Manufacture of gamma-iron (III) oxide
    1.
    发明授权
    Manufacture of gamma-iron (III) oxide 失效
    制造γ-铁(III)氧化物

    公开(公告)号:US4018882A

    公开(公告)日:1977-04-19

    申请号:US616863

    申请日:1975-09-25

    摘要: A process for the manufacture of acicular magnetic gamma-iron(III) oxide by reducing acicular alpha-iron(III) oxide to magnetite and then oxidizing it to gamma-iron(III) oxide, wherein the alpha-iron(III) oxide is treated with a water-soluble alkaline earth metal compound and an alkylphenol with one to three alkyl radicals, each of 4 to 24 carbon atoms, on the benzene nucleus. Gamma-iron(III) oxides manufactured in this way show better magnetic orientability in the binder-containing dispersion, and a higher coercive force than prior art magnetic pigments.

    摘要翻译: 通过将针状氧化铁(III)还原成磁铁矿然后将其氧化成γ-铁(III)氧化物来制造针状磁性γ-铁(III)氧化物的方法,其中氧化铁(III)为 在苯核上用水溶性碱土金属化合物和烷基酚与一至三个碳原子数为4〜24个的烷基进行处理。 以这种方式制造的γ-氧化铁(III)氧化物在含粘合剂的分散体中显示出更好的磁定向性,并且比现有技术的磁性颜料具有更高的矫顽力。

    Manufacture of gamma-iron(III) oxide
    2.
    发明授权
    Manufacture of gamma-iron(III) oxide 失效
    制造γ-铁(III)氧化物

    公开(公告)号:US4071610A

    公开(公告)日:1978-01-31

    申请号:US677920

    申请日:1976-04-19

    摘要: A process for the manufacture of acicular gamma-iron(III) oxide, in which the non-magnetic, acicular iron(III) oxide is treated with a solution of a compound of the formula I ##STR1## where R.sup.1 and R.sup.2 are ##STR2## or O--R.sup.5, R.sup.3 is H, OH, ##STR3## or O--R.sup.5, R.sup.4 is alkyl or cycloalkyl of 1 to 16 carbon atoms and the R.sup.4 's may be identical or different, and R.sup.5 is alkyl, cycloalkyl or aralkyl of 3 to 18 carbon atoms, and is then converted to gamma-iron(III) oxide by reduction to magnetite, followed by oxidation.The gamma-iron(III) oxide obtained is distinguished by a high coercive force and improved magnetic orientation when used as a magnetic pigment for the manufacture of magnetic recording media.

    摘要翻译: 一种用于制造针状γ-铁(III)氧化物的方法,其中非磁性针状铁(III)氧化物用式I化合物(I)的溶液处理,其中R1和R2 或者O-R5,R 3是H,OH,O或R 5,R 4是1至16个碳原子的烷基或环烷基,R 4可以相同或不同,R 5是烷基,环烷基或 3至18个碳原子的芳烷基,然后通过还原成磁铁矿转化为γ-铁(III)氧化物,随后进行氧化。

    Manufacture of cobalt-modified .gamma.-iron(III)oxides
    8.
    发明授权
    Manufacture of cobalt-modified .gamma.-iron(III)oxides 失效
    钴改性的{65-铁(III)氧化物的制造

    公开(公告)号:US4064292A

    公开(公告)日:1977-12-20

    申请号:US656800

    申请日:1976-02-10

    IPC分类号: G11B5/706 H01F10/02

    CPC分类号: G11B5/70689 G11B5/70673

    摘要: The invention relates to the manufacture of acicular cobalt-modified .gamma.-iron(III) oxide by coating an acicular .alpha.-iron(III) oxide or its hydrate with an inorganic protective coating, subsequent reduction to magnetite at 350.degree. to 650.degree. C, application of the cobalt compound to this magnetite or to the .gamma.-iron(III) oxide obtained therefrom by oxidation, and subsequent heat treatment at 80.degree. to 300.degree. C, if necessary with simultaneous oxidation of the magnetite to the corresponding .gamma.-iron(III) oxide. This iron oxide has high coercivity and can be used as the magnetic component in magnetic recording media for recording high frequencies without having the disadvantage of thermal and mechanical instability.

    摘要翻译: 本发明涉及通过用无机保护涂层涂覆针状α-铁(III)或其水合物,然后在350至650℃下还原成磁铁矿,制造针状钴改性的氧化钇(III) 通过氧化将钴化合物施加到该磁铁矿或由其获得的γ-铁氧合物(III),随后在80℃至300℃下进行热处理,如果需要,将磁铁矿同时氧化成相应的γ-铁( III)氧化物。 该氧化铁具有高的矫顽力,并且可以用作用于记录高频的磁记录介质中的磁性成分,而不存在热和机械不稳定性的缺点。