Preparation And Magnetic Properties Of Fe_73.5Cu₁Nb₃Si_13.5B₉ Hybrid Soft Magnetic Composites

With the rapid development of the new energy industry and electronic information industry,electromagnetic conversion core electronic devices will require high precision,high sensitivity,large capacity and miniaturized performance.This requires the core magnetic powder material used therein to have excellent magnetic properties.As the newly developed Fe_73.5Cu₁Nb₃Si_13.5B₉ core magnetic powder has received extensive attention due to its excellent characteristics:high frequency,high DC superposition and low loss.In this paper,Fe_73.5Cu₁Nb₃Si_13.5B₉ powder was used as a raw material while REN50 was used as the insulating adhesive to prepare Fe_73.5Cu₁Nb₃Si_13.5B₉ magnetic core powder by means of insulation coating,press molding and subsequent heat treatment.The XRD,DSC and BH analyzers were used to analyze the structure and magnetic properties of the core magnetic powder as well as the factors that influence its magnetic properties.The magnetic powder was further studied in depth,in terms of the powder’s annealing temperature;the influence of the content of the agent shaping force;the structure and properties of the core magnetic powder.In order to further optimize the magnetic properties of Fe_73.5Cu₁Nb₃Si_13.5B₉ core magnetic powder and achieve fine control of magnetic properties,Fe_73.5Cu₁Nb₃Si_13.5B₉/Fe-6.5wt%Si was prepared by adding Fe-6.5wt%Si alloy powder according to the composite effect of the composite material.The composite core magnetic powder was studied to investigate the influence of the composite amount of Fe-6.5wt%Si alloy powder on the magnetic permeability,loss and DC superposition characteristics of the composite core magnetic powder.The specific findings are as follows:1.The use of REN50 as an insulating binder can effectively insulate the coated and bonded Fe_73.5Cu₁Nb₃Si_13.5B₉ magnetic particles,and the insulating coating between the powder particles in the core magnetic powder can still exist stably after heat treatment at 500℃.The Fe_73.5Cu₁Nb₃Si_13.5B₉ nanocrystalline magnetic powder core has good magnetic properties.With the increase of binder content,the magnetic permeability of Fe_73.5Cu₁Nb₃Si_13.5B₉ magnetic powder core decreases first,then increases then decreases.The loss increases first and then decreases.When the content is 3%,the magnetic properties are the best:magnetic permeability is 32.59,and the loss（50mT,200kHz）is 329.87m W/cm³.As the molding pressure increases,the magnetic permeability of the Fe_73.5Cu₁Nb₃Si_13.5B₉ magnetic powder core increases first and then decreases,and the loss decreases firstly and then increases when the pressure is at 1100 MPa,the magnetic properties are the best:the magnetic permeability is33.03,and the loss（50 mT,200 kHz）is 320.30 mW/cm³.2.Fe-6.5wt%Si/Fe_73.5Cu₁Nb₃Si_13.5B₉ nanocrystalline composite magnetic powder core was successfully prepared with Fe_73.5Cu₁Nb₃Si_13.5B₉ nanocrystalline powder and Fe-6.5wt%Si powder.With the increase of the compound amount of Fe-6.5wt%Si powder,the density of the composite magnetic powder core increases to 6.01 g/cm³and the magnetic permeability increases to 38.25.When Fe-6.5wt%Si powder composition increased from 60%to 80%,the loss increases from 948m W/cm³ to1894mW/cm³（B=50mT,f=200kHz）.Therefore,the best compounding amount of Fe-6.5wt%Si powder should be controlled within 0-60%.3.Fe-6.5wt%Si/Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous composite magnetic powder core was prepared with Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous powder and Fe-6.5wt%Si powder.With the increasing content of Fe-6.5wt%Si powder,the density and magnetic permeability of the composite magnetic powder core increases,when Fe-6.5wt%Si powder content rise to 80%from 60%,sharply reduce loss by 1620 m W/cm³ to 563mW/cm³（f=200kHZ,B=50m T）.When Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous powder content is 30%,the content of the silicon resin REN is 3%,the pressure is 1000MPa,and the magnetic permeability is up to 43.03.