatalyst, belonging to the technical field of semiconductor photocatalysis nano-materials. The preparation method comprises the following steps: adding cadmium nitrate and thiourea into ethylenediamine to obtain a mixed solution, carrying out stirring,then transferring the mixed solution to a hydrothermal reaction kettle, and carrying out a hydrothermal reaction to obtain cadmium sulfide; adding lead acetate and sodium tungstate into deionized water, carrying out stirring, then transferring an obtained suspension to the reaction kettle, and carrying out a hydrothermal reaction to obtain lead tungstate; after separate ultrasonic treatment of lead tungstate and cadmium sulfide in ethanol, dropwise adding the suspension of lead tungstate into the suspension of cadmium sulfide, performing ultrasonic treatment, adding acetone, and then performing stirring and drying to obtain the lead tungstate / cadmium sulfide composite visible-light-driven photocatalyst. The prepared composite photocatalyst is greatly improved in activity and efficiency, and has stronger adsorption capacity in a visible light region and higher charge separation efficiency. The preparation method is simple in process, low in cost and easy in manufacturing process, and has potential application value.
Owner:CHANGZHOU UNIV

Yb and Er double doping plumbous tungstate crystal conversion material and preparation thereof

InactiveCN101328614AImprove the luminous intensity of green light bandWide coveragePolycrystalline material growthBy pulling from meltLuminous intensityTungstate
The invention relates to a transition material on a Yb and Er dual-doped lead tungstate crystal and a preparation method thereof, relating to the transition material on the lead tungstate crystal and a preparation method thereof. The method solves the problem of low luminous intensity of a transition material on an Er-doped lead tungstate crystal prepared by the prior art. The transition material on the Yb and Er dual-doped lead tungstate crystal is prepared by WO3, PbO, Er2O3 and Yb2O3. The method comprises the following steps: firstly, required compositions are weighed; secondly, sintering is performed; and thirdly, the crystal is grown by adoption of the crystal pulling method, and then the transition material on the Yb and Er dua-doped lead tungstate crystal is obtained. The method dopes element ytterbium (Yb) in the transition material on the Er-doped lead tungstate crystal, and improves the luminous strength on a green wave band of the Er-doped lead tungstate crystal by three times on the basis of preserving the prior superior performance of the Er-doped lead tungstate crystal.
Owner:HARBIN INST OF TECH

Ytterbium/bismuth dual-doped lead tungstate crystal and preparation method thereof

The invention relates to an Yb<3+> / Bi<3+> dual-doped lead tungstate crystal and a preparation method thereof, and belongs to the field of optical crystals. Bi ions in the PWO crystal generate multiband near-infrared luminescence through energy transfer between Yb<3+> and Bi <n+> (n is equal to 0, 1 and 2) under the sensitization of the Yb<3+> ions. The Yb<3+> / Bi<3+> dual-doped lead tungstate crystal is prepared by mixing Bi2O3 and Yb2O3 powder into a lead tungstate polycrystalline ingot by a Czochralski method and a crucible descending method, wherein the doping amount of Bi<3+> in the obtained crystal is between 0.1 and 2.0 atom percent, and the doping amount of the Yb<3+> is between 0.3 and 4.0 atom percent.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Preparation method of anti-radiation biomimetic membrane

The invention discloses a preparation method of an anti-radiation biomimetic membrane. The preparation method of the anti-radiation biomimetic membrane comprises the following steps: sodium-based montmorillonite nano-plates are taken as 'bricks', chitosan molecules are taken as 'mud', the chitosan molecules are absorbed onto the surfaces of the sodium-based montmorillonite nano-plates through electrostatic adsorption and hydrogen-bond interaction so as to form sodium-based montmorillonite and chitosan hybridized nano-plates, lead tungstate nano-particles are directly decorated on the sodium-based montmorillonite and chitosan hybridized nano-plates, and a montmorillonite and chitosan biomimetic laminated structure hybridized membrane containing the lead tungstate nano-particles can be obtained through vacuum filtration and self assembly. The anti-radiation biomimetic membrane prepared by the invention has a pearl mother imitated structure, the lead tungstate is distributed on the biomimetic membrane better, the membrane has the characteristics of relatively high intensity and radiation resistance, and is excellent in toughness, and the preparation method of the membrane is simple and high in efficiency.
Owner:SOUTHWEAT UNIV OF SCI & TECH

Horizontal growth method for lead tungstate scintillation crystal

The invention discloses a horizontal growth method for a lead tungstate scintillation crystal. The method includes the following steps: after being dewatered, PbO and WO3 powder materials with 99.999percent of purity are proportioned according to a stoichiometric ratio, are uniformly mixed, and then are arranged in a copple to be heated, temperature is raised so as to melt the raw materials, andthen the melted raw materials are injected into a mould; after temperature reduction, a polycrystalline ingot can be obtained, the obtained polycrystalline ingot is arranged in the copple, homogeneouscrystals which are prepared in advance are used as seed crystals, the seed crystals are inoculated in the copple and grow directionally, the growth rate ranges from 0.4 to 0.9 mm / h, and the temperature gradient of a growth interface ranges from 20 to 30 DEG C / cm; and after the growth of the crystals, the obtained PWO crystals and the copple are moved to a low temperature region to be processed by annealing so as to eliminate the thermal stress and to reduce the crystal cracking. The method has the following advantages: tabular crystals with different sizes can be grown, in situ annealing canbe realized, different gas atmospheres can be led inside for crystal annealing, and the operation can be accomplished at one step, thereby simplifying the working procedure of crystal growth, reducing the cost and contributing to the realization of crystal industrialization.
Owner:WENZHOU UNIVERSITY

Process for preparing lead tungstate-doped crystal

InactiveCN1962965AInhibit or retard volatilizationPolycrystalline material growthFrom frozen solutionsPlatinumCrucible
The invention discloses a preparing method of doped lead tungstate crystal, which comprises the following steps: (1) drying PbO, WO3 with purity at 99.99% and solid powder of doping agent under 150-200 Deg C; weighing the PbO and WO3 according to chemical weight; setting the molar rate density of doping agent at 0.01-0.1%; pressing weighted solid powder into dense solid under 10-50Kpa; sintering in the oxidizing environment at 750-1000Deg C; aerating oxygen in the sealed platinum copple; insulating at 1130-1200 Deg C to fuse the solid; (2) introducing fused raw material into growing copple with seed to form dense multi-crystal ingot; placing the growing copple in the temperature-gradient crystal growing furnace to inoculate and grow with introducing speed at 1.0mm / h. The invention is fit for effumable doping agent, which is also fit for doping agent without effumability.
Owner:JIAXING UNIV +1

Crucible for preparing large-section lead tungstate crystal and crystal growth method

The invention relates to a crucible for preparing large-section lead tungstate crystal and a crystal growth method. The crucible comprises a crystal seed section for placing crystal seeds, as well as more than or equal to two diameter enlarging sections and equal diameter sections located behind the crystal seed section and arranged alternately, wherein the diameters of the equal diameter sections are sequentially increased. For the crucible, alternated design of multiple diameter enlarging sections and equal diameter sections is adopted, so that the defects and thermal stress generated in the growth process of the diameter enlarging sections are sufficiently eliminated and reduced in the equal diameter sections, cracking caused by continuous accumulation of defects and stress in single diameter enlarging growth is avoided, and complete crystal is prepared.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Process for modifying lead tungstate crystal by utilizing diffusion method

The invention discloses a process for modifying a lead tungstate crystal by utilizing a diffusion method, which comprises the steps of (1) utilizing lead oxide (PbO) powder and tungsten trioxide (WO3) powder to serve as raw materials, performing accurate dosing according to the molar ratio of n (PbO) to n (WO3) being 1 to 1, and growing the lead tungstate crystal by using a bridgman method or a czochralski method; (2) accurately orientating, cutting and grinding generated lead tungstate crystal through an X ray orientation device into lead tungstate wafers with thicknesses of 2-5mm, and cleaning the lead tungstate wafers to obtain lead tungstate crystal samples; and (3) placing the lead tungstate crystal samples obtained in the step (2) into a crucible containing metallic oxide powder to enable the lead tungstate crystal samples to be tightly wrapped by the metallic oxide powder, placing the crucible into a muffle furnace, heating the muffle furnace to 800-1000 DEG C, finishing diffusion after keeping the temperature for 12-36 hours, cooling to the room temperature, and obtaining a modified lead tungstate crystal. The process for modifying the lead tungstate crystal by utilizing the diffusion method has the advantages of low energy consumption and high efficiency.
Owner:WENZHOU UNIVERSITY

Pr, Eu/Tb co-doped tungstate/molybdate fluorescent powder and preparation method thereof

The invention discloses a Pr, Eu / Tb co-doped tungstate / molybdate fluorescent powder. The chemical composition of the fluorescent powder is Al-x-yBO4:xPr, yTb / Eu, wherein an A element is one or more selected from Ca, Ba and Sr; a B element is W or Mo; x is more than 0.01 but less than or equal to 0.10; and y is more than 0.01 but less than or equal to 0.10. A preparation method thereof comprises the following steps: mixing the carbonate or oxide of the A element and the ammonium salt of tungstic acid / molybdic acid with the oxide of the Pr, Tb or Eu in the proportion of mole ratio of A:BO4:Pr:Tb / Eu being (1-x-y):1:x:y; mixing with less absolute ethyl alcohol; fully grinding and uniformly mixing, thereby obtaining a mixture; and sintering at high temperature, crushing, grinding and drying, thereby obtaining the fluorescent powder. Under the excitation of ultraviolet light (especially being 210nm-250nm), the sample of the fluorescent powder respectively emits 485nm blue light, 585nm yellow light, 545nm green light, and 612nm and 645nm red light; the green light, yellow light and white light can be respectively obtained by adjusting the variety and concentration of the doped rare earth Pr, Eu and Tb ions; and the preparation method is suitable for the preparation of the high-light white light LED fluorescent powder.
Owner:ZHOUKOU NORMAL UNIV

Transformer insulation paper with high heatproof grade

The invention discloses a transformer insulation paper with high heatproof grade. The transformer insulation paper is prepared from the following raw materials by weight part: 0.6-0.7 of a silane coupling agent kh550, 6-8 of mica, 1-1.5 of glycine, 0.3-0.4 of a silane coupling agent kh570, 0.1-0.2 of an emulsifier OP-10, 0.2-0.3 of sodium dodecyl sulfate, 2-3 of E44 epoxy resin, 0.3-0.5 of cerium stearate, and 500-550 of a pulp board, 3.4-4 of pectin fiber, 0.3-0.4 of an anti-aging agent MB, 1.2-1.6 of nano boron nitride, 0.3-0.5 of lead tungstate, and a proper amount of deionized water. The transformer insulation paper provided by the invention has the advantages of simple preparation method, wide raw materials, low production cost, high heatproof grade, and good stability, can be produced in large scale, and is worthy of promotion.
Owner:TONGLING SANJIA TRANSFORMER

Rapid stirring device for preparing monoclinic lead tungstate nanobelt crystal material

The invention discloses a rapid stirring device for preparing a monoclinic lead tungstate nanobelt crystal material, and mainly relates to the field of production of monoclinic lead tungstate nanobeltcrystal materials. The rapid stirring device comprises a stirring barrel body and a supporting seat, wherein a sliding block is arranged at the bottom of the stirring barrel body, an annular slidinggroove is formed in the top of the supporting seat, a supporting frame is arranged on one side of the stirring barrel body, the bottom end of the supporting frame is fixed on the supporting seat, a cover body matched with the stirring barrel body is arranged on the supporting frame, a lifting device used for adjusting the height of the cover body is arranged on the supporting frame, a supporting pipe is vertically arranged on the cover body, and a rotating shaft is vertically arranged in the supporting pipe. The rapid stirring device has the beneficial effects that the lifting type rotating shaft is matched with the stirring barrel body capable of moving annularly, so that the fluidity of raw materials in the stirring barrel body is improved, stirring dead corners in the stirring barrel body are eliminated, stirring of the raw materials can be completed rapidly, and the stirring efficiency and the stirring quality are improved.
Owner:CHONGQING VOCATIONAL INST OF ENG

Anion and cation co-doped PbWO4 crystal and its growth method

The present invention relates to improved crucible descending process to grow anion and cation double doped flash lead tungstate crystal with high light efficiency and fast attenuation, and belongs to the field of crystal growing technology. The present invention solves the problem of dopant volatilization and produces anion and cation double doped PWO crystal with light efficiency up to 7.3 % of that of BGO crystal. The present invention adopts PbF2 or BaFe and Y2O3 as dopant and has doping amount of 600-1000 ppm and 100-300 ppm separately. By means of using platinum crucible, sealing crucible, controlling the volatilization of material and dopant and adopting crucible with shape and size varying with the grown crystal, the present invention can grow 2, 6 or 28 pieces of lead tungstate crystal simultaneously and is suitable for mass production.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Preparation method of ultra-thin inorganic/organic composite dielectric layer material for supercapacitor

The invention relates to a preparation method of an ultra-thin inorganic / organic composite dielectric layer material for a supercapacitor. The method comprises the following steps of selecting lead tungstate as a matrix organic material, selecting nitrile group-containing polyimide as an organic polymer phase, synthesizing the lead tungstate and the nitrile group-containing polyimide into a novel nitrile group-containing polyimide solution through ternary copolymerization, coating lead tungstate ceramic powder with the nitrile group-containing polyimide solution, and performing vacuum defoamation, casting film formation, solvent evaporation, calendering and annealing on the coated lead tungstate ceramic powder to form the ultra-thin inorganic / organic composite dielectric layer material. Compared with the traditional polymer / barium titanate series composite dielectric layer material, the ultra-thin inorganic / organic composite dielectric layer material has the advantages of simple process. The thickness of the prepared ultra-thin inorganic / organic composite dielectric layer material is less than or equal to 3 mum, the dielectric constant is up to 44,700, the breakdown-resistant voltage is up to 400kV / mm, and the dielectric loss factor is less than 1 percent. The ultra-thin inorganic / organic composite dielectric layer material can be used for preparing a large-capacity multi-layer ceramic capacitor.
Owner:INST OF CHEM CHINESE ACAD OF SCI

Process for growing lead tungstate crystal by vertical gradient solidification method

The invention relates to a technique for growing a lead tungstate crystal by a vertical gradient solidification method, which belongs to the field of single crystal growth. The technique is characterized by comprising the following steps of: mixing initiative raw materials uniformly, wherein the initiative raw materials are prepared according to the set polycrystalline ingot chemically metering components; placing the mixture into a crucible and presintering the mixture for 2 to 4 hours at the temperature of between 700 and 800 DEG C, wherein a definitely-oriented seed crystal is arranged at the lower end of the mixture; heating the mixture to 1,130 to 1,200 DEG C to melt the raw materials, wherein the temperature gradient near the seed crystal and the melt is 15 DEG C / cm and the temperature gradient in the melt is 8 DEG C / cm; cooling the mixture at a speed of 2 DEG C / h, so that the crystal starts to grow, wherein the speed is maintained until the growth ended. A technique for growingthe lead tungstate crystal by the vertical gradient solidification method has the advantages of simple process, high repeatability, capacity of controlling all the procedures in the whole growth process and contribution to industrialized production.
Owner:WENZHOU UNIVERSITY

Polyurethane foam for preventing electromagnetic radiation

InactiveCN109280363ALow costHazard to use safetyElectromagnetic shieldingSilica gel
The invention relates to a special foam material, in particular to a polyurethane foam for preventing electromagnetic radiation. The foam comprises the following components in parts by weight: 100 parts of siloxane modified diethylene glycol phthalic anhydride polymer, 80-100 parts of isocyanate, 10-25 parts of nanometer lead tungstate silica gel, 25-35 parts of powder graphene microsheet, 5-15 parts of carboxymethyl starch, 3-8 parts of melamine, 5-10 parts of ammonium polyphosphate, 1-3 parts of triethylenediamine, 0.5-3 parts of water and 0.05-0.25 part of dibutyltindilaurate. The inventionsolves the problems of low electromagnetic shielding efficiency, poor anti-electromagnetic radiation ability and high cost of foamed plastics in the prior art and has features of (1) good anti-electromagnetic radiation performance; (2) good mechanical properties and machinability; (3) low cost and simple processing method.
Owner:德清舒华泡沫座椅有限公司

Method for preparing monoclinic lead tungstate nano belt crystal material

The invention discloses a method for preparing a monoclinic lead tungstate nano belt crystal material, which comprises the following steps of reaction solvent preparation, reaction raw material preparation, alkaline solution preparation, heating reaction, cooling and washing. The method has the following advantages of low reaction cost, easy monitoring and control over all parameters (temperature, pressure and the like) in a reaction process, environmental friendliness and clean product.
Owner:CHONGQING UNIV

Method for preparing lead tungstate nano-powder

The invention relates to a method for preparing a lead tungstate nano-powder by using a novel reactant self-emulsifying precipitation method. The method includes mixing a sodium aliphatate brine solution A and a soluble lead salt solution B (containing a trace amount of rare metal irons) according to a certain ratio of amount of substance, and subjecting the mixture to standing, filtering and washing to obtain a precipitate C; dissolving a certain amount of the C into a hot organic solvent to form a transparent emulsion D; dropwise adding a certain amount of a tungstic acid brine solution into the D to form an emulsion E; and cooling the emulsion E to the room temperature and subjecting the emulsion E to standing, precipitating, washing and drying, and calcining the emulsion E in a muffle furnace for 4 hours to obtain the lead tungstate nano-powder. According to the method, the prepared lead tungstate nano-powder reaches a nanoscale, the particle size of the lead tungstate nano-powder is 10-100nm, the morphology is regular, the distribution is narrow, the particle size of particles can be controlled by changing salinity of water phases, the operation is simple and convenient, the requirement on devices is low, and the method is applicable to scale production.
Owner:INST OF CHEM CHINESE ACAD OF SCI

Process for preparing lead tungstate-doped crystal

InactiveCN100587131CInhibit or retard volatilizationPolycrystalline material growthFrom frozen solutionsPlatinumCrucible
The invention discloses a preparing method of doped lead tungstate crystal, which comprises the following steps: (1) drying PbO, WO3 with purity at 99.99% and solid powder of doping agent under 150-200 Deg C; weighing the PbO and WO3 according to chemical weight; setting the molar rate density of doping agent at 0.01-0.1%; pressing weighted solid powder into dense solid under 10-50Kpa; sintering in the oxidizing environment at 750-1000Deg C; aerating oxygen in the sealed platinum copple; insulating at 1130-1200 Deg C to fuse the solid; (2) introducing fused raw material into growing copple with seed to form dense multi-crystal ingot; placing the growing copple in the temperature-gradient crystal growing furnace to inoculate and grow with introducing speed at 1.0mm / h. The invention is fit for effumable doping agent, which is also fit for doping agent without effumability.
Owner:JIAXING UNIV +1

Yb and Zn double-doped lead tungstate crystal and its preparation method

The invention discloses a kind of lead tungstate crystal doped with Yb and Zn, and the preparation method, relating to a kind of lead tungstate crystal and the preparation method. Said lead tungstate crystal comprises tungsten oxide, lead monoxide, ytterbium oxide and zinc oxide; the molar ratio between tungsten oxide and lead monoxide is 1: 1, the doping amount of ytterbium oxide is 50 -300 ppm of the total weight of tungsten oxide and lead monoxide, the doping amount of zinc oxide is 50 -1050 ppm of the total weight of tungsten oxide and lead monoxide. The preparation method comprises following steps: (1) calcinating, (2) growing crystal. The invention is characterized in that it dops ytterbium and zinc in lead tungstate crystal, which greatly improves its optical properties on the basis of retaining original good properties of lead tungstate crystal. It needs no vacuum suction or inert gas protection during said crystal preparation process.
Owner:HARBIN INST OF TECH

Bismuth ferrite-lead tungstate multiferroic ceramic and preparation method thereof

The invention discloses bismuth ferrite-lead tungstate multiferroic ceramic and a preparation method thereof. The general formula of the chemical composition of the bismuth ferrite-lead tungstate multiferroic ceramic is (1-x)BiFeO3-xPb(W1 / 3Fe2 / 3)O3, wherein 0<x<0.4 and x represents molar fraction. The preparation method comprises the following steps: taking ferric oxide, bismuth trioxide, lead oxide and tungsten trioxide at a stoichiometric ratio of (1-x)BiFeO3-xPb(W1 / 3Fe2 / 3)O3 (0<x<0.4); performing ball milling, granulating, moulding, discharging rubber, and performing high temperature sintering and other working procedures to finally prepare the bismuth ferrite-lead tungstate multiferroic ceramic with good ferroelectric-ferromagnetic property. By adopting the method disclosed by the invention, the problems that the bismuth ferrite ceramic has weak magnetism and the technology is unstable can be solved, and the multiferroic material with good ferroelectric and ferromagnetic properties can be obtained.
Owner:XINING KEJIN INDUSTRIAL DESIGN CO LTD
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