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US 4,306,921 AGranted
Production of magnetic powder
AssigneeKanto Denka Kogyo Co., Ltd.
InventorsShintaro Suzuki, Sadao Iizuka, Yoshimi Moriya
Life of this patent
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Abstract
The magnetic characteristics of magnetic powder consisting mainly of iron are improved by pre-treating the starting material from which the magnetic powder is prepared by reduction, with an aqueous solution and/or suspension of one member selected from the group consisting of cobalt, nickel, manganese and antimony compounds and mixtures thereof.
Claims18
A process for producing a magnetic powder consisting essentially of acicular iron particles and containing at least one metal selected from the group consisting of manganese and antimony suitable for magnetic recording which comprises the steps of
- (a) treating finely divided acicular particles of starting material selected from the group consisting of (i) iron oxyhydroxide and (ii) iron oxides with an aqueous solution or suspension of an applied metal compound selected from the group consisting of manganese and antimony compounds and mixtures thereof or a mixture of said solution and said suspension so that the applied metal is applied on said particles of starting material,
- (b) filtering the thus treated material off the liquid medium to form a cake and drying said cake, and
- (c) reducing said dry cake in a reducing gas stream at a temperature up to about 600.degree. C. to form acicular magnetic powder consisting essentially of iron.
Dependencies are inferred from the claim text.