Tdk Corporation

Kenya Takagawa

Taku Murase

Katsushi Yasuhara

Eiichiro Fukuchi

Takeshi Masuda

Yoshihiko Minachi

Takuya Aoki

Hidenobu Umeda

Fumitaka Baba

Masahiko Watanabe

Noboru Ito

Junichi Nagaoka

Akira Kakinuma

Yuji Sezai

Takashi Kajino

Shunsuke Kurasawa

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 AFeFeO(wherein A comprises at least one element selected from Sr, Ba and Pb; 1.5&#x2266;a&#x2266;2.1; and 12.9&#x2266;b&#x2266;16.3), a first additive containing a Ca constituent (0.3 to 3.0 wt % in terms of CaCO) and/or a Si constituent (0.2 to 1.4 wt % in terms of SiO), and a second additive containing at least one of an Al constituent (0.01 to 1.5 wt % in terms of AlO), a W constituent (0.01 to 0.6 wt % in terms of WO), a Ce constituent (0.001 to 0.6 wt % in terms of CeO), a Mo constituent (0.001 to 0.16 wt % in terms of MoO), and a Ga constituent (0.001 to 15 wt % in terms of GaO).

Ferrite magnetic material and ferrite sintered magnet

The present invention provides a production method of a ferrite material comprising as main constituents FeO: 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 m/g and a 90% particle size of 10 &#x3bc;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&#x2014;Zn based ferrite can be improved.

Method for producing ferrite material and ferrite material

The present invention provides a Mn&#x2014;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&#xb0; 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 m/g and a 50% particle size of 0.7 to 2.0 &#x3bc;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&#x2014;Zn ferrite comprises, as main constituents, 54 to 57 mol % of FeO, 5 to 10 mol % of ZnO, 4 mol % or less (not inclusive of 0%) of NiO, and the balance substantially being MnO.

Method for producing Mn-Zn ferrite

There is provided a Mn&#x2014;Zn based ferrite member excellent in mass productivity, high in withstand voltage, low in loss and excellent in direct current superposition property. The Mn&#x2014;Zn based ferrite member is provided with a surface layer portion having the properties that &#x3c1;5 defined in the specification satisfies the relation that &#x3c1;5&#x2267;10&#x3a9;m and &#x3c1;50 defined in the specification satisfies the relation that &#x3c1;50&#x2266;10&#x3a9;m.

Mn-Zn based ferrite member

An Mn&#x2014;Zn ferrite wherein 0 to 5000 ppm of a Co oxide in a CoOconversion is contained in a basic component constituted by FeO: 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 &#x3b1; in a formula (1) below in said ferrite satisfies &#x3b1;&#x2267;0.93.&#x3b1;=((Fe&#x2212;Mn&#x2212;Co)&#xd7;(4.291.912.192.01))/(()&#xd7;100)&#x2003;&#x2003;formula (1).Note that in the formula (1), (Fe&#x2212;Mn&#x2212;Co): [wt %], A: FeO[mol %], B: MnO [mol %], C: ZnO [mol %] and D: CoO [mol %]. According to the present invention, a highly reliable Mn&#x2014;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.

Mn-Zn ferrite, transformer magnetic core and transformer

Mn-Zn ferrite production process, Mn-Zn ferrite, and ferrite core for power supplies

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 SiO 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.

Manganese-zinc (Mn-Zn) based ferrite

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Tokyo, Japan

Kenya Takagawa