| 摘要 |
PURPOSE:To prepare barium ferrite powder having hexagonal plate shape suitable for magnetic recording by calcining hexagonal plate iron oxyhydroxide powder obtd, by a specified method or iron oxide powder prepd. by its dehydration by heating, after adding a Ba compd. thereto. CONSTITUTION:Powder consisting essentially of iron oxyhydroxide having uniform, fine hexagonal plate shape is obtd. by oxidizing quickly the precipitate contg. ferrous hydroxide obtd. from an aq. soln. contg. a ferrous salt such as FeSO4 using a strong oxidizing agent such as H2O2. Ba compd. such as BaCO3 is added to said iron oxyhydroxide powder or iron oxide powder obtd. by dehydrating said iron oxyhydroxide powder by heating at the melting temp. of said Ba compd. to obtain hexagonal plate barium ferrite powder. The barium ferrite powder has fine and uniform average particle size of <=ca. 0.5mum and superior magnetic characteristics; accordingly, it is useful for high density magnetic recording. |
