Magnetic materials with ultrahigh resistivity intergrain nanoparticles

Patent metadata

Field	Value
Publication number	US-11211187-B2
Application number	US-201816181298-A
Country	US
Kind code	B2
Filing date	Nov 5, 2018
Priority date	Nov 3, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A composite magnetic material has a plurality of grains having a magnetic ferrite phase, grain boundaries surrounding the grains, and a plurality of nanoparticles disposed at the grain boundaries. The nanoparticles of the composite material are both magnetic and electrically insulating, having a magnetic flux density of greater than about 100 mT and an electrical resistivity of at least about 10 8 Ohm-cm. Also provided is a method of making the composite material. The material is useful for making inductor cores of electronic devices.

First claim

What is claimed is:

1. A composite material comprising:
a plurality of grains having a magnetic ferrite phase and magnetic grain boundaries surrounding the grains; and
a plurality of nanoparticles disposed at the magnetic grain boundaries;
wherein the nanoparticles are both magnetic and insulating, having a magnetic flux density of greater than about 100 mT and an electrical resistivity of at least about 10 8 Ohm-cm; and
wherein the nanoparticles are present in the composite in an amount from 0.01 wt % to 0.8 wt %.

2. The composite material of claim 1 , wherein the electrical resistivity of the nanoparticles is from about 10 8 to about 10 12 Ohm-cm.

3. The composite material of claim 1 , wherein the material is capable of use as a core component at an operating frequency in the range from about 100 kHz to about 1 MHz.

4. The composite material of claim 1 , wherein the grains have a size of about 0.5 μm to about 50 μm.

5. The composite material of claim 1 , wherein the size of the nanoparticles is in the range from about 1 nm to about 100 nm.

6. The composite material of claim 1 , wherein the nanoparticles comprise garnet, hexaferrite, or spinel ferrite.

7. The composite material of claim 6 , wherein the nanoparticles comprise Y 3 Fe 5 O 12 (YIG).

8. The composite material of claim 1 , wherein the grains comprise a spinel ferrite.

9. The composite material of claim 8 , wherein the spinel ferrite is a zinc ferrite, a nickel-zinc ferrite, a manganese-zinc ferrite, or a cobalt ferrite.

10. The composite material of claim 9 , wherein the spinel ferrite is a manganese-zinc ferrite.

11. The composite material of claim 10 , wherein the manganese-zinc ferrite is (Mn 0.69 Zn 0.20 )Fe 211 O 4 .

12. An inductor core comprising the composite material of claim 1 .

13. The inductor core of claim 12 , wherein the grains comprise a spinel ferrite.

14. The inductor core of claim 13 , wherein the spinel ferrite is a zinc ferrite, a nickel-zinc ferrite, a manganese-zinc ferrite, or a cobalt ferrite.

15. The inductor core of claim 13 , wherein the nanoparticles are present in the composite in an amount from about 0.01 wt % to about 1 wt %.

16. The inductor core of claim 13 , wherein the wherein the nanoparticles comprise high resistivity garnet, hexaferrite, or spinel ferrite.

17. A method for making a composite material, the method comprising:
providing a plurality of grains having a magnetic ferrite phase and magnetic grain boundaries surrounding the grains;
adding a plurality of nanoparticles comprising high resistivity garnet, hexaferrite, or spinel ferrite, to the grains to form a mixture; wherein the nanoparticles are present in the mixture in an amount of 0.01 wt % to 0.8 wt %;
compacting the mixture to form a core;
sintering the core mixture; and
cooling the sintered mixture to room temperature, thereby obtaining the composite material.

18. The method of claim 17 , wherein prior to sintering, the core is compacted to have the shape of a core selected from the group consisting of: ferrite toroid, a ferrite plate, a ferrite disk, a ferrite E-core, a ferrite EI-core, a ferrite C core, a ferrite CI core, a planar E core, an EC core, a EFD core, a EP core, a ETD core, an ER core, a planar ER core, a U core, a RM/I core, a RM/LP core, a P/I core, a PT core, a PTS core, a PM core, a PQ core, a gapped toroid, and a bobbin core.

19. A device or device component comprising the core of claim 12 , wherein the device or device component is selected from the group consisting of a transformer; an electronic device; an inductor core; a switched mode power supply; a power electronic device; a power converter; a power generator; power conditioning components; an inductor device; a transmit and receive module; an electronically scanned phased arrays system; an electronic warfare system; and conditioning components for wireless and satellite communication, radar systems, power electronics, inductive devices, electronics utilizing a switched mode power supply, and a device or device component for wireless power transfer.

Assignees

• Univ Northeastern

Inventors

• Chen Yajie
• Andalib Parisa
• Harris Vincent

Classifications

• H01F41/0246 Primary

  Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36) · CPC title

• C04B2235/764

  Garnet structure A3B2(CO4)3 · CPC title

• C04B2235/6586

  Processes characterised by the flow of gas · CPC title

• C04B2235/656

  characterised by specific heating conditions during heat treatment · CPC title

• H01F3/08

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title