Abstract: A ferrite magnetic material comprising a main phase of W-type is provided which has magnetic properties improved through the optimization of additives. The ferrite magnetic material comprises a main constituent having a compound represented by composition formula AFe2+aFe3+bO27 (wherein A comprises at least one element selected from Sr, Ba and Pb; 1.5?a?2.1; and 12.9?b?16.3), a first additive containing a Ca constituent (0.3 to 3.0 wt % in terms of CaCO3) and/or a Si constituent (0.2 to 1.4 wt % in terms of SiO2), and a second additive containing at least one of an Al constituent (0.01 to 1.5 wt % in terms of Al2O3), a W constituent (0.01 to 0.6 wt % in terms of WO3), a Ce constituent (0.001 to 0.6 wt % in terms of CeO2), a Mo constituent (0.001 to 0.16 wt % in terms of MoO3), and a Ga constituent (0.001 to 15 wt % in terms of Ga2O3).

Abstract: The present invention provides a production method of a ferrite material comprising as main constituents Fe2O3: 62 to 68 mol %, ZnO: 12 to 20 mol %, and MnO substantially constituting the balance, wherein the method comprises a compacting step for obtaining a compacted body by using a powder containing the main constituents, the powder having a specific surface area falling within a range between 2.5 and 5.0 m2/g and a 90% particle size of 10 ?m or less, and a sintering step for sintering the compacted body obtained in the compacting step. Accordingly, the saturation magnetic flux density of the Mn—Zn based ferrite can be improved.

Abstract: The present invention provides a Mn—Zn ferrite which is low in the loss in the frequency range between a few 10 kHz and a few 100 kHz and high in the saturation magnetic flux density in the vicinity of 100° C. The present invention comprising the steps of compacting a powder having a specific surface area (based on the BET method) of 2.0 to 5.0 m2/g and a 50% particle size of 0.7 to 2.0 ?m into a compacted body having a predetermined shape and obtaining a sintered body by sintering the compacted body. It is preferable that a Mn—Zn ferrite comprises, as main constituents, 54 to 57 mol % of Fe2O3, 5 to 10 mol % of ZnO, 4 mol % or less (not inclusive of 0%) of NiO, and the balance substantially being MnO.

Abstract: There is provided a Mn—Zn based ferrite member excellent in mass productivity, high in withstand voltage, low in loss and excellent in direct current superposition property. The Mn—Zn based ferrite member is provided with a surface layer portion having the properties that ?5 defined in the specification satisfies the relation that ?5?103 ?m and ?50 defined in the specification satisfies the relation that ?50?102 ?m.

Abstract: A ferrite magnetic material comprising a main phase of W-type is provided which has magnetic properties improved through the optimization of additives. The ferrite magnetic material comprises a main constituent having a compound represented by composition formula AFe2+aFe3+bO27 (wherein A comprises at least one element selected from Sr, Ba and Pb; 1.5?a?2.1; and 12.9?b?16.3), a first additive containing a Ca constituent (0.3 to 3.0 wt % in terms of CaCO3) and/or a Si constituent (0.2 to 1.4 wt % in terms of SiO2), and a second additive containing at least one of an Al constituent (0.01 to 1.5 wt % in terms of Al2O3), a W constituent (0.01 to 0.6 wt % in terms of WO3), a Ce constituent (0.001 to 0.6 wt % in terms of CeO2), a Mo constituent (0.001 to 0.16 wt % in terms of MoO3), and a Ga constituent (0.001 to 15 wt % in terms of Ga2O3).

Abstract: The present invention provides a ferrite magnetic material comprising as a main constituent a compound represented by a composition formula, AFe2+aFe3+bO27 (wherein 1.1?a?2.4, 12.3?b?16.1; and A comprises at least one element selected from Sr, Ba and Pb), and also comprising as additives a Ca constituent in terms of CaCO3 and a Si constituent in terms of SiO2 so as to satisfy the relation CaCO3/SiO2=0.5 to 1.38 (molar ratio). By making the relation CaCO3/SiO2=0.5 to 1.38 (molar ratio) be satisfied, the coercive force (HcJ) and the residual magnetic flux density (Br) can be made to simultaneously attain high levels.

Abstract: A Mn—Zn based ferrite sintered body containing 62 to 68 mol % of Fe2O3 and 12 to 20 mol % of ZnO is made to contain, as main constituents, NiO and/or LiO0.5. Additionally, a Mn—Zn based ferrite sintered body containing 62 to 68 mol % of Fe2O3 and 12 to 23 mol % of ZnO is made to contain, as additives, Si and Ca. This sintered body can achieve such properties that the saturation magnetic flux density at 100° C. is 450 mT or more (magnetic field for measurement: 1194 A/m), the minimum core loss value is 1200 kW/m3 or less (measurement conditions: 100 kHz, 200 mT), the bottom temperature at which the minimum core loss value is exhibited is from 60 to 130° C., and the initial permeability at room temperature is 700 or more.

Abstract: The present invention provides a production method of a ferrite material comprising as main constituents Fe2O3: 62 to 68 mol %, ZnO: 12 to 20 mol %, and MnO substantially constituting the balance, wherein the method comprises a compacting step for obtaining a compacted body by using a powder containing the main constituents, the powder having a specific surface area falling within a range between 2.5 and 5.0 m2/g and a 90% particle size of 10 ?m or less, and a sintering step for sintering the compacted body obtained in the compacting step. Accordingly, the saturation magnetic flux density of the Mn—Zn based ferrite can be improved.

Abstract: There is provided a Mn—Zn based ferrite member excellent in mass productivity, high in withstand voltage, low in loss and excellent in direct current superposition property. The Mn—Zn based ferrite member is provided with a surface layer portion having the properties that ?5 defined in the specification satisfies the relation that ?5?103 ?m and ?50 defined in the specification satisfies the relation that ?50?102 ?m.

Abstract: The present invention provides a Mn—Zn ferrite which is low in the loss in the frequency range between a few 10 kHz and a few 100 kHz and high in the saturation magnetic flux density in the vicinity of 100° C. The present invention comprising the steps of compacting a powder having a specific surface area (based on the BET method) of 2.0 to 5.0 m2/g and a 50% particle size of 0.7 to 2.0 ?m into a compacted body having a predetermined shape and obtaining a sintered body by sintering the compacted body. It is preferable that a Mn—Zn ferrite comprises, as main constituents, 54 to 57 mol % of Fe2O3, 5 to 10 mol % of ZnO, 4 mol % or less (not inclusive of 0%) of NiO, and the balance substantially being MnO.

Abstract: An Mn—Zn ferrite wherein 0 to 5000 ppm of a Co oxide in a Co3O4 conversion is contained in a basic component constituted by Fe2O3: 51.5 to 57.0 mol % and ZnO: 0 to 15 mol % (note that 0 is not included) wherein the rest is substantially constituted by MnO; and a value ? in a formula (1) below in said ferrite satisfies ??0.93. ?=((Fe2+?Mn3+?Co3+)×(4.29×A+1.91×B+2.19×C+2.01×D))/((A?B?C?D)×100)??formula (1). Note that in the formula (1), (Fe2+?Mn3+?Co3+): [wt %], A: Fe2O3 [mol %], B: MnO [mol %], C: ZnO [mol %] and D: CoO [mol %]. According to the present invention, a highly reliable Mn—Zn ferrite used as a magnetic core of a power supply transformer, etc. of a switching power supply, etc., having a small core loss in a wide temperature range, furthermore, exhibiting a little deterioration of core loss characteristics under a high temperature (in a high temperature storage test) and having excellent magnetic stability, a transformer magnetic core and a transformer can be provided.

Abstract: An Mn—Zn ferrite wherein 0 to 5000 ppm of a Co oxide in a CO3O4 conversion is contained in a basic component constituted by Fe2O3: 51.5 to 57.0 mol % and ZnO: 0 to 15 mol % (note that 0 is not included) wherein the rest is substantially constituted by MnO; and a value &agr; in a formula (1) below in said ferrite satisfies &agr;≧0.93.

Abstract: The invention provides a manganese-zinc ferrite production process comprising a maximum temperature holding step for firing and a cooling step in a nitrogen atmosphere. The nitrogen atmosphere changeover temperature T in the cooling step is below 1,1500° C. and equal to or higher than 1,0000° C., and the cooling rate V1 conforms to the condition defined by: T≦(V1+1,450)/1.5  (1) Here T is the nitrogen atmosphere changeover temperature in ° C. and V1 is the cooling rate in ° C./hour from T down to 900° C.

Abstract: MnZn ferrite comprises a main component comprising iron oxide 52.5 to 54.0 mol % in terms of Fe2O3, zinc oxide 7.7 to 10.8 mol % in terms of ZnO, and manganese oxide of the remaining, and sub-components of silicon oxide 60 to 140 ppm in terms of SiO2 and calcium oxide 350 to 700 ppm in terms of CaO, and further contains nickel oxide 4500 ppm or lower (not including 0) in terms of NiO.

Abstract: The invention provides a manganese-zinc ferrite production process comprising a maximum temperature holding step for firing and a cooling step in a nitrogen atmosphere. The nitrogen atmosphere changeover temperature T in the cooling step is below 1,1500° C. and equal to or higher than 1,0000° C.