STABILITY OF SILICON NITRIDE-ALUMINA MIXED AQUEOUS SUSPENSIONS IN AQUEOUS-SOLUTIONS OF POLY(ETHYLENE OXIDE)

Stability of the mixed suspensions of the powders of silicon nitride a nd alumina in aqueous solutions of poly (ethylene oxyde) (PEO) was stu died. The powders were prepared by the low-temperature plasma synthesi s. Adsorption of nonionic polymer PEO on the surface of the particles of one of the dispersed phases (silicon nitride) does not prevent hete rocoagulation in the systems with oppositely charged phases. Partial d isaggregation takes place in such suspensions upon addition of electro lytes. Adsorption of PEO on silicon nitride in acidic media stabilizes the individual suspension and permits one to prepare the mixed disper se systems which are stable with respect to aggregation. The results o btained correlate with the calculations of the forces of interaction i n the systems examined.