| 摘要 |
PURPOSE:To manufacture hexagonal ferrite powder having high quality with excellent mass productivity by making fine droplets of fused glass liquid contg. ferrite component, quenching it to form fine amorphous glass powder, etching and removing the glass phase after heat-treating said glass powder. CONSTITUTION:Fused glass liquid contg. hexagonal ferrite component is poured on a disc 1 rotating at high velocity via a funnel nozzle 2 from a crucible 4 and a cooling gas (N2 and Ar, etc.) from a nozzle 3 is blown on the fine fused droplets which are formed by scattering said glass liquid by means of centrifugal force to cool the droplets forcibly and the produced fine glass powder is taken out through a recovery port 9. Then, the obtained said amorphous powder is heat-treated in atmosphere at about 740 deg.C for about 10hr to precipitate fine crystal of hexagonal ferrite and thereafter the fine crystal is subjected to etching- treatment by aq. acetic acid soln. (concn. is about 20%) to remove glass phase and crystalline ferrite granules having about 0.03mu thickness and about 0.08mu length are obtained.
|
