Study On Preparation And Magnetic Properties Of Fe-rich Fe-B-Cu-(Al) Amorphous Nanocrystalline Alloys

The Fe-rich amorphous/nanocrystalline soft magnetic material is a new type of soft magnetic material that has received widespread attention in recent years.Compared with traditional Fe-based soft magnetic materials,it not only has the advantages of low coercive force,high initial permeability,low loss,etc.,but also has higher saturation magnetic induction intensity,so it has broad application prospects.However,due to the high Fe content of the alloy（>83%）,the amorphous forming ability of the alloy is poor.In addition,some alloys also added precious elements（such as:Nb,Zr,Co,etc.）,which improves the cost of the alloy.Therefore,it is of great scientific significance and engineering application value to develop high-performance amorphous magnetic materials with excellent amorphous forming ability and low cost.In this paper,Fe-rich Fe BCu and Fe BCu Al systerm alloys were prepared through single-roll rapid quenching method,by adjusting the composition of Fe-Si-B-P-Cu alloy.X-ray diffractometer（XRD）,differential Scanning Calorimeter（DSC）,transmission electron microscope（TEM）,vibrating sample magnetometer（VSM）,DC soft magnetometers and other devices were employed to stduy the effects of different alloy compositions and different heat treatment processes on the structure and properties of materials.The main research results and conclusions of the paper are as follows:（1）In Fe₈₅Si_xB₈P_6-xCu₁（x=0,1,2,3）alloys,reducing the Si/P ratio of the alloy,adding an appropriate amount of Al and increasing the speed of the copper roller all reduce the degree of crystallization of the alloys,indicating these three methods can improve the amorphous forming ability of the alloys.Both Fe_83.5B_15.5Cu₁ and Fe_83.5B₁₅Cu_1.5 alloys have good amorphous forming ability.Compared with Fe_83.5B_15.5Cu₁ alloy,Fe_83.5B₁₅Cu_1.5 alloy has a wider crystallization temperature interval,so it is beneficial to the preparation of amorphous nanocrystalline alloys.（2）In Fe_83.5+xB_15-xCu_1.5（x=0,0.5,1,1.5,2）alloys,as the Fe content increases,the amorphous forming ability and thermal stability of the alloy decrease,and the crystallization temperature range becomes larger.In Fe₈₅B_13.5Cu_1.5 alloy,as the heat treatment temperature increases,the degree of crystallization of the alloy becomes larger,and the saturation magnetic induction intensity（B_s）shows a trend of first increasing and then decreasing,and the coercive force（H_c）shows a trend of first increasing,then decreasing,and then increasing sharply.When the heat treatment process is 430°C×10 min,theof Fe₈₅B_13.5Cu_1.5alloy reaches a maximum value of 2.02 T,andis 35 A/m.The effective composition range of Fe₈₅B_13.5Cu_1.5 alloy is Fe_{84.9≤x≤85}B_98.5-xCu_1.5.The alloy with this composition has good amorphous forming ability,when annealed at 430℃for 10 min,it can obtain excellent soft magnetic properties:B_s≈2.0 T,H_c≈35 A/m.（3）In Fe₈₅B_13.5-xCu_1.5Al_x（x=0,0.4,0.6,0.8,1.0）alloys,as the Al content increases,the amorphous forming ability of the alloys decreases,the thermal stability first increases and then decreases,and the crystallization temperature range first decreases and then increases.Among them,the preferred composition Fe₈₅B_13.1Cu_1.5Al_0.4 alloy has the best quenched magnetic properties:B_s=1.63 T,H_c=3.7 A/m.In Fe₈₅B_13.1Cu_1.5Al_0.4 alloy,as the heat treatment temperature（above the crystallization temperature）increases,the degree of crystallization of the alloy continues to increase,B_s shows a trend of first increasing and then unchanged,and H_c shows a trend of first increasing,then decreasing,and then increasing.When the heat treatment process is 430℃×10 min,Fe₈₅B_13.1Cu_1.5Al_0.4 alloy obtained the best magnetic properties:B_s=1.95 T,H_c=17.4 A/m.