MANUFACTURE OF TABULAR BA FERRITE FINE PARTICLE POWDER FOR MAGNETIC RECORDING

摘要

PURPOSE:To obtain tabular fine particles for magnetic recording by previously adding Si (IV) at the atomic ratio of 0.0025-0.036 in conversion into Si to Fe (III) to an alkaline ferric hydroxide (III) suspension in the manufacture of tabular Ba ferrite fine particle powder. CONSTITUTION:In a method in which tabular Ba ferrite fine particle powder is manufactured by thermally treating an alkaline ferric hydroxide (III) suspension containing Ba ions, Ti (IV) and at least Co (II) as bivalent metallic ions M (II) by water within a temperature range of 200-330 deg.C, the thickness of formed BaFe12-xMxTixO19 (x<=1.2) fine particles can be controlled freely by previously adding Si (IV) at a fixed ratio within a range of the atomic ratio of 0.0025-0.036 in conversion into Si to Fe (III) to the alkaline ferric hydroxide (III) suspension. This method is ineffective on the control of the thickness of fne particles when the atomic ratio is low, is also ineffective for increasing the thickness of fine particles when the atomic is high, and resultantly fine amorphous particles are mixed into ferrite fine particles.