In powder injection molding process, the rheological properties of feedstocks significantly influences the steady flow and the uniform filling into the mold. In this study, we investigated the effect of micro and nano size particles of Al2O3 on the rheological properties of Mg-Al2O3 feedstocks. A binder system containing Paraffin wax, Bees wax, and Stearic acid was synthesized. This binder was mixed with pure Mg and Al2O3 powders in various proportions. The Al2O3 powders contained both nano-and micro-Al2O3 differing in concentration from one sample to another. Flow characteristics of the samples were then investigated under different circumstances of shear rate and temperature by means of a rotary rheometer. Viscosity of the feedstocks was found to be decreased with micro size Al2O3 content whereas increased via nano size Al2O3.

Keywords: Injection moulding; Micro-Al2O3; Nano-Al2O3; Rheological properties; Mg-Al2O3