Rheological properties of ceramic slurries with colloidal binders used in the investment casting technology

Abstract

The article presents results of analyses of ceramic slurries made using materials currently tested in this technology, i.e.: colloidal silica (Ludox AM and Ludox SK) as a binder and Al2O3 as the ceramic matrix material. To characterise the binder, the size of colloidal binder particles, the Zeta potential and the binder pH were determined. Rheological properties were studied for slurries whose proportion of the (technologically justified) solid phase amounted to: 73; 74; 75 %. The impact of the solid phase proportion on the thickness of subsequent coats applied to the wax model, the dynamic viscosity and the density was determined. Research also included the impact of the size of matrix grains and the temperature on the above properties.

Keywords

• investment casting method
• rheological properties
• colloid silicate
• dynamic viscosity