Finemet nanocrystalline magnetic powder cores: Application of binder and warm compaction process

In this paper, Finemet flake amorphous powder with poor flowability is used as raw material to investigate the effect of the type of silicone resin and compaction method on the density and soft magnetic properties of the magnetic powder cores. The results show that due to the different thermal stability of the three silicone resins 600, S2 and JH, the permeability of the three magnetic powder cores has significant differences. Since the lubricant is in a viscous flow state during the warm compaction and reduces the friction between the particles, the density of the magnetic powder cores is increased, which further improves the soft magnetic properties of the magnetic powder cores. Among them, the density of Finemet magnetic powder cores prepared by warm compaction with the S2 silicone resin as binder is 5.62 g∙cm−3, the permeability is 43.86, the DC bias capability is 66.77 % at 100 Oe, and the total loss is 113.94 mW∙cm−3 (100 kHz, 50 mT), which has excellent comprehensive soft magnetic properties and is a very significant improvement compared with cold compaction. This shows that the warm compaction process is an effective method to further improve the soft magnetic properties of magnetic powder cores.