Dispersion stability of SiC, SiCN and Si3N4 ultrafine powders in aqueous and nonaqueous media

A successful colloidal processing of ultrafine powders to produce high quality ceramic materials gives demand for stable, high degree particle dispersions. The stability of ceramic suspensions on the basis of SiC, Si3N4 and SiCN nanopowders in water and organic solvents (octane, benzene, toluene, benzyl alcohol and 1-octanole) was examined within 24 hours by means of screen sedimentation tests. Experimental results of the settling velocities were related to the calculated values of the total interaction potential energy between the particles interacting over the solvent molecules-the dispersion (van der Waals) attraction in case of organic liquids in the absence of dispersants, and a combination of dispersion attraction acid electrostatic forces in case of water, and finally to the physical properties of the used solvents.