The role of powder particle size distribution in the processability of powder injection molding compounds

Abstract

The role of particle size distribution of hard-metal carbide powder compounds in structural changes caused by shear deformation is investigated via their response to dynamic viscoelastic strain. Materials employed in the study are intended for the production of sintered carbide components via powder injection molding. Four grades of hard-metal carbide powders differing in their particle size distribution were mixed thoroughly with a polymer binder containing low-density polyethylene, ethylene/vinyl acetate copolymer, and paraffin wax. From the results, it can be concluded that powder particle size distribution dominantly influences not only the magnitude of viscoelastic functions of highly filled compounds, but also their cause. As the demands on powder characteristics arising from the particular steps of powder injection molding are contradictory, thermogravimetric analysis was used as a complementary method for the investigation of the role of particle size distribution during debinding and sintering.