Mn-Zn BASED FERRITE MATERIAL

Abstract

For the purpose of providing a Mn—Zn based ferrite material that is small in loss in high frequency bands of 1 MHz or more and in the vicinity of 100° C., the Mn—Zn based ferrite material includes: as main constituents, Fe2O3: 53 to 56 mol %, ZnO: 7 mol % or less (inclusive of 0 mol %), and the balance: MnO; and as additives, Co: 0.15 to 0.65% by weight in terms of CoO, Si: 0.01 to 0.045% by weight in terms of SiO2 and Ca: 0.05 to 0.40% by weight in terms of CaCO3; wherein the 6 value (the cation defect amount) defined in the present specification defined in the present specification.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing a relation between an oxygen partial pressure PO₂ in a sintering atmosphere and a cation defect amount δ and a relation between the same partial pressure and a ratio Fe²⁺/Fe;

FIG. 2 is a graph showing a relation between a temperature for measuring a core loss and the core loss Pcv for each of the cation defect amounts δ;

FIG. 3 is a graph showing a relation between the cation defect amount δ and the core loss Pcv;

FIG. 4 is a graph showing a relation between the ratio Fe²⁺/Fe and the core loss Pcv;

FIG. 5 is a graph showing a relation between the amount of Fe₂O₃ and the core loss Pcv;

FIG. 6 is a graph showing a relation between the amount of ZnO and the core loss Pcv;

FIG. 7 is a graph showing a relation between the amount of CoO and the core loss Pcv;

FIG. 8 is a graph showing a relation between the amount of SiO₂ and the core loss Pcv;

FIG. 9 is a graph showing a relation between the amount of CaCO₃ and the core loss Pcv;

FIG. 10 is a graph showing a relation between the amount of TiO₂ and the core loss Pcv;

FIG. 11 is a graph showing a relation between the amount of Ta₂O₅ and the core loss Pcv; and

FIG. 12 is a graph showing the relations between the temperature and the core loss Pcv in the presence and the absence of TiO₂.

Claims

1. A Mn—Zn based ferrite material comprising: as main constituents,Fe2O3: 53 to 56 mol %;ZnO: 7 mol % or less (inclusive of 0 mol %); andthe balance: MnO; andas additives,Co: 0.15 to 0.65% by weight in terms of CoO;Si: 0.01 to 0.045% by weight in terms of SiO2; andCa: 0.05 to 0.40% by weight in terms of CaCO3;

2. The Mn—Zn based ferrite material according to claim 1, wherein the δ value satisfies the relation 10×10−3≦δ≦17×10−3.

3. The Mn—Zn based ferrite material according to claim 1, wherein the δ value satisfies the relation 11×10−3≦δ≦15×10−3.

4. The Mn—Zn based ferrite material according to claim 1, wherein the ratio of the amount (% by weight) of Fe2+ (divalent iron) to the total amount (% by weight) of Fe denoted by Fe2+/Fe satisfies the relation 0.04≦Fe2+/Fe≦0.05.

5. The Mn—Zn based ferrite material according to claim 1, wherein the ratio of the amount (% by weight) of Fe2+ (divalent iron) to the total amount (% by weight) of Fe denoted by Fe2+/Fe satisfies the relation 0.042≦Fe2+/Fe≦0.048.

6. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Fe2O3 is 54 to 55 mol %.

7. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Fe2O3 is 54.2 to 54.8 mol %.

8. The Mn—Zn based ferrite material according to claim 1, wherein the amount of ZnO is 0.1 to 5 mol %.

9. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Co is 0.2 to 0.55% by weight in terms of CoO.

10. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Si is 0.015 to 0.028% by weight in terms of SiO2.

11. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Ca is 0.05 to 0.30% by weight in terms of CaCO3.

12. The Mn—Zn based ferrite material according to claim 1, comprising at least one of Ti in an amount of 0.35% by weight or less in terms of TiO2 and Ta in an amount of 0.25% by weight or less in terms of Ta2O5.

13. The Mn—Zn based ferrite material according to claim 1, comprising Ti in an amount of 0.05 to 0.3% by weight in terms of TiO2.

14. The Mn—Zn based ferrite material according to claim 1, comprising Ta in an amount of 0.01 to 0.2% by weight in terms of Ta2O5.

15. The Mn—Zn based ferrite material according to claim 1, wherein: the core loss thereof is 2000 [kW/m3] or less at 125° C., an excitation magnetic flux density of 50 mT and a measurement frequency of 2 MHz.

16. The Mn—Zn based ferrite material according to claim 1, wherein the amount of Co is 0.2 to 0.55% by weight in terms of CoO, the amount of Si is 0.015 to 0.028% by weight in terms of SiO2, and the amount of Ca is 0.05 to 0.30% by weight in terms of CaCO3.

17. The Mn—Zn based ferrite material according to claim 16, comprising at least one of Ti in an amount of 0.05 to 0.3% by weight in terms of TiO2 and Ta in an amount of 0.01 to 0.2% by weight in terms of Ta2O5.

18. The Mn—Zn based ferrite material according to claim 16, wherein the δ value satisfies the relation 10×10−3≦δ≦17×10−3.

19. The Mn—Zn based ferrite material according to claim 16, wherein the ratio of the amount (% by weight) of Fe2+ (divalent iron) to the total amount (% by weight) of Fe denoted by Fe2+/Fe satisfies the relation 0.04≦Fe2+/Fe≦0.05.

20. The Mn—Zn based ferrite material according to claim 16, wherein the amount of ZnO is 0.1 to 5 mol %.