Plural Lubricant Layers Over Carbon Layer Patents (Class 428/833.4)
  • Patent number: 8338006
    Abstract: A method for planarizing a magnetic recording disk that has surface features of elevated lands and recessed grooves includes forming two coatings of cured perfluorinated polyether (PFPE) polymers over the surface features. The disk may have a protective carbon overcoat with a surface that replicates the topography of lands and grooves. A liquid functionalized-PFPE is applied over the disk surface and then cured to form a first coating with the functionalized end groups bonding to the carbon overcoat. A liquid non-functionalized-PFPE polymer is then applied over the functionalized-PFPE coating and cured to form a second coating. The combined coatings substantially planarize the disk surface so that there is minimal recession between the top of the coating over the lands and the top of the coating over the grooves.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: December 25, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Qing Dai, Xing-Cai Guo, Dan Saylor Kercher, Mike Suk
  • Patent number: 7998912
    Abstract: A composite lubricant for recording disk media, a recording disk media including a layer of the composite lubricant, and method of manufacturing the same are described. The composite lubricant may include a non-phosphazene component and a phosphazene component where the non-phosphazene component is a difunctional perfluoropolyether compound terminated with first and second polar end groups, the first polar end group comprising a first number of hydroxyls and the second polar end includes a second number of hydroxyls, greater than the first number of hydroxyls. The phosphazene component may be a difunctional perfluoropolyether compound terminated with a phosphazene functional group and with a third polar end group, the third polar end group comprising a third number of hydroxyls equal to the second number of hydroxyls.
    Type: Grant
    Filed: September 14, 2009
    Date of Patent: August 16, 2011
    Assignee: WD Media, Inc.
    Inventors: Shaun H. Chen, Yasuo Sakane, Henry S. Nishihira, Chi Kong Kwok, The V. Tran, Bing-Shiuan Chang
  • Patent number: 7510999
    Abstract: A lubricant composition is provided comprising a first liquid lubricant and a second liquid lubricant, wherein the first liquid lubricant contains a cyclotriphosphazene ring attached to at least one perfluoropolyether having a single terminal hydroxyl group, and the second liquid lubricant contains a perfluoropolyether having two end groups selected from hydroxyl, tertiary amine, and combinations thereof. A magnetic recording media is also provided, comprising a substrate, a magnetic layer, an overcoat layer and a lubricant layer thereon, wherein the lubricant layer is formed from the lubricant composition. A further aspect of the invention concerns a method of making a magnetic recording media comprising forming a magnetic layer on a substrate; forming a protective overcoat layer on the magnetic layer; and forming a lubricant layer on the surface of the overcoat layer by applying the lubricant composition to the surface of the overcoat layer.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: March 31, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hong Deng, Robert Waltman, Jinliu Wang
  • Patent number: 7440233
    Abstract: The present invention provides a magnetic recording medium with a reduced tendency for a free layer to become thicker near an outer periphery than near an inner periphery of a recording zone as well as provides an information reproducing apparatus which is equipped with the magnetic recording medium and reproduces information according to the magnetization at various points on the magnetic recording medium. A magnetic layer carries information in an outer zone outside a predetermined inner zone around a through-hole. That part of the free layer which is located in the outer zone is thinner near the outer periphery than near the inner periphery.
    Type: Grant
    Filed: February 14, 2005
    Date of Patent: October 21, 2008
    Assignee: Fujitsu Limitd
    Inventor: Shinichi Takahashi
  • Patent number: 7277254
    Abstract: A magnetic recording disk having a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a perfluoropolyether compound having an end moiety containing a phosphazene ring and a perfluoropolyether compound having an end moiety containing a hydroxyl group, or the lubricant layer containing a perfluoropolyether compound having an end moiety containing a hydroxyl group on the protective layer side and a perfluoropolyether compound having an end moiety containing a phosphazene ring on the other surface side, and a process for manufacturing each of these magnetic recording disks.
    Type: Grant
    Filed: April 4, 2005
    Date of Patent: October 2, 2007
    Assignee: Hoya Corporation
    Inventors: Koichi Shimokawa, Kota Hara
  • Patent number: 7252897
    Abstract: A magnetic recording disk having a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a perfluoropolyether compound having an end moiety containing a phosphazene ring and a perfluoropolyether compound having an end moiety containing a hydroxyl group, or the lubricant layer containing a perfluoropolyether compound having an end moiety containing a hydroxyl group on the protective layer side and a perfluoropolyether compound having an end moiety containing a phosphazene ring on the other surface side, and a process for manufacturing each of these magnetic recording disks.
    Type: Grant
    Filed: September 3, 2003
    Date of Patent: August 7, 2007
    Assignee: Hoya Corporation
    Inventors: Koichi Shimokawa, Kota Hara
  • Patent number: 7208236
    Abstract: In a magnetic recording medium which comprises a substrate (1), a magnetic layer (3) formed on the substrate, a carbon-based protection layer (4) comprising carbon and formed on the magnetic layer, and a lubrication layer (5) formed on the carbon-based protection layer, the carbon-based protection layer comprises a hydrogenated carbon protection layer (4a) facing the magnetic layer and a nitrogenated carbon protection layer (4b) facing the lubrication layer. The hydrogenated carbon protection layer (4a) comprises carbon and hydrogen. The nitrogenated carbon protection layer (4b) includes no hydrogen but comprises carbon and nitrogen.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: April 24, 2007
    Assignees: Hoya Corporation, Hoya Magnetics Singapore Pte. Ltd.
    Inventors: Takashi Morikawa, Teiichiro Umezawa, Hiroshi Tomiyasu, Masafumi Ishiyama
  • Patent number: 7060377
    Abstract: A magnetic recording medium having a lubricant film containing a non-phase separated additive and a lubricant a base layer, wherein the additive is bonded to the base layer, for better and faster mobility of a lubricant to ensure rapid healing of areas of the medium that have been depleted of the lubricant, and a method of manufacturing thereof, is disclosed.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: June 13, 2006
    Assignee: Seagate Technology
    Inventors: Jianwei Liu, Michael Joseph Stirniman, Jing Gui