Polycrystalline 18H hexaferrite, method of manufacture, and uses thereof

Patent metadata

Field	Value
Publication number	US-12110234-B2
Application number	US-202117171104-A
Country	US
Kind code	B2
Filing date	Feb 9, 2021
Priority date	Feb 10, 2020
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A polycrystalline ferrite composition comprises a formula of M 5 Me 2 Ti 3 Fe 12 O 31 , wherein M is Ba 2+ , Sr 2+ , or a combination thereof; and Me is Mg 2+ , Zn 2+ , Cu 2+ , Co 2+ , or a combination thereof; and has an average grain size of 1 micrometer to 100 micrometers. A composite comprises a polymer matrix; and the polycrystalline ferrite composition. Methods of making the polycrystalline ferrite composition and the composite are also disclosed.

First claim

What is claimed is:

1. An article comprising a polycrystalline ferrite composition having a formula of
M 5 Mg 2-y Zn y Ti 3 Fe 12 O 31 ,
wherein
M is Ba 2+ , Sr 2+ , or a combination thereof; and
Y=0.25 to 1.8,
having an average grain size of 1 micrometer to 100 micrometers,
wherein the article is an antenna, an inductor, a transformer, or an anti electromagnetic interference material.

2. An article comprising a polycrystalline ferrite composition, having a formula of
Ba 5 Mg 2-y Zn y Ti 3 Fe 12-z O 31 ,
wherein
Y=0.25 to 1.8,
Z=−4 to +4,
having an average grain size of 1 micrometer to 100 micrometers, and
having
a magnetic permeability (μ) of at least 2 at a frequency of 1 to 4 GHz,
a magnetic loss tangent (tan δ μ ) of less than 0.05 at a frequency of 1 to 4 GHz,
a permittivity (ε) of at least 13 to 16 at a frequency of 1 to 4 GHz,
a dielectric loss tangent (tan δ ε ) of less than 0.004 at a frequency of 1 to 4 GHz,
a magnetic loss factor (tan δ μ /μ′) less than 0.02 at a frequency of 1 to 4 GHz,
a cutoff frequency (resonance frequency, f r ) greater than 4 GHz,
a Snoek product greater than 9 GHz, wherein the Snoek product=u′×f r , or
a combination of the foregoing; and

wherein the article is an antenna, an inductor, a transformer, or an anti-electromagnetic interference material.

3. The article of claim 2 , wherein
Y=0.25 to 1.0.

4. The article of claim 1 , wherein Y=0.25 to 1.0.

5. The article of claim 3 , wherein the polycrystalline ferrite composition has
a magnetic permeability (μ) of at least 5 at a frequency of 1 to 4 GHz;
a magnetic loss tangent (tan δ μ ) of less than 0.02 at a frequency of 1 to 4 GHz;
a permittivity (ε) of at least 13 to 15 at a frequency of 1 to 4 GHz;
a dielectric loss tangent (tan δ ε ) of less than 0.003 at a frequency of 1 to 4 GHz;
a cutoff frequency (resonance frequency, f r ) greater than 6 GHz;
a Snoek product greater than 12 GHz, wherein the Snoek product=u′×f r ; or
a combination of the foregoing.

6. The article of claim 1 , wherein the polycrystalline ferrite composition has in-plane easy magnetization and/or an 18H structure.

7. A method of manufacturing a polycrystalline ferrite composition comprising
calcining blended metal source compounds for the polycrystalline ferrite composition as defined in claim 1 ;
reducing particle size of the calcined source compounds to obtain particles having an average particle size of 0.5 micrometer to 10 micrometers;
granulating a mixture of the particles and a binder to obtain granules;
compressing granules into a green body; and
sintering the green body to form the polycrystalline ferrite composition.

8. The method of claim 7 wherein calcining is performed at 900 to 1200° C. for 0.5 hour to 20 hours.

9. The method of claim 8 wherein calcining is performed in an atmosphere of air, nitrogen, oxygen, or a combination thereof.

10. The method of claim 7 wherein sintering is performed at 1000 to 1300° C. for 1 hour to 20 hours.

11. The method of claim 7 wherein sintering is performed in an atmosphere of air, nitrogen, oxygen, or a combination thereof.

12. The method of claim 7 wherein sintering is performed with a temperature heating rate of 1° C./minute to 5° C./min and/or with a cooling rate of 1° C./minute to 5° C./minute.

13. The method of claim 7 wherein reducing particle size comprises crushing and/or grinding the calcined source compounds.

14. The method of claim 7 further comprising sizing the particles.

15. The method of claim 7 further comprising blending the metal source compounds.

16. The method of claim 7 wherein the binder is polyvinylpyrrolidone (PVP), poly(vinyl alcohol) (PVA), polyacrylamide (PAM), poly(acrylic acid) (PAA), polyethylene glycol (PEG), polyethylene oxide (PEO), cellulose acetate, starch, polypropylene carbonate, polyvinyl butyral (PVB), or a combination thereof.

17. The article of claim 1 , wherein the article comprises a composite comprising:
a polymer matrix; and
the polycrystalline ferrite composition as defined in claim 1 , wherein the ferrite composition has a particle size of 0.5 micrometer to 30 micrometers.

18. The article of claim 17 , wherein the composite comprises 5 to 95 volume percent of the polycrystalline hexaferrite, based on the total volume of the composite.

19. The article of claim 17 , wherein the polymer matrix comprises polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), polymethylmethacrylate (PMMA), polyether ether ketone (PEEK), polyethersulfone (PES), or a combination thereof.

20. The article of claim 17 , wherein the composite has
an operating frequency of 1 GHz to 10 GH;
a magnetic permeability (μ) of at least 1.5 at a frequency of 1 to 10 GHz;
a magnetic loss tangent (tan δ μ ) of less than 0.02 at a frequency of 1 to 8 GHz;
a permittivity (ε) of 5 to 6 at a frequency of 1 to 10 GHz;
a dielectric loss tangent (tan δ ε ) of less than 0.004 at a frequency of 1 to 10 GHz;
a magnetic loss factor (tan δ μ /μ′) less than 0.01, or 0.008 at a frequency of 1 to 10 GHz;
a cutoff frequency (resonance frequency, f r ) greater than 8 GHz; or
a combination of the foregoing.

21. A method of making the composite as defined in claim 17 , the method comprising:
combining a polymer, the polycrystalline ferrite composition, optionally a solvent, and optionally an additive composition to form a composite; and
optionally removing the solvent from the composite.

22. The method of claim 21 , wherein the forming comprises shaping the composite.

23. The method of claim 22 , wherein shaping the composite comprises compression molding, injection molding, reaction injection molding, extruding, rolling, casting, or impregnating or laminating onto a reinforcing medium.

24. An article comprising a polycrystalline ferrite composition made by the method of claim 7 .

25. The article of claim 1 , wherein the article is an antenna.

Assignees

• Rogers Corp

Inventors

• Chen Yajie
• Li Qifan

Classifications

• C08L87/00

  Compositions of unspecified macromolecular compounds, obtained otherwise than by polymerisation reactions only involving unsaturated carbon-to-carbon bonds · CPC title

• C08L57/00

  Compositions of unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08K2003/2265

  of iron · CPC title

• C08K3/22

  of metals · CPC title

• H01F1/37

  in a bonding agent · CPC title