IRON OXIDE PARTICLES AND THEIR PRODUCTION

PROBLEM TO BE SOLVED: To provide iron oxide particles that have improved properties in well balance, for example, oil absorption, electric resistance, magnetic properties, resistance to environment, and the like, and is particularly useful as a powder for the static copy magnetic toner and as a black pigment powder for paint. SOLUTION: From the center of the particle to the surface, the silicon component is contained continuously in an amount of 0.2-1.0 wt.% based on the iron oxide, calculated as elemental silicon, and the outer shell of the particle is coated with at least one metal component selected from Zn, Mn, Cu, Ni, Co, Cr, Cd, Al, Sn, Mg and Ti linking to the silicon component, further the core particle where 0.01-0.3 wt.% of silicon components are exposed is coated with an agent that can make the coated part hydrophobic.