Measurement of hindered settling in magnetic dispersions

The measurement of hindered settling in a γ-Fe₂O₃ recording media dispersion has been carried out using a scanning column magnetometry technique. From subsequent analysis, a high trapped-liquid estimate (of ∼84% by volume of the settling unit) within the suspension structures was found that compares favorably with a previous computer simulation. Correction of hindered settling models to account for the trapped-liquid gave further confidence in the result. In each case, model parameters reduced near-to, or agreed with, those found originally in simple systems that contain little-to-no trapped-liquid.