Effect Of Microalloying On Glass Forming Ability And Magnetic Properties Of FeSiBPCuC Alloys

Fe-based amorphous/nanocrystalline alloys are popular to the market because of the excellent soft magnetic properties and application prospects.However,due to the low Fe content,the Fe-based amorphous/nanocrystalline alloys in the market have a low saturation magnetization?M_s?.Hence,the amorphous/nanocrystalline alloys with high Fe content have been developed,while the increase of Fe content leads to the decline of the Glass Forming Abilities?GFA?.Due to the existence of the nucleation sites in quenched-alloys,the?-Fe grains nucleate and grow rapidly during the heat treament,which is not conducive to the excellent magnetic properties of the alloys.Also,there are a lot of problems need to be solved,such as the two-stage crystallization temperature range is too narrow,the ribbons are brittle after heat teament and so on.In this paper,the transition metal elements are added to the high-Fe content alloys by the method of microalloying.The heat treatment with different heating rate was used to obtain excellent magnetic properties.The ribbons were prepared by melt-spun equipment.The structure of the alloys were identified by X-ray Diffraction Analysis?XRD?.The characteristic temperatures of the alloys were measured by Differential Scanning Calorimeter?DSC?.The coercivity was measured by DC B-H loop tracer.The saturation magnetization of the samples were measured by Vibrating Sample Magnetometer?VSM?.The conclusions are as follows:?1?In the Fe_85.5-x5.5-x Si_0.5B_9.5+x.5+x P_3.5Cu_0.7C_0.3?x=0,1.0,2.0?alloys.A partially amorphous structure of Fe_845.5Si_0.5B_10.5P_3.5Cu_0.7C_0.3?x=1.0?and a completely amorphous structure of Fe_835.5Si_0.5B_11.5P_3.5Cu_0.7C_0.3?x=2.0?alloys were obtained by adjusting the Fe/B ratio.The increase of B content improves GFA of the alloys.?2?Ti,V,Cr,Zr,Nb,Mo are added to the Fe_83.5Si_0.5B_10.5P_3.5Cu_0.7C_0.3M₁?M=Ti,V,Cr,Zr,Nb,Mo?alloys.These alloys show a completely amorphous structure after added Ti,Nb,and Mo,while those alloys shows a partially-amorphous structure after added V,Cr,and Zr.?3?The addition of Ti,Nb and Mo increases the glass forming ability?GFA?of Fe_84.5-x4.5-x Si_0.5B_10.5P_3.5Cu_0.7C_0.3M_x?M=Ti,Nb,Mo,x=0,0.5,1.0,1.5,2.0?alloys,and increases the first initial crystalline temperature(T_x1)and the second initial crystalline temperature(T_x2),broadens the temperature range?T_x(T_x2-T_x1),and improves the thermal stability of amorphous alloys and reduces the coercivity of quenched alloys.?4?The saturation magnetization?Ms?of Fe84.5-x Si0.5B10.5P3.5Cu0.7C0.3Mx?M=Ti,Nb,Mo,x=0,0.5,1.0,1.5,2.0?alloys has been improved after annealing,and the optimal annealing temperature range is about 460°C-480°C.The addition of Ti,Nb and Mo is beneficial to reduce the coercivity of the alloys after annealing,the alloy added Nb exhibits the best magnetic properties.The details are summarized as follows:The alloy with the addition of Ti?x=2.0?after annealed at 480°C for 10 min shows a minimum coercivity H_c?27.9 A/m,M_s?173.9 emu/g.The alloy with the addition of Nb?x=2.0?after annealed at 460°C for 10 min s hows a minimum H_c?24.5 A/m,M_s?171.3 emu/g.The alloys with the addition of Mo?x=2.0?after annealed at 460°C for 10 min exhibits a minimum H_c?25.7 A/m,M_s?169.4 emu/g.?5?The high-rate annealing process is beneficial to reduce the coercivity of Fe_84.5-x4.5-x Si_0.5B_10.5P_3.5Cu_0.7C_0.3Nb_x?x=0,0.5,1.0,1.5,2.0?alloys.The addition of Nb is also beneficial to reduce the coercivity of the annealed alloys.The alloy annealed at 480°C for 5 min exhibits excellent comprehensive soft magnetic properties,H_c?6.4 A/m,M_s?168.3 emu/g.?6?The Fe_84.5-x4.5-x Si_0.5B_10.5P_3.5Cu_0.7C_0.3Nb_x?x=0,0.5,1.0,1.5,2.0?alloys have a lower coercivity after annealed by ultra-rapid annealing process.The alloy Fe_82.5Si_0.5B_10.5P_3.5Cu_0.7C_0.3Nb₂ annealed at 480°C for 1 min exhibits the best comprehensive soft magnetic properties,including H_c?3.7 A/m and M_s?170.4 emu/g.