| 摘要 |
PURPOSE:To obtain stabilized reduced iron powder for magnetic recording having high performance with high reproducibility by bringing a gaseous mixture of an inert gas with oxygen into contact with reduced iron powder to stabilize the powder and by lowering the partial pressure of oxygen in the gaseous mixture during the stabilization treatment. CONSTITUTION:Reduced iron powder contg. Cr, Zn, Ni, Cu, etc. is charged into a reactor, and a gaseous mixture of an inert gas such as nitrogen or helium with oxygen is passed to stabilize the reduced iron powder while fluidizing the powder under a prescribed pressure. During the stabilization treatment, the partial pressure of oxygen in the gaseous mixture is lowered to zero or a value close to zero at least once. By this method, stabilized reduced iron powder for magnetic recording can be industrially manufactured with high reproducibility. |
