Pressureless moulding of 316L and D2 steel powders using a hybrid binder

A forming process for 316L and D2 steel powders has been studied. It consists of pressureless metal injection moulding of slurries containing, in addition to steel powder, a hybrid inorganic-organic binder. The slurries were prepared at room temperature and poured into polymeric moulds, where the binder polymerised within a few minutes. Rigid and resistant greens have been obtained. A curing process at 80°C has been performed in order to complete the crosslinking of the polymer. Different debinding cycles have been studied by thermogravimetric analyses, as a function of experimental parameters, such as heating rates and atmospheres. A number of bulk samples with different shapes have been debinded, using the optimised cycle and sintered under vacuum, reaching high densities (97% of theoretical). Microstructural characterisation has been performed on the sintered samples by scanning electron microscopy, along with microhardness measurements.