公开(公告)号：US4379183A

公开(公告)日：1983-04-05

申请号：US322667

申请日：1981-11-18

申请人： Yasuo Araki ,  Hajime Uno ,  Shigeharu Higuchi ,  Seiji Matsumoto

发明人： Yasuo Araki ,  Hajime Uno ,  Shigeharu Higuchi ,  Seiji Matsumoto

IPC分类号： C01G49/00 ,  G11B5/706 ,  H01F1/11 ,  C01G49/06

CPC分类号： G11B5/70673

摘要： A method of producing cobalt-modified magnetic particles is provided. The method comprises heating an aqueous suspension of ferric hydroxide at temperatures of 100.degree.-250.degree. C. at an alkaline pH in the presence of a water soluble organic or inorganic compound capable of forming complexes with iron as a growth regulating agent, and preferably also in the presence of .alpha.-ferric oxide seed crystals of minor axes not larger than 0.4 microns in average in amounts of 0.1-25 mole % in terms of the Fe content thereof in relation to the ferric hydroxide, converting the obtained .alpha.-ferric oxide into .gamma.-ferric oxide by reduction thereof followed by oxidation, maintaining an aqueous suspension of the .gamma.-ferric oxide at temperatures of 30.degree.-50.degree. C. at an alkaline pH in the presence of ferrous hydroxide and cobaltous hydroxide in amounts of 0.5-50 mole %, respectively, in relation to the Fe content of the .gamma.-ferric oxide in the suspension for a length of time sufficient to modify the .gamma.-ferric oxide particles.

摘要翻译： 提供了一种生产钴改性磁性颗粒的方法。 该方法包括在碱性pH下，在能与铁形成配合物的水溶性有机或无机化合物作为生长调节剂的情况下，在100-250℃的温度下加热氢氧化铁水悬浮液， 在相对于氢氧化铁的Fe含量换算为0.1-25摩尔％的平均值不大于0.4微米的短轴α-铁氧化物种晶的存在下，将所得α-二氧化铬转化为 通过还原γ氧化铁，然后氧化，在碱性pH下，在氢氧化亚钴和氢氧化钴存在下，保持γ-氧化铁的水悬浮液，温度为30-50℃，量为0.5-50 相对于悬浮液中的γ-氧化铁的Fe含量分别为足以改变γ-二氧化铬颗粒的时间长度的摩尔％。