| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a needle-shaped magnetic particle (a precursor) having a major axis length of 100 nm or shorter, and an axial ratio (an aspect ratio) of 4 or more and having a very uniform particle diameter and profile. <P>SOLUTION: When the concentration of ferrous iron in an iron raw material aqueous solution in the preparation process of the iron raw material aqueous solution is taken as X(mol/L), and the oxidation treatment temperature in the process of preparing iron oxyhydroxide ultrafine particles is taken as Y(°C), the treatment and the preparation are carried out within the conditions meeting the following formulas (1)-(4): formula (1) X=0.001-0.1(mol/L); formula (2) Y=1-50 (°C); formula (3) Y≤-309.1X+43.91; and formula (4) Y≤-800X+66. <P>COPYRIGHT: (C)2007,JPO&INPIT |
