Surface properties of Co- gamma Fe/sub 2/O/sub 3/ particles for digital recording

Commercial cobalt-iron-oxide particles for digital applications have been examined by several techniques: physisorption, mercury porosimetry, and electron microscopy. Surface properties, in particular acicularity and heterogeneity, are related to the rheological behavior of the powders, to their magnetic characteristics, to the characteristics of draw-down coatings, and to the response of experimental floppy disks at predetermined recording frequencies. Particles showing high and uniform dispersibility have a narrow particle size distribution and a relatively large number of high-energy sites.<
>