Electric and magnetic properties of Fe-Ni powders-polymeric matrix composites

This work presents a systematic study of the effect of compaction load on the electric resistivity and initial magnetic permeability of Fe-Ni powders-polymeric matrix composites for energy concentrators. Uniaxial compaction loads P ranged from 5 to 35 tons, founding that the composite electric resistivity decreased from 17 x 10(-4) to 1.66 x 10(-4) Omega cm, while the initial magnetic permeability exhibits a maximum value of 1400 at P = 30 tons. Optical microscopy and SEM images revealed that as the compaction load increased, Ni particles welded themselves while Fe particles fractured, together with a decreasing porosity, which in turn, result in an optimum grain size and porosity distribution for P = 25, 30 tons. Electric and magnetic property variations were explained in terms of microstructure features. (c) 2005 Elsevier B.V. All rights reserved.