The Preparation And Magnetic Properties Of The Amorphous Nanocrystalline Alloy With Medium Magnetic Permeability

Amorphous nanocrystalline soft magnetic materials are widely used in the fields of electronic power,in order to obtain good resistance to DC bias performance,and to have constant magnetic permeability in the range of larger current（magnetic field）,and the cheap alloy materials with low energy consumption are the market development demand.Finemet alloy has low magnetocrystalline anisotropy and weak magnetostriction coefficient,so it has high magnetic permeability,therefore,it is used in many electronic fields.However,the large magnetic permeability makes the material easily saturated in a low magnetic field（current）environment,so there are use some defects.Permalloy as a soft magnetic alloy with linear hysteresis loop,its magnetic permeability is easy to control,therefore,it is reused in components such as current transformers.However,the utilization is limited,due to the high cost.While various series of soft magnetic alloys have their advantages,there are still many shortcomings,therefore,the development of a soft magnetic material with comprehensive application performance is alwaysacontent of scientific research.This article is to improve the FeSiBCuNb alloy properties by adding Ni and Co elements,and through micro-alloying to control the composition of the alloy system,the alloy has resistance to DC bias characteristics and excellent soft magnetic properties.FeSiBCuNbNi（FeSiBCuNbNi Co）alloy ribbons were prepared by the melt quench method,and the effects of Ni and Co addition on the amorphous formation,soft magnetic properties and hysteresis loop of alloy ribbons were investigated.（1）In the FeSiBCuNbNi alloy system,increasing the content of B and Ni improves the amorphous forming ability of the alloy,when the B content is higher than 10at.%,and 3 at.%≤Ni at.%≤10 at.%,the alloy will be effectively prepared a completely amorphous alloy,when Ni at.%≥15 at.%,the Fe Ni₃phase exists in the alloy ribbon.After the amorphous ribbon annealed,onlyα-Fe（Ni）phase in the grainsoccurs,and the grain size is about 20nm.In the FeSiBCuNbNi Co alloy system,the addition of Co improves the amorphous forming ability of the alloy,when the Co content is higher than 4at.%,the solid solution Fe Co will appear.And reducing the Si content will weaken the amorphous forming ability,when the Si content drops to 4at.%,Fe Ni₃ phase will precipitate in the alloy ribbon.After annealed,α-Fe（Ni）grains and Fe Ni₃ solid solution will occur in the ribbon.（2）The thermal stability of the alloy is affected by their composition.In the FeSiBCuNbNi alloy system,increasing B content can improve T_x1 of the alloy,and the crystallization peak temperature differenceΔTx decreases.but when the amount of Ni content is more than 10 at.%,the first crystallization temperature of the alloy begins to decline,and the increase of Ni causesΔTx to narrow.In the FeSiBCuNbNi Co alloy system,as the amount of Co content increases,the alloy crystallization temperature T_x1,T_x2continue to increase,andΔTx keeps increasing.When the Si content of the alloy system is reduced,the ribbon is crystallized.Si content leads T_x1to decrease and T_x2 to increase,ΔTx is also improved.（3）The soft magnetic properties of the alloy system are effectively improved due to the addition of Co and Ni elements.In the FeSiBCuNbNi alloy system,the addition of Ni causes the saturation magnetization（Ms）,effective permeability（μe）and coercive force（Hc）of the alloy system to be reduced,with Ni 10at.%the nanocrystalline core of alloy ribbon annealed at 490℃showμis about 2 to 3k,and ribbon with Hc is about 17.8 A/m.As B content increases,the Ms of the alloyincreases and Hc andμreduce.In the FeSiBCuNbNi Co alloy system,the of Co makes Ms effectively improved,andμreduces to a certain extent.At Co1.5at.%,Ms is about 178.8 emu/g.When the Si content is reduced,the Br andμof alloy are reduced,and at Si3at.%,the Br is about 0.18T,and alloy ribbonhasμabout 2k and Hc around 50 A/m.（4）For the hysteresis loop of FeSiBCuNbNi alloy,the increase of B content improves the hysteresis loop linearity,it has good linearity when B is 12at.%,the addition of Ni is beneficial to improve the linearity of the loop,when the amount of Ni content increases,the linearity is significantly improved,Ni10at.%alloy shows good DC bias resistance in the magnetic field of 0～500 A/m.In the FeSiBCuNbNi Co alloy,the content of Co has no effect on the hysteresis loop,while the Si content is reduced,the hysteresis loop of the magnetic core is linearly enhanced,at Si 3at.%,the hysteresis loop is linear in the 0～600 A/m magnetic field,the alloy resistance to DC bias is enhanced.（5）In the FeSiBCuNbNi Co alloy system,the toughness of the alloy decreases after crystallization of the ribbon.As Si content decrease the toughness of the ribbon increases,while ribbon Vickers hardness（Hv）decreases,the Si 3at.%crystallized ribbon shows a lower Hv about 565.5,and a good toughness.After stress annealed the FeSiBCuNbNi alloy,itsμis reduced,the hysteresis loop increases linearly,and the DC bias resistance is enhanced.