23 results about "Barium ferrite" patented technology

The invention relates to a preparation method of a YIG-M type barium ferrite mixed material for a microstrip line circulator. The preparation method comprises the following steps: firstly, preparing YIG precursor powder and barium ferrite powder; pressing the YIG precursor powder into a green body, and sintering to obtain phase-formed YIG ferrite; and crushing the YIG ferrite, mixing the crushed YIG ferrite with the barium ferrite precursor powder according to a mass ratio of 1: 2-2: 1, pressing the mixture into a green body, and carrying out sintering phase formation to obtain the YIG-M type barium ferrite mixed material. The external bias magnetic field of the prepared mixed material is far smaller than that of a traditional YIG material, a good circulation effect can be achieved only through a smaller permanent magnet, and a circulator can be further miniaturized and integrated.

The invention relates to a method for preparing nano barium ferrite powder, in particular to a method for preparing nano barium ferrite through cooperation of laser annealing and neodymium doping. The method comprises the following steps: S1, preparing a ferrite amorphous strip from raw materials including Fe2O3, BaO, Nd2O3 and B2O3 by utilizing a smelting melt-spinning method; s2, irradiating the ferrite amorphous strip in the step S1 by using laser, and carrying out laser annealing; and S3, carrying out pickling crushing and filtering washing treatment on the annealed strip, and drying to obtain the neodymium-doped nano barium ferrite. According to the preparation method disclosed by the invention, through the synergistic effect of laser annealing and strong absorption of neodymium ions, overgrowth of crystal grains is effectively inhibited, and the particle size distribution of the nano ferrite is narrowed, so that the problems of wide particle size distribution of powder, low production efficiency and the like in the existing preparation technology are solved.

The invention provides a preparation method of a CeF3 doped M type barium ferrite single crystal. The preparation method comprises the following steps: S1, drying raw materials BaCO3, Fe2O3 and CeF3 and a fluxing agent LiF-NaF-B2O3; s2, raw materials BaCO3 and Fe2O3 are weighed, meanwhile, a proper amount of CeF3 powder is added, the raw materials and a fluxing agent LiF-NaF-B2O3 are mixed, and a mixed raw material is obtained; s3, putting the mixed raw material into a platinum crucible, sealing the platinum crucible, and filling protective gas; s4, the platinum crucible is heated, the temperature of the interior of the platinum crucible is increased to 1120-1200 DEG C, heat preservation is conducted, and the mixed raw materials are fully molten and homogenized; s5, cooling the interior of the platinum crucible to 990-1030 DEG C, lt; 001gt, 001gt; inserting the oriented seed crystal into a platinum crucible, and then cooling to 900-950 DEG C; s6, rotating the seed crystal, and meanwhile, adopting a lifting mode; and S7, annealing treatment is carried out, such that a complete single crystal is obtained. According to the invention, stable doping of Ce < 3 + > ions is realized, a pollution-free preparation process is adopted, large-size single crystals are prepared, and the performance of the prepared single crystals is optimized.

The invention belongs to the technical field of stealth coatings, and relates to a PI-based porous wave-absorbing coating based on flame spraying and a preparation method of the PI-based porous wave-absorbing coating. The PI-based porous wave-absorbing coating takes porous polyimide as a continuous matrix, and neodymium-doped barium ferrite and multi-walled carbon nanotubes are dispersed in the porous polyimide matrix; through a flame spraying method, spraying suspension liquid formed by 4, 4 '-diaminodiphenyl ether, pyromellitic dianhydride, neodymium-doped barium ferrite, multi-walled carbon nanotubes and an organic solvent is sprayed on the surface of a substrate. The PI-based porous wave-absorbing coating provided by the invention has excellent broadband strong absorption characteristic, can keep stable wave-absorbing performance in a wider thickness range, shows remarkable thickness insensitivity, and greatly reduces the precision requirement on thickness control of the coating.

The application belongs to the technical field of electronic information materials, and specifically provides a method for preparing M-type barium ferrite monocrystal thin film under low temperature conditions; the method is characterized by innovative design of liquid phase raw materials and strict design of liquid phase epitaxy process parameters, and can grow the M-type barium ferrite monocrystal thin film with excellent performance on SGGG (111) substrate by liquid phase epitaxy method under low temperature conditions of 830-850 DEG C, which is not only simple in process and low in cost, but also has high crystallization quality, no impurities and defects. The M-type barium ferrite monocrystal thin film prepared by the method is a single crystal material, the film thickness is up to 150 mu m, the saturation magnetization is about 4500 Oe, the remanence is about 1000 Oe, the easy magnetization axis (c axis) is perpendicular to the film surface, has high uniaxial magnetic crystal anisotropy field, and is very beneficial to realize self-bias design of the device.

This invention belongs to the field of magnetic nanomaterials technology, specifically relating to a method for chemically synthesizing fine M-type barium ferrite nanomaterials. This method involves co-precipitation of Fe and Ba salt solutions in a magnetic field to prepare small and uniform M-type barium ferrite nanomaterials. Applying a magnetic field increases the nucleation rate and refines the particles; adjusting the magnetic field strength controls the length of the M-type barium ferrite nanowires. Changing the type and amount of co-precipitating dispersant, the type of flux, and the mixing ratio of flux to precursor further controls the size of the nanomaterials and the length of the nanowires. Adjusting the sintering temperature and time controls the morphology and size of the product.

The invention provides anti-corrosion sacrificial concrete and a preparation method thereof. The anti-corrosion sacrifice concrete is prepared from the following components in parts by weight: 300 to 400 parts of cement, 30 to 50 parts of barium ferrite, 100 to 150 parts of fly ash, 10 to 50 parts of silica fume, 350 to 900 parts of quartz sand, 700 to 900 parts of hematite iron ore, 300 to 1300 parts of steel grit, 3 to 8 parts of polypropylene fiber, 210 to 230 parts of water and 3 to 9 parts of a water reducing agent. The preparation method comprises the following steps: sequentially mixing and stirring the raw materials, pouring, forming and curing. The sacrificial concrete disclosed by the invention has the synergistic advantages of high crack resistance and impermeability, and the corrosion rate of the aluminoferrite cement-based sacrificial concrete under extreme thermochemical erosion is fundamentally reduced; the doping of the steel grit leads to the formation of a discontinuous metal ceramic barrier layer in the holes of the sacrificial concrete at high temperature, so that the corrosion permeation rate of the sacrificial concrete is obviously reduced.

The invention provides a preparation method of an M-type barium ferrite single crystal, which comprises the following steps: S1, weighing raw materials BaCO3 and Fe2O3, mixing the raw materials to obtain a primary mixture, and mixing the primary mixture with a fluxing agent LiF-NaF-B2O3 to obtain a mixed raw material, s2, the mixed raw materials are put into a platinum crucible, the temperature is increased to 1200-1270 DEG C, and then heat preservation is conducted; s3, the platinum crucible is cooled to 1100-1150 DEG C, and then a tilt part is inserted; 001gt, 001gt; an oriented seed crystal; s4, continuously cooling, and rotating the seed crystal; s5, after the platinum crucible is cooled to 970-1000 DEG C, crystal growth is finished; and S6, lifting the crystal away from the liquid level, and carrying out annealing treatment to obtain the M-type barium ferrite single crystal. The problems of small crystal size, toxic pollution and microwave performance degradation in the prior art are solved, and size bottleneck breakthrough, pollution-free process, component stability control and microwave performance optimization are realized.

The invention provides anti-radiation concrete based on iron tailing waste and a preparation method thereof, and relates to the technical field of concrete preparation, the anti-radiation concrete is prepared from the following raw materials by weight: 200-240 parts of P.O42.5 cement, 100-130 parts of grade I fly ash, 90-100 parts of grade S95 mineral powder, 2000-2350 parts of composite aggregate, 150-165 parts of water, 10.5-12 parts of a water reducer and 1-3 parts of boron carbide powder, the composite aggregate comprises coarse aggregate and fine aggregate, and the fine aggregate is modified iron tailings and is prepared by ball-milling and coating iron tailings and barium ferrite powder. The anti-radiation concrete has the beneficial effects that the anti-radiation concrete is produced by using the tailing waste, solid waste is comprehensively utilized, and environmental pollution is reduced.

The invention relates to the technical field of preparation methods of high-strength ferrite plastic magnetic granules, in particular to high-strength ferrite plastic magnetic granules and a preparation method thereof.The high-strength ferrite plastic magnetic granules are prepared from, by weight, 84 wt%-90 wt% of ferrite magnetic powder, 8 wt%-13 wt% of binder, 1 wt%-3 wt% of flexibilizer, 0.3 wt%-0.8 wt% of coupling agent and 0.5 wt%-1.5 wt% of lubricant. 0.2 wt% to 0.5 wt% of an antioxidant; the ferrite magnetic powder is strontium ferrite or barium ferrite or combined magnetic powder of the strontium ferrite and the barium ferrite, and the average particle size is 0.8-2.0 microns; the binder is composed of nylon 6 powder modified by a fiber material, and the fiber material is selected from one of long glass fiber and carbon fiber. Tests prove that the ferrite injection molding granules provided by the invention have the maximum magnetic energy product (BH) max of more than or equal to 15.1 kJ / m < 3 >, the bending strength of not less than 150MPa and the crushing strength of more than or equal to 60MPa, have good magnetic properties and relatively high mechanical properties, and are suitable for extrusion of complex shapes.

The invention provides a preparation method of a CeO2 doped M type barium ferrite single crystal. The preparation method comprises the following steps: S1, carrying out vacuum drying on raw material BaCO3, Fe2O3 and CeO2 powder, a fluxing agent LiF-NaF-B2O3 and a reducing agent Zn powder; s2, weighing and mixing the raw materials, the fluxing agent and the reducing agent to obtain a mixed raw material; s3, filling the mixed raw materials into a platinum crucible; s4, the platinum crucible is subjected to programmed heating and heat preservation, so that the mixed raw materials are fully molten and react, and a melt with uniform chemical components is formed; s5, slowly cooling the platinum crucible, 001gt, 001gt; inserting the oriented seed crystal into the surface of the melt, and rotating; the programmed cooling of the platinum crucible is extremely slow, and meanwhile, the lifting operation is matched; s6, after crystal growth is completed, programmed cooling is conducted to the room temperature, then annealing treatment is conducted, and therefore the CeO2 doped M-type barium ferrite single crystal is obtained. Precise valence state regulation and control are achieved, size limitation is broken through, heavy metal pollution is thoroughly eliminated, and comprehensive performance is optimized.

The invention relates to an M-type barium ferrite polycrystalline material suitable for a Ka-band self-biased circulator and a preparation method of the M-type barium ferrite polycrystalline material, the molecular formula of the crystal is Ba0. 7La0. 3Fe (10.9-11.7)-xZn0. 3ScxO19, and x is more than 0 and less than 0.6. The preparation method comprises the following steps: calculating the element ratio, weighing the raw materials BaCO3, Fe2O3, La (OH) 3, ZnO and Sc2O3, mixing the raw materials, matching with a steel ball for wet grinding, standing after wet grinding, filtering water, drying a deposited material, grinding the dried material into powder, and pressing the powder into a cake blank; presintering the cake blank sample at high temperature to form an M phase; the method comprises the following steps: crushing an M-phase sample into powder, carrying out ball milling, controlling the particle size of the powder to be smaller than a single domain critical limit 0.9 mu m, standing ball-milled slurry on filter cloth for 8 hours, controlling the moisture content to be 30-40%, and then carrying out wet orientation to form a preferred orientation green body; and sintering the green body at high temperature. The magnetocrystalline anisotropic field has the advantages that the numerical value of the magnetocrystalline anisotropic field can meet about 8000 Oe, the magnetocrystalline anisotropic field can be adjusted according to the Sc content, and the service conditions of self-biased circulators with different center frequencies can be met.

The invention discloses a preparation method of magnetic hollow glass beads, and belongs to the technical field of functional material preparation. Comprising the following steps: 1, mixing various glass forming raw materials, melting at 1400-1600 DEG C to obtain molten glass, and carrying out water quenching, crushing and grading to obtain magnetic glass powder; step 2, mixing magnetic glass powder with the paste according to a mass ratio of 1: (1-2.5), adding sodium dodecyl benzene sulfonate, and performing spray granulation to form magnetic precursor particles; 3, placing the precursor particles in a negative pressure spheroidizing furnace, and carrying out foaming and spheroidizing treatment; and then, carrying out hydrofluoric acid surface etching on the obtained microbeads to form a frosted layer, coating the frosted layer with a barium ferrite magnetized layer, and carrying out separation and collection by a specific gravity separation method to obtain the magnetic glass microbeads.

The application discloses a preparation method of a chiral ferromagnetic monodomain liquid crystal material, and synthesizes Sc-doped barium ferrite nanosheets through a hydrothermal method, modifies the nanosheets by using citric acid, obtains ferromagnetic barium ferrite nanosheets, and uniformly disperses the ferromagnetic barium ferrite nanosheets into a chiral liquid crystal matrix; under the action of a weak magnetic field (as low as 30 mT), the anisotropic nanosheet orientation is coupled with the chiral liquid crystal orientation, the nanosheets are oriented along the magnetic field direction, and the ordered arrangement of the chiral liquid crystal matrix is guided; the chiral cluster aggregates and liquid crystal domains in the chiral liquid crystal matrix are migrated and fused, and finally, a wireless, planar defect chiral ferromagnetic monodomain structure is formed. The chiral ferromagnetic monodomain liquid crystal material has magnetic response, and the magneto-optic effect under the action of a magnetic field provides a basis for the application of the chiral ferromagnetic monodomain liquid crystal material in the fields of optical equipment and flexible machines.

To achieve simultaneous improvement of both corrective force Hc and a magnetocrystalline anisotropy constant Ku in finely pulverized hexagonal barium ferrite magnetic powder.SOLUTION: Provided is a method for producing hexagonal barium ferrite magnetic powder, which includes a crystallization step of synthesizing hexagonal barium ferrite crystals by subjecting a precursor to a crystallization heat treatment, the precursor containing a constituent element of hexagonal barium ferrite magnetic powder. As the precursor, there is used a material having a mass increase rate of 0.08% or less at 700°C based on a mass at 300°C when subjected to thermogravimetry which includes heating with a heating rate of 10°C / min from room temperature to a temperature of 700°C or higher in an air atmosphere and also has a saturation magnetization σs of 5.0 Am2 / kg or less.SELECTED DRAWING: Figure 4

The invention provides a preparation method of a barium ferrite loaded conductive MOF, and relates to the technical field of metal organic materials, and the preparation method comprises the following steps: placing barium ferrite in an MOF precursor solution, then carrying out a hydrothermal reaction, and enabling MOF to grow in situ on the surface of the barium ferrite and crystallize to obtain the barium ferrite loaded conductive MOF, wherein the MOF precursor solution contains metal ions and an MOF precursor solution of a conjugated organic ligand. The barium ferrite is a hard magnetic material and has strong magnetism, the barium ferrite is used as a substrate, the conductive MOF grows on the surface of the barium ferrite through hydrothermal reaction, and the obtained barium ferrite loaded conductive MOF inherits the strong magnetism of a barium ferrite core. After the barium ferrite loaded conductive MOF is applied, only one magnet is needed, the composite material can be rapidly and completely sucked out from a solution, rapid, efficient and nearly lossless recovery is achieved, and the problem that an MOF material powder material prepared through an existing method is difficult to recover is solved.

The application discloses a rare earth neodymium and pentavalent ion double-site substituted M-type barium ferrite double-band wave absorber and a preparation method thereof. 1‑x Nd x Fe 12‑y A y O 19 , wherein A is a pentavalent transition metal ion Nb or Ta, x=0.05-0.3, and y=0.05-0.3. The application realizes double-site substitution of the M-type barium ferrite by using the rare earth element Nd 3+ and the non-magnetic ion A (Nb 5+ , Ta 5+ ) to respectively replace part of Ba 2+ ions and part of Fe 3+ ions of the M-type barium ferrite, so that the obtained wave absorbing material has the characteristics of strong reflection loss, wide effective absorption bandwidth and thin matching thickness.

The invention provides a high-temperature-resistant and high-pressure-resistant glaze surface for a ceramic surface as well as a preparation method and application thereof. The method comprises the following steps: arranging first glaze slip on the surface of a ceramic substrate, and drying to obtain a first glaze layer; arranging second glaze slip on the surface of the first glaze layer, and drying to obtain a second glaze layer; sintering to obtain the ceramic surface high-temperature-resistant and high-pressure-resistant glaze. Each of the first glaze slip and the second glaze slip comprises a component A, a component B, water, a rheological agent, a binder, an opacifier, a cosolvent and other functional aids; the component A comprises titanium oxide and barium ferrite; the component B comprises silicon dioxide, calcite, dolomite and modified glass fibers; the second glaze slip further comprises spherical graphite which is used for forming an arc-shaped pit after sintering. The technical problem to be solved is how to prepare the high-temperature-resistant and high-pressure-resistant glaze on the ceramic surface, so that the high-temperature-resistant and high-pressure-resistant glaze can homogenize the voltage distribution on the surface of an insulator, improve the breakdown resistance of the insulator and effectively avoid pollution flashover, and can be applied to a high-temperature and high-humidity environment.

The invention discloses a barium ferrite doped carbon nanotube coating type wave-absorbing material and a preparation method thereof, and belongs to the technical field of coating type wave-absorbing materials. The barium ferrite-doped carbon nanotube coating type wave-absorbing material is prepared from the following raw material components: a barium ferrite-doped / spiral carbon nanotube composite material, a wave-transparent adhesive and an auxiliary agent, wherein the doped barium ferrite / spiral carbon nanotube composite material comprises doped barium ferrite and a spiral carbon nanotube, and the mass ratio of the spiral carbon nanotube to the doped barium ferrite is 1: (10-20); baFe < 11 > Co < 0.5 > Zr < 0.5 > O < 19 > is adopted as the doped barium ferrite; epoxy resin is adopted as the wave-transparent adhesive; the auxiliaries comprise a diluent, a solvent and a curing agent.

The invention provides a method for preparing a high C-axis orientation barium ferrite film based on a liquid phase epitaxy method. The method comprises the following steps: step 1, preparing a melt: taking BaCO3 and Fe2O3 as raw materials, taking K2CO3, Bi2O3 and B2O3 as fluxing agents, weighing the raw materials and the fluxing agents, and mixing and melting the raw materials and the fluxing agents to obtain the uniformly mixed melt; step 2, growing a thin film by a liquid phase epitaxy method: cooling to 850-900 DEG C, cooling a clamp with a substrate to a position above a melt after the temperature of the melt is stable, preheating, then cooling to be in contact with the liquid level of the melt, and applying a magnetic field to grow the thin film, the substrate being MgO (111); step 3, taking out the thin film: taking out the thin film after growth is finished, and cleaning the thin film; and step 4, processing the thin film: cutting, grinding, polishing and cleaning the cleaned thin film to obtain the high C-axis orientation barium ferrite thin film. The preparation of the high-C-axis orientation BaM film is realized by adopting an external magnetic field assistance mode, so that the magnetic performance of the film is remarkably improved.

This invention discloses a method for preparing a hollow fibrous barium ferrite, specifically in the field of composite materials. The method comprises three steps: First, polyvinylpyrrolidone is dissolved in a polar solvent and stirred until completely dissolved. A soluble barium salt, a soluble iron salt, and citric acid are then added in proportion to prepare a spinning precursor sol. Second, the spinning precursor sol is extruded through an injection device, with an air source flow at the outlet to blow the sol into filaments, which are then collected to obtain a barium ferrite precursor fiber sponge. Third, the barium ferrite precursor fiber sponge is heated and sintered until fully sintered, and then naturally cooled to obtain the hollow fibrous barium ferrite. The hollow barium ferrite synthesized by this invention achieves adjustable grain configuration and macroscopic hollow structure. Its impedance matching performance and electromagnetic wave attenuation characteristics are good, making it suitable for applications in high-density perpendicular magnetic recording materials, microwave devices, and microwave absorbing materials.

The application provides a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing stealth coating and a preparation method. The weight ratio of the ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder in the composite wave-absorbing stealth coating is 25-70:25-70:5-10, wherein the low-melting-point glass powder refers to a glass powder with a melting point of 100-400 DEG C, and the average particle size of the nano ZrO2 ceramic powder is 1-100 nm. The ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder with the above ratio are mixed, and are coated on the surface of a coated machine body by using a plasma spraying technology, and the coating thickness ranges from 0.1 mm to 5 mm. The application has the beneficial effects that the application can not only significantly improve the radar stealth performance, but also can lead to a series of improvements of the overall performance of an airplane. Experimental detection shows that the ceramic has better radar absorption than the existing polymer, can absorb 99% or more energy from the radar, the material is waterproof, is harder than sand, and can better withstand harsh conditions.

[Problem] A hexagonal barium ferrite magnetic powder formed of fine particles, wherein the anisotropic magnetic field distribution of a magnetic recording medium can be made to fall within a range effective in both improving the recording density and improving the SNR is provided.[Solution] A magnetic powder for a magnetic recording medium including magnetic particles in which Ba in hexagonal barium ferrite is partially substituted with Sr, wherein a Dx volume represented by the following formula (1) is 2,200 nm3 or less, an Sr / (Ba+Sr) molar ratio is 0.01 to 0.30, and an anisotropic magnetic field distribution is 1.00 or less.Dx volume (nm3)=Dxc×π×(Dxa / 2)2  (1)Here, Dxc is a crystallite diameter (nm) in a c-axis direction of a hexagonal ferrite crystal lattice, Dxa is a crystallite diameter (nm) in an a-axis direction of the same crystal lattice, and π is a circular constant.