Process for production of ferromagnetic powder

A ferromagnetic metal powder comprising at least about 75% by weight of a ferromagnetic metal selected from the group consisting of Fe, Co, Ni and combinations thereof;

• about 20% by weight of a non-magnetic metal selected from the group consisting of Al, Si, S, Sc, Ti, Vi, Cr, Mn, Zn, Y, Mo, Rh, Pd, Ag, Sn, Sb, Te, Ba, Ta, W, Re, Au, Hg, Pb, Bi, La, Ce, Pr, Nd, B, P and combinations thereof;
• and 15% by weight or less of a member selected from the group consisting of water, oxygen, hydroxyl groups, and combinations thereof;
• said ferromagnetic metal powder being produced by reducing, in a solution, a salt of said metal capable of forming a ferromagnetic metal powder and a salt of said non-magnetic metal with a reducing agent, and separating the ferromagnetic powder from the reaction bath, washing the ferromagnetic powder with water until the conductivity of the water after the washing is 50 m .mu./cm or less, and then treating said ferromagnetic metal powder with an aqueous solution containing at least one anionic surface active agent.

A ferromagnetic metal powder comprising at least 75% by weight of Co and about 25% by weight or less of P and a member selected from the group consisting of Ni, Cr, Ti, Pb, Sn, Sb, S, Pd and combinations thereof, and about 10% by weight or less of at least one member selected from the group consisting of water, oxygen, hydroxyl groups, and combinations thereof;

• said ferromagnetic metal powder being produced by reducing a solution containing a metal capable of forming a ferromagnetic powder with phosphinic acid or a salt thereof, separating the ferromagnetic powder from the reaction bath, washing the ferromagnetic powder with water until the conductivity of the water after the washing is about 50 m .mu./cm or less, and then treating said ferromagnetic metal powder with an aqueous solution containing at least one anionic surface active agent.

A ferromagnetic metal powder comprising at least 75% by weight Fe, about 25% by weight or less of B and a member selected from the group consisting of Co, Ni, Cr, Ti, Pb, Sn, Sb, S and combinations thereof, and about 10% by weight or less of a member selected from the group consisting of water, oxygen, hydroxyl groups and combinations thereof, said ferromagnetic metal powder being produced by reducing in a solution a salt of a metal capable of forming a ferromagnetic metal powder with a boron hydride compound or a derivative thereof, separating the ferromagnetic metal powder from the reaction bath, washing the ferromagnetic powder with water until the conductivity of the water after the washing is about 50 m.mu./cm or less, and then treating said ferromagnetic metal powder with an aqueous solution containing at least one anionic surface active agent.