With Group I Metal Patents (Class 252/62.6)
  • Patent number: 6251299
    Abstract: Magnetic material has a ceramics having a composition in the range of Fe2O3 35.0 to 44.5 mol %, NiO 47.0 to 56.5 mol % and CuO 5.0 to 12.0 mol %, and the ceramics having relative magnetic permeability of 15 or less, and composes the inductance element comprising this magnetic material and the internal metallic conductor. For making laminated inductance elements by concurrently baking ceramic green sheets and internal metallic conductors, substances to be used as ceramic green sheets, which substances have the composition in the above mentioned range are used, and a silver or silver alloys are used as the internal metallic conductor, and the calcination is carried out at temperature of 880 to 920° C.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: June 26, 2001
    Assignee: TDK Corporation
    Inventors: Takashi Ito, Yukio Takahashi, Fumio Uchikoba
  • Patent number: 6210597
    Abstract: Since the radio wave absorbent of the present invention has the main component of a magnesium-zinc system ferrite material containing 45 to 50 mol % of iron oxide, 7 to 19.7 mol % of magnesium oxide, 24 to 28.5 mol % of zinc oxide, 4 to 16 mol % of copper oxide, and 0.1 to 6 mol % of manganese oxide, a matching thickness is less than 8 mm, and the total weight of the radio wave absorbent for use in the inner wall of a radio wave dark room or the outer wall of a building or the like is remarkably reduced as compared with the radio wave absorbent obtained by sintering the conventional magnesium-zinc system ferrite material. Moreover, since the radio wave absorbent can be obtained by sintering the material at a relatively low sintering temperature of about 950 to 1150° C., the manufacture cost can be reduced relative to the radio wave absorbent obtained by sintering the conventional nickel-zinc system ferrite material.
    Type: Grant
    Filed: May 21, 1999
    Date of Patent: April 3, 2001
    Assignee: TDK Corporation
    Inventors: Taku Murase, Masatsugu Morita, Naoyoshi Sato
  • Patent number: 6210596
    Abstract: A magnetic ceramic composition containing ferrite serving as a primary component and a sintering aid. The composition can be sintered at low temperature. The sintering aid contains about 2-45 mol % Li2O; about 5-40 mol % RO, with R being at least one of Ba, Sr, Ca, and Mg; and about 30-70 mol % (Ti, Si)O2 with SiO2 accounting for at least about 15 mol %. The resultant composition provides inductor elements in which migration of inner conductors is suppressed, and insulation deterioration and increase of direct-current resistance is restrained.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: April 3, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Kazuhiko Takenaka, Tatsuru Takaoka
  • Patent number: 6200493
    Abstract: There is disclosed an MnMgCuZn ferrite material which contains ranges of 46.5 to 50.4 mol % of iron oxide, 10.5 to 22.0 mol % of magnesium oxide, 22.5 to 25.0 mol % of zinc oxide, 6.0 to 16.0 mol % of copper oxide, and 0.1 to 3.5 mol % of manganese oxide. Advantages of an MnMgCuZn ferrite material that resistivity is relatively high and material cost is low are utilized to realize a superior MnMgCuZn ferrite material which is much smaller in magnetic loss than conventional materials of the same series and which has a sufficient saturated magnetic flux density.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: March 13, 2001
    Assignee: TDK Corporation
    Inventors: Taku Murase, Takuya Aoki, Naoyoshi Sato, Isao Kanada
  • Patent number: 6187218
    Abstract: A method of producing a Ni—Cu—Zn ferrite material comprises the steps of preparing a mixture of an iron compound powder having a specific surface area of about 8.5 m2/g or more, a nickel compound powder, copper compound powder and a zinc compound powder, the mixture having a specific surface area of about 8.0 m2/g or more; pre-calcining the mixture such that the pre-calcined mixture has a surface area of about 5.0 m2/g or more and a spinel crystal synthesizability within a range of about 80.5% to 98%; and milling the pre-calcined mixture to obtain a powder of a Ni—Cu—Zn ferrite material having a specific surface area of about 6.0 m2/g or more.
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: February 13, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Takashi Kodama, Hideo Ajichi, Takehiro Konoike, Kunisaburo Tomono
  • Patent number: 6183659
    Abstract: A ferrite oxide magnetic material containing, as basic composition, 11 to 19 mol % of iron oxide calculated in terms of Fe2O3, 11 to 25 mol % of zinc oxide calculated in terms of ZnO, 0 to 10 mol % of copper oxide calculated in terms of CuO, and a residual part of nickel oxide, and further containing, as components subsidiary to the basic composition, 0.01 to 15 wt % of lead oxide calculated in terms of PbO, and 0.01 to 15 wt % of silicon oxide and/or talc calculated in terms of SiO2, wherein the ferrite oxide magnetic material has an initial magnetic permeability of not higher than 8, a sintered density of not lower than 4.8 g/cm3 and a stress-resisting and magnetic-field-resisting characteristic in a range of ±5% calculated in terms of the rate &Dgr;L/L of the change of inductance due to the condition of a magnetic field of 1000 G under a compressive stress P=5 (kg/mm2) parallel with a direction of magnetization.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: February 6, 2001
    Assignee: TDK Corporation
    Inventors: Satoshi Murayama, Motoi Kumagai
  • Patent number: 6180022
    Abstract: A Mn—Zn ferrite having large electrical resistance, which can withstand the use in high frequency region exceeding 1 MHz, is provided. The Mn—Zn ferrite comprises the following basic components: 44.0 to 50.0 mol % Fe2O3, 4.0 to 26.5 mol % ZnO, 0.1 to 8.0 mol % at least one member selected from the group consisting of TiO2 and SnO2, 0.1 to 16.0 mol % CuO, and the remainder being MnO. By the addition of TiO2, SnO2 and CuO, even if the material is sintered in the air, electrical resistance of 103 times or more as high as that of the conventional Mn—Zn ferrite can be obtained, and a high initial permeability of 300-400 as estimated can be secured even at high frequency of 5 MHz.
    Type: Grant
    Filed: August 16, 1999
    Date of Patent: January 30, 2001
    Assignee: Minebea Co., Ltd.
    Inventors: Osamu Kobayashi, Koji Honda, Shunji Kawasaki