| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide spherical iron oxide particles which are excellent in environmental resistance, low in residual magnetization, low in flocculation, and high in electric resistance, more particularly the spherical iron oxide particles adequate for powder material applications for magnetic toners for electrostatic copying, and a method for manufacturing the same. <P>SOLUTION: The spherical iron oxide particles have coating layers of composite iron oxide of Zn and Fe on the surfaces of core iron oxide particles containing Si, and the residual magnetization in a load magnetic field 796 kA/m<SP>2</SP>is 4 to 8 Am<SP>2</SP>/kg. Also, the spherical iron oxide particles have the coating layers of composite iron oxide of Zn and Fe on the surfaces of the core iron oxide particles containing Si and further have Al compound layers thereon and the residual magnetization in the load magnetic field 796 kA/m<SP>2</SP>is 4 to 8 Am<SP>2</SP>/kg. <P>COPYRIGHT: (C)2004,JPO |
