The effect of the addition of antimony on the physical and magnetic properties of iron particles in mercury

Abstract

Measurements of the resistivity and latent heat of iron-in-mercury magnetic liquids, to which antimony in the form of an antimony-lead eutectic has been added, confirm that the antimony forms a layer about the iron particles. The presence of a monolayer results in a marked reduction of the growth of the particles by diffusion or Ostwald ripening. The addition of antimony to the liquid at 15 degrees C, in quantities greater than that necessary to form a monolayer, results in a reduction in the saturation magnetisation, the magnitude of which depends on the quantity of antimony added. Iron-in-mercury liquids are highly viscous when more than 1 wt.% of iron is present. The addition of antimony to the liquid leads to a much reduced viscosity which permits higher concentrations (about 2.4 wt.%) of iron to be dispersed. Magnetic liquids with a saturation magnetisation of 900 G have been prepared using this technique.