216results about How to "Lower sintering temperature" patented technology

The invention relates to a low-density ceramic proppant and a preparation method thereof, which belong to the field of exploring petroleum and natural gas. The preparation method of the low-density ceramic proppant comprises the steps of forming an inner core made of bauxite and coal gangue and a shell made of bauxite and trimanganese tetroxide into a ball and sintering to obtain low-density ceramic. The ceramic has higher strength and low density and is applicable to a ceramic proppant for fracturing a deep-level oil-gas well with high closed pressure and low permeability; the sintering temperature is relatively reduced in the range of 1,300-1,380DEG C, so that thus the energy consumption is effectively reduced and the energy can be saved by 20 percent; and meanwhile, the effect with low crushing rate can be achieved.

The invention discloses a gravel-shaped attapulgite fireproof ceramsite. The key points of the technical scheme are as follows: the gravel-shaped attapulgite fireproof ceramsite is composed of high-viscosity attapulgite clay powder, attapulgite clay tailing powder, granulated blast furnace slag powder, iron tailing powder, coal gangue powder, bauxite tailing powder and diatomite tailing powder. After ingredients of the gravel-shaped attapulgite fireproof ceramsite are mixed, granulated, baked, cooled, crushed and screened, the obtained product is packaged to obtain the gravel-shaped attapulgite fireproof ceramsite. The gravel-shaped attapulgite fireproof ceramsite is a grain with an irregular shape and the grain is internally provided with a plurality of small air holes; and the gravel-shaped attapulgite fireproof ceramsite is the fireproof ceramsite which has the advantages of light weight, strong compressive strength, low coefficient of heat conductivity, high refractoriness, stablechemical performance, and good corrosion resistance and heat-preservation and sound-proof effects. The gravel-shaped attapulgite fireproof ceramsite can be produced by comprehensively utilizing a plurality of types of the tailings, so that the gravel-shaped attapulgite fireproof ceramsite is good for improving the resource utilization rate, changing wastes to valuable things, and protecting the environment; and the gravel-shaped attapulgite fireproof ceramsite is applicable to producing fireproof ceramsite concrete and heat-preservation and sound-proof materials.

The invention relates to (HfTaZrTiNb) C high-entropy ceramic powder and preparation methods of the high-entropy ceramic powder and high-entropy ceramic blocks. Five-face centered cube (FCC) carbonizedpowder is made into ceramic powder through a high-energy ball milling method, then a discharging plasma method is adopted to realize preparation of the high-entropy ceramic blocks, and quick sintering of ceramic within a temperature range of 1700-2350 DEG C can be realized to obtain high-entropy ceramic with single-phase-face centered cube (FCC) structure. The preparation method of (HfTaZrTiNb) Chigh-entropy block ceramic is solved; the high-entropy ceramic with the FCC structure is finally obtained by strictly controlling parameters of a discharging plasma sintering furnace or a hot press furnace and characterizing XRD, so that the ceramic material system is enriched.

A niobic acid potassium sodium system lead-free piezoelectric ceramic and its production are disclosed. The components of the niobic acid potassium sodium system lead-free piezoelectric ceramic are (1-n)KxNa1-xNbO3.nMH, it is prepared by SPS process. The production is carried out by grinding mixing raw materials, calcining synthesizing niobate, using SPS process for the obtained powdery material, annealing treating under oxygen atmosphere, and obtaining piezoelectric/ferroelectric ceramic materials. Its advantages include lead-free composition, good piezoelectric performance, low calcining temperature, short calcining time and fine tissue.

The invention relates to a sintered composite soft magnetic material and a method for preparing the same. The material comprises a metal soft magnetic material, a soft magnetic ferrite and a low-melting-point soft magnetic alloy, wherein the metal soft magnetic material is formed by at least one of an Fe-Ni system, an Fe-Co system, an Fe-Co-V system, an Fe-Al system and an Fe-Al-Me system (Me is one or more than two of Co, Cr and Mo), the soft magnetic ferrite is formed by at least one of an Mn-Zn system, an Ni-Zn-based, an Li-Zn system and a Cu-Zn system, and the low-melting-point soft magnetic alloy is an Re-Fe-M system alloy (Re comprises one or more of 17 rare earth elements including Sc and Y, and M is one or more of metal elements including B, Al, Si, Ti, V, Cr, Mn, Co, Cu, Mo, Ni, Zn, Ga, Nb, Ta and W). The method for preparing the soft magnetic material formed by the components has the advantages that cold pressing and then sintering or hot pressing or spark plasma sintering are selected, and the soft magnetic material not only overcomes the low resistivity of the metal soft magnetic material and the low magnetic induction of the ferrite, but also maintains the excellent performance of the metal soft magnetic material and the soft magnetic ferrite.

The invention discloses a ceramic binding agent for a ceramic grinding block and a preparation method thereof and belongs to the technical field of powder metallurgy materials. The ceramic binding agent aims at achieving the effects that the retention to diamond is good, the expansion coefficient is matched with expansion coefficients of silicon carbide, brown aluminum oxide and the diamond, and the sintering temperature of a finished product is low. The ceramic binding agent is formed by the following powder materials of, by weight, 20 to 55 kilograms of silicon dioxide, 5 to 25 kilograms of aluminum oxide, 0 to 5 kilograms of zinc oxide, 0 to 5 kilograms of titanium dioxide, 0 to 7 kilograms of zirconium oxide, 10 to 20 kilograms of sodium carbonate, 5 to 15 kilograms of lithium carbonate and 8 to 30 kilograms of boric acid. According to the ceramic binding agent for the ceramic grinding block, the ceramic grinding block has the advantages of being low in sintering temperature, good in self-sharpening, good in sharpness, long in service life, low in carbon and environmentally friendly.

The invention discloses a method for preparing polycrystalline cubic boron nitride, which comprises the following steps: using cubic boron nitride and a bonding agent as raw materials, mixing the cubic boron nitride and the bonding agent and then ball-milling the mixture, wherein the ball material ratio during the ball milling is (1-4):1, the rotating speed is between 400 and 800 revolutions per minute, and the ball milling time is between 4 and 20 hours; drying the mixed mixture after the ball milling, adding an organic binder into the mixture after drying, mixing the mixture evenly, and screening the mixture through a 100-mesh screen; performing cold compression and forming with the pressure of between 0.8 and 2 GPa; and sintering the formed green body at a sintering temperature of between 1,000 and 1,300 DEG C, and keeping the temperature for 4 to 20 hours so that the finished product is obtained after the sintering. The polycrystalline cubic boron nitride PcBN prepared by the method is gray and is a compact block which has the superior performances of high hardness, high grinding efficiency, good impact resistance toughness, easy conditioning, good grinding quality and the like. The method has the advantages of simple equipment, easily-controlled operation, low cost and easy large-scale production, has favorable social value and economic value, and is easy to popularize and apply.

The invention belongs to the field of new inorganic material preparation and technical study, in particular relates to the low-temperature sintering formulation of a high-performance piezoelectric ceramics and the technology thereof. By adding the sintering auxiliary combination of Ba (CU 0.5w 0.5) O3, LiBiO2 and CuO, and adopting the common solid-phase combinatorial synthesis, the method of the invention can prepare ceramics Pb (Ni1/3 Nb2/3) O3-Pb (Zr, Ti) O3. The ceramics can be sintered under the temperature as low as 950 DEG C. The ceramics also boost a sound ferro-voltage electrical property. The key steps of the technical scheme are: synthesizing Pb (Ni1/3 Nb2/3) O3-Pb (Zr, Ti) O3 ceramic powders using Pb3O4, NiO, Nb2O5, TiO2, ZrO2 as ingredients, sintering the ceramic powders into ceramics under different temperatures with additives of Ba (CU 0.5w 0.5) O3, LiBiO2 and CuO. By adding low-melting point sintering auxiliary combination, the sintering temperature can be lowered to 950 DEG C, and the property of the ceramics sintered under low temperature is enhanced.

The invention discloses a method for preparing aluminum oxide ceramics with excellent wear-resisting property. The method comprises the steps of: (1) preparing for the following components of raw materials in percent by weight: 70-99 percent of Al2O3, 0.01-10 percent of rare earth yttrium compound and 0.19-20 percent of calcium compound or mineral, magnesium compound or mineral and silicon compound or mineral; (2) ball-milling the raw materials prepared in the step (1) for 4-96 h; (3) after drying the raw materials obtained in the step (2), preparing a blank body by adopting isostatic compaction, roller forming or axial extrusion forming; and (4) sintering the blank body at a temperature of 1150-1700 DEG C, preserving the temperature for 15-360 min and cooling to room temperature to prepare the finished product, wherein the sintering is pressureless sintering, and the sintering atmosphere is air atmosphere or reducing atmosphere. According to the method, through adding the rare earth yttrium compound and by adopting common industrial equipment, the process is simple; and compared with rare earth-free aluminum oxide ceramics, the aluminum oxide ceramics is low in sintering temperature and excellent in wear-resisting property.

The invention discloses application of composite oxide Li2Zn2W2O9 as a microwave dielectric ceramic capable of being sintered at low temperature; and a preparation method of the dielectric ceramic comprises the following steps: (1) weighing for batching Li2CO3, ZnO and WO3 original powder with the purity of more than 99.9% according to the chemical formula Li2Zn2W2O9; (2) mixing the raw materials of the steps (1) by wet ball milling for 12 hours with a milling medium being distilled water, drying, then presintering at 650 DEG C in air atmosphere for 6 hours; (3) adding a binder into the powder prepared in the step (2), granulating, then pressing for forming, and finally sintering at 700-750DEG C in the air atmosphere for 4 hours; the binder is a polyvinyl alcohol solution with the mass concentration of 5%, and added polyvinyl alcohol accounts for 3% of the total mass of the powder. The prepared dielectric ceramic Li2Zn2W2O9 can be well sintered at 700-750DEG C, the dielectric constant reaches to 19-20, the quality factor Qf value reaches as high as 67000-82000GHz, the temperature coefficient of resonance frequency is low, and the dielectric ceramic has great application value in industry.

The invention discloses a cylindrical attapulgite construction waste ceramsite. The key point of the technical scheme is as follows: the cylindrical attapulgite construction waste ceramsite comprises high viscosity attapulgite clay powder, attapulgite clay tailing powder, construction waste powder, red bentonite powder, diatomite tailing powder and wood chip powder. The ingredients of the cylindrical attapulgite construction waste ceramsite are mixed, granulated, roasted, cooled, screened and packaged to obtain the cylindrical attapulgite construction waste ceramsite. The cylindrical attapulgite construction waste ceramsite is of cylindrical shape, has rough and hard surface and has a lot of fine pores in the interior; and the spherical attapulgite refractory ceramsite is a construction ceramsite with light weight, high strength, low thermal conductivity, high refractoriness, stable chemical property, durability and good heat insulation and sound insulation effect. The comprehensive utilization of construction wastes and tailings in producing the cylindrical attapulgite construction waste ceramsite is beneficial for increasing the resource utilization rate, turning waste into wealth and protecting the environment; and the cylindrical attapulgite construction waste ceramsite disclosed by the invention is suitable for producing ceramsite concrete as well as heat insulation and sound insulation materials.

The present invention relates to the application of nano-material in ferrite. The nano-material is an ideal crystal micro-structure 'control agent', and can be partly dissolved on a grain boundary in a solid way; thus the nano-material can effectively reduce the sintering temperature, prevent the excessive growth of ferrite, maintain the ferrite of single domain, and improve the function of density of sintered ferrite at the same time so as to improve the magnetic properties. Besides, the nano-material is a good ''replacement agent of ion''.In the solid-phase reaction, some elements enter the crystallite structure to perfect the crystal structure, so as to further improve saturated magnetic field strength of ferrite and improve the anisotropic constant and other functions of magnetic crystal.

The invention discloses a method for preparing binary nanometer cooperative reinforcing and toughening silicon carbide ceramics, and silicon carbide powder, yttrium aluminum garnet, nano particles and nano crystal whickers are taken as the main raw materials. The method comprises the following steps: 1) the main raw materials, a binder and a dispersant are added into de-ionized water, after being ball-milled and mixed, water-base silicon carbide slurry is prepared; 2) the water-base silicon carbide slurry is sprayed and dried by adopting a spray granulation technology; 3) the obtained silicon carbide granulating powder is formed by adopting pre-pressing of dry pressing and final pressing of cold isostatic pressing; and 4) the obtained green body of silicon carbide is put in a vacuum non-pressure sintering furnace to be treated, thus obtaining the binary nanometer cooperative reinforcing and toughening silicon carbide ceramics. The invention also discloses the binary nanometer cooperative reinforcing and toughening silicon carbide ceramics prepared in the method. The silicon carbide ceramics have the advantages of large flexural strength, good fracture toughness and the like.

The invention belongs to the field of rare-earth permanent magnetic materials and particularly provides a method for preparing high-density and fine-grain sintered Nd-Fe-B. The production method comprises the following steps: smelting and casting master alloy to make a rapid hardening thin band, grinding powder by hydrogen pulverizing gas flow, sintering and densifying under hot isostatic pressure after oriented molding, and finally carrying out tempering treatment to obtain a product. In the invention, through the application of gas pressure which is not lower than 0.5MPa in the sintering process, not only is the density of the magnet increased, the sintering temperature and the sintering time can also be lowered and shortened; and as a result, grains are obviously refined, and the distribution of Nd-rich phases among the grains is more uniform, so that the remanence and the coercivity of the magnet are improved, and the comprehensive performance is obviously improved.

The invention particularly relates to a metal bonding agent, a metal bonding agent diamond grinding wheel and a preparing method of the metal bonding agent diamond grinding wheel, and belongs to the technical field of grinding materials and grinding tools. The metal bonding agent comprises following components including, by mass percent, 5%-20% of copper, 2%-6% of tin, 1%-5% of titanium hydride and the balance a copper-tin alloy. The metal bonding agent diamond grinding wheel can be prepared with the metal bonding agent and titanium plating diamonds or nickel plating diamonds as raw materialsthrough material mixing and vacuum hot pressed sintering. The copper-tin alloy powder serves as a main component of the bonding agent, the grinding wheel sintering temperature is reduced in the hot press process, and the production cost is reduced. The titanium hydride is decomposed in the hot press process, metal powder of an oxidized part can be subjected to reducing, the strength of the bondingagent is improved, and accordingly the strength of the metal bonding agent diamond grinding wheel is improved.

The invention discloses a wearable castable material, which comprises the following components by weight: 15 to 25 parts of porcelain granule of 0 to 1mm; 10 to 20 parts of porcelain granule of 1 to 5mm; 35 to 55 parts of calcined andalusite granule of 1 to 5mm; 4 to 6 parts of 1000-mesh Alpha aluminum micro-powder; 3 to 5 parts of silicon micro-powder; 4 to 5 parts of pure calcium aluminate cement; 0.1 to 0.3 parts of a water reducer of silicate type; 5 to 7 parts of water. The invention further discloses a preparation method of the wearable castable material. The wearable castable material has high alkali-proofness, resistance to erosion of chlorine, fire resistance, and abrasive resistance, and is applicable for masonry of various large cement rotary furnaces and destructors.

The invention discloses microwave dielectric ceramic LiMg2V3O10 allowing low-temperature sintering and a preparation method of the microwave dielectric ceramic LiMg2V3O10. The preparation method includes the steps that (1), Li2CO3 original powder, MgO original powder and V2O5 original powder are weighed and proportioned according to components of LiMg2V3O10, wherein the purity of the original powder is over 99.9%; (2), wet-type ball milling is performed on the raw material in the step1 for 12 hours with distilled water being ball milling media and pre-sintered for 6 hours in the atmosphere at 750 DEG C after drying; (3), binding agents are added into powder obtained in the step2, granulation is performed, then, compression forming is performed, and finally sintering is performed for 4 hours in the atmosphere at 800 DEG C-830 DEG C, wherein polyvinyl alcohol solutions with the 5% concentricity are adopted as the binding agents, and the additive amount of polyvinyl alcohol accounts for 3% of the total mass of the powder. According to the prepared ceramic, sintering is good at 800 DEG C-830 DEG C, the dielectric constant reaches 12-13, the quality factor (Qf) value is up to 75000 GHz-89000 GHz, the temperature coefficient of resonance frequency is small, and the microwave dielectric ceramic has great application value in the industry.

The invention relates to a biodegradable iron-zinc alloy and a preparation method thereof, and belongs to the technical field of design and manufacture of biomedical iron-zinc alloys. The iron-zinc alloy consists of 80-95% of iron and 5-20% of zinc according to the mass percentage. The preparation method comprises the steps: preparing an iron powder and a zinc powder according to the designed components, carrying out ball milling for more than 20 h at the rotational speed of 240-400 r/min under protection of argon gas, to obtain an iron-zinc alloy powder; then using the iron-zinc alloy powder,and under the protection of argon gas, adopting a selective laser sintering process, controlling the laser power to 100-200 W, controlling the scanning rate to 10-30 mm/s, controlling the sintering temperature to 750-1400 DEG C, controlling the light spot diameter to 80-120 [mu]m, and thus preparing the iron-zinc alloy. The biodegradable iron-zinc alloy is molded by combining mechanical alloyingwith selective laser sintering. The biodegradable iron-zinc alloy has suitable degradation rate, high mechanical strength and good biocompatibility, and has a good application prospect in the field ofbone tissue repair.

The invention relates to a method of preparing a porous silicon carbide support at low temperature. The method includes: using sodium dodecyl benzene sulfonate (SDBS) and ZrO2 as sintering auxiliaries, activated carbon powder as a pore forming agent and silicon carbide powder as aggregate; mixing well; obtaining a blank through dry pressing; drying in an oven; sintering at sintering temperature of about 1150 DEG C to obtain the silicon carbide support. By using the method, sintering temperature can be lowered, and energy consumption can be saved. The support prepared by the method has high strength, high gas permeation performance and excellent chemical stability and has quite wide application prospect in the aspects of high-temperature flue gas dedusting and wastewater treatment.

The present invention discloses low-temperature thick film circuit paste and a preparation method therefor. The low-temperature thick film circuit paste comprises, in percentage by mass, 1%-5% of an inorganic adhesive phase, 10%-30% of an organic solvent carrier, and 65%-85% of high-purity silver powder; the inorganic adhesive phase comprises, in percentage by mass, 40%-60% of Bi2O3, 20%-40% of B2O3, 15%-20% of ZnO, and 0.5%-2.5% of CuO; and the organic solvent carrier comprises, in percentage by mass, 85%-90% of a main solvent, 5%-10% of a thickening agent, 1%-5% of a leveling agent, 0.5%-1.5% of a thixotropic agent, and 0.5%-1% of a defoaming agent; The low-temperature thick film circuit paste is low in sintering temperature, short in sintering time, low in resistance value, good in adhesion and good in solderability. The preparation method sequentially comprises the process steps of: preparing the inorganic adhesive phase; preparing the organic solvent carrier; and preparing the low-temperature thick film circuit paste. The preparation method can effectively prepare the low-temperature thick film circuit paste.

The invention discloses a Bi Cu 1-x SeO-based oxide thermoelectric ceramic material and a preparation method thereof, wherein x is more than or equal to 0 but less than or equal to 0.1; the preparation method comprises the following steps of: (1) according to the stoichiometric proportion in Bi Cu 1-x SeO, weighing Bi, Cu, Se and Bi2O3, mixing to obtain mixture; (2) grinding the obtained mixture to obtain precursor powder; and (3) carrying out spark plasma sintering on the precursor powder to obtain the Bi Cu 1-x SeO-based oxide thermoelectric ceramic material. The Bi Cu 1-x SeO-based oxide thermoelectric ceramic material not only has higher electrical property, but also maintains lower heat transmission performance and has good thermoelectric transmission performance by introducing Cu defect, thus being a novel high-temperature oxide thermoelectric ceramic material with a wide application prospect. Compared with the common solid phase sintering, the method is short in reaction time, low in sintering temperature and simpler in synthesis process, and can be used for further synthesizing a Bi Cu 1-x SeO-based ceramic sample.

The invention discloses a low-cost tantalum carbide coating preparation method. The method comprises the following steps that a matrix is pretreated at first, then, tantalum carbide, sintering aids, adhesives and solvents are adopted for preparing turbid liquid, the turbid liquid is uniformly sprayed or brushed to the surface of the matrix, and finally the matrix with the sprayed or brushed matrix is subjected to pre-temperature or sintering treatment, and a tantalum carbide coating with the uniform thickness and dense structure can be obtained on the matrix. The surface of the matrix is coated with the TaC coating with the completely dense structure, and the surface of the matrix can be isolated and protected to a large extent due to the coating; the method can be used for crystal and semiconductor production device or components, and the phenomenon that crystal defects are caused due to the fact that device or component surface layer particles enter crystals during crystal growth is avoided. Compared with the CVD deposition technology, the technological process is low in cost, and the method is simpler, easy to implement, good in repeatability and capable of directly forming the compact and crack-free coating on the surface of a material.

The invention discloses a low-temperature-sintering microwave dielectric ceramic Li2MgNb2O7 and a preparation method thereof. The preparation method comprises the following steps: (1) weighing and proportioning Li2CO3, MgO and Nb2O5 original powders with the purity of higher than 99.9% according to the composition of the Li2MgNb2O7; (2) carrying out wet ball milling mixing on the raw materials in the step (1) for 12 hours by using distilled water as a ball milling medium, drying, and presintering in an 850 DEG C atmospheric atmosphere for 6 hours; and (3) adding an adhesive into the powder prepared in the step (2), granulating, compacting, and finally, sintering in a 900-930 DEG C atmospheric atmosphere for 4 hours, wherein the adhesive adopts a 5 wt% polyvinyl alcohol solution, and the addition amount of the polyvinyl alcohol is 3% of the total mass of the powder. The ceramic has favorable sintering property at 900-930 DEG C, the dielectric constant reaches 25.6-26.3, the quality factor Qf value is up to 79000-88000 GHz, the temperature coefficient of resonance frequency is small, and the ceramic has great application value in industry.

The invention relates to the technical field of an electronic material, and particularly to PERC crystal silicon solar battery positive silver paste. The silver paste comprises the following components based on mass percentages: 1-90% of silver powder, 5-15% of organic carrier, 1-8% of glass powder, 0-3% of auxiliaries and 0.01-0.2% of fluxing agent, wherein the sum of the component contents is equal to 100%; and the fluxing agent is one or several kinds of metal or metal oxide or metal resinate selected from La, Ce, Nd, Eu, Gd, Tm or Er. By adding metal or metal oxide or metal resinate to the paste, the needed temperature in sintering is lowered, so that the paste is suitable for low-temperature sintering and the PERC technological use can be satisfied.

There is provided a process of preparing low-temperature sintered microwave dielectric ceramics, prepared by a process comprising co-precipitating Nb and Bi or Zn in an aqueous basic solution to obtain a BiNbO₄ or Zn₃Nb₂O₈ precursor powder, thermally decomposing the powder to obtain BiNbO₄ or Zn₃Nb₂O₈ powder, adding CuO and V₂O₅, pulverizing and sintering the mixture, which produces ceramics having small dielectric losses (Q·f₀>15,000 GHz) and high dielectric constant (k=20–45) at microwave frequencies by sintering at a low temperature of 700 to 750° C. Thus, the microwave dielectric ceramics prepared in accordance with the present invention can be advantageously used in multi-layer ceramic packaging such as filter planar antenna, microwave oscillator, etc., which comprise base metals such as silver (Ag) and copper (Cu) as an internal electrode.

The invention discloses a method for low-temperature rapid sintering of alumina-based transparent ceramics with high thermal conductivity through hot pressing. The method takes alumina as raw materials, employs silicon dioxide and lithium carbonate as sintering aids, and uses a spark plasma sintering method to prepare alumina-based transparent ceramics with high thermal conductivity. Compared with traditional alumina ceramics, the alumina-based transparent ceramics provided by the method of the invention have obvious advantages that: the ceramics have substantially improved thermal conductivity, thus meeting the thermal dissipation requirements of ceramic substrates and enabling high power LED to work normally; also, the difficult problem of excess sintering temperature of pure alumina ceramics is solved; and rare earth-doped alumina-based transparent ceramics prepared by the formula and method of the invention have a sintering temperature of only 1370DEG C.

The invention discloses high-quality-factor temperature-stable low-dielectric-constant microwave dielectric ceramic CaLi3NdV8O24 capable of being sintered at low temperature, and a preparation method thereof. The preparation method comprises the following steps: (1) weighing and burdening original powder, having the purity over 99.9% (by weight), of CaCO3, Li2CO3, Nd2O3 and V2O5 according to the constitution of CaLi3NdV8O24; (2) carrying out wet ball-grinding and mixing on the raw materials in the step (1) for 12 hours, wherein a ball grinding medium is distilled water, drying and then pre-sintering for 6 hours at an air atmosphere at 700 DEG C; (3) adding a binder to the powder obtained in the step (2), granulating, then carrying out compression moulding, and finally sintering for 4 hours at an air atmosphere of 750-800 DEG C; a polyvinyl alcohol solution having the mass concentration of 5% is adopted as the binder, and the addition amount of the polyvinyl alcohol accounts for 3% of the total mass of the powder. The ceramic prepared by using the preparation method can be favorably sintered below 800 DEG C, wherein the dielectric constant reaches 20.6-21.4, the quality factor QF is up to 91000-126000GHz, and the temperature coefficient of resonance frequency is low; the microwave dielectric ceramic CaLi3NdV8O24 has a great application value in the industry.

The invention belongs to the technical field of materials, and in particular relates to upconversion fluorescent powder and a preparation method thereof. The preparation method comprises the following steps of: preparing an Er<3+>/Yb<3+>codoped mayenite gel precursor by adopting a chemical coprecipitation method, proportionally dissolving high-purity Er2O3, Yb2O3, Al(NO3)3.9H2O and Ca(NO3)2.4H2O into deionized water, dripping a proper amount of nitric acid, heating and uniformly stirring; adding a proper amount of precipitator NH3.H2O, drying the obtained gel precursor, and sintering to obtain Er<3+>/Yb<3+>codoped mayenite up-conversion fluorescent powder. Mayenite is used as a base material, and because the band-gap width thereof reaches 5.9eV, the temperature quenching effect of Er<3+> ion luminescence can be weakened, which is beneficial to the upconversion emission of Er<3+> ions. The Er<3+>/Yb<3+>codoped mayenite up-conversion fluorescent powder can be applied to the fields of biological molecular marker probes, optoelectronic devices and the like.

The invention provides a cathode material precursor which is of a core-shell structure. The material chemical formula of the core is Ni<1-x-y-z>Co<x>Al<y>Mn<z>(OH)2, and the material chemical formulaof the shell is Ni<1-r-s>Co<r>Mn<s>CO3, wherein 1-x-y-z is a value in the range of 0.80 to 0.96, x is greater than 0, y is a value in the range of 0.01 to 0.10, z is a value in the range of 0.01 to 0.10, 1-r-s is a value in the range of 0.34 to 0.70, r is greater than 0, and s is a value in the range of 0.20 to 0.40. The cathode material of the invention has a stable structure, high safety performance, long cycle life and good thermal stability.

The invention discloses a low-temperature sintered crystalline silicon solar cell positive electrode silver slurry and a preparing method thereof. The method comprises the steps of 1, preparing glasspowder, wherein raw materials are weighed, mixed evenly, smelted, then taken out, subjected to water quenching, smashing and ball-milling, sieved, dried and sieved to obtain the glass powder; 2, preparing an organic carrier, wherein resin and an organic solvent are weighed, the resin is dissolved in the organic solvent, a dispersant and an anti-settling agent are added as additives, and a mixtureis stirred evenly to form the organic carrier; 3, weighing silver powder, the glass powder and metallic oxide powder, adding the silver powder, the glass powder and the metallic oxide powder into theorganic carrier, stirring a mixture evenly, grinding the mixture, conducting vacuum degassing on the mixture, and obtaining the silver slurry when detection is qualified.