The Preparation And Soft Magnetic Properties Of FeNiSiBCuNb Amorphous Soft Magnetic Alloy

As a new type of structural and functional soft magnetic material,Fe Ni-based amorphous alloy has many excellent performances such as low coercivity（H_c）,high permeability（μ）and good frequency characteristics.It shows great development prospect in electronic power,energy and other applications.However,Fe Ni based alloys still have some problems such as weak amorphous forming ability and poor thermal stability,which need to be improved.Therefore,it is very important to develop and prepare Fe Ni based amorphous soft magnetic alloys with high amorphous forming ability,thermal stability and good soft magnetic properties.In this paper,(Fe_40-xCo_xNi₄₀Si_6.33B_12.66Cu₁)₉₇Nb₃（x=0,6,7,8,9）、(Fe₃₃Co₇Ni₄₀Si_6.33B_12.66Cu₁)₉₇Nb_3-xZr_x（x=0,1,2,3）amorphous alloys ribbons were obtained by using the melt-spinning mean.The microstructure,thermal stability and soft magnetic properties of amorphous ribbons were characterized by X-Ray Diffractometer（XRD）,Magneto-Optical Kerr Microscope（Moke）,Differential Scanning Calorimeter（DSC）,DC soft magnetic measuring instrument（B-H meter）and Vibrating Sample Magnetometer（VSM）.The effects of composition and annealing process on the structure and magnetic properties of the alloys were investigated and the non-isothermal crystallization kinetics were analyzed.The main research contents are as follows:（1）The prepared(Fe_40-xCo_xNi₄₀Si_6.33B_12.66Cu₁)₉₇Nb₃（x=0,6,7,8,9）alloy ribbons are amorphous.After the addition of Co element,the amorphous formation ability of alloy ribbons are improved.When x=7 at.%,the two-stage crystallization temperature rangeΔT_xis the highest,indicating the best thermal stability.(Fe₃₃Co₇Ni₄₀Si_6.33B_12.66Cu₁)₉₇Nb₃alloy annealed at 673 K for 10 min has the best soft magnetic properties,with lower coercivity H_cof 0.12 A/m and saturation magnetization M_sof 88.7 Am²/kg and the effective permeabilityμ_eof 13800 at 1 k Hz.There are many napping points in the magnetic domain of the melt-spun alloy when Co content is 7 at.%,and the domain becomes smoother after annealing,indicating that the napping effect basically disappears.At the same time,the minimum pinning field of this alloy is 20 A/m.The analysis of isothermal crystallization kinetics shows that the primary crystallization activation energy E_p1of the alloys is increased by adding the appropriate amount of Co element,which indicates that the thermal stability of the alloy is improved.When the Co content is 7 at.%,the thermal stability is the best.（2）The prepared(Fe₃₃Co₇Ni₄₀Si_6.33B_12.66Cu₁)₉₇Nb_3-xZr_x（x=0,1,2,3）alloy ribbons are amorphous.After the addition of Zr,the thermal stability is improved.(Fe₃₃Co₇Ni₄₀Si_6.33B_12.66Cu₁)₉₇Nb₃alloy annealed at 698 K for10 min has the best soft magnetic properties,with coercivity of 0.99 A/m and saturation magnetization of 91.4 Am²/kg and the maximum effective permeability of 15900 at 1 k Hz.The pinning effect of magnetic domains in this alloy is significantly weakened after annealing.The crystallization kinetics study shows that after the addition of Zr element,the primary crystallization activation energy E_p1increase from 372.3 k J/mol to 456.44k J/mol,effectively improving the thermal stability.