Aqueous silicon nitride suspensions: Effect of surface treatment on the rheological and electrokinetic properties

• 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 break-up of strong, liquid immobilizing agglomerates. Additionally, the effect of added dispersants – anionic small molecules and polyelectrolytes – were also briefly mentioned.

Nyckelord

Silicon nitride

slurry processing

aqueous dispersion

rheology

electroacoustics

dispersing agent

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