Study on Stability of Si3N4-nano BN Aqueous Suspension using Polyethylenimine as Dispersant
摘要：In this paper, a novel colloidal forming process has been developed to prepare silicon nitride –nano Boron nitride composites. In the present work, the dispersion of mixed silicon nitride –nano Boron nitride powders in aqueous media was investigated by adjusting the concentration of dispersant, p H value of the solution and other parameters. polyethylenimine（PEI） was used as dispersant for Si3N4 and BN powders in water. Well-dispersed Si3N4 and BN aqueous suspensions were obtained using 1 wt% PEI at p H 9. It depends upon the synthetic effects of dissociation of PEI and sufficient positive adsorption sites on the particle surfaces in aqueous media. The rheological behavior of Si3N4– BN aqueous suspensions was also investigated. Finally, a high solid loading（42 vol%）, low viscosity（380 m Pa s at 100 s-1） Si3N4–BN aqueous suspension was successfully prepared. It was observed that the suspensions exhibited shear thinning behaviours with relatively low viscosity which could satisfy the gelcasting process.
8th International Conference on Chemical, Ecology and Environmental Sciences （ICCEES’2016）