公开(公告)号：US20150123026A1

公开(公告)日：2015-05-07

申请号：US14529544

申请日：2014-10-31

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. ,  FUJIFILM Corporation

Inventor： Kenji MASADA ,  Hirohisa OMOTO ,  Futoshi NAGASHIMA ,  Daisuke ABE ,  Toshio TADA ,  Norihito KASADA

IPC: H01F1/03

CPC classification number: H01F1/11 ,  C01G49/0036 ,  C01P2002/76 ,  C01P2006/42 ,  G11B5/70678

Abstract: Provided is magnetic powder capable of enhancing simultaneously both magnetic characteristics including SNP and durability of a magnetic recording medium. The hexagonal ferrite magnetic powder for a magnetic recording medium has a Ba/Fe molar ratio of 8.0% or more, a Bi/Fe molar ratio of 2.5% or more and an Al/Fe molar ratio of from 3.0 to 6.0%. The magnetic powder preferably has an activation volume Vact of from 1,400 to 1,800 nm3. The magnetic powder particularly preferably has a coercive force Hc of from 159 to 279 kA/m (which is approximately from 2,000 to 3,500 Oe) and a coercivity distribution SFD of from 0.3 to 1.0. The magnetic powder may contain, as an element that substitutes an Fe site of the hexagonal ferrite, at least one kind selected from divalent transition metals M1 and tetravalent transition metals M2.

Abstract translation: 提供了能够同时提高包括SNP的磁特性和磁记录介质的耐久性的磁粉。 用于磁记录介质的六方晶系铁氧体磁粉的Ba / Fe摩尔比为8.0％以上，Bi / Fe摩尔比为2.5％以上，Al / Fe摩尔比为3.0〜6.0％。 磁性粉末优选具有1400至1800nm 3的活化体积Vact。 磁性粉末特别优选具有159至279kA / m（约2,000至3,500Oe）的矫顽力Hc和0.3至1.0的矫顽力分布SFD。 作为代替六方晶系铁氧体的Fe部位的元素，可以含有选自二价过渡金属M1和四价过渡金属M2中的至少一种。

公开(公告)号：US20160217817A1

公开(公告)日：2016-07-28

申请号：US15002599

申请日：2016-01-21

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. ,  FUJIFILM Corporation

Inventor： Kenji MASADA ,  Hirohisa OMOTO ,  Futoshi NAGASHIMA ,  Hiroyuki SUZUKI ,  Toshio TADA

IPC: G11B5/72

CPC classification number: G11B5/70678 ,  H01F1/11

Abstract: A hexagonal ferrite magnetic powder for a magnetic recording medium, containing magnetic powder contains hexagonal ferrite particles having coated on the surface thereof an aluminum hydroxide material, having a Ba/Fe molar ratio of 0.080 or more, a Bi/Fe molar ratio of 0.025 or more, and an Al/Fe molar ratio of from 0.030 to 0.200. The magnetic powder preferably has an activation volume Vact of from 1,300 to 2,000 nm3. The magnetic powder particularly preferably has a coercive force Hc of from 159 to 287 kA/m (approximately from 2,000 to 3,600 Oe) and a coercivity distribution SFD of from 0.3 to 1.0. The magnetic powder may contain one or two or more kinds of a divalent transition metal M1 and a tetravalent transition metal M2, as an element that replaces Fe of the hexagonal ferrite. The magnetic powder has improved magnetic characteristics including SNR and durability.

Abstract translation: 含有磁性粉末的磁记录介质的六方晶系铁氧体磁粉包含六方晶系铁氧体颗粒，其表面上涂有BaO / Fe摩尔比为0.080以上，Bi / Fe摩尔比为0.025或 更多，Al / Fe摩尔比为0.030〜0.200。 磁性粉末的活化体积V act优选为1300〜2000nm 3。 磁性粉末特别优选具有159至287kA / m（约2,000至3600Oe）的矫顽力Hc和0.3至1.0的矫顽力分布SFD。 磁性粉末可以含有一种或两种以上的二价过渡金属M1和四价过渡金属M2，作为取代六方晶系铁氧体的Fe的元素。 磁粉具有改善的磁特性，包括SNR和耐久性。