Rheological properties of hydrated zirconium dioxide

Abstract

The sol–gel transition of the ZrOCl 2–alkaline reagent (MeOH, Me(OH) 2, MeHCO 3, Me 2CO 3, etc.)–NH 4Ac system has been studied using rheological measurements. Hydrated zirconium dioxide has been prepared with the use of new two-stage neutralization scheme of the initial ZrOCl 2 solution. At the first step any alkaline reagent can be used. On the second step the solution of the slightly basic agents with pH less than 10, for example NH 4Ac, NaHCO 3 etc. added in one sitting, have been used for neutralization to obtain final product. The effect of temperature, molar ratio of initial reagents, shear rate, pH of zirconium containing gels on the gelation process, namely on the change of dynamic viscosity and shear modules of temporary rapid and slow elastic deformations has been investigated. The structure formation processes of hydrated zirconium dioxide have been studied with dynamic technique and method of physico-chemical mechanics. The last method possesses some essential advantages allowing the definition of most factors, which influence on structure and mechanical properties of investigated samples and the complete analysis of the investigated system without its destruction.