Effect of PVP addition on mechanical and magnetic properties of organic-inorganic insulated FeSi powder cores
PVP with different contents was added to epoxy resin/SiO2 insulation procedures as a novel kind of reinforcing agent,and the influences of PVP on green strength,product strength and magnetic properties of Fe-Si magnetic powder cores were systematically investigated.The results show that PVP in green bodies contrib-utes to the increase of the bonding force between each component of the insulating layer,as well as between the insulating layers and magnetic powders,resulting in an increase in tensile strength.Furthermore,melting PVP during the annealing process with the appropriate content would promote the rearrangement of nano silica,which significantly improves the tensile strength of the annealed products.Similarly,the formation of a stable uniform SiO2 insulating layer at a proper dosage of PVP is also conducive to optimizing DC-bias performance,maintaining good frequency stability of permeability and low core loss.The optimal PVP dosage is determined to be 0.3 wt％,and the corresponding FeSi powder core owns a green strength of 22 N,a product strength of 305.76 N,a stable effective permeability at about 60 μ level in the frequency range of 20～2 000 kHz,a percent permeability as high as 86.5％at 8000 A/m DC-bias field and a low core loss of 522.7kW/m3 at 50 kHz/100 mT.
FeSiPVPsoft magnetic powder coretensile strengthmagnetic properties
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