55results about How to "High sintering activity" patented technology

The invention provides a preparation method of a high-temperature-resistant antioxidant chopped carbon fiber reinforced ceramic-based composite material, and relates to the field of ceramic-based composite material preparation, and the preparation method comprises the following steps: S1, selection and surface treatment of reinforced fibers: selecting chopped carbon fibers as a reinforced material, and carrying out surface modification treatment on the chopped carbon fibers to obtain the reinforced fibers; according to the present invention, the surface modification treatment is performed on the short carbon fiber, and particularly the SiC coating is coated on the fiber surface by using the chemical vapor deposition (CVD) method, such that the oxidation resistance of the carbon fiber under the high temperature condition is effectively improved. The coating enhances the stability of the fiber, reduces the oxidation loss of the fiber at high temperature, enhances the interface bonding force between the fiber and the ceramic matrix, and avoids stripping or interface failure in a high-temperature environment, thereby ensuring the overall stability and service life of the material.

The invention discloses a preparation method of ultra-fine grain high-entropy carbide-based metal ceramic, which comprises the following steps: step 1, dispersing multi-component carbide powder or micron-sized high-entropy carbide powder in an organic solvent, adding phenolic resin and ceramic grinding balls, and carrying out ball milling; step 2, pre-sintering the dried high-entropy ceramic powder; 3, the obtained high-entropy carbide ceramic powder and metal powder are subjected to conventional ball milling, 1-3 wt% of paraffin or a rubber forming agent is added, a ball milling medium is absolute ethyl alcohol, and then the mixture is subjected to spray granulation; step 4, pressing and forming the granulated powder; and fifthly, the pressed blank is degreased and sintered, and the ultra-fine grain high-entropy carbide-based metal ceramic is obtained. The ultra-fine grain high-entropy carbide-based metal ceramic material with the bending strength superior to 2300 MPa, the fracture toughness superior to 9.5 MPa.m < 0.5 > and the Rockwell hardness superior to 92.0 HRA can be obtained, and the ultra-fine grain high-entropy carbide-based metal ceramic material can be widely applied to the fields of bearing materials, cutting tools, mold materials and the like.

The embodiment of the invention provides a preparation method of a tungsten-copper alloy and the tungsten-copper alloy, and relates to the technical field of alloy preparation.The method comprises the steps that superfine tungsten oxide powder, tungsten salt, copper salt and a polymer additive are added into deionized water to be evenly mixed, and a precursor mixed solution is obtained; carrying out spray granulation on the precursor mixed solution by adopting a spray dryer to obtain spherical tungsten-copper precursor composite powder; roasting the spherical tungsten-copper precursor composite powder to obtain tungsten-copper oxide composite powder, and carrying out segmented reduction on the tungsten-copper oxide composite powder to obtain tungsten-copper composite powder with tungsten grains having a nanocrystalline / ultra-fine grain bimodal distribution characteristic; and the tungsten-copper composite powder is pressed to obtain an alloy blank, the alloy blank is sintered, and the tungsten-copper alloy is prepared. According to the double-peak distribution tungsten-copper composite powder, full densification of the alloy can be promoted through coupling rearrangement of large and small tungsten particles in the sintering process, and the compactness, the heat conductivity and the electric conductivity of the tungsten-copper alloy can be improved.

The invention relates to the technical field of soft magnetic ferrite materials, and particularly discloses a NiCuZn-MgO composite material and a preparation method thereof. The NiCuZn-MgO composite material comprises main components and additives, and the main components comprise the following components in percentage by weight: 36-72 wt% of Fe2O3, 13-16 wt% of ZnO, 6-9 wt% of NiO, 3-6 wt% of MgO and the balance of CuO; based on the total weight of the main components, the additive comprises the following components in percentage by weight: 0.5 to 1.5 weight percent of Bi2O3, 0.3 to 1.5 weight percent of SiO2 and 0.3 to 1.5 weight percent of CaO. According to the NiCuZn-MgO composite material prepared by the invention, the cost of soft magnetic ferrite can be reduced, and the NiCuZn-MgO composite material has high magnetic conductivity and high Bs.

The invention relates to a fly ash sintered material with high fly ash mixing amount and a preparation method and application thereof. The method comprises the following steps: uniformly mixing silicon powder, alkali, water and a dispersing agent, and stirring and reacting at 75-95 DEG C for 4-12 hours to obtain a special silicon aggregate solution; uniformly mixing a sintering aid and the waste incineration fly ash to obtain solid powder, and then putting the solid powder and the special silicon aggregate solution into a forming and granulating device for forming and granulating to obtain formed particles; the waste incineration fly ash is calcined for 0.2-1.2 h in high-temperature treatment equipment at the temperature of 600-900 DEG C, the fly ash sintered material is obtained, the mass fraction of the waste incineration fly ash in the fly ash sintered material is 70-85%, and the mass fraction of the sintering aid is 2-5%; according to the method, the high doping amount of the waste incineration fly ash can be achieved in the fly ash sintering heat treatment process, the sintering temperature can be reduced, and the fly ash sintered material with the heavy metal leaching toxicity reaching the standard and the strength reaching the standard can be obtained by conducting low-temperature sintering treatment on the waste incineration fly ash with the high fly ash doping amount.

The present application provides a method for preparing a nano silver powder with high sintering activity, belonging to the technical field of nano silver powder preparation. The method separates the seed crystals from the mother liquor in the crystal nucleus solution, and then stores the seed crystals in a dispersant solution. When preparing the nano silver powder later, the dispersant solution containing the seed crystals is directly poured into a silver nitrate solution, and a reducing agent solution is added dropwise, and the water bath is heated at the same time. After the reaction is complete, a flocculant is added, and the solution is washed. After freeze drying and polishing, a nano silver powder with high sintering activity can be obtained. The present invention stores the seed crystals in a dispersant solution, and the seed crystals can be stored for a long time, and the volume of the seed crystals used in the subsequent reaction to prepare the nano silver powder can be greatly reduced, and the dispersant does not need to be added again when the nano silver powder is prepared later. The present invention prepares silver powder with a particle size between 50-200nm with a simple process, and the silver powder has good dispersibility, good sintering activity, and can be sintered at a low temperature of 180°C, which can be applied to the field of low-temperature sintering nano silver paste.

The invention discloses a jack-fruit-shaped manganese-rich precursor as well as a preparation method and application thereof. The manganese-rich precursor is of a composite multilevel structure, the composite multilevel structure is three-stage particles, the three-stage particles are composed of first-stage particles and second-stage particles jointly, and the second-stage particles are formed by stacking a plurality of first-stage particles and are of a sphere-like structure; the third-stage particles are formed by stacking a plurality of second-stage particles and are of jack-fruit-shaped structures; the specific surface area SSA of the manganese-rich precursor is larger than or equal to 80 and smaller than or equal to 200 m < 2 > / g, and the tap density TD of the manganese-rich precursor is larger than or equal to 1.3 g / cm < 3 >. The manganese-rich precursor has high specific surface area and high tap density at the same time, the change rule that the specific surface area and tap density of the precursor always present opposite changes is broken, and the positive electrode material end prepared from the precursor has higher capacity.

The invention discloses a method for preparing hexagonal SrFe by liquid phase doping 12 O 19 The invention relates to the field of permanent magnet ferrite preparation, and aims to solve the problem that the existing doping method easily leads to uneven raw material composition and the formation of mixed phases in the magnet; the invention comprises the following steps: 3+ / Sr 2+ Atomic ratio, weigh analytical pure Fe 2 O 3 、SrCO 3 ; The weighed raw materials were placed in a mortar and ground thoroughly to mix; C was added to the resulting mixture 8 H 20 O 4 Si and fully grind and mix evenly; put the ground and mixed powder into a mold for tableting to obtain a cylindrical sample; take the sample and sinter it in a muffle furnace and then cool it to room temperature with the furnace to obtain a liquid-phase doped SrM ferrite block; the present invention can use liquid C 8 H 20 O 4 Si as an additive for liquid phase doping of hexagonal SrFe 12 O 19 The saturation magnetization of ferrite is further improved, and the generation of impurity phase can be effectively suppressed.

The invention provides a diamond trephine which comprises a steel base body and a tool bit, the tool bit comprises the following raw materials in percentage by weight: 50%-60% of superfine iron-nickel pre-alloy powder, 15%-30% of superfine copper powder, 2%-5% of tin powder, 15%-30% of superfine tungsten carbide powder, 5%-10% of yttrium oxide powder and the balance of diamond raw materials, and the diamond raw materials comprise the superfine iron-nickel pre-alloy powder, the superfine copper powder, the tin powder, the superfine tungsten carbide powder, the yttrium oxide powder and the diamond raw materials. The trephine is characterized in that the trephine comprises a steel base body, the steel base body is provided with a plurality of tool bits, the tool bits comprise 3%-6% by volume of yttrium oxide powder and 15%-50% by volume of diamond, the granularity of the tool bits is 400-700 microns, one faces of the tool bits are arranged on the steel base body at intervals through laser welding, the other faces of the tool bits are provided with U-shaped grooves, and the two side faces of the tool bits are further provided with V-shaped grooves. The method specifically comprises the steps of burdening, mixing, coating, cold press molding, hot press sintering, laser welding and the like. According to the trephine, the cutting speed of the trephine can be effectively increased, the service life of the trephine can be effectively prolonged, the U-shaped groove and the V-shaped groove are formed in the tool bit, the contact area between the tool bit and a cutting material is reduced, friction cutting resistance is reduced, and the chip removal capacity and sharpness of the trephine can be obviously improved.

The invention discloses a preparation method of aluminum-doped quartz sand, which comprises the following steps: dispersing fumed alumina, fumed silica, a dispersing agent, a defoaming agent and a binder in ultrapure water to obtain a mixed solution, and uniformly dispersing the mixed solution by using a nano grinding machine to form milky white turbid liquid; carrying out spray granulation on the turbid liquid by utilizing a centrifugal drying spray granulation tower to form spherical particles; mixing the spherical particles with a release agent, and carrying out compression molding by virtue of cold isostatic pressing equipment, so as to obtain a molded body; and the formed body is subjected to high-temperature glue discharging, sintering and crushing treatment, and the aluminum-doped quartz sand is obtained. The aluminum-doped quartz sand with excellent performance is obtained by adopting nano-scale gas-phase aluminum oxide and gas-phase silicon dioxide through treatment of processes such as a material mixing mode, high-pressure forming and high-temperature sintering, the purity is greater than or equal to 99.999%, the density is high, the temperature resistance is excellent, the aluminum content is controllable and is uniformly distributed, and the aluminum-doped quartz sand has the advantages of high-temperature resistance, high-temperature resistance and the like. The requirements of high purity and high temperature resistance of the quartz sand in the fields of photovoltaics, semiconductors and the like can be met.

The invention relates to silver powder, and particularly discloses active silver powder and a preparation method and application thereof. The silver powder prepared by the preparation method provided by the invention has high sintering activity and strong chemical stability, and can meet the requirements of the field of low-temperature slurry in photovoltaic cells on high-reliability and high-performance new materials.

The invention relates to the technical field of high-temperature infrared stealth resin-based composite materials, and particularly discloses a resin-based heat-proof composite material coated with a low-temperature curing high-temperature infrared stealth coating on the surface, which sequentially comprises a resin-based heat-proof composite material and a high-temperature infrared stealth coating from inside to outside, according to the high-temperature infrared stealth coating, nano metal and flaky metal powder serve as low-emissivity filler, and a glass phase and organic resin serve as binding phases. The preparation method of the composite material has the characteristics of low cost and low energy consumption, and the damage to the resin-based heat-proof composite material is reduced. The high-temperature infrared stealth coating on the surface of the composite material has the characteristics of wide temperature range, low emissivity and high combination, so that falling and stripping of the high-temperature infrared stealth coating caused by decomposition of the composite material in a use environment are avoided, and the stealth problem of an aircraft in a wide temperature range is solved.

The invention discloses a preparation method of high-entropy carbide-based metal ceramic, which comprises the following steps: step 1, preparing according to the molar ratio of a carbide addition phase, putting powder into a sand mill, and carrying out first ball milling; 2, carrying out secondary ball milling, adding a metal binder, carbon black, paraffin, rubber or polyvinyl alcohol and other binders into the mixed carbide powder, carrying out ball milling, mixing, and carrying out spray drying on the mixed powder after the ball milling is finished; thirdly, the powder is subjected to pressing forming, and the pressing pressure ranges from 50 MPa to 200 MPa; and fourthly, the pressed blank is degreased and sintered, and the high-entropy carbide-based metal ceramic is obtained. The high-entropy carbide-based metal ceramic material with the bending strength superior to 2100 MPa, the fracture toughness superior to 8.5 MPa.m < 0.5 > and the Rockwell hardness superior to 92.0 can be obtained, and the high-entropy carbide-based metal ceramic material can be widely applied to the fields of bearing materials, cutting tools, mold materials and the like.

The application provides a ceria / yttria composite stabilized zirconia grinding medium and a preparation method. The method comprises the following steps: step one, mixing zirconia, ceria, yttria and kaolin, and then adding an appropriate amount of dispersant and water to obtain a slurry; step two, performing centrifugal spray drying on the slurry to obtain ceria / yttria composite stabilized zirconia powder; step three, adding the ceria / yttria composite stabilized zirconia powder into a binder, and then rolling to form a green body of spherical grinding medium; and step four, sintering and polishing the green body of spherical grinding medium to obtain the ceria / yttria composite stabilized zirconia grinding medium. The method can obtain low particle size and high specific surface area through high-temperature ball milling, and can also promote the solid solution of the stabilizer into the zirconia crystal lattice through heat treatment, so as to improve sintering activity, reduce sintering temperature and reduce production cost.

The application discloses a preparation method of a high-strength aluminum nitride substrate and relates to the technical field of aluminum nitride substrate preparation. The method comprises the following steps: preparing modified aluminum nitride powder; adding a non-oxygen composite sintering aid composed of fluorides and borides to the modified aluminum nitride powder to obtain a mixture; the adding amount of the composite sintering aid is 0.5wt%-5wt% of the total mass of the modified aluminum nitride powder; the mixture, a binder and a dispersant are mixed in a planetary ball mill to obtain a uniform slurry; the slurry is subjected to flow casting to form a green porcelain embryo, and then, glue removal treatment is performed under the protection of flowing inert gas to remove the binder; the green porcelain embryo after glue removal is placed in an atmosphere sintering furnace to perform a multi-stage temperature rising sintering procedure to form a ceramic body; and the sintered ceramic body is subjected to heat treatment and then cooled to obtain the aluminum nitride substrate. The application reduces the lattice thermal resistance of the aluminum nitride substrate and improves the mechanical strength of the aluminum nitride substrate.

The invention discloses a preparation method of silver powder and a silver powder surface nano-structure, and the preparation method comprises the following steps: (1) mixing micron silver powder, a nano silver seed crystal solution, an organic solvent and a binding agent to form a mixture solution; preparing a complexing silver ion solution and a reducing agent solution; the binding agent is organic acid containing carbon-oxygen double bonds and hydroxyl, the complexing silver ion solution is a silver ion solution containing a complexing agent, and silver ions exist in a complexing state; (2) the complexing silver ion solution, the reducing agent solution and the mixture solution are mixed and react, newly generated silver is formed on the surface of the micron silver powder, and the surface of the micron silver powder is wrapped; and (3) after the reaction is finished, separating to obtain silver powder, cleaning, filtering and drying to obtain a silver powder product. By means of all-directional coating of silver particles, the higher coating rate of follow-up surface nanocrystallization silver powder is achieved, and therefore the silver powder product with high sintering activity is obtained.

The invention discloses a (Ti, W) C-AlCrCoNiMo high-entropy metal ceramic material as well as a preparation method and application thereof, and belongs to the technical field of metal ceramic materials. The invention provides a metal ceramic material which is prepared by taking (Ti, W) C ceramic as a matrix, adding Al, Cr, Co, Ni and Mo as a high-entropy alloy binding phase, carrying out two-step wet-dry composite ball milling process treatment and carrying out spark plasma coupling high-frequency induction sintering. The problem of segregation can be solved after two-step wet-dry composite ball milling process treatment, ideal pre-alloyed powder is obtained, the components are more uniform, the dispersity is better, and the composite powder treated by an optimized ball milling method is sintered through spark plasma coupling high-frequency induction. And the high-entropy metal ceramic material with high bending strength, high hardness and excellent fracture toughness can be obtained at the sintering temperature of 1300 DEG C.

The present invention relates to the field of piezoelectric ceramic materials, in particular to a high-temperature piezoelectric ceramic and a preparation method thereof, the structural formula of which is as follows: (1-x-y)(Bi 1‑p Ln p )FeO3‑xBa(Ti 1‑q Al q )O3‑yBiYbO3‑zwt%GeO2 wherein Ln is a lanthanide element; 0.1≤x≤0.5, 0.01≤y≤0.05; 0.1≤z≤1; 0.1≤p≤0.5, 0.01≤q≤0.05, and does not contain lead, and will not cause harm to human health and living environment during the manufacturing, use and waste disposal processes.

The invention provides an anti-oxidation coating for the surface of nickel-iron-based alloy, which is prepared by the following method, with nickel-iron-based alloy as substrate, and a lanthanum zirconate anti-oxidation coating is deposited on the substrate surface using a pulsed laser deposition method; during the pulsed laser deposition process, the substrate temperature is 550-800°C, the laser energy is 200-400J, the pulse frequency is 2-6Hz, the spacing between the lanthanum zirconate target and the substrate is 4-5cm, and a mixed atmosphere of oxygen and an inert gas with a volume ratio of 4-6:1 is used as a protective atmosphere. The obtained lanthanum zirconate anti-oxidation coating not only has good interface bonding with the nickel-iron-based high-temperature alloy, but also has good anti-oxidation performance under a saturated water vapor environment, and can achieve the purpose of alloy protection without affecting the mechanical properties of the alloy.

The present application relates to a flaky stacked porous silver powder and a preparation method thereof, the preparation method comprising: configuring a first solution, a second solution, a third solution and a fourth solution, the first solution comprising silver nitrate, the second solution comprising a reducing agent, at least one of the first solution and the second solution further comprising a crystal form disruptor, the third solution comprising a seed crystal and a dispersant, and the fourth solution comprising a surfactant; adjusting the pH value of the second solution to a preset value and then adding the second solution to the third solution for reaction to obtain a reaction solution; adding the fourth solution to the reaction solution for surface treatment to obtain a silver powder slurry; separating the flaky stacked porous silver powder from the silver powder slurry, the flaky stacked porous silver powder being a porous structure formed by flaky stacking, thereby being able to prepare a flaky stacked porous silver powder having a high specific surface area, so as to achieve high sintering activity of the silver powder, and having broad application prospects in the field of photovoltaic silver paste.

This invention discloses an active metal brazing paste and its preparation method. The active metal brazing paste is characterized by comprising brazing powder and a binder, wherein the binder component accounts for 8-20% by mass. The brazing powder comprises the following components by mass percentage: 10-30% nano-silver powder; 60-80% silver-copper alloy powder; 5-10% aluminum-silicon alloy powder / titanium-aluminum alloy powder; 2-5% titanium hydride powder. The binder comprises the following components by mass fraction: 75-90% solvent; 5-10% thickener; 2-4% surfactant; 1-2% dispersant; 2-5% thixotropic agent. Compared with the prior art, the active metal brazing paste of this invention has the following beneficial effects: the ceramic copper-clad laminate prepared by the active metal brazing paste has high connection reliability and excellent resistance to thermal cycling.

The invention relates to alumina toughened zirconia ceramic powder as well as a preparation method and application thereof. The invention develops a modification preparation method which integrates precise proportioning, multi-stage PH regulation and control, composite coating agent modification and controllable aging process, and definitely adopts a solid-to-liquid ratio of (50-200): (100-1500) (the solid-to-liquid mass ratio is (0.5-2): (1-15)) to ensure the stability of the slurry, so that uniform dispersion of powder, strong interface bonding and collaborative optimization of mechanical properties and chemical stability are realized. Compared with the prior art, the invention has the advantages of good powder dispersibility, strong phase interface bonding, high slurry stability, excellent ceramic mechanical properties and chemical stability, and the like.

The invention discloses a low-temperature sintered and low-loss manganese zinc ferrite material and a preparation method thereof, and the preparation method comprises the following steps: (1) uniformly mixing Fe2O3, Mn2O3 and ZnO powder, and carrying out mechanical ball milling in water; pre-sintering at the temperature of 850-950 DEG C to obtain a ferrite pre-sintered material; (2) adding a sintering aid containing V2O5 and Al2O3 into the ferrite pre-sintered material to obtain a mixture, and then performing plasma-assisted ball milling to obtain refined powder; preparing a green body sample; and (3) carrying out low-temperature sintering on the green body sample in a nitrogen atmosphere at the sintering temperature of 1050-1250 DEG C for 2-5 hours, and then cooling to obtain the manganese-zinc ferrite material. According to the invention, the densified sintering of the ceramic material is realized at a relatively low temperature (-1200 DEG C) by adding the specific sintering aid and combining with plasma-assisted ball milling, and the power loss value in a relatively wide range is lower than 300kW / m < 3 >.

This application relates to the field of infrared transparent ceramic materials technology. Specifically, an embodiment discloses an infrared transparent ceramic material and its preparation method. The preparation method includes: dissolving yttrium nitrate hexahydrate and magnesium nitrate hexahydrate in deionized water according to a stoichiometric ratio; adding citric acid and ethylene glycol as chelating agents and binders; stirring to form a transparent sol; subsequently evaporating and drying to obtain a gel; placing the gel in a muffle furnace for a two-step high-temperature foaming treatment to obtain composite nanoparticles; ball milling the nanoparticles and pre-firing to obtain biphasic nanoparticles; loading the pre-firing nanoparticles into a graphite mold and sintering under axial pressure using SPS technology to obtain ceramic sheets; after furnace cooling, annealing the ceramic sheets in air; and polishing to obtain the infrared transparent ceramic material. The method of this application reduces scattering losses caused by pores and grain boundaries, overcoming the technical challenge of simultaneously achieving broad spectral coverage and high transmittance.

The invention relates to the technical field of aluminum oxide preparation, in particular to calcined alpha aluminum oxide with high sintering activity and a preparation method thereof. The preparation method comprises the following steps: mixing an aluminum hydroxide raw material with boric acid to obtain a primary mixed raw material; mixing alumina seeds with the primary mixed raw material to obtain a secondary mixed raw material; wherein the adding mass m1 of the aluminum oxide seeds and the adding mass m2 of the boric acid meet the condition that m1: m2 is greater than or equal to 8: 1; and calcining the secondary mixed raw material to obtain calcined alpha alumina. According to the preparation method, the sintering activity of the calcined alpha alumina is synergistically improved through three key links of boric acid fluxing, alumina seed phase change promotion and mass ratio regulation and control of boric acid and alumina seeds. And finally, the calcined alpha-alumina with the original grain size of 2.75 mu m or less, the specific surface area of 0.85 m < 2 > / g or more and the sodium oxide content of 0.271% or less can be obtained, which shows that the calcined alpha-alumina has high sintering activity.

This invention discloses a method for preparing Zr-2.5Nb alloy by hot-pressing sintering coarse-grained pre-alloyed spherical powder below the β phase transformation temperature. The method includes: 1. Selecting coarse-grained spherical Zr-2.5Nb alloy pre-alloyed powder prepared by the plasma rotating electrode method as raw material; 2. Placing the raw material into a mold and placing it in a hot press furnace under vacuum; 3. Heating to a temperature below the β phase transformation temperature of Zr-2.5Nb alloy and holding at that temperature for hot-pressing sintering; 4. Cooling to room temperature to obtain a dense Zr-2.5Nb alloy. This invention utilizes the characteristics of coarse-grained spherical Zr-2.5Nb alloy pre-alloyed powder—namely, its fine grain structure, crystal defects, and metastable α′ martensitic phase transformation activity—to achieve efficient densification at lower temperatures and suppress grain coarsening, resulting in a Zr-2.5Nb alloy material with uniform structure, high density, and excellent overall performance, suitable for the field of biomedical implants.

The invention belongs to the technical field of ceramic powder preparation, and provides nano ceramic powder as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing raw materials of a target product with a solvent according to a stoichiometric ratio to obtain a mixed solution; or mixing the raw materials of the target product with a solvent and acid according to a stoichiometric ratio to obtain a mixed solution; placing ammonia water and the mixed solution in the same space; or introducing ammonia gas into the mixed solution, stirring, and carrying out ultrasonic dispersion to obtain a precipitate; and drying the precipitate to obtain the product. The invention also discloses the nano ceramic powder prepared by the method, and a solid oxide fuel cell, which comprises an anode, a cathode and an electrolyte, the material of the anode, the cathode or the electrolyte comprises the nano ceramic powder. The preparation process disclosed by the invention is simple, the powder is nanocrystallized by taking gaseous ammonia as a precipitator, and the phase can be formed without high-temperature calcination; and the prepared nano ceramic powder has small particles, so that the sintering activity of the nano ceramic powder can be greatly improved.

The invention discloses silver particles with holes in the surface and a preparation method and application of the silver particles. Holes exist in the surfaces of the silver particles, and the maximum diameter or the diagonal distance of the holes is smaller than 500 nm. The surfaces of the silver particles are modified with nanometer hole structures, and the sintering activity of the silver particles is improved by means of the high diffusion rate after nearby defective atoms are heated. According to the preparation method, surface holes are formed in the synthesis process of silver particles by using a template method, and the monodispersity of the silver particles in the growth process is improved by taking nano-silver as a seed crystal and combining the use of a protective agent.

The present application relates to the technical field of metal powder material preparation, and particularly relates to a porous silver powder, a preparation method and application, by introducing a carbonate foaming agent into raw materials, the carbonate foaming agent can react with nitric acid generated in a liquid phase reduction process of silver nitrate and a reducing agent to generate carbon dioxide bubbles, and the carbon dioxide bubbles play an inducing role in a silver microcrystal formation process, so that the generated silver powder has a rich pore structure and a high specific surface area. Compared with the porous silver powder in the prior art, the porous silver powder has a higher specific surface area and sintering activity, by controlling the addition amount of the foaming agent, the pore structure, the specific surface area and the sintering activity of the silver powder can be accurately controlled, and the control method is simple, and the problems of low pore structure and high cost in the preparation of the porous silver powder in the prior art are solved.

The invention belongs to the technical field of silver powder preparation, and particularly relates to a preparation method of sphere-like porous silver powder, which comprises the following steps: (1) dissolving silver nitrate in deionized water to obtain a silver-containing solution A; (2) adding a surface treating agent into a water-soluble organic ester solvent, adding deionized water while stirring, and adding ascorbic acid to obtain a reaction base solution B; (3) diluting the aqueous solution of hydrazine hydrate with deionized water, and adding a pH value regulator to obtain a reducing agent solution C; (4) adding the silver-containing solution A and the reducing agent solution C into the reaction base solution B for reaction; and (5) after the reaction is finished, the reaction liquid in the step (4) is subjected to centrifugal separation, washing and drying, and then the sphere-like silver powder with holes is obtained. The method has the beneficial effects that ascorbic acid serving as a reducing agent is added into the reaction base solution B, hydrazine hydrate serving as a reducing agent solution C and the silver-containing solution A are added at the same time, and the silver powder generates a porous structure under the state that the silver powder is kept in a sphere-like state.