Influence of compaction pressure and sintering temperature in developing Fe-5wt%Al soft magnetic composites

Abstract This research elucidates the development of Fe-5wt%Al Soft Magnetic Composite (SMC) through the cold sintering process. The 5 wt% Al reinforcement acts as a metal binder in the hard Fe matrix composite during cold compaction is the novel idea of this work. The applied pressure of 200, 250, and 300 kN formed the green compacts with 82, 84, and 88% relative densities respectively. The green compacts were initially pre-sintered at 600 °C and then post-sintered at 1200 °C. The pre-sintering enhanced shrinkage at an average of 0.66% and the Fe-Al boundaries in the compacts formed Al-rich disordered Al 82 Fe 18 intermetallic. The rate of change in shrinkage was 0.03% for every 50 kN increase in compaction pressure. The average hardness of 56.52, 74.32, and 77.04 HV in pre-sintered compacts reveals that an increase in compaction pressure increases hardness. The high saturation of 204 emu g −1 and low coercivity of 9.77 Oe at 1.35 T was observed in 250 kN pre-sintered compact. Further, the post-sintering of pre-sintered compacts enhanced irregular swelling of compacts by diffusion of Al atoms into the Fe particles. Also, an ordered Al 13 Fe 4 intermetallic was formed by rearranging the diffused Fe atoms in Al particles. The average hardness of 80.08, 82.8, and 90.52 HV in post-sintered compacts reveals that the strength distribution was impacted by sintering temperature and initial compaction pressure. Comparing the blended Fe-5wt%Al powder, the material reaction during the post-sintering process reduced the magnetic property. The post-sintered Fe-5wt%Al SMC which was compacted at 250 kN pressure, resulted in better magnetic saturation of 178 emu g −1 and lower coercivity of 7.70 Oe for the applied field of 1.45 T.