| 摘要 |
PURPOSE:To manufacture ferromagnetic iron powder having excellent dispersibility and stability by sticking compound of phosphoric acid and the specific metal on surface of the ferromagnetic iron powder after oxidizing the surface at the time of manufactur ing the ferromagnetic iron powder as magnetic recording medium. CONSTITUTION:After treating the surface of alpha-oxy iron hydrooxide with sinter- preventing agent, dehydration and burning are executed to make Fe2O3, and the ferro magnetic iron powder obtaining it with dry type reduction by using hydrogen gas as reducing agent having < 1mum length and > 3 acicular ratio is surface-oxidized under oxygen-containing atmosphere, to give corrosion resistance and weather resis tance. This surface-oxidized ferromagnetic iron powder is suspended into water, and in this suspended water, the phosphoric acid compound of hydroxy ethane disulfonic acid, etc., and salt kind of sulfate, hydrochloride, nitrate, acetate, etc., of at least one kind metal among Zn, Co, Ni, Cr, Cu, Fe, Al, etc., are added at each 0.1 - 20wt.% ratio to stick the compound of the phosphoric acid, and the above metal is stuck on surface of the ferromagnetic iron powder. As this has high ignition point, this is easily treated and has excellente dispersibility and the magnetic recording medium using this has excellent orientatability and stability. |
