Precursor of iron-based oxide magnetic particle powder and method for producing iron-based oxide magnetic particle powder using the same

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a precursor suitable for obtaining an iron-based oxide magnetic particle powder having a narrow coercive force distribution and being suitable for increasing the recording density of a magnetic recording medium, and to provide a method for producing an iron-based oxide magnetic particle powder using the precursor.SOLUTION: A precursor of an ε-type iron-based oxide magnetic particle powder containing a substituted metal element is produced by reacting one or more selected from a divalent iron ion and a trivalent iron ion, a substituted metal ion, and a neutralizer in an aqueous solution in the presence of a hydroxycarboxylic acid to neutralize the pH to 7.0-10.0. An ε-type iron-based oxide magnetic particle powder containing a substituted metal element is obtained by, preferably after washing the precursor with water, coating the precursor with a silicon oxide and heating the coated precursor.SELECTED DRAWING: Figure 1