18H hexaferrite, its manufacturing method and use

Abstract

Ba x Ni 2-y Cu y Ti3Fe z O 31 wherein 4.5≦x≦5.5 and 0

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 424,616, filed November 11, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to, for example, 18H hexaferrite compositions having high frequency magnetic permeability, composites including 18H hexaferrite compositions, methods for making same, and uses thereof. [Background technology]

[0003] Improved performance and miniaturization are needed to meet the increasing demands of devices used in ultra-high frequency, L-band, and S-band applications of interest to various commercial and defense-related industries. Miniature antenna elements are constantly being developed as key components in radar and modern wireless communication systems. However, developing ferrite materials for use in such high-frequency applications has been difficult because most ferrite materials exhibit relatively high magnetic losses at high frequencies. The method for producing the present ferrite materials can affect the crystalline structure of the material and thus improve performance.

[0004] Therefore, there remains a need for ferrite materials and methods of making ferrite materials with low magnetic loss, high magnetic permeability, and low permittivity and dielectric loss in the gigahertz range. Summary of the Invention

[0005] The ferrite composition is Ba x Ni 2-y Cu y Ti3Fe z O 31 wherein 4.5≦x≦5.5, 0 <y<2または0.05≦y≦1.5、および11≦z≦13である。

[0006] A method for producing a ferrite composition includes the steps of calcining a blend of metal raw compounds for the ferrite composition, reducing the particle size of the calcined raw compounds to obtain particles having an average particle size of 0.5 to 100 micrometers or 0.5 to 10 micrometers, granulating the mixture of the particles and a binder to obtain granules, compressing the granules into green bodies, and sintering the green bodies to form the ferrite composition.

[0007] The composite includes a polymer matrix and a ferrite composition.

[0008] Articles comprising the ferrite composition or composite material are also described, including antennas, inductors, transformers, or electromagnetic interference prevention materials.

[0009] The following figures are exemplary embodiments provided to explain the present disclosure. The figures are illustrative examples and are not intended to limit devices manufactured in accordance with the present disclosure to the materials, conditions, or process parameters described therein. [Brief explanation of the drawings]

[0010] [Figure 1] 18H hexaferrite Ba5Ti3Ni2-yCuyFe12O31 18-layer stacking arrangement of the unit cell, where 0 <y<2である。 [Figure 2] 1 is a graph of magnetization (emu / g) versus temperature (° C.) for Examples 1-8. [Figure 3] 1 is a graph of actual permeability μ′ versus frequency (f) in gigahertz (GHz) for Examples 1 to 8. [Figure 4] 1 is a graph of imaginary permeability μ″ versus frequency (GHz) for Examples 1 to 8. [Figure 5] 1 is a graph of real and imaginary permeability μ′ and μ″ versus frequency (f) in GHz showing the magnetic spectrum of the composite of Example 9. [Figure 6]A graph of real dielectric constant ε’ and imaginary dielectric constant ε” versus frequency (f) (GHz) showing the magnetic spectrum of the composite material of Example 9.

DETAILED DESCRIPTION OF THE INVENTION

[0011] It has been discovered that an 18H type ferrite composition containing nickel and copper has a low dielectric tangent and a high magnetic permeability at high frequencies, while also showing a low magnetic loss tangent and a high dielectric constant. It has further been discovered that the properties of the ferrite composition, such as magnetic permeability, saturation magnetization, coercive force, Curie temperature, cut-off frequency (resonance frequency), or combinations thereof, can be adjusted by varying the copper content, for example, the molar ratio of copper to nickel in the ferrite composition.

[0012] Advantageously, the 18H type ferrite composition does not require expensive elements such as rare earths or precious elements, making it cost-effective to prepare. The ferrite composition can be blended with a polymer to provide a composite material with low magnetic loss, high magnetic permeability, low dielectric constant, and low dielectric loss. The ferrite compositions and composite materials described herein are useful for applications such as antenna substrates, inductor cores, and electromagnetic interference (EMI) suppressors over a wide range of frequencies (0.5 to 10 gigahertz (GHz)).

[0013] FIG. 1 shows a schematic view of 1 / 2 of an 18-layer stacked arrangement of a unit cell of 18H hexaferrite Ba5Ti3Ni 2-y Cu y Fe 12 O 31 (0 < y < 2), showing three layers of a semi-Y block, three layers of hexagonal barium titanate (HBT), and three layers of a semi-Y block. The actual distribution of the inter-lattice cations can be different to provide a path for magnetic coupling along the c-axis. The HBT layer can contain iron ions, copper ions, nickel ions, or combinations thereof.

[0014] The ferrite composition is Ba x Ni 2-y Cu y Ti3Fe zO 31 It has the formula: 4.5 ≦ x ≦ 5.5, 0 < y < 2 or 0.05 ≦ y ≦ 1.5, and 11 ≦ z ≦ 13. The ferrite composition can have a 18H structure. The ferrite composition can have in-plane (basal c-plane) easy magnetization (also called planar anisotropy). The ferrite composition can be a single crystal or polycrystalline ferrite composition.

[0015] The ferrite composition can have a Curie temperature of 200 °C or higher, 210 °C or higher, 220 °C or higher, 230 °C or higher, 240 °C or higher, or 250 °C or higher. The ferrite composition can have a Curie temperature of 300 °C or lower. The 18H-type ferrite composition containing no nickel and copper can have a Curie temperature of less than 180 °C.

[0016] The ferrite composition can have a coercive force of less than 50 oersted (Oe) (3.98 kiloampere per meter (kA / m)), less than 30 Oe (2.39 kA / m), less than 15 Oe (1.19 kA / m), less than 5 Oe (0.40 kA / m), less than 4 Oe (0.32 kA / m), less than 3 Oe (0.24 kA / m), less than 2 Oe (0.16 kA / m), or less than 1 Oe (0.08 kA / m). The ferrite composition can have a coercive force greater than 0 Oe (0 kA / m), greater than 0.01 Oe (0.80 ampere per meter (A / m)), or greater than 0.1 Oe (7.96 A / m). The 18H-type ferrite composition containing no nickel and copper can have a coercive force exceeding 50 Oe (3.98 kA / m).

[0017] The grain size of the ferrite composition can be selected to provide the ferrite composition with magnetic and dielectric properties suitable for a given application. The grain size can be controlled by controlling the ferrite synthesis conditions, such as temperature, heating time, and heating or cooling rate. The average grain size of the ferrite composition can be 1 to 100 μm, or 5 to 50 μm. The average grain size can be determined, for example, by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), or a combination thereof.

[0018] The ferrite composition is Ba x Ni 2-y Cu y Ti3Fe z O 31 , where 5.0≦x≦5.1, 0.05≦y≦1.5, and 11.7≦z≦12.0. In one embodiment, the ferrite composition comprises Ba 5.1 Ni 1.8 Cu 0.2 Ti3Fe 11.7 O 31 , Ba 5.1 Ni 1.6 Cu 0.4 Ti3Fe 11.7 O 31 , Ba 5.1 Ni 1.4 Cu 0.6 Ti3Fe 11.7 O 31 , Ba 5.1 Ni1Cu 1.0 Ti3Fe 11.7 O 31 , Ba 5.1 Ni 0.8 Cu 1.2 Ti3Fe 11.7 O 31 , Ba 5.1 Ni 1.7 Cu 1.3 Ti3Fe 11.7 O 31 , Ba 5.1 Ni 1.6 Cu 1.4 Ti3Fe 11.7 O 31 , or Ba5.1 Ni 0.5 Cu 1.5 Ti3Fe 11.7 O 31 It can have the formula:

[0019] The ferrite composition has a magnetic permeability (μ) of 1.5 to 2 at frequencies between 1 and 9 GHz, and a magnetic loss tangent (tanδ) of less than 0.05 at frequencies between 1 and 9 GHz. μ ), a dielectric constant (ε) of 10 to 15 at frequencies from 1 to 9 GHz, and a dielectric loss tangent (tanδ) of less than 0.004 at frequencies from 1 to 3 GHz. ε ), cutoff frequency greater than 10 GHz (resonant frequency f r ), or a combination thereof. In one embodiment, the ferrite composition has a magnetic permeability (μ) of 1.5 to 2 at a frequency of 1 to 9 GHz and a magnetic loss tangent (tanδ) of less than 0.05 at the same frequency. μ )

[0020] Hexaferrite particles can be produced by any suitable method, such as a ceramic process, a sol-gel process, hydrothermal synthesis, co-precipitation, or thermal plasma sintering. Methods for producing ferrite compositions include a single-step sintered ceramic process, a wet chemical process, and the like. In one embodiment, a method for producing a ferrite composition may include calcining a blend of metal raw materials for the ferrite composition, reducing the particle size of the calcined raw materials to obtain particles having an average particle size of 0.5 to 100 μm or 0.5 to 10 μm, granulating a mixture of the particles and a binder to obtain granules, compressing the granules into green bodies, and sintering the green bodies to form the ferrite composition.

[0021] Metal source compounds are compounds necessary for the synthesis of ferrite. Metal source compounds may be selected based on factors such as cost and availability. Exemplary source compounds of a given metal include oxides, carbonates, acetates, nitrates, sulfates, or chlorides of the metal. Exemplary precursors include barium carbonate (e.g., BaCO), iron oxide (e.g., α-FeO, Fe(NO)·9H0, FeCl·6H0, or Fe(SO)·H0), nickel oxide (e.g., NiO), titanium oxide (e.g., TiO), and copper oxide (e.g., CuO). Metal source compounds may be combined in amounts to achieve a desired metal stoichiometry. In one embodiment, the desired metal stoichiometry may be non-stoichiometric, e.g., iron-deficient (e.g., iron-deficient, as defined by the formula Ba x Ni 2-y Cu y Ti3Fe z O 31 (The z in could be 11.7 instead of 12).

[0022] The blended metal raw compounds can be fired at an appropriate temperature for a certain period of time to synthesize the desired ferrite and achieve the desired grain size. For example, the temperature can be 800 to 1,300°C, or 900 to 1,200°C, or 1,000 to 1,200°C. The firing time can be, for example, 0.5 to 200 hours, or 1 to 15 hours. The firing is carried out in an atmosphere of air, nitrogen, oxygen, or a combination thereof. The heating or cooling rate for firing in a furnace can also be selected to obtain the desired ferrite, grain size, or structural morphology. For example, the heating or cooling rate can be 2 to 3°C / min.

[0023] The particle size of the calcined blend can be reduced by any suitable method. Examples of particle size reduction methods include grinding, grinding, milling, mechanical milling, and combinations thereof. Particle size reduction equipment includes media mills, ball mills, two-roll mills, three-roll mills, bead mills, air jet mills, cryogenic polishers, and the like. After particle size reduction, the particles can be subjected to a sizing procedure, such as sieving, to alter the particle size distribution.

[0024] The mixture of ferrite particles and binder can be granulated by any suitable method, such as spray-drying granulation or vibration extrusion granulation. For example, a slurry of ferrite particles, binder, and various additives as desired can be dispersed in a solvent such as water, and then spray-dried using a spray dryer or the like to produce granules. In one embodiment, the ferrite particles, binder, and various additives as needed can be mixed and granulated in an agitation granulator to produce a granulated powder. The granulated powder can then be extruded and granulated in a vibration granulator to produce granules.

[0025] The binder is selected to be removable from the green body by heating and, optionally, to be soluble in a solvent. Examples of binders include polyvinylpyrrolidone, poly(vinyl alcohol), polyvinyl butyral, polyacrylamide, poly(acrylic acid), polyethylene glycol, polyethylene oxide, cellulose acetate, starch, polypropylene carbonate, polyvinyl acetate, and combinations thereof. In one embodiment, the binder is polyvinyl alcohol, polyvinyl butyral, or a combination thereof.

[0026] In one embodiment, the granules may be formed from a mixture containing ferrite particles and 0.5 to 5 wt % polyvinyl alcohol based on the total weight of the mixture. The granules may have a particle size of, for example, 50 to 300 μm.

[0027] The granulated ferrite composition is molded into a predetermined shape by a compression molding method such as injection molding, calendar lamination, extrusion molding, single press method, double press method, floating die method, or drawing method to obtain a green body. The compressor may be a mechanical press, hydraulic press, servo press, or the like, and is appropriately selected depending on the size, shape, and quantity of the green body. The molding pressure for forming the green body is 0.3 to 3 metric tons per square centimeter (MT / cm). 2 ), or 0.5~2MT / cm 2 It can be said that:

[0028] The green body can then be sintered in a suitable atmosphere to form the ferrite composition. Sintering can be performed at sintering temperatures of 800-1,300°C, 900-1,250°C, or 1,000-1,200°C. Sintering can be performed for sintering times of 1-20 hours, or 2.55-12 hours. The atmosphere can be air, nitrogen, oxygen, or a combination thereof. Sintering can be performed at a heating rate of 1-5°C / min, a cooling rate of 1-5°C / min, or a combination thereof.

[0029] The ferrite may be a bulk ceramic or may be present in a composite material, for example, including ferrite particles and a polymer. The composite may include a ferrite composition and a polymer matrix. The composite may include 5 to 95 volume percent (vol%), 10 to 90 volume%, 20 to 80 volume%, or 30 to 70 volume% of the ferrite composition, based on the total volume of the composite. The composite may include 5 to 95 volume%, 10 to 90 volume%, 20 to 80 volume%, or 30 to 70 volume% of the polymer, based on the total volume of the composite.

[0030] The ferrite composition present in the composite has a particle size of 0.5 to 100 μm, 0.5 to 30 μm, or 1 to 10 μm. Particle size can be determined using a Horiba LA-910 laser light scattering PSD analyzer or equivalent instrument, or in accordance with ASTM D4464-15. Reported particle sizes are median D50 particle sizes by volume. Ferrite composition particles of appropriate size can be obtained by any suitable method. For example, any suitable ceramic or chemical process can be used to synthesize ferrite composition particles of the desired size. In one embodiment, the ferrite composition particles can be obtained by grinding and polishing a sintered green body obtained by the method described herein.

[0031] The polymer matrix can comprise a thermosetting or thermoplastic polymer. As used herein, the term "thermoplastic" refers to a plastic or deformable material that melts to a liquid when heated and freezes to a brittle glassy state when cooled sufficiently. Examples of thermoplastic polymers that can be used include cyclic olefin polymers (including polynorbornene and copolymers containing norbornenyl units, e.g., copolymers of cyclic polymers such as norbornene with acyclic olefins such as ethylene or propylene), fluoropolymers (e.g., polyvinyl fluoride, polyvinylidene fluoride, fluorinated ethylene-propylene, polytetrafluoroethylene, poly(ethylene-tetrafluoroethylene, or perfluoroalkoxy)), polyacetals (e.g., polyoxyethylene and polyoxymethylene), poly(C 1-6 alkyl) acrylates, polyalkylacrylamides (unsubstituted and mono-N- or di-N-(C 1-8alkyl)acrylamides), polyacrylonitrile, polyamides (e.g., aliphatic polyamides, polyphthalamides, or polyaramids), polyamideimides, polyanhydrides, polyarylene ethers (e.g., polyphenylene ether), polyarylene ether ketones (e.g., polyetheretherketone, polyetherketoneketone), polyarylene ketone, polyarylene sulfides (e.g., polyphenylene sulfide), polyarylene sulfones (e.g., polyethersulfone, polyphenylene sulfone), polybenzothiazole, polybenzoxazole Examples of suitable polymers include olefins, polybenzimidazoles, polycarbonates (including homopolycarbonates or polycarbonate copolymers such as polycarbonate siloxanes, polycarbonate esters, or polycarbonate ester siloxanes), polyesters (e.g., polyester copolymers such as polyethylene terephthalate, polybutylene terephthalate, polyarylates, or polyester ethers), polyetherimides (e.g., copolymers such as polyetherimide siloxane copolymers), polyimides (e.g., copolymers such as polyimide-siloxane copolymers), poly(C 1-6 alkyl) methacrylates, polyalkylacrylamides (e.g., unsubstituted and mono-N- or di-N-(C 1-8alkyl)acrylamides), polyolefins (e.g., polyethylenes such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene, polypropylene, and halogenated derivatives thereof (e.g., polytetrafluoroethylene), and copolymers thereof (e.g., ethylene-α-olefin copolymers), polyoxadiazoles, polyoxymethylenes, polyphthalides, polysilazanes, polysiloxanes (silicones), polystyrenes (e.g., copolymers such as acrylonitrile-butadiene-styrene or methyl methacrylate-butadiene-styrene), polysulfides, polysulfonamides, polysulfonates, polysulfones, polythioesters, polytriazines, polyureas, polyurethanes, vinyl polymers (e.g., polyvinyl alcohol, polyvinyl esters, polyvinyl ethers, polyvinyl halides (e.g., polyvinyl chloride), polyvinyl ketones, polyvinyl nitriles, or polyvinyl thioethers), paraffin waxes, or combinations thereof.

[0032] Thermosetting polymers are derived from thermosetting monomers or prepolymers (resins) that can be irreversibly hardened and rendered insoluble by polymerization or curing, which can be induced by exposure to heat or radiation (e.g., ultraviolet, visible, infrared, or electron beam (e-beam) radiation). Thermosetting polymers include alkyds, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, benzocyclobutene polymers, benzoxazine polymers, diallyl phthalate polymers, epoxies, hydroxymethylfuran polymers, melamine-formaldehyde polymers, phenolics (including phenol-formaldehyde polymers such as novolacs and resols), benzoxazines, polydienes such as polybutadiene (including homopolymers and copolymers thereof, e.g., poly(butadiene-isoprene)), polyisocyanates, polyureas, polyurethanes, triallyl cyanurate polymers, triallyl isocyanurate polymers, certain silicones, or polymerizable prepolymers (e.g., prepolymers with ethylenic unsaturation, e.g., unsaturated polyesters, polyimides). Prepolymers include, for example, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, acrylic acid, (meth)acrylic acid, (C 1-6 alkyl) acrylate, (C 1-6 It can be polymerized, copolymerized or crosslinked with reactive monomers such as alkyl)methacrylate, acrylonitrile, vinyl acetate, allyl acetate, triallyl cyanurate, triallyl isocyanurate or acrylamide.

[0033] The polymer can include a fluoropolymer (e.g., polyvinylidene fluoride or polytetrafluoroethylene), a polyolefin (e.g., polyethylene, high density polyethylene, low density polyethylene), a poly(arylene ether ketone) (e.g., polyether ether ketone), a polyalkyl(meth)acrylate (e.g., polymethyl methacrylate), a poly(ether sulfone), or a combination thereof.

[0034] The composite may contain additional additives such as dielectric fillers or flame retardants, as long as the additives are less than 5% by volume of the total volume of the composite.

[0035] Particulate dielectric fillers can be used to tailor the dielectric constant, dissipation factor, coefficient of thermal expansion, and other properties of the composite. Exemplary dielectric fillers include titanium dioxide (rutile and anatase), barium titanate, strontium titanate, silica (including fused amorphous silica), corundum, wollastonite, BaTiO 20 , solid glass spheres, synthetic glass or ceramic hollow spheres, quartz, boron nitride, aluminum nitride, silicon carbide, beryllia, alumina, alumina trihydrate, magnesia, mica, talc, nanoclay, magnesium hydroxide, or combinations thereof.

[0036] Flame retardants can be halogenated or non-halogenated. Exemplary inorganic flame retardants are metal hydrates, such as hydrates of metals such as Mg, Ca, Al, Fe, Zn, Ba, Cu, Ni, or combinations thereof. In one embodiment, the hydrates can include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, iron hydroxide, zinc hydroxide, copper hydroxide, or nickel hydroxide, or hydrates of calcium aluminate, gypsum dihydrate, zinc borate, or barium metaborate. Organic flame retardants can be used in place of or in addition to inorganic flame retardants. Inorganic flame retardants include, for example, melamine cyanurate, fine-grained melamine polyphosphate, various other phosphorus-containing compounds such as aromatic phosphinates, diphosphinates, phosphonates, and phosphates, certain polysilsesquioxanes, siloxanes, halogenated compounds such as hexachloroendomethylenetetrahydrophthalic acid (HET acid), tetrabromophthalic acid, or dibromoneopentyl glycol.

[0037] The composite can have an operating frequency of 0.5 GHz to 10 GHz.

[0038] The composite has a magnetic loss tangent (tanδ) of less than 0.08 at frequencies between 1 and 10 GHz.μ Such a magnetic material having low magnetic loss can be advantageously used in high frequency applications such as antenna applications.

[0039] The composite can have a magnetic permeability (μ) of 1.2 or greater at frequencies between 1 and 10 GHz.

[0040] The composite may have a dielectric constant (ε) of 5 to 10 at frequencies between 1 and 12 GHz.

[0041] The composite has a dielectric loss tangent (tanδ) of less than 0.005 at frequencies between 1 and 12 GHz. ε ) can be included.

[0042] A method for making a composite includes combining a polymer, a ferrite composition, optionally a solvent, and any additives to form a composition. The polymer may be melted before or after combining with the ferrite composition. Optionally, the method further includes removing the solvent. The combining may be performed by any suitable method, such as blending, mixing, or stirring. In one embodiment, the polymer is melted and the ferrite composition and any additives are dissolved or suspended in the molten polymer. In one embodiment, the components used to form the composite, including the polymer and ferrite composition and any additives, may be combined by dissolving or suspending them in a solvent to provide a mixture or solution.

[0043] The solvent, if included, is selected to dissolve the polymer, disperse the ferrite composition and any additives that may be present, and have a convenient evaporation rate for formation and drying. A non-exclusive list of possible solvents is xylene, toluene, methyl ethyl ketone, methyl isobutyl ketone, higher liquid straight-chain alkanes such as hexane, heptane, octane, or nonane, cyclohexane, isophorone, various terpene-based solvents, or blended solvents. Exemplary solvents include xylene, toluene, methyl ethyl ketone, methyl isobutyl ketone, or hexane. In one embodiment, the solvent is xylene or toluene.

[0044] The concentration of the components of the composition in the solution or dispersion is not critical and depends on the solubility of the components, the additive levels used, the method of application, and other factors. Solutions can contain 10-80% by weight solids (all components other than solvent), or 50-75% by weight solids, based on the total weight of the solution.

[0045] Any solvent is evaporated under ambient conditions or with forced or heated air, and the composition is cooled to yield the composite. The composition may be shaped, for example, by extrusion, molding, or casting.

[0046] The mixture can be molded to form a composite, for example, by compression molding, injection molding, or reaction injection molding. In one embodiment, the mixture can be extruded or subjected to rolling techniques to form a composite.

[0047] The composite can be prepared by reaction injection molding the thermosetting composition. Reaction injection molding can include mixing at least two streams to form the thermosetting composition and injecting the thermosetting composition into a mold, where the first stream can include a catalyst and the second stream can include an activator. One or both of the first and second streams, or the third stream, can include a monomer. One or both of the first and second streams, or the third stream can include a crosslinker, a ferrite composition, an additive, or a combination thereof. One or both of the ferrite composition and the additive can be added to the mold before injecting the thermosetting composition.

[0048] Mixing can be done in the headspace of an injection molding machine. Mixing can be done in an in-line mixer. Mixing can be done during injection into the mold. Mixing can be done at temperatures of 0-200°C, 15-130°C, 0-45°C, or 23-45°C or higher.

[0049] The mold may be maintained at a temperature of 0°C to 250°C, or 23°C to 200°C, or 45°C to 250°C, or 30°C to 130°C, or 50°C to 70°C or higher. Filling the mold may take 0.25 to 0.5 minutes, during which time the mold temperature may decrease. After the mold is filled, the temperature of the thermosetting composition may be increased, for example, from a first temperature of 0 to 45°C to a second temperature of 45 to 250°C. Molding may be performed at a pressure of 65 to 350 kilopascals (kPa). Molding may be performed for 5 minutes or less, or 2 minutes or less, or for 2 to 30 seconds. After polymerization is complete, the composite may be removed at the mold temperature or a lower mold temperature, for example, at a release temperature T r is the molding temperature T m 10℃ lower than the temperature (T r ≦T m -10℃).

[0050] After the composite is removed from the mold, it can be post-cured at temperatures between 100 and 150°C, or between 140 and 200°C, for at least 5 minutes.

[0051] Articles including the ferrite composition or composite are also included herein. The article can be a microwave device, such as an antenna or inductor. The article can be a transformer, inductor, or electromagnetic interference prevention material. The article can be an antenna, such as a patch antenna, an inverted-F antenna, or a planar inverted-F antenna. The article can be, for example, a magnetic busbar for wireless charging, an NFC shielding material, or an electronic bandgap metamaterial. The article can be intended for use in the 1-10 GHz or 2-12 GHz frequency range. The article can be used in various devices capable of operating in the ultra-high frequency range, such as radio frequency or microwave antennas, filters, inductors, circulators, or phase shifters. The article can operate at frequencies above 1 GHz, or at frequencies from 1-10 GHz for ceramics, e.g., bulk ceramics, or at frequencies from 2-12 GHz for composites. Such articles can be used in commercial and military applications, weather radar, scientific communications, wireless communications, autonomous vehicles, aircraft communications, space communications, satellite communications, or surveillance.

[0052] The following examples are provided to illustrate the present disclosure. The examples are merely illustrative and are not intended to limit the scope of the invention.

[0053] Example A series of 18H hexaferrite compositions were prepared. The chemical formulas of hexaferrite are shown in Table 1.

[0054] [Table 1]

[0055] Each of these eight hexaferrite compositions is generally produced according to the following procedure. The metal source compounds used are BaCO3 (>99.5%), NiO (>99.5%), CuO (>99.5%), TiO2 (>99.5%), and Fe2O3 (>99.2%). The metal source compounds are blended together in a wet planetary mill in a ratio that provides the desired formula. The mixture of metal source compounds is calcined by heating to 1,100°C in air for a 4-hour soak time. The calcined ferrite material is then crushed and sieved through a 40# sieve. The sieved ferrite particles are then polished in a wet planetary mill to achieve a size of 0.5 to 10 micrometers. The polished ferrite particles are mixed with 0.5 to 5 wt% polyvinyl alcohol, then sieved through a 40# sieve and granulated into granules. The granules are compressed to form ferrite green bodies under a pressure of 1 metric ton per square centimeter. Two different shapes of green bodies are formed: toroids (outer diameter 7 mm, inner diameter 3 mm, thickness 3-3.5 mm) for permeability and permittivity measurements or disks (diameter 6 mm) for magnetic hysteresis measurements.

[0056] The polyvinyl alcohol is removed from the green bodies to obtain the ferrite composition by first heating them in air at 600°C for 2 hours, followed by sintering the green bodies in an oxygen atmosphere at 1,000 or 1,250°C for 4 hours. The oxygen gas flow rate is 0.5 liters per minute, the heating ramp rate is 1 to 5°C per minute, and the cooling rate is 1 to 5°C per minute.

[0057] Magnetic hysteresis measurements were performed using a vibrating sample magnetometer (VSM). Magnetization versus temperature was measured under 50 Oe (3.98 kiloamperes per meter (kA / m)) using a Quantum Design Physical Property Measurement System (PPMS). Magnetic permeability / permittivity was measured using a vector network analyzer (VNA) using the Nicholson-Ross-Weir (NRW) method at frequencies from 0.1 to 10 gigahertz (GHz) with a coaxial airline.

[0058] FIG. 2 is a graph of magnetization (emu / g) versus temperature (°C) for Examples 1 to 8. From FIG. 2, it can be seen that the magnetization is 1.5 (emu / g) (1.5 amperes squared meters per kilogram (A m 2 It can be seen that Examples 6 to 8, in which the porosity is 1 / kg or more, provide more desirable results in terms of magnetization, for example, compared to Examples 1 to 5.

[0059] Fig. 3 is a graph of actual permeability μ' versus frequency (f) (gigahertz (GHz)) for Examples 1 to 8. Fig. 3 shows that Examples 6 to 8, which exhibit a maximum actual permeability of less than 1.9 in the range of 0.1 GHz to 10 GHz, can achieve more desirable results, for example, in terms of actual permeability, than Examples 1 to 5.

[0060] FIG. 4 is a graph of imaginary permeability μ″ versus frequency (GHz) for Examples 1 to 8. From FIG. 4, it can be seen that Examples 6 to 8, which exhibit a maximum imaginary permeability of less than 1 in the range of 0.1 GHz to 10 GHz, can obtain more desirable results than Examples 1 to 5, for example, from the viewpoint of imaginary permeability.

[0061] Table 2 shows the saturation magnetization, coercive force, and Curie temperature of each ferrite composition in Table 1. The saturation magnetization, coercive force, and Curie temperature vary depending on the copper content, for example, the molar ratio of copper to nickel in the ferrite composition.

[0062] [Table 2]

[0063] Tables 3-5 show the real permeability, loss tangent, permittivity, and dielectric loss tangent for each of the ferrite compositions in Table 1 at various frequencies. Example 2 exhibited a desirable combination of high real permeability and low loss tangent at 4 GHz (1.50 and 0.04, respectively) and 5 GHz (1.67 and 0.04, respectively). Example 3 exhibited a desirable combination of high real permeability and low loss tangent at 4 GHz (1.52 and 0.04, respectively) and 5 GHz (1.76 and 0.04, respectively). A desirable combination of high permeability and low loss tangent can be, for example, 1.50 or greater and less than 0.05, respectively (see Example 2 at 4 or 5 GHz and Example 3 at 4 or 5 GHz), or 1.50 or greater and 0.04 or less, respectively (see Example 2 at 4 or 5 GHz and Example 3 at 4 or 5 GHz). The dielectric constants (dielectric constant (ε')) of Examples 1 to 4 and 6 to 8 were 10 to 15 over the frequency band of 1 to 9 GHz, and the dielectric loss tangents (ε" / ε') were 0.0002 to 0.01 over the frequency band of 1 to 5 GHz (excluding Example 4, Example 6, and Example 8 at 5 GHz).

[0064] [Table 3]

[0065] [Table 4]

[0066] [Table 5]

[0067] Example 9 A polymer-ferrite composite material was fabricated using the hexaferrite composition of Example 4. The fired ferrite material of Example 4 was pulverized into a powder with an average particle size of 4 - 6 micrometers and then mixed with paraffin wax having various ferrite contents. This composite material was formed into a toroid with an outer diameter of 7 mm, an inner diameter of 3 mm, and a thickness of 3 - 4 mm for magnetic and dielectric spectrum measurements using a vector network analyzer (VNA) by the Nicholson-Ross-Weir (NRW) method at frequencies of 0.1 - 18 GHz.

[0068] The results are shown in Table 6 and plotted in FIGS. 5 and 6. FIG. 5 is a graph of the real permeability μ' and the imaginary permeability μ against frequency, and FIG. 6 is a graph of the real dielectric constant ε' and the imaginary dielectric constant ε against frequency. The polymer-ferrite composite material can be used at frequencies of 1 - 3 GHz with a permeability of 1.2 - 1.5, a magnetic loss tangent of 0.06 - 0.08, a dielectric constant of 6 - 8, and a dielectric tangent of 0.002 - 0.006.

[0069] [Table 6]

[0070] The following are non-limiting aspects of the present disclosure.

[0071] Aspect 1 Ba x Ni 2-y Cu y Ti3Fe z O 31 having the formula, where 4.5 ≤ x ≤ 5.5, 0 < y < 2 or 0.05 ≤ y ≤ 1.5, and 11 ≤ z ≤ 13, a ferrite composition.

[0072] Aspect 2 Ba x Ni 2-y Cu y Ti3Fe z O 31 having the formula, where 5.0 ≤ x ≤ 5.1, 0.05 ≤ y ≤ 1.5, and 11.7 ≤ z ≤ 12.0, the ferrite composition according to Aspect 1.

[0073] Aspect 3 3. The ferrite composition of embodiment 2, wherein x=5.1.

[0074] Aspect 4 4. The ferrite composition of embodiment 2 or 3, wherein z=11.7.

[0075] Aspect 5 5. The ferrite composition of any of the preceding aspects, having a Curie temperature of 200°C or greater, 210°C or greater, 220°C or greater, 230°C or greater, 240°C or greater, or 250°C or greater.

[0076] Aspect 6 6. The ferrite composition of any of the preceding embodiments, having a coercivity of less than 50 Oersteds (Oe) (3.98 kiloamperes / meter), less than 30 Oe (2.39 kiloamperes / meter), less than 15 Oe (1.19 kiloamperes / meter), less than 5 Oe (0.40 kiloamperes / meter), less than 4 Oe (0.32 kiloamperes / meter), less than 3 Oe (0.24 kiloamperes / meter), less than 2 Oe (0.16 kiloamperes / meter), or less than 1 Oe (0.08 kiloamperes / meter).

[0077] Aspect 7 7. The ferrite composition of any of the preceding embodiments, having an average grain size of 1 to 100 micrometers.

[0078] Aspect 8 Magnetic permeability (μ) of 1.5 to 2 at frequencies of 1 to 9 GHz; Magnetic loss tangent (tanδ) of less than 0.05 at frequencies from 1 to 9 GHz μ ), a dielectric constant (ε) of 10 to 15 at frequencies from 1 to 9 GHz, and a dielectric loss tangent (tanδ) of less than 0.01, less than 0.08, or less than 0.004 at frequencies from 1 to 9 GHz. ε ), cutoff frequency greater than 10 GHz (resonant frequency f r 8. The ferrite composition of any of the preceding embodiments, having:

[0079] Aspect 9 9. The ferrite composition of any of the preceding embodiments, having an in-plane easy magnetization, an 18H structure, or a combination thereof.

[0080] Aspect 10 10. A method for producing a ferrite composition, comprising: calcining a blend of metal raw materials for the ferrite composition of any one of aspects 1 to 9; reducing the particle size of the calcined raw materials to obtain particles having an average particle size of 0.5 to 100 micrometers or 0.5 to 10 micrometers; granulating the mixture of the particles and a binder to obtain granules; compressing the granules into green bodies; and sintering the green bodies to form the ferrite composition.

[0081] Aspect 11 11. The method of claim 10, wherein the calcining is performed at 900-1,200° C. for 0.5-20 hours, the calcining is performed in an atmosphere of air, nitrogen, oxygen, or a combination thereof, the sintering is performed at 1,000-1,300° C. for 1-20 hours, the sintering is performed in an atmosphere of air, nitrogen, oxygen, or a combination thereof, the sintering is performed at a heating rate of 1-5° C. / min, a cooling rate of 1-5° C. / min, or a combination thereof, and the particle size reduction step comprises grinding the calcined raw compound, polishing the calcined raw compound, or a combination thereof, or a combination thereof.

[0082] Aspect 12 12. The method of embodiment 10 or 11, further comprising sizing the particles.

[0083] Aspect 13 13. The method of any one of embodiments 10 to 12, further comprising blending metal source compounds.

[0084] Aspect 14 14. The method of any one of aspects 10 to 13, wherein the binder is polyvinylpyrrolidone, poly(vinyl alcohol), polyacrylamide, poly(acrylic acid), polyethylene glycol, polyethylene oxide, cellulose acetate, starch, polypropylene carbonate, polyvinyl butyral, or a combination thereof.

[0085] Aspect 15 10. A composite comprising: a polymer matrix; and the ferrite composition of any of embodiments 1 to 9, wherein the ferrite composition has a particle size of 0.5 to 30 micrometers.

[0086] Aspect 16 16. The composite of embodiment 15, comprising 5 to 95 volume percent hexaferrite, based on the total volume of the composite.

[0087] Aspect 17 17. The composite of embodiment 15 or 16, wherein the polymer matrix comprises polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, high density polyethylene, low density polyethylene, polymethyl methacrylate, polyetheretherketone, polyethersulfone, or a combination thereof.

[0088] Aspect 18 10. An article comprising the ferrite composition of any of embodiments 1 to 9.

[0089] Aspect 19 20. The article of embodiment 18, wherein the article is an antenna, an inductor, a transformer, or an electromagnetic interference prevention material.

[0090] Aspect 20 20. The article of embodiment 18 or 19, wherein the article is a microwave device.

[0091] In general, the compositions, methods and articles can alternatively comprise, consist of, or consist essentially of any component, step, or ingredient disclosed herein. The compositions, methods and articles may additionally or alternatively be formulated, performed, or manufactured to be devoid of, or substantially free of, any component, step, or ingredient that is not necessary to achieve the function or purpose of the claims.

[0092] The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The term "or" means "and / or" unless clearly indicated otherwise by context. The endpoints of all ranges directed to the same component or property are inclusive, independently combinable, and include all intermediate points. The disclosure of a narrower range or more specific group in addition to a broader range is not a disclaimer of the broader range or larger group. "Combinations thereof" is open and includes combinations of one or more of the specified elements with one or more similar elements, optionally not specified.

[0093] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The term "combination" includes blends, mixtures, alloys, reaction products, and the like. The permittivity and permeability used herein may be determined at a temperature of 23°C.

[0094] Throughout this specification, references to "aspects," "aspects," "embodiments," etc. mean that the particular element (e.g., feature, structure, step, or characteristic) described in connection with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. Thus, while particular combinations of features are described, it will be understood that these combinations are for illustrative purposes only, and that any combination of any of these features may be employed, individually or in combination with any other of the features disclosed herein, in any combination, all in accordance with the aspects, explicitly or equivalently. Any and all such combinations are contemplated herein and are considered to be within the scope of the present disclosure.

[0095] While the present disclosure has been described with reference to exemplary embodiments, those skilled in the art will recognize that various changes can be made and equivalents substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications can be made to adapt a particular situation or material to the teachings without departing from essential scope thereof. Therefore, the disclosure is not limited to the particular embodiment disclosed as the best or only mode contemplated for carrying out the invention, but the disclosure is intended to include all embodiments falling within the scope of the appended claims.

Claims

1. Yes ｘ Yes ２－ｙ Cu ｙ Till ３ Fe ｚ Oh ３１ and has the formula During the ceremony, 4.5≦x≦5.5, 0<y<2 or 0.05≦y≦1.5, 11≦z≦13, Ferrite composition.

2. Yes ｘ Yes ２－ｙ Cu ｙ Till ３ Fe ｚ Oh ３１ and has the formula During the ceremony, 5.0≦x≦5.1, 0.05≦y≦1.5, 2. The ferrite composition of claim 1, wherein 11.7≦z≦12.

0.

3. The ferrite composition of claim 2, wherein x=5.

1.

4. 4. The ferrite composition according to claim 2, wherein z=11.

7.

5. 5. The ferrite composition according to claim 1, having a Curie temperature of 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, 240°C or higher, or 250°C or higher.

6. 6. The ferrite composition of claim 1, having a coercivity of less than 50 Oersteds (Oe) (3.98 kiloamperes / meter), less than 30 Oe (2.39 kiloamperes / meter), less than 15 Oe (1.19 kiloamperes / meter), less than 5 Oe (0.40 kiloamperes / meter), less than 4 Oe (0.32 kiloamperes / meter), less than 3 Oe (0.24 kiloamperes / meter), less than 2 Oe (0.16 kiloamperes / meter), or less than 1 Oe (0.08 kiloamperes / meter).

7. 7. The ferrite composition of claim 1 having an average grain size of 1 to 100 micrometers.

8. Magnetic permeability (μ) of 1.5 to 2 at frequencies of 1 to 9 GHz, Magnetic loss tangent (tanδ) of less than 0.05 at frequencies of 1 to 9 GHz μ ), A dielectric constant (ε) of 10 to 15 at frequencies between 1 and 9 GHz, A dielectric loss tangent (tanδ) of less than 0.01, less than 0.08, or less than 0.004 at a frequency of 1 to 9 GHz ε ), A cutoff frequency greater than 10 GHz (resonant frequency f ｒ ),or combinations of these The ferrite composition according to any one of claims 1 to 7, wherein

9. 9. The ferrite composition of claim 1, having an in-plane easy magnetization, an 18H structure, or a combination thereof.

10. sintering a blend of metal raw material compounds for the ferrite composition of any one of claims 1 to 9; reducing the particle size of the calcined precursor compound to obtain particles having an average particle size of 0.5 to 100 micrometers or 0.5 to 10 micrometers; granulating the mixture of particles and a binder to obtain granules; compressing the granules into a green body; sintering the green body to form the ferrite composition; A method for producing a ferrite composition, comprising:

11. Calcination is carried out at 900 to 1,200°C for 0.5 to 20 hours; The firing is carried out in an atmosphere of air, nitrogen, oxygen, or a combination thereof; sintering is carried out at 1,000 to 1,300°C for 1 to 20 hours; sintering is carried out in an atmosphere of air, nitrogen, oxygen, or a combination thereof; sintering is carried out at a heating rate of 1 to 5°C / min, a cooling rate of 1 to 5°C / min, or a combination thereof; the particle size reduction step comprises grinding the calcined precursor compound, grinding the calcined precursor compound, or a combination thereof; or including combinations thereof, The method of claim 10.

12. 12. The method of claim 10 or 11, further comprising the step of sizing the particles.

13. 13. The method of any one of claims 10 to 12, further comprising blending the metal source compounds.

14. 14. The method of any one of claims 10 to 13, wherein the binder is polyvinylpyrrolidone, poly(vinyl alcohol), polyacrylamide, poly(acrylic acid), polyethylene glycol, polyethylene oxide, cellulose acetate, starch, polypropylene carbonate, polyvinyl butyral, or a combination thereof.

15. a polymer matrix; The ferrite composition according to any one of claims 1 to 9, the ferrite composition has a particle size of 0.5 to 30 micrometers; Composite material.

16. 16. The composite of claim 15, comprising 5 to 95 volume percent hexaferrite, based on the total volume of the composite.

17. 17. The composite of claim 15 or 16, wherein the polymer matrix comprises polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, high density polyethylene, low density polyethylene, polymethyl methacrylate, polyether ether ketone, polyethersulfone, or a combination thereof.

18. An article comprising the ferrite composition of any one of claims 1 to 9.

19. 20. The article of claim 18, wherein the article is an antenna, an inductor, a transformer, or an electromagnetic interference prevention material.

20. 20. The article of claim 18 or 19, wherein the article is a microwave device.

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