WERKWIJZE TER BEREIDING VAN EEN MAGNETISCH POEDER VOOR EEN MAGNETISCH REGISTREERMATERIAAL, EN DAARMEE VERKREGEN MAGNETISCH REGISTREERMATERIAAL.

摘要

A magnetic recording medium having more than 550 Oersted of a coercive force, less than 1.8 of a ratio of a coercive force at -196 DEG C. to a coercive force at 25 DEG C., less than 1.0 wt. % of a content of Fe2+ is prepared by incorporating a magnetic powder obtained by dispersing acicular gamma -Fe2O3 in an aqueous solution of a cobalt salt and reducing it with a reducing agent to deposit a cobalt compound on the acicular gamma -Fe2O3.