Fabrication of diamond whiskers by powder injection molding

Abstract

Diamond whiskers with large aspect ratio and strong bonding strength were produced by powder injection molding. The main fabrication process were mixing, injection molding, debinding and sintering. Firstly, The diamond grits and Cu-Sn-Ti powders were mixed with a multi-components binder to prepare feedstock. The feedstock was then injected into the mold cavity to form the green part with desired shape, and defect-free green parts were obtained by optimizing the injection molding parameters (injection pressure 12 MPa, injection temperature 165 °C and mold temperature 40 °C). Next, a solvent-thermal debinding process was employed to extract the binders in the green parts. Finally, The debound samples were sintered in vacuum atmosphere at 920 °C for 10 min to obtain diamond whiskers.The single whisker grinding test was carried out to discuss the cutting performance of diamond whiskers machining WC/12Co coating. The results indicated that diamond whisker had good cutting performance, and diamond grits in the diamond whisker mainly occurred integrity, micro-fracture, fracture and rubdown, diamond grits pullouts were not easy to happen due to the presence of the chemical bonding between the diamond grits and Cu-Sn-Ti alloy. And it has great potential to further prepare the diamond whiskers wheels which the diamond whiskers serving as the abrasives oriented radially in the wheel.