Preparation And Soft Magnetic Properties Of FeSiBPCu Alloy Powder

With the development of miniaturization,lightweight and high-frequency electronic information technology of electronic equipment,the higher requirements for DC superposition characteristics of magnetic powder cores were put forward.Improving the saturation magnetization?M_S?value of alloy powder was an effective way to improve the DC superposition characteristics of magnetic powder cores and Snoke limit of alloy powder.In this paper,the starting point is to increase the M_S value of alloy powder.Firstly,the composition design and powder preparation technology of FeSiBPCu alloy powder were systematically studied.The FeSiBPCu magnetic powder core was prepared by moulding forming,and the soft magnetic properties were studied;Secondly,combined with the requirement of Ms value,the salt bath nitridation preparation process of FeN compound powder was systematically studied,and the flaky single phase?-Fe(SiBP_0.5Cu)₃N powder was successfully prepared.And the absorbing properties of FeSiBPCu and FeN alloy powders at0.3-8.5 GHz were also studied;Finally,GR/FeSiBP_0.5Cu composite powders were prepared by vibration ball milling process,and its absorbing properties were optimized.?1?In the aspect of the preparation of FeSiBPCu alloy powders,the combination technology of"Medium Frequency Melting+3D Printing+Vibration Ball Milling process"was developed,and the flaky FeSiBP_0.5Cu alloy powders,polygonal Fe_93.5Si₁B₂P₂Cu_1.5 alloy powders and Fe_90.5Si₁B₂P₅Cu_1.5 alloy powders were successfully prepared.When the P content in the alloy powder is 0.5wt%,the alloy phase structure is a single-phase solid solution??-Fe?P??,and the powder is pulverized into flaky powders by vibration;When the P content is more than 2.0wt%,the alloy is pulverized into polygonal powders by vibration;The FeSiBPCu alloy powder with P content of 0.5wt%has the highest saturation magnetization?Ms=148emu/g?,and the Ms of the alloy powder decreases as the P content increases.?2?In the aspect of the preparation and performance of magnetic powder core,the effect of P content on magnetic powder cores was studied.The FeSiBPCu magnetic powder core with P content of 0.5wt%shows the best soft magnetic properties.The magnetic core density can be increased by adjusting the ratio of A powder?100-200 mesh?and B powder?200-300 mesh?.The?=6.02g/cm³ is the“permeation enthalpy value”of the magnetic powder core.The FeSiBP0.5Cu magnetic powder core shows the best comprehensive soft magnetic properties after annealed by heat treatment at 450°C×60min when A/B powder is 5:5,and the content of coating agent is 2.0wt%.The effective magnetic permeability is 53,and the permeability retention of the magnetic powder core is 70%?50Oe?,44%?130Oe?under the external DC applied field,which is equivalent to that of Fe-Si-Ni the magnetic core at 100Oe.?3?In the aspect of powder nitriding,the single phase?-Fe(SiBP_0.5Cu)₃N powder was synthesized by using the salt bath nitriding reaction method with flaky FeSiBP_0.5Cu alloy powder as the iron source and non-toxic CO?NH₂?₂ as the nitrogen source.The optimal nitriding conditions for the preparation of the single-phase?-Fe(SiBP_0.5Cu)₃N powder is at 550?for 60 min.The saturation magnetization is as high as 126emu/g.The powder has good thermal stability and magnetic temperature characteristics.It has good temperature stability before the weight loss inflection point temperature of 486°C.When the temperature rises from300 K to 454 K,the saturation magnetization decreases by only about 10%,and the temperature continues to rise to 600 K,the saturation magnetization is still as high as nearly 90emu/g,which is obviously better than nanometer?-Fe₃N powder.?4?In the aspect of absorbing properties of powders,the effect of P content on the absorbing properties of FeSiBPCu alloy powders was studied.Among them,FeSiBPCu alloy powder with P content of 0.5wt%has the best absorbing properties.In the frequency range of 0.3-8.5 GHz,the dielectric constant??of the powders is16¹2,the magnetic permeability?'is 4¹,and the value of electromagnetic loss tan?is 1.0-1.2 in 6.0⁸.5 GHz band.In 6.0⁸.5 GHz,the interference thickness of the powders is about 2.5mm,which have strong interference absorption effect.After nitriding treatment at 500°C×60min,??of the FeSiBP_0.5Cu alloy powders is increased by 2.4 times,and the tan?value reaches 0.94¹.18 in 0.3⁸.5 GHz.?5??0.3¹.0wt%?GR/FeSiBP_0.5Cu composite powders were successfully prepared by high energy ball milling process.The addition of graphene increases??of the powders by 50%in 0.3¹ GHz band,and??of the powders by 50%in 0.3⁸.5GHz band.When the ball milling time is 24 hours,the composite powders with1.0wt%graphene content have the best absorbing properties,and in 0.3-8.5GHz,??is7.3-1.0,??is 182.4¹8.2,tan?m is 0.48-3.46,and the value of electromagnetic loss tan?is 5.28⁸.60,which show excellent wave absorbing performances.