Patents by Inventor Masaharu Shiroyama

Masaharu Shiroyama has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5432016
    Abstract: A material for a magnetic head slider consists essentially of 0.1 to 20.0 vol % of at least one of oxides the group Va elements of the International Periodic Table (Ta, Nb, V) and 80.0 to 99.9 vol % of stabilized cubic ZrO.sub.2 containing a stabilizer (Y.sub.2 O.sub.3, MgO, CeO.sub.2). It has improved precision machinability, machining efficiency, high strength, densified structure, affinity with the recording medium or lubricity, besides wear resistance. It may be machined precisely into a thin film magnetic head slider with a reduced amount of chipping.
    Type: Grant
    Filed: June 11, 1994
    Date of Patent: July 11, 1995
    Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Seiichi Hirao, Toyoshige Sasaki, Masaharu Shiroyama, Mitsuhiko Furukawa
  • Patent number: 5302560
    Abstract: A sintered material for recording/reading (particularly magnetic) head slider is produced by:preparing a powdery mixture which comprises 0.5 to 6.0% by weight of at least one component selected from the component group A consisting of the following elements and compounds thereof, a garnet type compound consisting essentially of erbium oxide and aluminum oxide in amounts of 2 to 12% by weight and 0 (exclusive) to 2 (inclusive) % by weight based on the total composition, respectively, and expressed by the formula Er.sub.3 (Al,Er).sub.2 (AlO.sub.4).sub.3 through (Er, Al).sub.3 Al.sub.2 (AlO.sub.4).sub.3, and the balance being silicon carbide powder:the elements for the component group A being Ti, V, Cr, Mn, Mg, Y, Zr, Nb, Mo, Ba, La, Ce, Gd, Hf, Ta, W, Th, and Cs; andsintering the resultant mass under the application of a high pressure.Further sintering aids of Be, BeO, B and B.sub.4 C may be present. For the garnet type compound, erbium oxide may be used, preferably in combination with alumina.
    Type: Grant
    Filed: January 8, 1992
    Date of Patent: April 12, 1994
    Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Yoshiaki Katsuyama, Mitsuhiko Furukawa, Takashi Kitahira, Michito Miyahara, Kiyohito Misumi, Masaharu Shiroyama
  • Patent number: 5093290
    Abstract: The deterioration of strength at high temperature of Si.sub.3 N.sub.4 --Y.sub.2 O.sub.3 --AlN series silicon nitride-type sintered bodies is reduced by employing Y.sub.2 O.sub.3 --MgO--AlN series as a sintering aid wherein the stoichiometrical ratio of Y, Mg and Al in the sintered body is controlled to a specific range, thereby decreasing the glass phase to decrease deterioration of strength at high temperatures. Assuming Y as A.sub.1 mol, Mg as B.sub.1 mol and A.sub.1 as C.sub.1 mol based on one mol of Si.sub.3 N.sub.4 in the sintered body, the specific range, wherein each of A.sub.1, B.sub.1 and C.sub.1 is not less than 0, satisifies the conditions: ##EQU1## and the crystal phase of Si.sub.3 N.sub.4 consisting of an .alpha.-Si.sub.3 N.sub.4 phase in which a part of Si.sub.3 N.sub.4 is replaced by Y, Mg, O and Al, and a .beta.-Si.sub.3 N.sub.4 phase in which a part of Si.sub.3 N.sub.
    Type: Grant
    Filed: March 2, 1990
    Date of Patent: March 3, 1992
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Mitsuhiko Furukawa, Masaharu Shiroyama, Mitsuyoshi Nagano, Yasumi Takano
  • Patent number: 4902651
    Abstract: A material for thin film magnetic head slider particularly suited for high recording, which is obtained by sintering a mixture consisting essentially of:5 to 45% by weight of titanium carbide component;0.2 to 10% by weight of zirconium oxide;0.05 to 2% by weight of oxide of yttrium;0.2 to 25% by weight of aluminum nitride; and the balance of Al.sub.2 O.sub.3 component substituted with 0.5 to 8% by weight being at least one machinability agent selected from the group consisting of oxides of Mg, Ca, B, Ni and Cr and complex oxides thereof.
    Type: Grant
    Filed: March 3, 1987
    Date of Patent: February 20, 1990
    Assignees: Sumitomo Special Metals, Co., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Masaharu Shiroyama, Mitsuyoshi Nagano, Michito Miyahara, Takashi Kitahira, Shigeki Mohri
  • Patent number: 4859638
    Abstract: A sintered material for recording/reading (particularly magnetic) head slider is produced by:preparing a powdery mixture which comprises 0.5 to 6.0% by weight of at least one component selected from the component group A consisting of the following elements and compounds thereof, a garnet type compound consisting essentially of erbium oxide and aluminum oxide in amounts of 2 to 12% by weight and 0 (exclusive) to 2 (inclusive) % by weight based on the total composition, respectively, and expressed by the formula Er.sub.3 (Al,Er).sub.2 (AlO.sub.4).sub.3 through (Er,Al).sub.3 Al.sub.2 (AlO.sub.4).sub.3, and the balance being silicon carbide powder:the elements for the component group A being Ti, V, Cr, Mn, Mg, Y, Zr, Nb, Mo, Ba, La, Ce, Gd, Hf, Ta, W, Th, and Cs; andsintering the resultant mass under the application of a high pressure.Further sintering aids of Be, BeO, B and B.sub.4 C may be present. For the garnet type compound, erbium oxide may be used, preferably in combination with alumina.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: August 22, 1989
    Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Yoshiaki Katsuyama, Mitsuhiko Furukawa, Takashi Kitahira, Michito Miyahara, Kiyohito Misumi, Masaharu Shiroyama
  • Patent number: 4814915
    Abstract: A magnetic head slider and a material for it which comprises a sintered body obtained by sintering a raw material powder composed of 65 to 90% by weight of ZrO.sub.2 component containing therein a stabilizer and the balance of Al.sub.2 O.sub.3 component, 2% by weight or below of which has been substituted with a binder. The stabilizer is Y.sub.2 O.sub.3, MgO or CeO and the binder is Y.sub.2 O.sub.3 or MgO.
    Type: Grant
    Filed: May 26, 1987
    Date of Patent: March 21, 1989
    Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Masaharu Shiroyama, Michito Miyahara, Shigeki Mohri, Mitsuyoshi Nagano
  • Patent number: 4796127
    Abstract: A recording head slider comprises a slider body having a fluid bearing surface on a primary surface thereof and at least one transducer on at least one side of the slider body, the slider body being made of a sintered body produced by sintering a base composition consisting essentially of 10-40 percent by volume of silicon carbide and the balance being alumina. The base composition may comprise 0.2-10 percent by weight of sintering aids MgO, Y.sub.2 O.sub.3, ZrO.sub.2, CaO, Er.sub.2 O.sub.3 and Cr.sub.2 O.sub.3. This slider has high precision machinability and compatibility with recording media.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: January 3, 1989
    Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Masaharu Shiroyama, Michito Miyahara, Mitsuyoshi Nagano, Shigeki Mohri
  • Patent number: 4582812
    Abstract: Aluminum oxide substrate material for magnetic heads having improved toughness consisting essentially of: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO.sub.2), and that provided TiO.sub.2 /(TiC+TiO.sub.2).times.100=5 to 15, (2) 0.5 to 5 parts by weight of addition of free cutting comprising at least one from the group of MgO, NiO, Cr.sub.2 O.sub.3 and ZrO.sub.2, and (3) 0.05 to 2 parts by weight of Y.sub.2 O.sub.3.The method of hot-forming aluminum oxide substrate material for magnetic head having improved sinterability consisting of (a) preparing a green compact by molding a raw material mixture which contains: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 percent by weight of (TiC+TiO.sub.2), and that provided TiO.sub.2 /(TiC+TiO.sub.2).times.100=5 to 15, (2) 0.5 to 5 parts by weight of machinability agents comprising at least one from the group of MgO, NiO, Cr.sub.2 O.sub.3 and ZrO.sub.2, and (3) 0.05 to 2 parts by weight of Y.sub.2 O.
    Type: Grant
    Filed: August 9, 1984
    Date of Patent: April 15, 1986
    Assignees: Nippon Tungsten Co., Ltd., Sumitomo Special Metals Co., Ltd.
    Inventors: Mitsuhiko Furukawa, Michito Miyahara, Takashi Kitahira, Kiyohito Misumi, Masaharu Shiroyama, Toshiaki Wada
  • Patent number: 4478871
    Abstract: Tungsten carbide and nickel-phosphorus alloy coexist in individual particles. The composite powder produced by a mechanical mix of these two substances consists of 30.about.95 percent by weight of tungsten carbide and valanced nickel-phosphorus alloy. This powder is sprayed to the ferrous base material, resulting in a uniform dispersion of both tungsten carbide and nickel-phosphorus, causing tight adhesion to the surface because the tungsten carbide and nickel-phosphorus alloy coexist in individual particles in the composite. A hard metal coating is produced having high hardness and excellent wear resistance, after the surface of the hard metal coating is heated and the high temperature of the nickel-phosphorus alloy causes a liquid phase under the condition of a nonoxidizing atmosphere. This hard metal coating is used for various kinds of the wear-resistant materials.
    Type: Grant
    Filed: December 20, 1983
    Date of Patent: October 23, 1984
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Shigeya Sakaguchi, Masaharu Shiroyama, Hiroshi Ito
  • Patent number: 4438213
    Abstract: Magnetic head slider material consisting of 5.about.10 percent by weight of silicon, 1.3.about.7.8 percent by weight of tungsten silicide and essentially balanced silicon carbide. And it is method for producing said magnetic head slider material that at the time of which the mixed powder consisting of silicon carbide, carbon and tungsten is sintered, cellulose is also mixed with said mixed powder and sintered together at the same time. And then fibrous micropores are caused to the sintered body by the above-described sintering, after that molten metallic silicon infiltrated into fibrous micropores.
    Type: Grant
    Filed: August 31, 1982
    Date of Patent: March 20, 1984
    Assignees: Nippon Tungsten Co., Ltd., Sumitomo Special Metals Co., Ltd.
    Inventors: Mitsuhiki Furukawa, Michito Miyahara, Takashi Kitahira, Kiyohito Misumi, Masaharu Shiroyama, Toshiaki Wada
  • Patent number: 4430440
    Abstract: A material for magnetic head sliders comprises a mixed powder consisting of 40 to 80% by weight of Al.sub.2 O.sub.3 and 20 to 60% by weight of TiO.sub.2, and further contains, per 100 parts by weight of the Al.sub.2 O.sub.3 and TiO.sub.2 mixture, 0.5 to 5 parts by weight of at least one of CaO, MgO and Y.sub.2 O.sub.3, and 0.5 to 10 parts by weight of ZrO.sub.2.
    Type: Grant
    Filed: May 28, 1982
    Date of Patent: February 7, 1984
    Assignees: Sumitomo Special Metal Co. Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Michito Miyahara, Masaharu Shiroyama, Kiyohito Misumi, Takashi Kitahira