Y-type hexaferrite, method for producing the same, and use thereof

Abstract

In one aspect, the Co2Y-type ferrite is an oxide of at least Ba, La, Co, Me, Fe, and optionally Ca; Me is at least one or more of Ni, and optionally Zn, Cu, Mn, or Mg, and includes an oxide. The composite may include a Co2Y-type ferrite and a polymer. The article may include a Co2Y-type ferrite.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 350,248, filed on June 8, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure is directed to Y - type hexaferrites containing lanthanum and nickel.

Background Art

[0003] To meet the growing demand for devices used in ultra - high - frequency applications, which are of particular interest in various commercial and defense - related industries, performance improvement and miniaturization are necessary. As important components of radar and global positioning system (GPS) navigation systems, small - sized antenna elements have been continuously developed. However, since most ferrite materials exhibit relatively high magnetic losses at high frequencies, it has been difficult to develop ferrite materials for such high - frequency applications.

[0004] Generally, hexagonal ferrites, i.e., hexaferrites, are a type of iron - oxide ceramic compound having a hexagonal crystal structure and exhibiting magnetic properties. Some types of hexaferrite families are known, including Z - type ferrite Ba3Me2Fe 24 O 41 and Y - type ferrite Ba2Me2Fe 12 O 22 where Me may be a small divalent cation such as Co or Zn, and Sr can be used instead of Ba. Other hexaferrite types include M - type ferrite ((Ba,Sr)Fe 12 O 19 ), W - type ferrite ((Ba,Sr)Me2Fe 16 O 27 ), X - type ferrite ((Ba,Sr)2Me2Fe 28 O 46 ), and U - type ferrite ((Ba,Sr)4Me2Fe 36 O60 ) can be mentioned.

[0005] Hexaferrites having a high crystalline magnetic anisotropy field are good candidates for gigahertz antenna substrates because they have a high crystalline magnetic anisotropy field and thereby have a high ferromagnetic resonance frequency. However, an improved ferrite with a low loss value near 1 gigahertz is desired.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Means for Solving the Problems

[0007] This specification discloses Co2Y-type hexaferrites.

[0008] In one aspect, the Co2Y-type ferrite includes oxides of at least Ba, La, Co, Me, Fe, and optionally Ca, wherein Me is at least one or more of Ni and optionally Zn, Cu, Mn, or Mg.

[0009] In another aspect, the composite includes a Co2Y-type ferrite and a polymer.

[0010] In yet another aspect, the article may include a Co2Y-type ferrite.

[0011] In yet another aspect, a method of fabricating Co2Y-type ferrite includes a step of pulverizing a ferrite precursor compound containing at least oxides of Ba, La, Co, Me, and Fe to form a magnetic oxide mixture, where Me includes another divalent element such as Ni and optionally one or more of Zn, Cu, Mn, or Mg; and a step of firing the magnetic oxide mixture in an oxygen or air atmosphere to form Co2Y-type ferrite.

[0012] The above features and other features are illustrated by the following detailed description and the claims.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0014] It has been discovered that Co2Y-type ferrite containing both lanthanum and nickel exhibits very low losses over a frequency range of 1 to 2 gigahertz (GHz), which is difficult to achieve with Y-type ferrite. For example, Co2Y-type ferrite may have a specific magnetic loss of 0.02 or less, or 0.03 or less, or 0.015 or less, or 0.012 to 0.03 over a frequency range of 1 to 2 GHz or at 1.2 GHz. Co2Y-type ferrite includes oxides of at least Ba, La, Co, Me, Fe, and optionally Ca, where Me includes at least Ni and optionally one or more of Zn, Cu, Mn, or Mg. Co2Y-type ferrite may have formula (1) or formula (2). Ba 1-x La x Ca n Co 2-y-z Me y Fe 12-m O 22 (1) Ba 1-x La x Ca n Co 2-y-z Ni y Fe 12-m O 22 (2) Me includes Ni and optionally one or more of Zn, Cu, Mn, or Mg. The variable x may be 0.01 to 0.5, or 0.4 to 0.5. The variable y may be 0.01 to 1.5, or 0.1 to 1, or 0.2 to 0.5. The variable z may be -0.5 to 0.5, or -0.2 to 0. The variable m may be -2 to 2, or 0.1 to 0.5. The variable n may be 0 to 0.5.

[0015] The Co2Y-type ferrite can be in the form of particles (e.g., having a spherical or irregular shape), or in the form of platelets, whiskers, flakes, etc. The volume-based D of particulate Co2Y-type ferrite 50 The particle size may be 0.5 to 50 micrometers, or 0.5 to 20 micrometers, or 1 to 10 micrometers, or 0.1 to 1 micrometer. When measured using a scanning electron microscope, the Co2Y-type ferrite may have an average particle size of 0.5 to 50 micrometers, or 0.5 to 20 micrometers, or 1 to 10 micrometers. The platelets of the Co2Y-type ferrite may have an average maximum length of 0.1 to 100 micrometers and an average thickness of 0.05 to 1 micrometer. The Co2Y-type ferrite may have a porosity of 0 to 50 volume% (vol%) or 20 to 45 volume% based on the total volume of the Co2Y-type ferrite.

[0016] The Co2Y-type ferrite may be formed by a process of mixing precursor compounds containing at least oxides of Ba, La, Co, Me, Fe, and optionally Ca to form a magnetic oxide mixture, where Me includes another divalent element such as Ni and optionally one or more of Zn, Cu, Mn, or Mg, and a process of firing the magnetic oxide mixture in an oxygen or air atmosphere to form the Co2Y-type ferrite. The obtained Co2Y-type ferrite may have formula (1) or (2). Examples of the oxides can include BaCO3, CaCO3, Co3O4, Fe2O3, La2O3, NiO, MgO, ZnO, and CuO.

[0017] The Co2Y-type ferrite can be fired. The firing can be carried out at a firing temperature of 800 - 1,300 °C, or 800 - 1,280 °C, or 900 - 1,250 °C. The firing can be carried out for a firing time of 0.5 - 20 hours, or 1 - 10 hours. The temperature gradient rate of the firing process is not particularly limited, but it can be carried out at a heating and cooling rate of 1 - 5 °C (°C / min), or 2 - 4 °C / min. The firing can be carried out in an air or oxygen environment, for example, under an oxygen flow rate of 0.1 - 10 liters per minute. The firing process can be the only heating process used in the production of the Co2Y-type ferrite.

[0018] After the firing process, the fired ferrite can be ground and screened to form coarse particles. The coarse particles can be ground to a volume-based D particle size of 0.1 - 20 micrometers, or 0.5 - 20 micrometers, or 1 - 10 micrometers, or 0.1 - 1 micrometer. 50 The particle size can be ground.

[0019] Co2Y-type ferrite can be milled. The milling can be carried out for a milling time of 1 to 10 minutes or more, or 5 to 60 minutes, or 1 minute to 10 hours. The milling can be carried out at a mixing speed of 300 revolutions per minute (rpm) or more, or 300 to 1,000 rpm, or 600 rpm or less, or 400 to 500 rpm. The milling can be carried out in a wet planetary ball mill. The milled mixture can optionally be sieved using, for example, a sieve of 10 to 300 mesh. The milled mixture can be mixed with a polymer such as poly(vinyl alcohol) to form granules. The granules may have a volume-based average D 50 particle size of 50 to 300 micrometers. The milled mixture can be shaped or formed, for example, by compression at a pressure of 0.2 to 2 megatons per square centimeter. The particulate or formed milled mixture can be heated at a temperature of 50 to 500 °C, 200 to 1,280 °C, or 100 to 250 °C. The particulate or formed milled mixture can be post-annealed at an annealing temperature of 900 to 1,275 °C, or 1,200 to 1,250 °C. The heating or annealing can be carried out for 1 to 20 hours, or 4 to 6 hours, or 5 to 12 hours. The annealing can be carried out in air or oxygen.

[0020] Co2Y-type ferrite may include a surface coating. The coating can increase the amount of Co2Y-type ferrite in the composite. The coating may be a hydrophobic coating. The coating may include at least one of a silane coating, a titanate coating, or a zirconate coating.

[0021] The silane coating may be formed from silane, which may include at least one of a linear silane, a branched silane, or a cyclo silane. The silane may include precipitated silane. The silane may not include a solvent (such as toluene) or dispersed silane. For example, the silane may include 0 to 2% by weight (wt%) (e.g., 0 wt%) of solvent-dispersed silane based on the total mass of the silane.

[0022] To form the coating, various different silanes including one or both of phenylsilane and fluorosilane can be used. Phenylsilane may be p-chloromethylphenyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, phenyl-tris-(4-biphenylyl)silane, hexaphenyldisilane, tetrakis-(4-biphenylyl)silane, tetrakis-Z-thienylsilane, phenyltris-Z-thienylsilane, 3-pyridyltriphenylsilane, or a combination including at least one of the foregoing. Functionalized phenylsilanes as described in U.S. Patent No. 4,756,971, for example, of the formula R’SiZ 1 R 2 Z 2 can also be used, wherein R’ is alkyl having 1 to 3 carbon atoms, -SH, -CN, -N3, or hydrogen; Z 1 and Z 2 are each independently chlorine, fluorine, bromine, alkoxy having 6 or fewer carbon atoms, NH, -NH2, -NR2’; R 2 is

[0023]

Chemical formula

[0024] (wherein each of the S-substituents, S1, S2, S3, S4, and S5 is independently hydrogen, alkyl having 1 to 4 carbon atoms, methoxy, ethoxy, or cyano, provided that at least one of the S-substituents is other than hydrogen, and when there are methyl or methoxy S-substituents, (i) at least 2 of the S-substituents are other than hydrogen, (ii) two adjacent S-substituents together with the phenyl nucleus form a naphthalene or anthracene group, or (iii) three adjacent S-substituents together with the phenyl nucleus form a pyrene group, and X is -(CH2) n-yl (wherein n is from 0 to 20, specifically, when n is not 0, it is from 10 to 16, in other words, X is an optional spacer group, an S-substituent). The term "lower" related to a group or a compound means from 1 to 7, or from 1 to 4 carbon atoms).

[0025] The fluorosilane coating may be formed from a perfluorinated alkylsilane having the formula: CF3(CF2) n -CH2CH2SiX: wherein X is a hydrolyzable functional group and n = 0 or an integer. The fluorosilane may include at least one of (3,3,3-trifluoropropyl) trichlorosilane, (3,3,3-trifluoropropyl) dimethylchlorosilane, (3,3,3-trifluoropropyl) methyldichlorosilane, (3,3,3-trifluoropropyl) methyldimethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-trichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-methyldichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-dimethylchlorosilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-methyldichlorosilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-trichlorosilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-dimethylchlorosilane, (heptafluoroisopropoxy)propylmethyldichlorosilane, 3-(heptafluoroisopropoxy)propyltrichlorosilane, 3-(heptafluoroisopropoxy)propyltriethoxysilane, or perfluorooctyltriethoxysilane.

[0026] Instead of phenylsilane or fluorosilane, or in addition to phenylsilane or fluorosilane, other silanes can be used, such as aminosilanes and silanes containing polymerizable functional groups such as acrylic groups and methacrylic groups. Examples of aminosilanes include N-methyl-γ-aminopropyltriethoxysilane, N-ethyl-γ-aminopropyltrimethoxysilane, N-methyl-β-aminoethyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-methyl-γ-aminopropylmethyldimethoxysilane, N-(β-N-methylaminoethyl)-γ-aminopropyltriethoxysilane, N-(γ-aminopropyl)-γ-aminopropylmethyldimethoxysilane, N-(γ-aminopropyl)-N-methyl-γ-aminopropylmethyldimethoxysilane, and γ-aminopropylethyldiethoxysilane aminoethylaminotrimethoxysilane, aminoethylaminopropyltrimethoxysilane, 2-ethylpiperidinotrimethylsilane, 2-ethylpiperidinomethylphenylchlorosilane, 2-ethylpiperidinedimethylhydridosilane, 2-ethylpiperidinedicyclopentylchlorosilane, (2-ethylpiperidino)(5-hexenyl)methylchlorosilane, morpholinovinylmethylchlorosilane, n-methylpiperazinophenyldichlorosilane, or a combination containing at least one of the foregoing.

[0027] Silanes containing polymerizable functional groups include those of the formula R a x SiR b (3-x) wherein each R a is the same or different (e.g., the same), a halogen (e.g., Cl or Br), C 1~4 alkoxy (e.g., methoxy or ethoxy), or C 2~6 acyl; each R b is C 1~8 alkyl or C 6~12 aryl (e.g., R bmay be methyl, ethyl, propyl, butyl, or phenyl); x is 1, 2, or 3 (e.g., 2 or 3); R is -(CH2) n OC(=O)C(R c )=CH2, wherein R c is hydrogen or methyl, and n is an integer from 1 to 6 or from 2 to 4. The silane may contain at least one of methacrylsilane (3-methacryloxypropyltrimethoxysilane) or trimethoxyphenylsilane.

[0028] The titanate coating may be formed from neopentyl(diallyl)oxy, trineodecanonyl titanate; neopentyl(diallyl)oxy, tri(dodecyl)benzene-sulfonyl titanate; neopentyl(diallyl)oxy, tri(dioctyl)phosphato titanate; neopentyl(diallyl)oxy, tri(dioctyl)pyro-phosphato titanate; neopentyl(diallyl)oxy, tri(N-ethylenediamino)ethyl titanate; neopentyl(diallyl)oxy, tri(m-amino)phenyl titanate; and neopentyl(diallyl)oxy, trihydroxycaproyl titanate; or a combination containing at least one of the foregoing. The zirconate coating may be formed from neopentyl(diallyloxy)tri(dioctyl)pyro-phosphate zirconate, neopentyl(diallyloxy)tri(N-ethylenediamino)ethyl zirconate, or a combination containing at least one of the foregoing.

[0029] The Co2Y-type ferrite may be coated at a level of 10 wt% or less, or 5 wt% or less, or 0.1 to 5 wt%, or 0.1 to 3 wt% based on the total mass of the Co2Y-type ferrite and the coating.

[0030] Co2Y-type ferrite particles can be used to produce composites, for example, composites containing Co2Y-type ferrite and a polymer. The polymer may include a thermoplastic or a thermosetting material. As used herein, the term "thermoplastic" refers to a material that is plastic or deformable, melts into a liquid when heated, and freezes into a brittle glassy state when sufficiently cooled. Examples of thermoplastic polymers that can be used include cyclic olefin polymers (including polynorbornene and copolymers containing norbornenyl units, such as copolymers of cyclic polymers such as norbornene and acyclic olefins such as ethylene or propylene), fluoropolymers (e.g., polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), poly(ethylene-tetrafluoroethylene) (PETFE), or perfluoroalkoxy (PFA)), polyacetals (e.g., polyoxyethylene or polyoxymethylene), poly(C 1~6 alkyl) acrylate, polyacrylamide (unsubstituted and mono-N- or di-N-(C 1~8(including alkyl)acrylamide), polyacrylonitrile, polyamide (e.g., aliphatic polyamide, polyphthalamide, or polyaramide), polyamideimide, polyanhydride, polyarylene ether (e.g., polyphenylene ether), polyarylene ether ketone (e.g., polyetheretherketone (PEEK) or polyetherketoneketone (PEKK)), polyarylene ketone, polyarylene sulfide (e.g., polyphenylene sulfide (PPS)), polyarylene sulfone (e.g., polyethersulfone (PES) or polyphenylene sulfone (PPS)), polybenzothiazole, polybenzoxazole, polybenzimidazole, polycarbonate (including homopolycarbonate, or polycarbonate copolymers such as polycarbonate - siloxane, polycarbonate - ester, or polycarbonate - ester - siloxane), polyester (e.g., polyethylene terephthalate, polybutylene terephthalate, polyarylate, or polyester copolymers such as polyester - ether), polyetherimide (e.g., copolymers such as polyetherimide - siloxane copolymer), polyimide (e.g., copolymers such as polyimide - siloxane copolymer), poly(C 1~6 (alkyl)methacrylate, polyalkylacrylamide (e.g., unsubstituted and mono - N - or di - N-(C 1~8(alkyl)acrylamide), polyolefin (e.g., polyethylene such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), or linear low-density polyethylene (LLDPE), polypropylene, or their halogenated derivatives (such as polytetrafluoroethylene), or their copolymers, e.g., ethylene-α-olefin copolymer), polyoxadiazole, polyoxymethylene, polyphthalide, polysilazane, polysiloxane (silicone), polystyrene (e.g., copolymers such as acrylonitrile-butadiene-styrene (ABS) or methyl methacrylate-butadiene-styrene (MBS)), polysulfide, polysulfonamide, polysulfonate, polysulfone, polythioester, polytriazine, polyurea, polyurethane, vinyl polymer (e.g., polyvinyl alcohol, polyvinyl ester, polyvinyl ether, polyhalogenated vinyl (e.g., polyvinyl chloride), polyvinyl ketone, polyvinyl nitrile, or polyvinyl thioether), paraffin wax, etc. A combination containing at least one of the aforementioned thermoplastic polymers can be used.

[0031] A thermosetting polymer is derived from a thermosetting monomer or prepolymer (resin) that can irreversibly solidify and become insoluble upon polymerization or curing, and the polymerization or curing can be induced by exposure to heat or radiation (e.g., ultraviolet, visible light, infrared, or electron beam (e-beam) radiation). Examples of thermosetting polymers include alkyds, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, benzocyclobutene polymers, benzoxazine polymers, diallyl phthalate polymers, epoxies, hydroxymethyl furan polymers, melamine-formaldehyde polymers, phenolics (including phenol-formaldehyde polymers such as novolac and resole), benzoxazine, polydienes such as polybutadiene (including homopolymers or copolymers thereof, e.g., poly(butadiene-isoprene)), polyisocyanates, polyureas, polyurethanes, triallyl cyanurate polymers, triallyl isocyanurate polymers, certain silicones, and polymerizable prepolymers (e.g., prepolymers having ethylenic unsaturation such as unsaturated polyesters, polyimides, etc.). The prepolymer can be polymerized, copolymerized, or crosslinked with a reactive monomer such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, acrylic acid, (meth)acrylic acid, (C 1~6 alkyl) acrylate, (C 1~6 alkyl) methacrylate, acrylonitrile, vinyl acetate, allyl acetate, triallyl cyanurate, triallyl isocyanurate, or acrylamide.

[0032] The polymer may contain at least one of paraffin wax, polytetrafluoroethylene, polyethylene, polypropylene, polyolefin, polyurethane, silicone polymer, liquid crystal polymer, poly(ether ether ketone), or poly(phenylene sulfide) (PPS). The polymer may contain a fluoropolymer (e.g., polytetrafluoroethylene (PTFE)). The polymer may contain poly(phenylene sulfide).

[0033] When the polymer contains PTFE, the powders of PTFE and Co2Y-type ferrite can be blended together and then air milled. An example of a commercially available air mill is the MICRON-MASTER mill from Jet Pulverizer. The air-milled powder can allow for the addition of more fillers without the article becoming brittle. Other energy-intensive methods can also be used, such as blending in a V-blender from Patterson Kelly equipped with an intensifier bar. The highly mixed powder can then be compression molded.

[0034] The PTFE composite can be prepared by dispersion casting, for example, as described in U.S. Patent No. 5,506,049 by G. S. Swei and D. J. Arthur. Dispersion casting can enable the production of a PTFE composite filled with more than 60 vol% while retaining excellent flexibility. The film can be cast onto a carrier sheet and then sintered to form a free film, or the film can be cast onto a glass cloth to form a fabric-reinforced composite sheet. The composite sheet can be used as a "cast-as-is" dielectric loading, or stacked to the desired final thickness and densified with a press. The casting mixture can be made by dispersing the particles in water, combining the slurry with a PTFE dispersion and a stabilizing additive, and increasing the viscosity so that the particles do not settle.

[0035] The PTFE composite can be prepared by paste extrusion and calendaring, and a flexible particle-filled PTFE composite having a filler content exceeding 60 vol% can be obtained. The ferrite filler can be dispersed in water, mixed with the PTFE dispersion, and then co-coagulated with the PTFE to form a "dough". As described in U.S. Patent No. 4,518,787 by G. R. Traut, the dough can then be lubricated with a hydrocarbon liquid, extruded into a ribbon, and then calendared into a sheet. Alternatively, the filler and PTFE "fine powder" (also known as "coagulated dispersed" PTFE) can be mixed, lubricated in a V-blender, and then extruded into a paste and calendared. The lubricant can be removed, the sheets can be stacked to the desired basis weight, and laminated using a flatbed printing press.

[0036] The Co2Y-type ferrite composite may contain 5 to 95 vol%, or 50 to 80 vol%, or 40 to 60 vol% of Co2Y-type ferrite based on the total volume of the Co2Y-type ferrite composite. The Co2Y-type ferrite composite may contain 20 to 50 vol% of a polymer based on the total volume of the Co2Y-type ferrite composite. The Co2Y-type ferrite composite may be formed by compression molding, injection molding, reaction injection molding, lamination, extrusion, calendaring, casting, rolling, etc.

[0037] The composite may have voids. The porosity of the composite may be 0 to 45 vol%, or 15 to 35 vol% based on the total volume of the composite. Without being bound by theory, it is believed that the porosity of the composite helps to reduce the dielectric constant of the composite compared to the permeability. The porosity can be adjusted by changing one or more of the firing temperature or the particle size of the ferrite. Conversely, the composite may have no interstitial space.

[0038] The Co2Y-type ferrite may have a specific magnetic loss of 0.02 or less, or 0.03 or less, or 0.015 or less, or 0.012 to 0.03 over a frequency range of 1 to 2 GHz or at 1.2 GHz.

[0039] The Co2Y-type ferrite may have a permeability (μ’) of 3 or more, or 3 to 6, or 3 to 4 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a permeability of 1.5 or more, or 1.5 to 4, or 1.5 to 2 over a frequency range of 1 to 2 GHz or at 1.2 GHz.

[0040] The Co2Y-type ferrite may have a magnetic loss (magnetic loss tangent, tanδ μ or also called μ’’ / μ’) of 0.75 or less, or 0.5 or less, or 0.09 or less, or 0.07 to 0.2 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a magnetic loss tangent of 0.1 or less, or 0.03 or less, or 0.02 or less, or 0.015 to 0.1 over a frequency range of 1 to 2 GHz or at 1.2 GHz.

[0041] The Co2Y-type ferrite may have a low specific loss defined by tanδ μ’ / μ’ or μ’’ / μ’ 2 For example, the Co2Y-type ferrite may have a low specific loss of 0.013 to 0.03 over a frequency range of 1 to 2 GHz.

[0042] The Co2Y-type ferrite may have a dielectric constant (ε’) of 9 or less, or 8 to 13 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a dielectric constant of 5 to 8 over a frequency range of 1 to 2 GHz or at 1.2 GHz depending on the polymer matrix.

[0043] The Co2Y-type ferrite may have a dielectric loss (dielectric loss tangent, tanδ ε or also called ε’’ / ε’) of 0.01 or less, or 0.002 to 0.009 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a dielectric loss of 0.008 or less, or 0.006 or less, or 0.002 to 0.006 over a frequency range of 1 to 2 GHz or at 1.2 GHz.

[0044] As used herein, the phrase "at a frequency of" can mean at a single frequency value within that range or over the entire frequency range. For example, the phrase "the permeability can be 2 to 10 at a frequency of 0.5 to 3 GHz" can mean that the permeability is a single value within the range of 2 to 10, such as 3, at a single frequency within the range of 0.5 to 3, for example 1 GHz; or that the permeability can be a value defined by the range of 2 to 10 over the entire frequency range spanning 0.5 to 3 GHz (e.g., varying within this range depending on the frequency).

[0045] The magnetic and dielectric properties of the ferrite can be measured over a frequency range of 0.1 to 6 GHz using a coaxial air line with a vector network analyzer (VNA) in the Nicholson-Ross-Weir (NRW) method.

[0046] The operating frequency of the Co2Y-type ferrite can be up to 6 GHz or may be in the range of 0.5 to 2 GHz.

[0047] The article may include Co2Y-type ferrite. The article may be, for example, an antenna for GPS tracking. The article can be used in various devices operable in the ultra-high frequency range, such as high-frequency or microwave antennas, filters, inductors, circulators, or phase shifters. The article may be an antenna (e.g., a patch antenna), filter, inductor, circulator, or EMI (electromagnetic interference) suppressor. Such articles can be used in commercial and military applications, weather radar, scientific communication, wireless communication, autonomous vehicles, aircraft communication, space communication, satellite communication, or surveillance.

[0048] The article may include a dielectric layer containing a composite; and a conductive layer. Useful conductive layers include, for example, stainless steel, copper, gold, silver, aluminum, zinc, tin, lead, transition metals, and alloys containing at least one of the foregoing. There is no particular limitation on the thickness of the conductive layer, nor is there any limitation on the shape, size, or texture of the surface of the conductive layer. The conductive layer may have a thickness of 3 to 200 micrometers, or 9 to 180 micrometers. When two or more conductive layers are present, the thicknesses of the two layers may be the same or different. The conductive layer may include a copper layer. Suitable conductive layers include thin layers of conductive metals such as copper foils currently used in circuit formation, for example, electrodeposited copper foils. The copper foil may have a root mean square (RMS) roughness of 2 micrometers or less, specifically 0.7 micrometers or less, where the roughness is measured using a Veeco Instruments WYCO Optical Profiler with white light interferometry.

[0049] The conductive layer can be applied by placing the conductive layer in a mold before forming the composite, by laminating the conductive layer on the composite (also referred to herein as the substrate), by direct laser structuring, or by attaching the conductive layer to the substrate via an adhesive layer. Other methods known in the art, such as electrodeposition, chemical vapor deposition, etc., can be used to apply a conductive layer acceptable for a particular material and form of the circuit material.

[0050] In lamination processing, in order to form a layered structure, it may be necessary to laminate a multi-layer stack including a substrate, a conductive layer, and an optional intermediate layer between the substrate and the conductive layer. The conductive layer can be in direct contact with the substrate layer without an intermediate layer. Then, the layered structure can be placed in a press, such as a vacuum press, under pressure, temperature, and time suitable for bonding the layers to form a laminate. The lamination processing and optional curing can be carried out by a one-step process using, for example, a vacuum press, or by a multi-step process. In a one-step process, the layered structure is placed in a press, the lamination pressure can be increased to, for example, 150 - 400 pounds per square inch (psi) (1 - 2.8 megapascals (MPa)), and heated to a lamination temperature of, for example, 260 - 390 degrees Celsius (°C). The lamination temperature and pressure can be maintained for a desired soaking time, i.e., 20 minutes, and then cooled to 150°C or less (while under pressure).

[0051] When an intermediate layer is present, the intermediate layer may include a polyfluorocarbon film that can be installed between the conductive layer and the substrate layer, and an optional layer of a fluorocarbon polymer reinforced with microglass can be installed between the polyfluorocarbon film and the conductive layer. The layer of fluorocarbon polymer reinforced with microglass can enhance the adhesion of the conductive layer to the substrate. The microglass may be present in an amount of 4 - 30 weight percent (wt%) based on the total mass of the layer. The microglass may have a longest length scale of 900 micrometers or less, or 500 micrometers or less. The microglass may be of a type commercially available from Johns-Manville Corporation of Denver, Colorado. The polyfluorocarbon film includes a fluoropolymer (such as polytetrafluoroethylene (PTFE)), a fluorinated ethylene-propylene copolymer (such as Teflon® FEP), or a copolymer having a tetrafluoroethylene backbone with a fully fluorinated alkoxy side chain (such as Teflon® PFA).

[0052] The conductive layer can be applied by direct laser structuring. Here, the substrate may contain an additive for direct laser structuring, and direct laser structuring may include irradiating the surface of the substrate using a laser, forming tracks of the additive for direct laser structuring, and applying a conductive metal to the tracks. The additive for direct laser structuring may include metal oxide particles (such as titanium oxide and copper chromium oxide). The additive for direct laser structuring may include spinel-based inorganic metal oxide particles such as spinel copper. The metal oxide particles can be coated, for example, with a composition containing tin and antimony (for example, 50 to 99 wt% tin and 1 to 50 wt% antimony based on the total mass of the coating). The additive for direct laser structuring may include 2 to 20 parts of the additive based on 100 parts of each composition. The irradiation can be performed using a yttrium aluminum garnet (YAG) laser having a wavelength of 1,064 nanometers under an output of 10 watts, a frequency of 80 kilohertz (kHz), and a speed of 3 meters per second. The conductive metal can be applied using, for example, a plating process in an electroless plating bath containing copper.

[0053] A conductive layer can be applied by adhering it with an adhesive. The conductive layer may be a circuit (a metallization layer of another circuit), for example, a flex circuit. The adhesive layer can be disposed between one or more conductive layers and the substrate. When appropriate, the adhesive layer may include at least one of poly(arylene ether), or carboxy-functionalized polybutadiene or polyisoprene polymer containing butadiene, isoprene, or butadiene units and isoprene units and 0 to 50 wt% of a co-curable monomer unit. The adhesive layer may be present in an amount of 2 to 15 grams per square meter. The poly(arylene ether) may include carboxy-functionalized poly(arylene ether). The poly(arylene ether) may be a reaction product of poly(arylene ether) and a cyclic anhydride or a reaction product of poly(arylene ether) and maleic anhydride. The carboxy-functionalized polybutadiene or polyisoprene polymer may be a carboxy-functionalized butadiene-styrene copolymer. The carboxy-functionalized polybutadiene or polyisoprene polymer may be a reaction product of polybutadiene or polyisoprene polymer and a cyclic anhydride. The carboxy-functionalized polybutadiene or polyisoprene polymer may be maleinized polybutadiene-styrene or maleinized polyisoprene-styrene copolymer.

[0054] The Co2Y type ferrite may include oxides of at least Ba, La, Co, Me, Fe, and optionally Ca, where Me is at least one or more of Ni and optionally Zn, Cu, Mn, or Mg. The Co2Y type ferrite has the formula Ba 1-x La x Ca n Co 2-y-z Me y Fe 12-m O 22(where x is 0.01 to 0.5, or 0.1 to 0.5; y is 0.01 to 1.5, or 0.1 to 1, or 0.2 to 0.5; z is -0.5 to 0.5, or -0.2 to 0; m is -2 to 2, or 0.1 to 0.5; n is 0 to 0.5, or 0.01 to 0.5) may be included. The Co2Y type ferrite has the formula Ba 1-x La x Ca n Co 2-y-z Ni y Fe 12-m O 22 and may include. The Co2Y type ferrite may have a D 50 particle size of 2 to 10 micrometers. The Co2Y type ferrite may have a porosity of 0 to 50% by volume, or 20 to 45% by volume, based on the total volume of the Co2Y type ferrite. The Co2Y type ferrite may have a permeability of 3 or more, or 3 to 6, or 3 to 4 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The Co2Y type ferrite may have a magnetic loss of 0.75 or less, or 0.5 or less, or 0.09 or less, or 0.07 to 0.2 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The Co2Y type ferrite may have a dielectric constant of 9 or less, or 8 to 9 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The Co2Y type ferrite may have a dielectric loss of 0.01 or less, or 0.002 to 0.009 over a frequency range of 1 to 2 GHz or at 1.2 GHz.

[0055] A composite containing a polymer and Co2Y-type ferrite. The polymer may contain at least one of paraffin wax, polytetrafluoroethylene, polyethylene, polypropylene, polyolefin, polyurethane, silicone polymer, liquid crystal polymer, poly(ether ether ketone), or poly(phenylene sulfide). The polymer may contain polytetrafluoroethylene or poly(phenylene sulfide). The composite may have a permeability of 1.5 or more, or 1.5 to 4, or 1.5 to 2 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a specific magnetic loss of 0.02 or less, or 0.03 or less, or 0.015 or less, or 0.012 to 0.03 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a dielectric constant of 6.5 or less, or 5 to 6.5 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may have a dielectric loss of 0.008 or less, or 0.006 or less, or 0.002 to 0.006 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite may contain 5 to 95 volume %, or 50 to 80 volume %, or 40 to 60 volume % of Co2Y-type ferrite based on the total volume of the composite. The composite may have a porosity of 0 to 45 volume %, or 15 to 35 volume % based on the total volume of the composite.

[0056] An article containing a ferrite composition or composite. The article may be an antenna.

[0057] A method for producing Co2Y-type ferrite includes a step of pulverizing a ferrite precursor compound containing at least oxides of Ba, La, Co, Me, and Fe to form a magnetic oxide mixture, where Me includes another divalent element such as Ni and optionally one or more of Zn, Cu, Mn, or Mg; and a step of firing the magnetic oxide mixture in an oxygen or air atmosphere to form Co2Y-type ferrite. The step of firing the mixed ferrite can be carried out at a firing temperature of 800 to 1,300 °C or 900 to 1,250 °C. The step of firing the mixed ferrite can be carried out for a firing time of 0.5 to 20 hours or 1 to 10 hours. The method may further include a step of forming a composite including Co2Y-type ferrite and a polymer.

[0058] The following examples are presented to illustrate the present disclosure. The examples are merely illustrative and are not intended to limit the devices fabricated in accordance with the present disclosure to the materials, conditions, or process parameters described in the present disclosure.

Examples

[0059] The permeability and magnetic loss of the ferrite were measured by a vector network analyzer (VNA) using a coaxial air line over a frequency range of 0.1 to 6 gigahertz (GHz) according to the Nicholson-Ross-Weir (NRW) method.

[0060] The Co2Y-type ferrite formulations used in the examples are shown below as Formulations 1 to 3. Formulation I: Ba 1.9 La 0.1 Co 1.6 Zn 0.4 Fe 11.8 O 22 Formulation II: Ba 1.9 La 0.1 Co 1.4 Ni 0.4 Zn 0.4 Fe 11.7 O 22 Formulation III: Ba 1.9 La0.1 Ca 0.1 Co 1.4 Ni 0.4 Zn 0.4 Fe 11.7 O 22

[0061] (Examples 1 - 5: Influence of Nickel on the Magnetic Properties of Co2Y - type Ferrite in Paraffin Wax) Co2Y ferrite was prepared by mixing BaCO3 (99.9%), CaCO3 (99.5%), Co3O4 (99.9%), La2O3 (99.9%), NiO (99%), ZnO (99.9%), and Fe2O3 (99.4%) in amounts that form the ferrite of Formulations 1 - 3. The oxide mixture was mixed in a wet planetary ball mill at 350 revolutions per minute (rpm) for 2 hours, dried in an oven at 100 °C, and sieved through a 40 - mesh sieve to form coarse particles. Subsequently, the coarse particles were fired in air at a temperature of 1,030 °C for a soaking time of 4 hours to form a Co2Y ferrite having the formula Ba 0.9 La 0.1 Co 2-x-y-z Ca n Ni x Zn y Fe 12-m O 22 Then, the Co2Y ferrite was subjected to jaw crusher treatment and grinding in a planetary ball mill at 350 rpm for 3 minutes in a stainless - steel jar, and finally sieved through a 40 - mesh screen and then a 200 - mesh screen. The ferrite particles had a volume - based D 50 particle size of 2 - 6 micrometers. Subsequently, the Co2Y ferrite was mixed with paraffin wax to form a composite containing 25 - 45 vol% of Co2Y ferrite.

[0062] [Table 1]

[0063] Table 1 (Table 1) shows that Examples 2 to 5 have a specific magnetic loss value of 0.014 to 0.028, which is lower than the value of Example 1 (0.016 to 0.031).

[0064] (Examples 6 - 8: Influence of Nickel on Magnetic Properties in Co2Y-Type Ferrite in PPS) A 50 cubic centimeter double Banbury rotor mixing bowl was attached to the drive unit of a Brabender Intelli-Torque Plasti-Corder torque rheometer. The bowl heater was set to a temperature of 315 °C. The rotor speed was set to a speed of 75 rpm. The mixer body temperature was heated until it reached a steady state. 29.6 grams (g) of polyphenylene sulfide (PPS) (SOLVAY QA321) and 96.4 g of ferrite powder were weighed separately. Half of the ferrite was manually blended with the PPS, and the other half was set aside. The rotor was started, and the machine calibrated the torque of the unfilled chamber. After calibration, the PPS-ferrite powder was slowly introduced and the powder was melted to form a melt. The remaining ferrite powder was fed into the melt and mixed for 4 minutes. The torque for 4 minutes was 1126 milligrams and the temperature was 336 °C. After the operation was completed, the torque rheometer was stopped and disassembled, and the melt of the composite material was taken out as a teaspoon-sized lump (commonly known as a fossil) and cooled.

[0065] The 25 square inch platen of a Carver hydraulic laboratory press was electrically heated to 310 °C. A certain amount of the compound fossil was placed in the hole of the mold. When the platen reached the temperature, the mold was inserted into the press and heated for 1 - 2 minutes under the minimum pressure, and then a pressure of 10,000 pounds per square inch (psi) was applied to the press ram for complete compression. The mold was kept under pressure for 1 - 2 minutes, then the heat was shut off and cooling air was circulated through the platen. When the platen temperature dropped below 30 °C, the pressure applied to the ram was released. The mold was removed from the press, the part was taken out of the mold, and subsequently cut into toroids for electromagnetic measurement.

[0066]

Table 2

[0067] Table 2 (Table 2) shows that Example 6 has a specific magnetic loss (μ'' / μ') of 0.024 at 1.2 GHz, while Examples 7 and 8 have significantly lower specific magnetic loss values of 0.020 and 0.018, respectively. This behavior is evident at frequencies from 1 to 1.6 GHz. 2 ) respectively, indicating significantly lower specific magnetic loss values. This behavior is evident at frequencies from 1 to 1.6 GHz.

[0068] (Examples 9 - 11: Influence of Nickel on Magnetic Properties in Co2Y - type Ferrite in PTFE) Before incorporating the ferrite powder into PTFE, the powder was pretreated with a mixture of aromatic alkoxysilane (phenyl - trimethoxysilane) and fluorinated aliphatic alkoxysilane ((tridecafluoro - 1,1,2,2 - tetrahydrooctyl)triethoxysilane) at a mass ratio of 3:1. The silane was added at a level of 2.0 mass% (wt%) based on the total mass of the ferrite powder. For each sample, the silane treatment was applied to approximately 300 g of ferrite and mixed at 2,500 rpm for 15 seconds in a Flaktek Speedmixer. The sample jar was removed from the mixing, scraped off with a spatula, and remixed at 2,500 rpm for 15 seconds. The samples were cured in an oven at 500°F (260°C) for 5 hours.

[0069] PTFE composite samples were prepared using DYNEON 2029Z PTFE micro - powder resin. At 45 vol% filling, 66.9 wt% of the treated filler was blended with 33.1 wt% of PTFE powder (on a dry solid basis) and mixed at 2,500 rpm for 15 seconds in a Flaktek mixer. The jar was removed, 21 wt% of dipropylene glycol (DPG) was added based on the total mixed mass, and stirred with a spatula. The lubricated crumb was mixed at 2,500 rpm for 15 seconds in FLAKTEK, removed, stirred with a spatula, and remixed in Flaktek under the same conditions.

[0070] The lubricated clamps were pressed into billets measuring 7 centimeters (cm) × 7 cm, formed from a three-piece mold in the shape of a rectangle, resulting in billets measuring 7 cm × 7 cm × approximately 7 millimeters (mm). The billets were calendared in a FARRELL LABORATORY CALENDER with the rolls heated to 50 °C to form a sheet approximately 0.7 mm thick. The sheet was immersed in warm water to remove the DPG lubricant and then baked at 500 °F (260 °C) for 16 hours.

[0071] The dried sheet was trimmed to 7 centimeters (cm) × 7 cm and placed in a three-piece mold. The sheet was laminated in a 6-inch × 6-inch (15.2 cm × 16.2 cm) laboratory CARVER PRESS mold with a total force of 7,500 pounds per square inch (51.7 megapascals (MPa)) and a soaking time of 45 minutes at 345 °C.

[0072] [Table 3]

[0073] Table 3 shows that the Co2Y-type ferrite maintains a low specific magnetic loss (0.013 - 0.03) over a frequency range of 1 - 2 GHz.

[0074] (Example 3: Co2Y-type Ferrite) Co2Y-type ferrite particles were prepared according to Example 1 to obtain the ferrite of Formulation II. The Co2Y-type ferrite powder was mixed with a 10 wt% poly(vinyl alcohol) solution and then sieved through a 40# screen to form granules. The granules were pressed into toroids under 1,800 pounds and sintered in a tubular furnace at 1,200 °C for 2 hours while flowing oxygen at a rate of 0.5 liters per minute. The sintered toroids had the following dimensions: an outer diameter of 7 millimeters (mm), an inner diameter of 3 mm, and a height of 3 - 4 mm. The porous ceramic had a relative density of approximately 78%.

[0075] The magnetodielectric properties of the sample were determined over a frequency range of 0.1 to 18 GHz, and the results are shown in Table 4.

[0076] [Table 4]

[0077] The data shows that the Co2Y-type ferrite has a very low magnetic loss of 0.09 or less at 1.2 GHz and at the same time maintains a permeability of more than 3. Furthermore, the Co2Y-type ferrite has a relative permittivity of less than 9 while maintaining a low dielectric loss of 0.006 or less at 1.2 GHz. The data also shows that the Co2Y-type ferrite has a very low magnetic loss of 0.15 or less at 1.6 GHz and at the same time maintains a permeability of more than 3. Furthermore, the Co2Y-type ferrite has a relative permittivity of less than 9 while maintaining a low dielectric loss of 0.008 or less at 1.6 GHz.

[0078] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of any suitable materials, steps, or components disclosed herein. The compositions, methods, and articles can be formulated, additionally or alternatively, to exclude or substantially exclude any materials (or species), steps, or components that are not particularly necessary for the achievement of the functions or objectives of the compositions, methods, and articles.

[0079] As used herein, the terms "a", "an", "the", and "at least one" are not intended to indicate a limitation of quantity, and are intended to cover both the singular and plural forms unless the context clearly indicates otherwise. For example, "an element" has the same meaning as "at least one element" unless the context clearly indicates otherwise. The term "combination" includes blends, mixtures, alloys, reaction products, and the like. Also, "at least one of" means that the list includes each element individually, as well as combinations of two or more elements in the list, and combinations of at least one element in the list with like elements not named in the list.

[0080] The term "or" means "and / or" unless the context clearly indicates otherwise. References throughout this specification to "an aspect", "another aspect", "some aspects", etc. mean that a particular element (e.g., a feature, structure, step, or property) 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. Furthermore, it should be understood that the described elements may be combined in any suitable manner in various aspects.

[0081] Unless otherwise specified herein, all test standards are the latest valid standards as of the filing date of this application, or, if priority is claimed, as of the filing date of the earliest priority application on which the test standard is published.

[0082] All endpoints of ranges targeting the same component or property include the endpoints and can be combined individually, including all intermediate points and ranges. For example, the range of "up to 25 wt%, or 5 - 20 wt%" includes the endpoints and all intermediate values of the range "5 - 25 wt%", such as 10 - 23 wt%, etc.

[0083] Unless otherwise defined, technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0084] All cited patents, patent applications, and other references are hereby incorporated by reference in their entirety. However, if the terms of this application conflict with or are inconsistent with the terms of the incorporated references, the terms of this application shall prevail over the conflicting terms of the incorporated references.

[0085] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not presently foreseeable or may not be foreseeable to the applicant or one of ordinary skill in the art may occur. Accordingly, the appended claims, as filed and as may be amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. Co contains at least an oxide of Ba, La, Co, Me, Fe, and optionally an oxide of Ca ２ It is a Y-type ferrite; Me is at least Ni, and optionally one or more of Zn, Cu, Mn, or Mg, Co ２ Y-type ferrite.

2. Formula Ba １－ｘ La ｘ Ca ｎ Co ２－ｙ－ｚ Me ｙ Fe １２－ｍ O ２２ (where x is 0.01 to 0.5, or 0.1 to 0.5; y is 0.01 to 1.5, or 0.1 to 1, or 0.2 to 0.5; z is -0.5 to 0.5, or -0.2 to 0; m is -2 to 2, or 0.1 to 0.5; n is 0 to 0.5, or 0.01 to 0.5), the Co according to claim 1 ２ Y-type ferrite.

3. Formula Ba １－ｘ La ｘ Ca ｎ Co ２－ｙ－ｚ Ni ｙ Fe １２－ｍ O ２２ Co according to claim 2, having ２ Y-type ferrite.

4. D 2 to 10 micrometers ５０ Co according to claim 1, having particle size ２ Y-type ferrite.

5. The aforementioned Co ２ The Co according to claim 1, having a porosity of 0 to 50 volume% or 20 to 45 volume% based on the total volume of the Y-type ferrite. ２ Y-type ferrite.

6. Co according to claim 1, having a permeability of 3 or more, or 3 to 6, or 3 to 4 over a frequency range of 1 to 2 GHz or at 1.2 GHz. ２ Y-type ferrite.

7. Co according to claim 1, having a magnetic loss of 0.75 or less, or 0.5 or less, or 0.09 or less, or 0.07 to 0.2 over a frequency range of 1 to 2 GHz or at 1.2 GHz. ２ Y-type ferrite.

8. Co according to claim 1, having a dielectric constant of 9 or less, or 8 to 9, over a frequency range of 1 to 2 GHz or at 1.2 GHz. ２ Y-type ferrite.

9. Co according to claim 1, having a dielectric loss of 0.01 or less, or 0.002 to 0.009, over a frequency range of 1 to 2 GHz or at 1.2 GHz. ２ Y-type ferrite.

10. Polymer and Co according to claim 1 ２ A composite containing Y-type ferrite.

11. The composite according to claim 10, wherein the polymer comprises at least one of paraffin wax, polytetrafluoroethylene, polyethylene, polypropylene, polyolefin, polyurethane, silicone polymer, liquid crystal polymer, poly(ether ether ketone), or poly(phenylene sulfide).

12. The composite according to claim 10, wherein the polymer comprises polytetrafluoroethylene or poly(phenylene sulfide).

13. Permeability of 1.5 or greater, 1.5 to 4, or 1.5 to 2 over a frequency range of 1 to 2 GHz or at 1.2 GHz; Magnetic loss of 0.02 or less, 0.03 or less, 0.015 or less, or 0.012 to 0.03 over a frequency range of 1 to 2 GHz or at 1.2 GHz; A dielectric constant of 6.5 or less, or 5 to 6.5, over a frequency range of 1 to 2 GHz or at 1.2 GHz; or Dielectric loss of 0.008 or less, 0.006 or less, or 0.002 to 0.006 over a frequency range of 1 to 2 GHz or at 1.2 GHz. The composite according to claim 10, having at least one of the following.

14. Based on the total volume of the composite, 5 to 95 volume% or 50 to 80 volume% or 40 to 60 volume% of the Co ２ The composite according to claim 10, comprising Y-type ferrite.

15. The composite according to claim 10, having a porosity of 0 to 45 volume% or 15 to 35 volume% based on the total volume of the composite.

16. An article comprising a ferrite composition according to any one of claims 1 to 9 or a composite according to any one of claims 10 to 15.

17. The article according to claim 16, which is an antenna.

18. Co ２ A method for producing Y-type ferrite, A step of pulverizing a ferrite precursor compound containing at least Ba, La, Co, Me, and Fe oxides to form a magnetic oxide mixture, wherein Me contains Ni and optionally one or more other divalent elements such as Zn, Cu, Mn, or Mg; The magnetic oxide mixture is fired in an oxygen or air atmosphere, and the Co ２ A method comprising the step of forming a Y-type ferrite.

19. The method according to claim 18, wherein the firing step of the mixed ferrite is carried out at a firing temperature of 800 to 1,300°C or 900 to 1,250°C, or for a firing time of 0.5 to 20 hours or 1 to 10 hours.

20. The aforementioned Co ２ The method according to claim 18 or 19, further comprising the step of forming a composite comprising a Y-type ferrite and a polymer.

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