Stabilization of aqueous silicon nitride suspension with Dolapix A 88

The dispersing phenomenon of silicon nitride suspension has been investigated systematically by measuring surface charge density, sediment volume and turbidity of the suspension. Dolapix A 88 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 pHiep = 6.91 and there was no shift in iep due to 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 between dispersion characteristics, surface charge and streaming potential inflection. The paper also describes the selection and optimisation of the dispersant in controlling 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 suspension in both dilute as well as in concentrated suspensions