| 摘要 |
PURPOSE:To produce plate Ba ferrite particles suitable for perpendicular magnetic recording, at a reduced cost, by adding a mixed aqueous solution of iron (III) chloride, cobalt (II) chloride, titanium (IV) chloride and barium chloride to a mixed aqueous solution of an alkali metal carbonate and a water-soluble silicate and subjecting the resultant coprecipitate to aging, drying, calcination, quenching and pulverization. CONSTITUTION:A mixed aqueous solution containing iron (III) chloride, cobalt (II) chloride, titanium (IV) chloride and barium chloride is added to a mixed aqueous solution of an alkali metal carbonate and a water-soluble silicate until the pH of the mixture of both solutions becomes 4.5-5.5. A solid coprecipitate is produced by this treatment. The coprecipitate is aged by pressurizing the mixed liquid under carbon dioxide gas atmosphere, and the aged coprecipitate is separated from the liquid, dried, calcined at 850-950 deg.C, quenched and pulverized to the powder. |
