Low loss power ferrites and method of manufacture

1. A method for manufacturing a multiphase ferrite composition, comprising combining

MnZn ferrite particles,

0.01 to 10 weight percent microscaled inclusion particles comprising an orthoferrite RFeO 3 wherein R is a rare earth ion, and

optionally 0.01 to 5 weight percent additive

to form a ferrite mixture,

wherein weight percent is based on the total weight of the ferrite mixture,

wherein the microscaled inclusion particles have an average particle size (D50) of 0.1 micron to 5 microns, and

wherein the D50 of the microscaled inclusion particles is smaller than the D50 of the MnZn ferrite particles;

granulating a slurry comprising the ferrite mixture and a binder solution to obtain granules of 50 to 750 microns;

compressing the granules to form a green body; and

sintering the green body in 0.01 to 20% oxygen to form a multiphase ferrite composition.

2. The method of claim 1 wherein the MnZn ferrite particles comprise Mn 1−x Zn x Fe 2+y O 4 , wherein x=0.1 to 0.9, and y=0 to 0.4, and optionally a dopant.

3. The method of claim 2 wherein the dopant comprises Co, Ni, Ti, Zr, Sn, Si, V, Ta, Nb, Ca, or a combination thereof.

4. The method of claim 1 , wherein the microscaled inclusion particles further comprise a dopant.

5. The method of claim 4 wherein the microscaled inclusion particles comprise orthoferrite and the dopant comprises Zr, Ti, or a combination thereof.

6. The method of claim 1 , wherein the microscaled inclusion particles comprise YFeO 3 .

7. The method of claim 1 , wherein the optional additive is CaO, SiO 2 , TiO 2 , ZrO 2 , SnO 2 , V 2 O 5 , Nb 2 O 5 , Ta 2 O5, CoO, or a combination thereof.

8. The method of claim 1 , wherein the MnZn ferrite particles have an average particle size (D50) of 0.5 micron to 10 microns.

9. The method of claim 1 , further comprising

grinding the ferrite mixture to obtain MnZn ferrite particles having an average particle size (D50) of 0.5 micron to 10 microns;

synthesizing the MnZn ferrite particles;

synthesizing the microscaled inclusion particles; or

cooling the sintered green body to obtain the multiphase ferrite composition.

10. The method of claim 1 , wherein the binder solution comprises polyvinyl alcohol (PVA) or polyvinyl butyral (PVB).

11. The method of claim 1 , wherein granulating is performed by spray drying the slurry.

12. The method of claim 1 , wherein compressing the granules to form a green body is performed at 0.3 to 4 Tonne/cm 22 .

13. A multiphase ferrite composition comprising:

a primary phase consisting of a MnZn ferrite matrix comprising MnZn ferrite particles; and

0.01 to 10 weight percent microscaled inclusion particles comprising

an orthoferrite RFeO 3 wherein R is a rare earth ion,

wherein the microscaled inclusion particles have an average particle size (D50) of 0.1 micron to 5 microns, and

wherein the D50 of the microscaled inclusion particles is smaller than the average particle size (D50) of the MnZn ferrite particles; and

optionally 0.01 to 5 weight percent additive;

wherein weight percent is based on the total weight of the multiphase ferrite composition.

14. The multiphase ferrite composition of claim 13 wherein the MnZn ferrite matrix comprises Mn 1−x Zn x Fe 2+y O 4 , wherein x=0.1 to 0.9, and y=0 to 0.4, and optionally a dopant.

15. The multiphase ferrite composition of claim 14 wherein the dopant comprises Co, Ni, Ti, Zr, Sn, Si, V, Ta, Nb, Ca, or a combination thereof.

16. The multiphase ferrite composition of claim 13 , wherein the microscaled inclusion particles further comprise a dopant.

17. The multiphase ferrite composition of claim 16 wherein the microscaled inclusion particles comprise orthoferrite and the dopant is Zr, Ti, or a combination thereof.

18. The multiphase ferrite composition of claim 13 , wherein the microscaled inclusion particles comprise YFeO 3 .

19. The multiphase ferrite composition of claim 13 , wherein the optional additive is CaO, SiO 2 , TiO 2 , ZrO 2 , SnO 2 , V 2 O 5 , Nb 2 O 5 , Ta 2 O5, CoO, or a combination thereof.

20. The multiphase ferrite composition of claim 13 having a power loss (Pv) of 50 to 150 mW/cm 3 at 200 kHz, 100 mT; a permeability of 1000 to 3500; a magnetic flux density of at least 450 mT, or a combination thereof.

21. An article comprising the multiphase ferrite composition of claim 13 .

22. The article of claim 21 which is a transformer, an electronic device, an inductor, a power electronic device, a power system, a power supply, or a power converter.