Optimisation of injection moulding process for silicon nitride components

The major objective of this study was to develop an optimised process for manufacturing silicon nitride components. The effects of solid content, binder type, debinding solvent, and thermal debinding heat profile were investigated. Injection parameters such as pressure, speed, and temperature were also investigated and were found to have substantial influence on the mechanical properties of products. Solvent debinding before thermal debinding substantially reduced the debinding time through the formation of open channels in the binder. A debinding model is proposed based on experimental observations. The defects were considerably reduced and strength was enhanced by cold isostatic pressing without causing significant dimensional changes in the sintered body. Complex shaped silicon nitride blades with density 97% of theoretical and 880 MN m^-2 in bend strength were made successfully.