ELECTROOPTICAL STUDY OF OXIDE DISPERSIONS AND THEIR STABILITY

Oxide/solution interface is with the clear origin of the surface charg e, obtained through ionization of surface hydroxyl groups. The oxide p articles produced by name hydrolysis present fractal aggregates built from nearly spherical particles with constant diameter (Al2O3, SiO2). In the process of acid hydrolysis particles with well defined form (sp heres, rods, ellipsoids) and high monodispersity could be obtained (al pha-Fe2O3, alpha-beta-FeOOH). Different types of oxides are investigat ed by the means of electric light scattering. An information on the el ectric surface properties of oxide/solution interface as well as in pr esence of various additives, particles dimensions and fractal structur e is obtained. The process of slow coagulation in presence of bivalent electrolyte and surface active substance is studied electrooptically. The change of dynamic electric behaviour (induced dipole moment) in t he processes of interaction is followed. Some considerations are made on the nonequillbium electric properties of the interface and the conn ection with suspension stability.