| 摘要 |
PURPOSE:To enhance the magnetic powder agglomeration preventive effect by coating the surfaces of the magnetic powder particles with dispersant in the state that water is interposed among the magnetic powder particles to perform preferable dispersion, thereby suppressing the bonding of the particles. CONSTITUTION:Iron oxide magnetic powder, metallic salt containing cobalt salt and suspension containing alkali are heat treated to coat cobalt compound on the magnetic powder crystal, and the powder is then rinsed with water, filtered and dried. In this case, the surfaces of the magnetic powder particles are coated with alkylamine salt, or alkylsulfuric acid or the like as a dispersant during the step of rinsing to drying, that is, in the state that water is interposed among the magnetic powder particles to perform preferable dispersion. |
