Process for producing plate-like magnetite particles and plate-like
maghemite particles
    7.
    发明授权
    Process for producing plate-like magnetite particles and plate-like maghemite particles 失效
    板状磁铁矿颗粒和板状磁赤铁矿颗粒的生产方法

    公开(公告)号:US4865834A

    公开(公告)日:1989-09-12

    申请号:US156508

    申请日:1988-02-16

    IPC分类号: G11B5/706

    CPC分类号: G11B5/70689

    摘要: Plate-like magnetite particles, plate-like maghemite particles and the processes for producing these particles are herein disclosed. The plate-like magnetite particles and the plate-like maghemite particles provided according to the present invention are fine plate-like particles which are poreless and non-sintered as the plate-like magnetite particles are produced directly from an aqueous solution and these plate-like magnetite particles are oxidized by heating to produce the plate-like maghemite particles. Therefore, these particles can be filled to a high density in a vehicle or resin, have good dispersibility and orientability and are also high in a degree of particle contact, so that they are suited for use as electromagnetic wave absorbing and shielding material, magnetic material for magnetic recording, black or brown pigment for paints and colorant for rubber and plastic products.

    Acicular magnetic metal particles containing iron as main ingredient and
process for producing the same
    8.
    发明授权
    Acicular magnetic metal particles containing iron as main ingredient and process for producing the same 失效
    含有铁的主要磁性金属颗粒作为主要成分及其生产方法

    公开(公告)号:US5137783A

    公开(公告)日:1992-08-11

    申请号:US502553

    申请日:1990-04-02

    IPC分类号: G11B5/712

    摘要: Disclosed herein are acicular magnetic metal particles containing iron as the main ingredient the surfaces of which are coated with a polymer formed from at least one of silicone compounds represented by the following formula (I):(R.sup.1 HSiO).sub.a (R.sup.2 R.sup.3 SiO).sub.b (R.sup.4 R.sup.5 R.sup.6 SiO.sub.1/2)c (I)wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 respectively represent a hydrogen atom or hydrocarbon group having 1 to 10 carbon atoms which hydrocarbon group may be substituted by at least one halogen atom, a and b are respectively 0 or integers of not less than 1, and c is 0 or 2, provided that when c is 0, the sum of a and b is an integer of not less than 3 and which have a coercive force of not less than 1400 Oe, a saturation magnetization of not less than 100 emu/g, a major axial diameter of not more than 0.25 .mu.m and an S.F.D. of not more than 0.38, and a process for producing the acicular magnetic metal particles containing iron as the main ingredient.