PRODUCTION OF FINE PARTICLE OF FERROMAGNETIC METAL OXIDE

摘要

PURPOSE:To obtain fine particles of various kinds of ferromagnetic metal oxide in high efficiency by heating a mixture of plural kinds of metal hydroxides composed mainly of iron hydroxide with microwave plasma to effect the ferrite- forming reaction. CONSTITUTION:Microwave is applied to a mixture of plural kinds of metal hydroxides composed mainly of iron hydroxide. The mixture is converted to a ferrite by the heat of plasma generated by the microwave. Fine ferrite particles of spinel-type, hexagonal-type or garnet-type can be produced by selecting the kind of metal hydroxide to be combined with the ferric hydroxide. In each case, the atmosphere of the system is selected so as to keep a stable plasma. Especially preferably the reaction is carried out in a reduced pressure atmosphere containing a proper amount of oxygen.