Ferrite magnetic powder and method for production thereof

摘要

A ferrite magnetic powder for bonded magnets bonded using a rubber-base resin as binder, which powder is a ferrite magnetic powder containing an alkaline earth metal and having a chlorine content of 0.05 wt % or less and a powder pH of less than 6. The magnetic powder is produced by pulverizing a calcinated product of ferrite composition containing an alkali earth metal, annealing the pulverized ferrite composition to relieve crystal strain, dispersing the annealed powder in water and adding to it a mineral acid, adding a dispersant thereto, and subjecting the dispersion to solid-liquid separation followed by vacuum drying to obtain a ferrite magnetic powder having a chlorine content of 0.05 wt % or less and a powder pH of less than 6.