Process for producing needle-shaped highly coercive gamma-iron(III) oxide.

摘要

Acicular gamma-iron(III) oxide of high coercive force is produced by reducing acicular nonmagnetic iron(III) oxides or oxide hydroxides at between 250 and 700 DEG C with a superheated vapour mixture of an organic compound which is decomposable within this temperature range in the presence of iron oxides and an inert gas to form magnetite and subsequently oxidising the magnetite with oxygen-containing gases at 150 to 450 DEG C to give gamma-iron(III) oxide.