| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hexagonal ferrite particle powder, which has an average plate surface diameter of above 20.5 nm and at most 30 nm and is obtained by using hydrothermal synthesis process with excellent productivity in industry. <P>SOLUTION: In a production method, the hexagonal ferrite particle powder is obtained by: adding a suspension, which is composed of a mixture of a metal salt containing at least one kind of metal ion selected from Ba, Sr and Ca, an iron compound and one or two kinds or more of metal salts selected from di- to pentavalent metal elements, to an alkaline aqueous solution; allowing to react by using an autoclave; filtering out and drying an obtained precursor of hexagonal ferrite particles; and after calcinating the particles in the presence of a flux, removing the flux. When the suspension is added to the alkaline aqueous solution, the addition should be gradually performed over at least 20 minutes to obtain the hexagonal ferrite particle powder, having an average plate surface diameter of above 20.5 nm and at most 30 nm. <P>COPYRIGHT: (C)2011,JPO&INPIT |
