Manufacture of acicular cobalt-modified magnetic iron oxide
    2.
    发明授权
    Manufacture of acicular cobalt-modified magnetic iron oxide 失效
    针状钴改性磁性氧化铁的制造

    公开(公告)号:US4188302A

    公开(公告)日:1980-02-12

    申请号:US872262

    申请日:1978-01-25

    摘要: A process for the manufacture of an acicular magnetic iron oxide containing from 0.5 to 10 percent by weight of cobalt and up to 24 percent by weight of divalent iron, each based on the amount of iron(III) oxide, wherein an aqueous suspension of gamma-iron(III) oxide, containing cobalt(II) and iron(II) ions, the suspension having a hydroxyl ion concentration of more than 3.6.times.10.sup.-6 moles/liter, is heated at from 50.degree. to 100.degree. C. for at least 15 minutes, and the resulting precipitate is filtered off, washed until neutral, dried at below 100.degree. C. and thereafter heated at from 100.degree. to 200.degree. C.The products thus obtained give, even when their cobalt content is low, a very high coercive force, while the effect of temperature on the coercive force and residual induction is very slight.

    摘要翻译: 一种用于制造针状磁性氧化铁的方法,其含有0.5至10重量%的钴和至多24重量%的二价铁,每个基于氧化铁(III)的量,其中γ 氧化铁(III),含有钴(II)和铁(II)离子,羟基离子浓度大于3.6×10 -6摩尔/升的悬浮液在50℃至100℃下加热至 至少15分钟,滤出所得沉淀物,洗涤至中性,在100℃以下干燥,然后在100〜200℃下加热。由此得到的产物即使在钴含量低的情况下也能得到 矫顽力非常高,而温度对矫顽力和残余感应的影响非常小。