Abstract:Nearly spherical composite powders of high nitrogen nickel-saving stainless steel were synthesized by a high energy milling technique, and the MIM (metal injection molding) feedstock was prepared by mixing these metal powders with paraffin based multi-component binder. The rheological properties of MIM feedstock including feedstock viscosity and its sensitivity to the shear rate and the temperature were also investigated. The results show that the high energy milling can remarkably improve technological characteristics of the powders, and it is found that the powders milled for 60 h have fine particle size, good sphericity and high tap density, suitable for making high-quality MIM feedstock. The feedstock with powder loading of 58% presents the minimum shear rate sensitivity factor, the lowest viscous flow activation energy, and the largest general rheological index, which are n=0.45, E=28.70 kJ/mol and αSTV=2.96, respectively, exhibiting the best rheological properties and meeting process requirements for subsequent injection procedure very well