The Potential of Starch As An Eco-Friendly Binder In Injection Moulding of 316L Stainless Steel For Medical Devices Applications

摘要

Two starch/wax based binders were formulated for metal injection moulding of 316L stainless steel. The formulations difffer in term of the starch type which substitute the backbone polyethelene. Feedstock having powder loading of the stainless steel powder up to 65 vol.% can be injection moulded successfully. Solvent debinding was performed in water at a temperature of 60°Cfor 3 hours and followed by immersion n-heptane for duration of 2 hours to remove the residual wax. The remaining binder was thermally extracted at 4500 with heating rate of 30C/min, with no defects. The parts were then sintered in vacuum atmosphere within a temperature range of 1300°C to 1380°C. Approximately, 6.8 g/cm~3 theoretical density, hardness of 188.8 HV and tensile strength of 229.3 MPawere achieved for cassava starch/wax based binder while rice starch/wax based binder possessed 8.6g/cm~3 theoretical density, hardness of 385 HV and tensile strength of 462.1 MPa.