Process for preparing ferromagnetic oxides obtained from na faith alpha o2 and ammonium salts.

摘要

Process for preparing ferromagnetic oxides obtained from alpha - NaFeO_2 and ammonium salts.; The preparation process of ferromagnetic oxides object of the invention consists of a first step in performing an ion exchange reaction on the substrate alpha - NaFeO_2 using as reaction medium various ammonium salts, either melted or dissolved in adequate moisture-free medium. And ferromagnetic materials near HFe_5O_8 formula are obtained, with spinel structure (cubic crystallographic parameter around 8332 Å and saturation magnetization to 60 emu next / g.; The subsequent heat treatment of these materials causes the iron oxide gamma-Fe_2O_3 -maghemita-, spinel structure (cubic crystallographic parameter around 8362 Å and magnetization near 70 emu / g saturation. This oxide is one of the first and pigments used in magnetic recording technology.; The saturation magnetization values ​​found for the materials described as soft magnets allow their.