| 摘要 |
PURPOSE:To obtain high-purity ferrite powder at low cost by adding an aqueous NH4OH solution at a specific concentration to a solution containing a ferrous metal salt and a salt of a metal other than the Fe constituting the final ferrite to produce a precipitate. CONSTITUTION:An aqueous NH4OH solution at a concentration of 0.05-5mol/l is added to an aqueous metal salt solution containing (A) a ferrous metal salt and (B) a second metal salt, a sulfate, chloride or nitrate of at least one kind of metal selected from Sr, Ba, Pb, Zn, Ni, Mn, Co, Cu, Mg, Y, Al, Bi and Ti to produce a precipitate. The above-mentioned addition is conducted in the presence of an enough amount of oxygen to convert the Fe<2+> into Fe<3+>. The precipitate is then taken after filtration and heat treated at 500-1000 deg.C for 0.1-10hr either directly or after dried to obtain the objective ferrite powder. |
