On a correlation between the aggregation stability and integral electrosurface characteristics of oxide dispersions

Results of complex investigations of electrosurface properties and the aggregation stability of dispersions of alpha -Fe2O3, alpha -FeOOH, alpha -Al2O3, gamma -Al2O3, gamma -AlOOH, alpha -Cr2O3, SiO2, TiO2, Nb2O5. ZrO2, and natural diamond over a wide range of pH and concentrations of a 1 : 1 electrolyte are summarized. The values of the integral electrosurface characteristics of the dispersions-the point of zero charge (PZC), the isoelectric point (IEP), the K-al(int) and K-a2(int) constants determined using the 2-pK model, the fraction of ionized surface hydroxy groups at the PZC, and a(+/-PZC)-as well as the degree of aggregation and the stability factor of the dispersions in the isoelectric state are presented. A correlation between the experimental values of the stability factor of the dispersions in the isoelectric state and values of Delta pK = K-a2(int) - K-al(int) and q(+/-PZC) is found.