Effect of hydrolysis on the colloidal stability of fine alumina suspensions

Peculiarities of electrophoretic deposition and morphology of deposited films in non-aqueous suspensions of Al2O3–Al nanopowder

“…The change in pH over time had a similar character at different concentrations of the suspensions. The noted peculiarities of the dynamics of pH and ζ-potential may be associated with the hydrolysis of aluminum cations with the formation of hydrated complexes (Al2(OH)2(H2O)8) 4+ , (Al3(OH)4(H2O)9) 5+ , as well as (Al13O4(OH)24(H2O)12) 7+ , as shown in [32]. The suspensions of various concentrations are characterized by a high initial value of ζ-potential (fresh, not aged suspensions), which may be associated with the effect of self-stabilization due to the formation of aluminum cations in the dispersion medium as a result of the hydrolysis of trace amounts of nitrates, which inevitably appear on the surface of Al2O3 nanoparticles during their production by the EEW method [24].…”