The Research Into The Preparation And Properties Of Amorphous And Nanocrystalline Magnetic Alloys

Soft magnetic materials are an important functional material with low coercivity and high magnetic permeability.With the rapid development of power,energy,communications and other fields,the demand for soft magnetic materials is increasing,and the requirements for high frequency,light weight,miniaturization,high performance,and energy saving are becoming higher and higher.Soft magnetic materials are increasingly difficult to meet demand.Iron-based amorphous alloy soft magnetic materials were studied under such a background.Iron-based amorphous alloy is a new type of soft magnetic material with a microstructure different from that of crystal.It has low coercive force(H_c),high saturation magnetic induction(B_s),high effective permeability(?_e),and high.Curie temperature(T_c),good mechanical properties and other characteristics.Compared with the traditional soft magnetic material silicon steel,the iron-based amorphous alloy has the advantages of large resistivity,small core loss,energy saving,and a magnetic core-based transformer with excellent performance,which can reduce the loss by 30%.After decades of research,iron-based amorphous alloy soft magnetic materials have made great progress,but the research and development of iron-based amorphous alloys are still in the initial stage,which has great potential,and there are some solutions.The problem.At present,the iron-based amorphous alloy which has been developed has a very limited amorphous forming ability and a small critical dimension,and thus is currently limited to application to an amorphous alloy ribbon.The small size not only affects the manufacturing process,but also reduces the filling factor of the core,increases the length of the exciting winding,and reduces the efficiency of the core.The saturation magnetic induction strength of iron-based amorphous alloys is also lower than that of conventional soft magnetic materials,and it is very urgent to increase the saturation magnetic induction.Solving the problem of brittleness after alloy annealing,improving the corrosion resistance of the alloy and further reducing the cost are all practical problems.It is of great significance to explore the inherent potential of iron-based amorphous alloys.In this study,according to the experimental phenomena,mechanism,experience,etc.,the alloy composition with excellent performance is designed.According to the composition,the alloy is accurately prepared with high-purity raw materials;then the alloy raw material is repeatedly smelted into an alloy ingot under high-purity argon atmosphere;In a high-purity argon atmosphere,the alloy is melted by a tape puller to form a thin strip.The strip is annealed under suitable conditions.X-ray diffraction analysis(XRD),differential scanning calorimetry(DSC),transmission electron microscopy(TEM),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),Vickers hardness(HV),magnetic Material properties tester(BH instrument)and other means to study the microstructure,thermal stability,soft magnetic properties,surface morphology and mechanical properties of the alloy.In this paper,we first studied the quaternary alloy Fe-B-Si-C and found an amorphous alloy with high saturation magnetic induction(more than 1.70 T),low coercivity and good toughness.Then,on the basis of the alloy Fe₈₂B₁₅Si₂C₁,the element substitution method is used to replace the iron with cobalt,which can significantly improve the saturation magnetic induction of the alloy Fe₈₂B₁₅Si₂C₁ and improve the corrosion resistance.On the basis of the alloy Fe₆₇Co₁₅B₁₅Si₂C₁,the chromium was replaced by chromium and niobium.It was found that chromium and niobium can significantly improve the thermal stability,mechanical properties and corrosion resistance of Fe₆₇Co₁₅B₁₅Si₂C₁ alloy.