Preparation And Properties Of Fe-based Amorphous Magnetic Powder Core

Magnetic powder core as one kind of functional materials with the role of storage and electromagnetic conversion,is widely used in transformers,inductors,filters,switching power supply and other electronic devices.As the electronic components develop gradually towards the direction of high precision,high sensitivity,large capacity and miniaturization,it requires the magnetic core with high saturation magnetization,high permeability,low core loss and other excellent performance.FeSiB amorphous magnetic powder core has high saturation magnetization,low core loss,good DC bias performance and good corrosion resistance,and has wide application prospect.But the permeability of FeSiB amorphous magnetic core is low,it can not meet the requirements of high precision and miniaturization of electronic products.In this thesis,the preparation processes of FeSiB amorphous magnetic powder core were optimized to improve the permeability of amorphous magnetic powder core.Then FeSiB/FeNi50 composite magnetic powder core was prepared by using FeNi50 powder with smaller particle size as filler material to enhance the permeability of amourphous magnetic powder core.In this thesis,the effects of coating agent type and content,compaction pressure and compaction method,annealing temperature on the density,permeability,core loss and quality factor of FeSiB amorphous magnetic powder were studied.Then,based on the research of FeSiB amorphous magnetic core,the influences of the particle size and content of the Permalloy,the content of the coating agent and the annealing method on the performance of FeSiB/FeNi50 composite magnetic core were researched.Through gradual optimization of the preparation process of FeSiB amorphous magnetic powder core,the best process conditions for FeSiB amorphous magnetic powder core were including using 4wt.% DC805 as coating agent,compaction pressure of 1400 MPa and annealling at 400℃ for 1h.The permeability of FeSiB amorphous magnetic core were 32.63,magnetic core loss reduced to 70.53W/kg.Based on the studying of the preparation process of FeSiB amorphous magnetic powder core,FeSiB/FeNi50 composite magnetic powder core was prepared by using DC805 as coating agent,pressing pressure of 1400 MPa and annealing temperature of 400℃.After adding the Permalloy powder,the saturated magnetization of the mixed powder is as high as 1.493 T.Compared with the saturated magnetization of FeSiB amorphous powder,the saturated magnetization of the mixed powder was increased by 60.7%.When the content of Permalloy is 10 wt.%,The saturated magnetization of mixed powder is the highest.The magnetic properties of the composite magnetic core containing the-800 mesh Permalloy powder are better than those composite magnetic core with-200~+400 mesh and-600~+800 mesh Permalloy.At this point,the permeability of composite magnetic core is 38.02,core loss is 40.69W/kg,quality factor Q is up to 110.6.Compared with the best performance of FeSiB amorphous magnetic core,the permeability of composite magnetic core is increased by nearly 20%,and the core loss is approximately reduced by 42%,and the quality factor of composite magnetic core is high.When the content of-800 mesh Permalloy is 15 wt.%,the permeability of composite magnetic core is the highest,which is 43.5.Compared with the magnetic permeability of FeSiB amorphous magnetic core,the magnetic permeability of composite magnetic core is increased by 33.3%.For FeSiB/FeNi50 composite magnetic powder core,a suitable coating agent content is 3wt.%.At this time,the permeability of composite magnetic core can reach 46.27,which is 41.8% higher than that of FeSiB amorphous magnetic core.The core loss of composite magnetic powder core is 34.16W/kg,which is 51.6% lower than that of FeSiB amorphous magnetic core.The optimum process of preparing FeSiB/FeNi50 composite magnetic powder core are as follows: the content of-800 mesh Permalloy is 15 wt.%,the amount of coating agent is 3wt.%,the magnetic powder core is pressed at 1400 MPa and annealed under the condition of 400℃ for 1h,the heating rate of annealing is 10℃/min with the furnace cooled to room temperature.