Process for preparing ferromagnetic fine particles for magnetic

Details Process for preparing ferromagnetic fine particles for magnetic Process for preparing ferromagnetic fine particles for magnetic

1992-08-20

1993-09-21

Cooper, Jack

Compositions

Magnetic

Iron-oxygen compound containing

252 6258, 252 6262, 252 6263, 423594, C04B 3526

Patent

active

052466094

ABSTRACT:
A process for producing ferromagnetic fine particles for magnetic recording which comprises preparing a starting material solution containing Ba, Fe and Me (Me representing at least one element selected from the group consisting of Co, Ti, Ni, Mn, Zr, Zn, Ge, Nb and V, the amount of which is 0.2 mol or less per mol of Fe) selected such that the molar ratio of Ba/(Fe+Me) is (1+m)/12 (m being a number of 0.1 to 2), mixing this starting material solution with an alkaline solution to form a coprecipitate-containing alkaline suspension, collecting and using the coprecipitate as precursor, or subjecting the coprecipitate-containing alkaline suspension to a heat treatment at a temperature below 250.degree. C. to form a precursor, and calcining such precursor at 650.degree.-950.degree. C. to produce the hexagonal platelet Ba-ferrite particles. The process is further characterized in that a boron compound is contained in the precursor in an amount of (0.01 to 1) mmol (calculated as B.sub.2 O.sub.3) per 12 mols of Fe and Me combined.

REFERENCES:
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Patent Abstracts of Japan, unexamined applications, P field, vol. 10, No. 32 Nov. 7, 1986, The Patent Office Japanese Government, p. 32 P513, *Kokai-No. 61-133 022 (Hitachi Maxell Ltd.)*.
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