Particles of coercivity magnetic high based on oxides of iron ferrimagnetic doped with cobalt, their preparation and their applications.

摘要

Highly coercive, cobalt-doped ferrimagnetic iron oxide particulates comprised of ferrous iron and well-adapted for the manufacture of various magnetic recording media, are prepared by (i) thermally decomposing a beta -diketone/cobalt complex onto fluidized iron oxide particles having the formula (FeO)xFe2O3, wherein 0/=x/=1.5, (ii) next annealing the particulates which result at a temperature ranging from about 300 DEG to 500 DEG and then (iii) permitting the same to cool, while at the same time sweeping the cooling zone with an inert gas, and then (iv) controlledly re-oxidizing the annealed/cooled particles.