Equation for Simple Binary Dispersions? An Experimental Assessment by Use of a Ball of

The dielectric behavior of a "one-sphere " system in which only one solid sphere of glass, metal or gelatin having a 1-2 mm diameter comprises the suspended phase has been studied. With a glass bead system of volume fraction below 0.4, changes in its conductivity as a function of bead size was as predictable from the Wagner equation for non-conducting spheres uspended in conductive media. For steel balls suspended in electrolytic solutions, their dielectric dispersions were unexpectedly large with dielectric increments of about 5 X106. The dispersion behavior could not be predicted from a simple binary mixture of a homogeneous sphere with high conductivity, but was satisfactorily explained by taking account of an additional non-conducting layer with a capacitance of 7-20 uF/cm2 covering the highly conducting sphere. The large capacitances a sociated with the steel-ball system was attributable to the electrical double layer formed at the metal/solution interface. Gelatin balls suspended in deionized water, on the other hand, showed dielectric dispersions having dielec-tric increment of some 102 and characteristic frequency of 106-107 Hz. In addition, the dispersion curves for the hydrated-gelatin-ball system were significantly broader than the curves of a single relaxation type the Wagner equation should conform to. The spectral broadening here observed was successfully explained by a mechanism based on the reasonable assumption that a frequency depen