Preparation And Magnetic Property Regulation Of FeSiBNbCuP Amorphous Nanocrystalline Soft Magnetic Alloy

In the context of“green,energy saving and emission reduction”and sustainable development strategy,with excellent performance(including high B_s,high?,low H_c,etc.)as a guarantee and significant energy-saving and environmental advantages,Fe-based amorphous nanocrystalline alloys have a very vast market in the electrical equipment manufacturing industry.FINEMET alloys have been industrially produced due to their low cost and excellent soft magnetic properties.However,due to the weak amorphous formation ability and poor thermal stability,it is difficult to meet the needs of high-temperature applications.Therefore,how to improve the comprehensive soft magnetic properties of Finemet alloys has became a hot and difficult research area.In this paper,by adding appropriate amount of P elements to replace B and Si elements on the basis of Fe Si Nb Cu B system and combining with the heat treatment process,we obtained the Fe Si Nb Cu BP system nanocrystalline soft magnetic alloy with good comprehensive soft magnetic properties.The correlation between alloy composition,heat treatment process,microstructure and magnetic properties was investigated by using X-ray diffractometer(XRD),differential scanning calorimeter(DSC),vibrating sample magnetometer(VSM),B-H meter,transmission electron microscope(TEM)and other testing methods to reveal the mechanism of magnetic property evolution and provide innovative theoretical basis for the development of Fe-based amorphous nanocrystalline soft magnetic alloys.The main results achieved are as follows:1.In Fe_73.5Si_13.5Nb₃Cu₁B_9-xP_x(x=0,3,6,9)alloys,the obtained ribbons are completely amorphous when the P content is within 6 at.%.The moderate addition of P effectively inhibits the growth of?-Fe(Si)grains during annealing,resulting in finer nanograins and lower coercivity of 0.25 A/m or less.The best soft magnetic properties were obtained for Fe_73.5Si_13.5Nb₃Cu₁B₆P₃ alloy annealed at500-550°C with an optimum coercivity of 0.21-0.32 A/m,a saturation magnetization of 1.07-1.11 T,and an effective permeability of about 2.35×10⁴ at1 k Hz.Also,the alloy still has a permeability higher than x=0 at a high frequency of 100 k Hz,indicating that the alloy has a good frequency stability.2.In the Fe_73.5Si_13.5-xNb₃Cu₁B₉P_x(x=0,3.5,7,10)alloys,firstly,all four alloys are completely amorphous in the quenched state.Secondly,the increase of P content also reduces the amorphous thermal stability of the alloys.At the same time,the P element replaces part of the Si to make the?-Fe(Si)grains of the nanocrystalline alloy finer,which reduces the coercivity of the alloy.The best soft magnetic properties were obtained after annealing at 500-525°C with a P content of 3.5at.%,with an optimum coercivity of 0.02-0.04 A/m and a saturation magnetization of 1.14-1.19 T.The optimum permeability at 1 k Hz was obtained for this alloy after annealing at 525°C for 1 min,with a specific value of 3.22×10⁴,which is higher than the optimum permeability of Fe_73.5Si_13.5Nb₃Cu₁B₆P₃ alloy.