公开(公告)号：US3720618A

公开(公告)日：1973-03-13

申请号：US3720618D

申请日：1971-02-25

Applicant: TODA KOGYO CORP

Inventor： TODA H ,  SHIMIZU S ,  IHARA H

IPC: C01G49/06 ,  G11B5/706 ,  C04B35/00

CPC classification number: B82Y30/00 ,  C01G49/06 ,  C01P2004/03 ,  C01P2004/10 ,  C01P2004/54 ,  C01P2004/62 ,  C01P2004/64 ,  C01P2006/12 ,  C01P2006/42 ,  G11B5/70673 ,  Y10S264/58

Abstract: Procedure is described for producing a powder of cobaltcontaining, needle-like shaped gamma-ferric oxide, gamma -Fe2O3 particles useful for magnetic recording and the making of magnetic tape, magnetic sheet and magnetic disk with the powder which has high coercive force, high remanence and good dispersibility, uniform chemical composition, the cobalt uniformly dispersed on each particle, no twin particle structure, a particle length of 0.2-0.5 micron, a specific surface area of 15-25 m2/g and a content of anion such as SO42 less than 0.1 percent. Alkali is added to a mixture of a ferrous salt solution and a cobalt salt solution until the pH exceeds 11, an oxidizing gas of constant oxygen partial pressure is blown into the solution as uniformly fine air bubbles, also causing agitation while maintaining the solution at 30*-50*C, whereupon alpha-Fe2O3 hydrate particles precipitate with the cobalt ions in solid solution, and by washing, dehydrating, reducing and oxidizing conversion into the desired gamma -Fe2O3 particles results.

Abstract translation: 描述了制备含钴针状γ-氧化铁粉末，用于磁记录的γ-Fe2O3颗粒和制备具有高矫顽力的粉末的磁带，磁性片和磁盘的粉末的方法， 高残留性和良好的分散性，均匀的化学成分，钴均匀分散在每个颗粒上，没有双颗粒结构，颗粒长度为0.2-0.5微米，比表面积为15-25 m2 / g，阴离子含量如 SO42 < - >小于0.1％。 将碱加入到亚铁盐溶液和钴盐溶液的混合物中，直到pH超过11，将氧分压恒定的氧气气体均匀地吹入溶液中，同时在使溶液保持在30℃的同时引起搅拌 ℃-50℃，此时α-Fe 2 O 3水合物颗粒与固溶体中的钴离子一起沉淀，并通过洗涤，脱水，还原和氧化转化成所需的γ-Fe 2 O 3颗粒。