Stabilization of aqueous silicon nitride suspension with Dolapix A88

Abstract

The dispersing phenomenon of silicon nitride suspension has been investigated systematically by measuring surface charge density, sediment volume, and turbidity of the suspension. Dolapix A88 has been used as dispersant to improve the stability of the suspension, and assessed through measurement of the specific surface charge of the Si3N4 system. The isoelectric point (IEP) of Si3N4 powder has been found to be at pH iep =6.91, and there was no shift in IEP due to the presence of dispersant, indicating that the interaction between the powder and the dispersant Dolapix A88 is purely physisorbing in nature. Good agreement has been observed among dispersion characteristics, surface charge, and streaming potential inflection. The article also describes the selection and optimization of the dispersant in controlling the stability of an aqueous suspension of Si3N4 . It can be concluded from this investigation that the PCD technique for measurement of specific surface charge can be conveniently used for the assessment of dispersibility of ceramic suspensions in dilute as well as in concentrated suspensions.