Tdk Corporation

Other

Taku Murase

Naoyoshi Sato

Hiroshi Kurihara

Takuya Aoki

Motonari Yanagawa

Toshifumi Saitoh

Kyoichi Fujimoto

Kozo Hayashi

Kenya Takagawa

Takeshi Masuda

Hidenobu Umeda

Hiroyuki Morita

Masanori Ikeda

Yoshihiko Minachi

Kyung-Ku Choi

Taeko Tsubokura

Yoshitaka Murakawa

Isao Kanada

Noboru Ito

Junichi Nagaoka

Eiichiro Fukuchi

Shunsuke Kurasawa

Yohtaro Yamazaki

Hiroyuki Ono

Akira Sato

Kazushige Ito

Jun Sawai

Kensaku Asakura

Fumitaka Baba

Akira Kakinuma

Takashi Kajino

Tatsuya Shimazaki

Kazuhiro Takakura

Masatsugu Morita

There is provided a ferrite sintered magnet having a high residual magnetic flux density. A ferrite sintered magnetincludes a plurality of main phase particlesincluding ferrite having a hexagonal structure, the number of core-shell structured particlesA having a coreand a shellcovering the core, among the main phase particles, is smaller than the number of the main phase particlesother than the core-shell structured particlesA.

Ferrite sintered magnet

A method for manufacturing an R-T-B permanent magnet comprises a diffusion step of adhering a diffusing material to the surface of a magnet base material and heating the magnet base material with the diffusing material adhered thereto, wherein the magnet base material comprises rare-earth elements R, transition metal elements T and boron B; at least some of R are Nd; at least some of T are Fe; the diffusing material comprises a first component, a second component and a third component; the first component is at least one of a simple substance of Tb and a simple substance of Dy; the second component comprises a metal comprising at least one of Nd and Pr and not comprising Tb and Dy; and the third component is at least one selected from the group consisting of a simple substance of Cu, an alloy comprising Cu, and a compound of Cu.

Method for manufacturing R-T-B permanent magnet

The present invention provides a ferrite sintered magnet comprising (1) main phase grains containing a ferrite having a hexagonal structure, (2) two-grain boundaries formed between two of the main phase grains, and (3) multi-grain boundaries surrounded by three or more of the main phase grains. The above ferrite sintered magnet comprises Ca, R, Sr, Fe and Co, with R being at least one element selected from the group consisting of rare earth elements and Bi, and comprising at least La. The number Nm of the above main phase grains and the number Ng of the above multi-grain boundaries in the cross section including the direction of the easy magnetization axis of the above ferrite sintered magnet satisfy the formula (1A):50%&#x2264;/()&#x2264;65%&#x2003;&#x2003;(1A).

An R-T-B permanent magnet comprises rare-earth elements R, transition metal elements T, and boron B; wherein at least some of the rare-earth elements R is Nd and at least one of Tb and Dy; at least some of the transition metal elements T are Fe; the R-T-B permanent magnet comprises a plurality of main phase grains and grain boundary triple points each surrounded by the main phase grains; the grain boundary triple points comprise at least one of Nd and Pr, at least one of Tb and Dy, at least one of Fe and Co, and copper; the average contents of Nd, Pr, Tb, Dy, Fe, Co and Cu each (unit: atom %) are represented by [Nd], [Pr], [Tb], [Dy], [Fe], [Co] and [Cu]; ([Fe]+[Co])/([Nd]+[Pr]) is 2 or more and 5 or less; and [Cu]/([Tb]+[Dy]) is 1 or more and 4 or less.

R-T-B permanent magnet

W-type ferrite has improved magnetic properties, in particular, coercive force. A high coercive force (HcJ) and a high residual magnetic flux density (Br) can be simultaneously attained by a ferrite magnetic material comprising an oxide having a composition wherein metal elements Sr, Ba and Fe in total have a composition ratio represented by the formula SrBaFeFein which 0.03 &#x2266;x&#x2266;0.80, 1.1&#x2266;a&#x2266;2.4, and 12.3&#x2266;b&#x2266;16.1. The ferrite magnetic material can form any of a ferrite sintered magnet, a ferrite magnet powder, a bonded magnet as a ferrite magnet powder dispersed in a resin, and a magnetic recording medium as a film-type magnetic phase. As for the ferrite sintered magnet, there can be attained a fine sintered structure that has a mean grain size of 0.6 &#x3bc;m or less.

Ferrite magnetic material and ferrite sintered magnet

A dielectric ceramic composition having a main ingredient including a dielectric oxide expressed by the formula {(MeCa)O}.(ZrTi)O, where the symbol Me indicating the name of the element in said formula is at least one of Sr, Mg, and Ba and where the symbols m, x, and y indicating the molar ratios of the formulation in the formula are in relationships of 0.995&#x2266;m&#x2266;1.020, 0&#x3c;x&#x2266;0.15, and 0&#x2266;y&#x2266;1.00, a first sub ingredient including an oxide of R (where R is a rare earth element), a second sub ingredient including an oxide of Mg, and a third sub ingredient including an oxide of Mn, wherein the ratios of the sub ingredients with respect to 100 moles of the main ingredient are first sub ingredient: 0.1 to 6 moles (value converted to oxide of R), second sub ingredient: 0.1 to 5 moles (value converted to oxide of Mg), and third sub ingredient: 0.1 to 2.5 moles (value converted to oxide of Mn), said dielectric ceramic composition further having as a fourth sub ingredient an oxide of A (where A is at least one type of element selected from the group of anionic elements having an effective ion radius at the time of hexacoordination of 0.065 nm to 0.085 nm).

Dielectric ceramic composition and electronic device

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).

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

A high frequency magnetic thin film characterized by comprising a first layer made of a T-L composition (here, T is Fe or FeCo, and L is one or more of C, B, and N) and a second layer comprising a Co-based amorphous alloy arranged on either of the surfaces of the first layer. The high frequency magnetic thin film is a multilayer film of a plurality of the first layers and a plurality of the second layers or desirably is a multilayer film of alternately laminated first and second layers. The high frequency magnetic thin film of the present invention exhibits the properties such that the real part (&#x3bc;') of the complex permeability is 400 or more at 1 GHz, a quality factor Q (Q=&#x3bc;&#x2032;/&#x3bc;&#x2033;) is 4 or more, and a saturation magnetization is 14 kG (1.4 T) or more.

High frequency magnetic thin film, composite magnetic thin film and magnetic device using them

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 Ni&#x2014;Cu&#x2014;Zn-based ferrite material contains TiOalone as an additive in an amount of 0.1 wt %&#x3c;x&#x2266;4.0 wt % in which x denotes a content of the TiOand unavoidable impurities. The principal components thereof are 43.0 to 49.8 mol % of FeO, 4.0 to 13.0 mol % of CuO, 5 to 35 mol % of ZnO and the balance of NiO.

Ni-Cu-Zn-based ferrite material and process for the production thereof

A high frequency magnetic thin film characterized by comprising a first layer made of a T-L composition (here, T is Fe or FeCo, and L is one or more of C, B, and N) and a second layer comprising a Co-based amorphous alloy arranged on either of the surfaces of the first layer. The high frequency magnetic thin film is a multilayer film of a plurality of the first layers and a plurality of the second layers or desirably is a multilayer film of alternately laminated first and second layers. The high frequency magnetic thin film of the present invention exhibits the properties such that the real part (&#x3bc;') of the complex permeability is 400 or more at 1 GHz, a quality factor Q (Q=&#x3bc;&#x2032;/&#x3bc;&#x2033;) is 4 or more, and a saturation magnetization is 14 kG (1.4T) or more.

High-frequency magnetic thin film, composite magnetic thin film, and magnetic device using same

A ferrite material having a high Q value and also having a small absolute value of &#x3b1;&#x3bc;ir in a wide temperature range between &#x2212;40&#xb0; C. and 160&#xb0; C. A ferrite material, which comprises, as main constituents, 45.5 to 48 mol % of FeO, 5 to 10.5 mol % of CuO, 26 to 30 mol % of ZnO, and the balance substantially being NiO, and further comprises, as an additive, cobalt oxide within a range between 0.005 and 0.045 wt % in terms of CoO. The ferrite material of the present invention has properties such as each of the absolute value of &#x3b1;&#x3bc;irand the absolute value of &#x3b1;&#x3bc;irof 3 ppm/&#xb0; C. or less, and a Q value at 125 kHz of 170 or more.

Ferrite material, ferrite sintered body, and inductor

There is provided a sintered body at least 80% of which is constituted of a Y-type hexagonal ferrite. The sintered body contains, as main components, a cobalt oxide, a copper oxide, an iron oxide and AO (AO is at least one of BaO or SrO) in predetermined amounts in mol %, more preferably contains MO (MO is at least one of NiO, ZnO or MgO) in a predetermined amount in mol % in addition to the above components, and also contains, as additional components, bismuth oxide (Bi O ), borosilicate glass, borosilicate zinc glass or bismuth glass in predetermined amounts in wt %. Thus, a sintered body which exhibits good magnetic properties and is usable up to a high frequency band ranging from several hundred megahertz to gigahertz, contains as few hetero phases other than a Y-type hexagonal ferrite as possible and can be calcined at a temperature of not higher than 1,000&deg; C., particularly about 900&deg; C., and a high-frequency circuit component using the sintered body can be provided.

Growing community of inventors

Tokyo, Japan

Taku Murase