Design of trimodal Fe micro-nanopowder feedstock for micro powder injection molding

Abstract

The design of the trimodal powder feedstock and its feasibility for micro powder injection molding (mu-PIM) were investigated. The feedstock was prepared by mixing Fe micropowder (D-50 = 4 mu m) and nanopowder agglomerate composed of a bimodal particle distribution (D-50 = 330 nm and D-50 = 30 nm, respectively) with low viscosity wax-based binders. The homogeneity of the feedstock was evaluated by torque rheometer, microstructure observations, binder burnout analysis, and an extrusion test. The trimodal concept in this study effectively improved the powder loading up to 72 vol%, and the feedstock with 70 vol% powder loading exhibited good homogeneity and flowability. By using the feedstock, the microparts were successfully replicated with sufficient shape retention to be potentially useful for a range of mu-PIM applications. (C) 2017 Elsevier B.V. All rights reserved.