Formation And Properties Of（FeSiBPCu）_100-xM_x（M=Co,Mn And Ni）Nanocrystalline Alloys

Fe-based nanocrystalline alloy has been widely used in the fields of electricity and electronics due to its excellent soft magnetic properties,such as high saturation magnetic induction(Bs),low coercivity(Hc),high permeability(μe),etc.In addition,the dual energy-saving features of its manufacture procedure and application are also in line with our country’s development strategy of carbon peaking and carbon neutrality.The rencently developed NANOMET(FeSiBPCu)nanocrystalline alloys exhibits excellent soft magnetic properites.Especially,its saturation magnetic induction(greater than 1.80 T,close to silicon steel)is significantly higher than that of the currently widely used FINEMET(FeSiBCuNb)nanocrystalline soft magnetic alloy,and the cost is significantly reduced,leading to the great value and prospect in applications.However,its magnetic permeability is lower than that of FINEMET,which limits its high-frequency application.In addition,due to its high Fe-content and Nb-free composition feature,the alloy has harsh requirements on nanocrystallization conditions,restricting its practical industrial applications.In order to solve the above problems,novel(Fe83.Si4B8P4Cu0.7)100-xMx(M=Co,Mn and Ni)alloy system was designed based on the NANOMET(Fe83.3Si4B8P4Cu0.7)alloy,through addition of Co,Mn and Ni elements by means of overall substitution.The structure,magnetic properties,thermal stability and corrosion resistance of the designed alloy system were investigated systematically,and the appropriate addition amount of different elements was determined.The main research contents and achievement obtained in this paper are as follows:(1)Based on the formation theory of amorphous alloy and calculation results of the atomic mismatch degree(δ)and the mixing enthalpy ΔHmix,the addition content in(Fe83.3Si4B8P4Cu0.7)100-xMx(M=Co,Mn and Ni)alloy system was determined(x≤7)and the corresponding alloy ribbons were prepared.The structure,thermal stability and corrosion resistance of the quenched alloy strips were analyzed and studied.The results show that with the addition of alloying elements,the GFA of the alloy system is reduced,and the alloy exhibits a wide enough annealing temperature interval(>130℃).In addition,the addition of Co and Ni elements can effectively improve the corrosion resistance of the alloy in the quenched state.(2)The effects of different element additions on the crystallization behavior and magnetic properties of the as-prepared(Fe83.3Si4B8P4Cu0.7)100-xMx(M=Co,Mn and Ni)amorphous alloy ribbons were investigated.The results show that the addition of Co element can improve the Bs of the alloy effectively.The Co4 alloy has a high Bs of 1.79 T and a low coercivity of 7.849 A/m;the addition of Mn can broaden the optimal annealing temperature range of the alloy;an appropriate addition of Ni significantly refines the grain size of α-Fe,which can reduce Hc and increase,μe effectively.Ni2 alloy has a Bs of 1.66 T,Hc of 4.3 A/m and μe of 12032,respectively.(3)The effects of magnetic field annealing on the crystalline structure and magnetic properties of(Fe83.3Si4B8P4Cu0.7)100-xMx(M=Co and Mn)fast-quenched ribbons were further studied.The results show that nanocrystalization is suppressed when the alloy is annealed under a small external magnetic field,and the amorphous and magnetic structures of the alloy become more uniform with the increase in the magnetic field intensity.