Microstructure Evolution During Rapid Debinding of MIM Compact

This paper discusses the microstructure changes during solvent solvent extraction and polymer burnout process of injection moulded component using a new developed palm stearin binder system. The samples were prepared by injection moulding mixture of stainless steel with palm stearin and polyethylene. Debinding was carried out in two steps; first, the moulded parts were immersed in heptane at a temperature of 40 degrees C, 60 degrees C and 80 degrees C to remove the palm stearin (solvent extraction process) then followed by thermal debinding to remove the insoluble binder of polyethylene. The results show that large pore were formed from the surface to the interior of the debound part during solvent extraction, allowed easy escape of pyrolysis gases during thermal debinding. The rate of extraction of palm stearin from the green body increased with increasing solvent extraction temperature.