| 摘要 |
PURPOSE:To obtain cobalt-contg. iron oxide ferromagnetic powder having a narrow coercive force distribution by mixing a dispersion of iron oxide magnetic powder and a cobalt salt in an alcohol and an aq. alkali soln. and treating the mixt. at a temp. below the b.p. CONSTITUTION:A cobalt salt such as cobalt chloride or cobalt sulfate is dissolved in an alcohol having compatibility with water, e.g. methanol or ethylene glycol. Iron oxide magnetic powder such as gamma-Fe2O3 or partially reduced gamma-Fe2O3 is added to form a dispersion of the powder in the alcohol. This dispersion is then mixed with an aq. alkali soln. contg. alkali in an amt. of an equivalent or more to the cobalt salt, and the mixt. is treated at a temp. below the b.p. for an adequate time. |
