Soft Magnetic Properties Of Fe-based Amorphous Alloys Developed By Alloy Steel And Magnetic Powder Cores

The Fe-based amorphous soft magnetic alloys have a broad application prospect as a new soft magnetic material due to high saturation magnetic induction（Bs）and permeability（μe）and low coercivity（Hc）.At present,due to excess steel overcapacity,in the background of accelerating the development of new materials in China,this paper developed a new type Fe-based amorphous soft magnetic alloy based on the component characteristic of medium alloy steel,and investigated the influence of three alloy elements Ni,Cr and Co on the soft magnetic properties of amorphous alloy.On this basis,amorphous powders were fabricated by new amorphous strips with excellent soft magnetic properties and novel amorphous powder cores were preparated to broaden the application field.This paper focuses on the following aspects of the research work:（1）New amorphous alloy is developed by alloy steel,and the soft magnetic properties of amorphous alloy are investigated.On the basis of the composition of alloy steel Fe_92.27Si_1.43C_0.14Mn_0.58P_0.15Cu_0.03Mo_0.01Ni_1.51Cr_3.75Co_0.13（at%,named as S0）,based on the widely used Fe-based amorphous alloy Fe₈₀Si₉B₁₁,the alloy elements were adjusted by adding Fe,Si,B and other elements and quenched amorphous alloy ribbon Fe_75.1Si_8.9Cu_0.03Mo_0.01Mn_0.47B_10.87C_0.11P_0.12Ni_1.23Cr_3.05Co_0.11（at%,named as S1）was fabricated by using melt spinning method.The microstructure,thermal stability,magnetic properties（Bs,μe and Hc）,and so on,of the amorphous ribbons were tested by XRD,DSC,VSM,DC B-H hysteresis loop and impedance analyzer,respectively.The results show that Bs=1.45 T,μe=22846.96（f=1 kHz）and Hc=1.033 A/m of the amorphous ribbon S1.（2）The effects of main alloy elements Ni,Cr and Co on the microstructure,amorphous formation ability,thermal stability and soft magnetic properties of the amorphous alloy Fe_75.1Si_8.9Cu_0.03Mo_0.01Mn0.47B10.87C_0.11P_0.12Ni_1.23Cr_3.05Co_0.11（at%,named as S1）were investigated and two new amorphous alloys were obtained.The seven new alloy components were designed by adjusting the composition of Ni,Cr and Co alloy elements.Seven kinds of alloy ribbons with good apparent quality were prepared by melt quenching method which contained two kinds of amorphous alloys Fe_78.55Si_9.31Cu_0.02Mo_0.01Mn_0.49B_11.37C_0.12P_0.13（at%,named as E1）and Fe_78.46Si_9.3Cu_0.02 Mo_0.01Mn_0.49B_11.36C_0.12P_0.13Co_0.11（at%,named as E4）with excellent soft magnetic properties,and the other alloy ribbons（named as E2,E3,E5,E6 and E7,respectively）occured crystallization to some extent.The results show that not only the amorphous formation ability of alloys are affected,but also the Bs and μe of amorphous alloys are affected by the addition of Ni,Cr and Co elements alone or simultaneously.In addition,the Bs,μe and Hc of E1 are 1.62 T,6403.59（f=1 kHz）and 0.053 A/m and the Bs,μe and Hc of E4 are 1.67 T,8351.66（f=1 kHz）and 0.04 A/m,respectively.（3）Amorphous powders were prepared by excellent soft magnetic properties of Fe_78.46Si_9.3Cu_0.02Mo_0.01Mn0.49B11.36C0.12P_0.13Co_0.11（at%,named as E4）amorphous alloy as raw materials and new amorphous powder cores were prepared.On the basis of the results of（2）,completely amorphous state magnetic powders were prepared by mechanical milling in air with E4 amorphous alloy ribbon as raw materials after stress relief annealing embrittlement treatment in vacuum.Amorphous powder cores were prepared when the amorphous powders were passivated,insulated,bonded and cold pressed.The results show that the μe of amorphous powder cores reach about 12.7（f=1 kHz）and Bs are more than 1.0 T,and amorphous powder cores have excellent DC bias properties.when f=100 kHz and DC bias field strength reaches 120 Oe,their effective permeability are still above 90%,and remain stable in the range of 10 MHz even wider frequency.The innovation of this paper is that amorphous alloys with excellent soft magnetic properties have been developed by medium alloy steel firstly and soft magnetic powders with completely amorphous phase were prepared under atmospheric conditions,and that has important practical significance.