| 摘要 |
PURPOSE:To obtain excellent transfer characteristic in a magnetic recording material, by employing Ba or Sr with Co to modify magnetized iron particles under specific conditions, thereby providing a recording material having high coercive force. CONSTITUTION:An aqueous Co salt solution and Ba or Sr salt are added to a liquid dispersion of magentic iron oxide particles (FeOx.Fe2O3, where 0<=x<=1). Then, an alkali is added to this solution so that OH group concentration in the solution becomes 0.05-3.0mol/l. Then, this solution is stirred at 50-100 deg.C in a non-acidic atmosphere, thereby modifying magnetic iron oxide particles with Co and Ba or Sr. Subsequently, the particles are filtered and dried. According to this method, magnetic iron oxide particle powder having high coercive force and high saturation magnetization, and excellent transfer characteristic as a magnetic recording material can be obtained. |
