| 摘要 |
PURPOSE:To produce Co-modified ferromagnetic iron oxide powder which has high magnetic force and is less in pressurized demagnetization by depositing a cobalt compd. on the surface of lepidocrosite surface-treated if necessary and thereafter calcining it. CONSTITUTION:A cobalt compd. (e.g. cobalt ferrite) is added to aq. suspension of lepidocrosite grain (e.g. gamma-FeOOH) wherein surface treatment is performed by an aq. dispersion soln. or an aq. soln. of SiO2, Al2O3 and water glass, etc., if necessary, and thereby a mixture deposited with the cobalt compd. on the surface of gamma-FeOOH grain is obtained. Then after washing this mixture with water, filtering and drying it, it is calcined at 150-350 deg.C in air. |
