Magnetic iron oxide pigments and a process for their preparation
    1.
    发明授权
    Magnetic iron oxide pigments and a process for their preparation 失效
    磁性氧化铁颜料及其制备方法

    公开(公告)号:US4933014A

    公开(公告)日:1990-06-12

    申请号:US90929

    申请日:1987-08-31

    IPC分类号: C01G49/00 G11B5/706 H01F1/11

    CPC分类号: G11B5/70647 Y10T428/2991

    摘要: Magnetic iron oxide pigments useful in magnetic signal recordings having a dependence of coercivity on temperature in the temperature range of from 76K to 298K of less than 0.13 kA/mK and having a coercivity on powder compressed to 0.9 g/cm.sup.3 of greater than 51 kA/m are prepared by coating a magnetic iron oxide core material having the composition FeO.sub.x where x is a number from 1.33 to 1.5 in a first step with a compound containing divalent and trivalent iron having a ratio of Fe(III): Fe(II) from 0.01 to less than 2, and then in a second step coating the pre-coated core with a second coating of a cobalt compound.

    摘要翻译: 磁性氧化铁颜料可用于具有小于0.13kA / mK的76K至298K的温度范围内矫顽力与温度相关的磁信号记录,并且具有压缩至0.9g / cm 3的粉末矫顽力大于51kA / m是通过在第一步中用含有Fe(III):Fe(II)的二价和三价铁的化合物涂覆具有组成FeO x的磁性氧化铁芯材料,其中x为1.33至1.5, 0.01至小于2,然后在第二步中用钴化合物的第二涂层涂覆预涂芯。

    Magnetic iron oxide pigments and a process for their preparation
    2.
    发明授权
    Magnetic iron oxide pigments and a process for their preparation 失效
    磁性氧化铁颜料及其制备方法

    公开(公告)号:US4923519A

    公开(公告)日:1990-05-08

    申请号:US91059

    申请日:1987-08-31

    IPC分类号: C01G49/00 G11B5/706 H01F1/11

    CPC分类号: G11B5/70647 Y10T428/2991

    摘要: Magnetic iron oxide pigments having a monomolecular coating of a cobalt compound useful in magnetic signal recordings having a dependence of coercivity on temperature in the temperature range of from 76 K to 298 K of less than 0.13 kA/mK and having a coercivity on powder compressed to 0.9 g/cm.sup.3 of greater than 51 kA/m are prepared applying a preliminary coating of Fe.sub.3 O.sub.4 or a bertholloid compound to a magnetic iron oxide core material having the composition FeO.sub.x where x is a number from 1.33 to 1.55 and then covering the preliminary coating with a cobalt compound.

    摘要翻译: 具有钴化合物的单分子涂层的磁性氧化铁颜料,其可用于在76K至298K的温度范围内的矫顽力与温度的相关性小于0.13kA / mK的磁信号记录,并且具有压缩至 制备大于51kA / m 3的0.9g / cm 3,其中将Fe 3 O 4或硼氢化合物的初步涂层施加到具有FeO x组成的磁性氧化铁芯材料,其中x为1.33至1.55的数值,然后用 钴化合物。

    Process for the preparation of magnetic iron oxides and the pigments
obtained therefrom
    4.
    发明授权
    Process for the preparation of magnetic iron oxides and the pigments obtained therefrom 失效
    制备磁铁氧化物的方法及其获得的颜料

    公开(公告)号:US5116419A

    公开(公告)日:1992-05-26

    申请号:US448505

    申请日:1989-12-11

    摘要: Magnetic iron oxide pigments useful in manufacturing magnetic recording media are prepared by a method which comprises coating a magnetic iron oxide core particle material having the composition FeO, wherein x is from 1.33 to 1.5, in a first step with a preliminary coating of a cobalt-containing bertholloid material or a material having the composition Co.sub.x Fe.sup.II.sub.l-x Fe.sup.III.sub.2 O.sub.4 wherein x is greater than zero but less than or equal to 1 and then in a second step the preliminary coated particle is coated with a cobalt compound.

    摘要翻译: 可用于制造磁记录介质的磁性氧化铁颜料通过以下方法制备:在第一步骤中,涂覆具有组成为FeO的组成为FeO的磁性氧化铁芯颗粒材料,其中x为1.33至1.5, 含有贝壳体材料或具有组成CoxFeII1-xFeIII2O4的材料,其中x大于零但小于或等于1,然后在第二步骤中,预涂覆的颗粒涂覆有钴化合物。

    Production of magnetic iron oxides
    5.
    发明授权
    Production of magnetic iron oxides 失效
    生产磁性氧化铁

    公开(公告)号:US4358431A

    公开(公告)日:1982-11-09

    申请号:US286134

    申请日:1981-07-23

    摘要: In the production of needle-shaped magnetic iron oxide pigments by treating iron with a nitro-aromatic in the presence of .alpha.-FeOOH nuclei to form .alpha.-FeOOH particles and an amino-aromatic, and thereafter dehydrating the .alpha.-FeOOH particles and reducing them, the improvement which comprises forming the .alpha.-FeOOH nuclei at about 0.degree. to 90.degree. C. in a suspension of metallic iron, an iron-(II)-salt and a nitro-aromatic by adding a basic precipitant in about 10 to 95% of the amount required for the complete precipitation of the iron in the iron-(II)-salt. Advantageously the metallic iron comprises cast iron, the nitro-aromatic comprises nitrobenzene, the amino-aromatic comprises aniline, the basic precipitant comprises at least one of ammonia and a basically reacting alkali metal, alkaline earth metal or ammonium salt, the nuclei formation is carried out at about 10.degree. to 60.degree. C., and the basic precipitant is added in about 20 to 80% of the amount required for the complete precipitation of the iron in the iron-(II)-salt, additional iron and nitrobenzene being added to the suspension of precipitated nuclei to form the .alpha.-FeOOH particles.

    摘要翻译: 在通过在α-FeO​​OH核的存在下用硝基芳族化合物处理铁以形成α-FeO​​OH颗粒和氨基芳族化合物来生产针状磁性氧化铁颜料,然后使α-FeO​​OH颗粒脱水并还原 包括在金属铁,铁 - (II) - 盐和硝基 - 芳族化合物的悬浮液中在约0至90℃下形成α-FeO​​OH核的改进,通过在约10至95 在铁 - (II) - 铁中完全沉淀铁所需的量的%。 有利地,金属铁包括铸铁,硝基芳族包括硝基苯,氨基 - 芳族包括苯胺,碱性沉淀剂包括氨和基本上反应的碱金属,碱土金属或铵盐中的至少一种,承载核形成 在约10℃至60℃下加入碱性沉淀剂,其中添加铁(II) - 铁中完全沉淀所需的量的约20至80%,添加额外的铁和硝基苯 到析出的核的悬浮液以形成α-FeO​​OH颗粒。