公开(公告)号：US20160203894A1

公开(公告)日：2016-07-14

申请号：US15073730

申请日：2016-03-18

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA ,  Yoichi HOSOYA

IPC: H01F1/113 ,  G11B5/714 ,  G11B5/706 ,  C01G49/00

CPC classification number: H01F1/113 ,  C01B13/366 ,  C01G49/0036 ,  C01P2004/22 ,  C01P2004/54 ,  C01P2004/64 ,  C01P2006/12 ,  C01P2006/42 ,  G11B5/70678 ,  G11B5/714 ,  H01F1/11

Abstract: A production method for metal oxide particles includes: obtaining precursor particles of a metal oxide by performing a synthesis reaction of the precursor particles in the presence of an organic compound; and converting the obtained precursor particles into metal oxide particles by heating an aqueous solution containing the precursor particles to 300° C. or higher and pressurizing the aqueous solution at a pressure of 20 MPa or higher.

Abstract translation: 金属氧化物粒子的制造方法包括：在有机化合物的存在下进行前体粒子的合成反应，得到金属氧化物的前体粒子; 并且通过将含有前体颗粒的水溶液加热至300℃以上，并将该水溶液加压至20MPa以上的压力，将得到的母体粒子转化为金属氧化物粒子。

公开(公告)号：US20150279406A1

公开(公告)日：2015-10-01

申请号：US14671125

申请日：2015-03-27

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA

IPC: G11B5/706 ,  H01F1/37 ,  C01G49/00 ,  H01F1/34

CPC classification number: G11B5/70678 ,  C01G49/0018 ,  C01G49/0036 ,  C01P2004/51 ,  C01P2004/64 ,  C01P2006/42 ,  H01F1/11 ,  Y10T428/2982

Abstract: An aspect of the present invention relates to A method of manufacturing hexagonal ferrite powder, which comprises heating to equal to or higher than 300° C. and pressurizing to equal to or higher than 20 MPa a hexagonal ferrite precursor-containing water-based solution, to convert the precursor to hexagonal ferrite, wherein the water-based solution comprises at least a reducing compound selected from the group consisting of a reducing inorganic compound and a reducing organic compound that have a reducing property and exist as a solid or a liquid at ordinary temperature and ordinary pressure, as well as, when the reducing compound is a reducing inorganic compound, the water-based solution further comprises an organic compound.

Abstract translation: 本发明的一个方面涉及一种六方晶系铁氧体粉末的制造方法，该方法包括加热至等于或高于300℃，并加压至等于或高于20MPa的含六方晶系铁氧体前体的水性溶液， 将前体转化为六方晶系铁氧体，其中所述水性溶液至少包含选自具有还原性的还原性无机化合物和还原性有机化合物的还原性化合物，并且作为固体或液体以普通的方式存在 温度和常压，以及当还原性化合物为还原性无机化合物时，水性溶液还包含有机化合物。

公开(公告)号：US20180358046A1

公开(公告)日：2018-12-13

申请号：US15996622

申请日：2018-06-04

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA ,  Takashi FUJIMOTO

IPC: G11B5/78 ,  G11B5/706

CPC classification number: G11B5/78 ,  G11B5/70621

Abstract: Provided is a magnetic recording medium including: a non-magnetic support; and a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of ε-Fe2O3 and a compound represented by Formula (1), an abrasive, and a binding agent, at least on one surface of the non-magnetic support, in which an average equivalent circle diameter of the particles of the epsilon type iron oxide-based compound is 7 nm to 18 nm, an average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 20 nm to 1,000 nm, and a coefficient of variation of the equivalent circle diameter of the abrasive is 30% to 60%. In Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0

公开(公告)号：US20170287515A1

公开(公告)日：2017-10-05

申请号：US15474418

申请日：2017-03-30

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA

IPC: G11B5/65

CPC classification number: G11B5/653 ,  G11B5/70678 ,  H01F1/11

Abstract: The hexagonal ferrite powder has an activation volume of greater than or equal to 800 nm3 but less than 1,200 nm3, a rare earth atom content falling within a range of 0.5 to 8.0 atom % per 100 atom % of iron atoms, and a localized presence of rare earth atoms in the surface layer portion, as well as is in the form of ellipsoidal powder.

公开(公告)号：US20160141084A1

公开(公告)日：2016-05-19

申请号：US14757517

申请日：2015-12-23

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA

IPC: H01F1/11 ,  G11B5/706

CPC classification number: H01F1/11 ,  G11B5/70678

Abstract: Provided are hexagonal ferrite magnetic powder for magnetic recording, being comprised of hexagonal ferrite magnetic particles having a crystalline metal oxide adhered to a surface thereof, a method for producing hexagonal ferrite magnetic particles having a crystalline metal oxide adhered to a surface thereof, and a magnetic recording medium.

Abstract translation: 提供了用于磁记录的六方晶系铁氧体磁粉，由具有结合金属氧化物附着在其表面上的六方晶系铁氧体磁性颗粒组成，具有附着在其表面上的结晶金属氧化物的六方晶系铁氧体磁性颗粒的制造方法和磁性 记录介质。

公开(公告)号：US20150187472A1

公开(公告)日：2015-07-02

申请号：US14584602

申请日：2014-12-29

Applicant: FUJIFILM CORPORATION

Inventor： Masashi SHIRATA

IPC: H01F1/03 ,  G11B5/706 ,  C01G49/00

CPC classification number: G11B5/70678 ,  C01G49/0036 ,  C01P2002/50 ,  C01P2004/64 ,  C01P2006/42 ,  H01F1/11 ,  Y10T428/2982

Abstract: An aspect of the present invention relates to magnetic powder, which is magnetoplumbite hexagonal strontium ferrite magnetic powder comprising 0.05 atomic percent to 3 atomic percent of Ca per 100 atomic percent of Fe, but comprising no rare earth elements or transition metal elements other than Fe, the average particle size of which ranges from 10 nm to 25 nm, and which is magnetic powder for magnetic recording.

Abstract translation: 本发明的一个方面涉及磁性粉末，它是每100原子％Fe含0.05原子％-3原子％Ca的磁铅石六方锶铁氧体磁粉，不包含除Fe以外的稀土元素或过渡金属元素， 其平均粒径为10nm〜25nm，为磁记录用磁粉。

公开(公告)号：US20150187380A1

公开(公告)日：2015-07-02

申请号：US14584568

申请日：2014-12-29

Applicant: FUJIFILM CORPORATION

Inventor： Masashi SHIRATA

IPC: G11B5/706 ,  C01G49/00 ,  G11B5/84 ,  H01F1/03

CPC classification number: G11B5/70678 ,  C01G49/0036 ,  C01P2002/50 ,  C01P2002/52 ,  C01P2002/54 ,  C01P2002/72 ,  C01P2004/64 ,  C01P2004/84 ,  C01P2006/42 ,  H01F1/11 ,  H01F1/113 ,  Y10T428/2982

Abstract: An aspect of the present invention relates to magnetic powder, which is magnetoplumbite hexagonal strontium ferrite magnetic powder comprising 1 atomic percent to 5 atomic percent of Ba per 100 atomic percent of Fe, the average particle size of which ranges from 10 nm to 25 nm, and which is magnetic powder for magnetic recording.

Abstract translation: 本发明的一个方面涉及磁性粉末，它是每100原子％Fe含有1原子百分比至5原子％的Ba的磁铅石六方锶铁氧体磁粉，其平均粒度范围为10nm至25nm， 并且是用于磁记录的磁粉。

公开(公告)号：US20190096551A1

公开(公告)日：2019-03-28

申请号：US16132662

申请日：2018-09-17

Applicant: FUJIFILM Corporation

Inventor： Kenji NAOI ,  Masashi SHIRATA ,  Takashi FUJIMOTO

IPC: H01F1/11 ,  C01G49/06 ,  C01G49/08

Abstract: The invention provides a core-shell particle which can provide, by being calcinated, epsilon type iron oxide-based compound particles that have a small coefficient of variation of primary particle diameter and show excellent SNR and running durability when employed in a magnetic recording medium as well as applications thereof. The core-shell particle includes: a core including at least one iron oxide selected from Fe2O3 or Fe3O4, or iron oxyhydroxide; and a shell that coats the core, the shell including a polycondensate of a metal alkoxide and a metal element other than iron, as well as applications thereof.

公开(公告)号：US20180358043A1

公开(公告)日：2018-12-13

申请号：US15986882

申请日：2018-05-23

Applicant: FUJIFILM Corporation

Inventor： Kenji NAOI ,  Takashi FUJIMOTO ,  Masashi SHIRATA

IPC: G11B5/706

CPC classification number: G11B5/70615

Abstract: A magnetic recording medium includes: a non-magnetic support; and a magnetic layer including a binding agent and a ferromagnetic powder including at least one epsilon-type iron oxide compound selected from the group consisting of ε-Fe2O3 and compound represented by Formula (1) (A represents at least one metal element other than Fe, and a satisfies 0

公开(公告)号：US20180147626A1

公开(公告)日：2018-05-31

申请号：US15825469

申请日：2017-11-29

Applicant: FUJIFILM Corporation

Inventor： Masashi SHIRATA ,  Takashi FUJIMOTO

IPC: B22F1/00 ,  G11B5/706 ,  H01F1/06

CPC classification number: B22F1/0059 ,  B22F2999/00 ,  G11B5/70615 ,  G11B5/70642 ,  H01F1/06 ,  H01F1/065

Abstract: Provided is an ε-iron oxide type ferromagnetic powder with a ratio Hc173K/Hc296K between a coercive force Hc173K measured at a temperature of 173 K and a coercive force Hc296K measured at a temperature of 296 K is higher than 1.00 and less than 2.00, and a magnetic recording medium containing the ε-iron oxide type ferromagnetic powder in a magnetic layer.