The soluble aluminum compounds and nanocomposite materials based on them. Part III

Abstract

Simple aluminum compounds are precursors for all processes for the production of nanocomposite materials based on aluminum oxides. The present work analyzes the state of Al3+ aluminum ions in aqueous solutions. The state of Al3+ ions in aqueous solutions determines the mechanism and structure of the produced nanocomposites. The analysis of phase transformations in systems of aluminum salts, hydrated oxides and oxides is carried out. The main conditions to obtain final materials are determined on the basis on these data. An analysis of various methods used to prepare colloidal solutions of hydrated aluminum oxides has been performed. Such solutions are the main precursors in the production of nanocomposite materials based on aluminum oxides. The processes of obtaining alumina-sol by precipitation-peptization method which is one of the main methods were investigated. For the synthesis of alumina-sol, the possibilities of using ion exchange methods and controlled hydrolysis of aluminum compounds have also been considered. Analysis of the silica-sol and alumina-sol interaction processes was conducted to obtain a mixed oxide material in the system SiO2–Al2O3. The possibility of applying homogeneous precipitation of hydrated alumina to prepare nanocomposites based on aluminum oxide has been studied.

Keywords

• alumina-sol; aluminum aquacomplexes; aluminum hydroxocomplexes; aluminum alkoxides; Hydrolysis of aluminum compounds; Hydrated aluminum oxides; boehmite; pseudoboehmite; hydrargillite; alumina-silica-sol; homogeneous precipitation.