The influence of a third phase on the rheology of suspensions

The plasticity (thixotropy) of suspensions of small glass beads in CCl4 and similar media was studied in connection with the dependence of the yield value on the water content. In the case of suspensions of glass the magnitude of the surface of the disperse phase is known; quantitative results can therefore be obtained. Our investigations lead to the conclusion that the plasticity of the suspensions studied is to be ascribed to the work necessary to break the water linkages which join the particles as a third phase. It is not the non‐polarity of the medium, but the insolubility of water in the medium; this causes the formation of a third phase, which leads to the occurrence of plasticity in cases when water shows a preference to adhere to the particles. As a converse to the suspensions of starch, quartz and glass in CCl4 with addition of water, the system coal in water with addition of xylene is described.