Micro-powder injection molding (μPIM) of tungsten carbide

Abstract

Tungsten carbide (WC) is a well-known hard alloy material due to its hardness, resistance to wear and extensive applications. The current demand for WC in micro-applications is continually increasing. The production of micro-WC–10%Co parts through micro-powder injection molding (μPIM) technique is challenging for researchers. The thermal phenomenon plays a significant role during the μPIM of WC–Co due to its outstanding thermal conductivity. The heat transfer involved in the microinjection molding (Model: DSM explore) of WC–10%Co in this study is illustrated and highlighted. The mold temperature is demonstrated to influence microinjection molding due to the high thermal conductivity of WC–10%Co. A higher surface area-to-volume ratio of 1.25:1 is beneficial in the debinding process, in which the majority of the soluble organic binder is lost within the first 5min. WC–10%Co sinters in the temperature range of 1380–1420°C with a dwell time of 2min during liquid phase sintering (LPS). The sintered part exhibits a densification of 96% of the theoretical density, a hardness of 1700kg/mm2, a bending strength of 2100MPa and a surface roughness of 1.17μm. The consequential effect of the injection parameter by type and characteristic of powder during micro-powder injection molding are determined.