SURFACTANT ASSISTED BALL-MILLING OF BARIUM FERRITE

The effects of wet-milling barium ferrite in the presence of cationic or anionic surface active substances have been investigated by x-ray d iffraction and Mossbauer spectroscopy measurements. Evidence for super paramagnetic relaxation of fine particles, both in the surfactant assi sted ball-milled samples and in samples dry-milled in air is obtained from the room temperature and 4.2 K Mossbauer spectra. The similarity between samples milled at pH 3 with the cationic or anionic surfactant s is due to electrostatic interactions of the surfactants' hydrocarbon groups with the positively charged barium ferrite surface.