Aqueous Silicon Nitride Suspensions: Effect of Surface Treatment on the Rheological and Electrokinetic Properties

摘要

The effect of surface treatment on the colloidal stability and rheological properties of concentrated aqueous silicon nitride suspensions has been studied. Oxidized, leached and as-received, non-treated powders were studied using electroacoustic and rheological methods. At pH=10, the silicon nitride powder is well dispersed irrespective of surface treatment. However, the viscosity was affected by the surface treatment; oxidation caused a slightly higher and leaching a significantly lower viscosity. Several possible causes of the leaching effect on viscosity was discussed, e.g. leaching causing a smooth particle surface or facilitating breat-up of strong, liquid immobilizing agglomerates. Additionally, the effect of added dispersants-anionic small molecules and polyelectrolytes-were also briefly mentioned.