Filling Behaviour and Magnetic Properties of Fe-45Ni Permalloy Micro-MIM Parts

This study aims to manufacture the micro-MIM parts exhibiting excellent soft magnetic properties. The effects of solid loading of feedstock and injection speed on the sintered density and the coercivity were investigated. The feedstock composed of Fe-47Ni powder and binders was prepared by changing the solid loading of 60-67% and were injection-moulded into micro-dumbbell specimen with 0.16mm in parallel portion and 2.52mm in diameter of chucking parts. The internal mould pressure was measured in the chucking parts. The filling behaviour of feedstock into the micro-dumbbell specimen was investigated by comparing the results of flow simulation and short shot test, then the internal pressure drop and jetting phenomena were revealed. It could be concluded that the coercivity of the sintered parts was significantly influenced by the density reduction and the remaining carbon content, thus the solid loading of feedstock and injection speed in addition to debinding-sintering conditions should be optimized.