64 results about "Lead tungstate" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The invention discloses an oil-resistant and aging-resistant natural rubber composite material for an instrument cable. The oil-resistant and aging-resistant natural rubber composite material comprises the following raw materials by weight: 55 to 80 parts of natural rubber, 20 to 45 parts of nitrile rubber, 2 to 3.5 parts of stearic acid, 1 to 3 parts of zinc oxide, 1.5 to 3 parts of sulfur, 1 to3.2 parts of calcium carbonate whiskers, 5 to 17 parts of carbon black, 3 to 8 parts of calcined kaolin, 5 to 9.8 parts of lead tungstate, 2 to 5 parts of a samarium compound, 0.1 to 0.3 part of an accelerator and 0.8 to 1.8 parts of an anti-aging agent. The oil-resistant and aging-resistant natural rubber composite material for the instrument cable provided by the invention has the advantages ofhigh strength, good oil resistance and excellent aging resistance.

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.

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.

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.

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.

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.