PRODUCTION OF FINE PLATY BARIUM FERRITE POWDER

摘要

PURPOSE:To reduce the temp. dependency of coercive force by depositing a Zn compd. on the surface of a precursor of nickel ferrite modified barium ferrite formed by allowing a precursor of substd. barium ferrite to react with an Ni salt and by calcining the precursor with the deposited Zn compd. CONSTITUTION:A coprecipitate consisting of ions of the constituent elements of barium ferrite represented by the general formula (where n is 0.8-1 and x is 0.5-1) is heated to form a precursor of Co and Ti substd. barium ferrite. This precursor is allowed to react with an Ni salt in the presence of hydrogen to form a precursor of barium ferrite modified with spinel type nickel ferrite and having a mixed phase of two phases of magnetoplumbite type barium ferrite and spinel type nickel ferrite. A Zn compd. is deposited on the surface of the precursor and this precursor is calcined together with barium chloride to obtain fine powder of substd. barium ferrite modified with spinel type nickel.zinc ferrite and having <=+1Oe/ deg.C temp. coefft. The average particle size of the powder is 0.03-0.15mum.