Study On Fe-Based Amorphous Nanocrystalline Soft Magnetic Materials And Preparation Of Magnetic Source

Compared with traditional soft magnetic materials,Fe-based amorphous and nanocrystalline alloys have more excellent soft magnetic properties and are widely used in high-tech fields such as power,electronics,information,and energy.With the progress of the high-tech field,new demands for high frequency,miniature,integration,low cost,energy saving,and environmental protection have been proposed for soft magnetic materials.In order to meet these needs,this dissertation is to study the Fe-based amorphous alloys with high magnetization,and to improve the magnetic properties of commercial Fe-based amorphous and nanocrystalline alloys by simple heat treatment process,and to design and fabricate magnetic sources with commercial amorphous ribbons after heat treatment.X-ray diffraction,transmission electron microscope,scanning electron microscope,vibration sample magneto-meter,soft magnetic DC measuring device,Gauss meter,and other characterization methods were used to analyze and study the morphology,structure,properties and magnetic field distribution of the magnetic source.The specific research contents and conclusions are as follows:（1）Amorphous ribbons with excellent properties were successfully prepared at high Fe（≥84 at%）content,and among them,the Fe₈₆Si₂B₁₂2 amorphous ribbon prepared at 40 m/s spinning speed had the best properties,with coercivity of 6.3 A/m and saturation magnetization of 1.64 T.When the Fe content increased to 88,the amorphous forming ability was poor and amorphous ribbons could not be obtained.（2）Adding a small amount of Ni to replace Fe in Fe₈₄Si₄B₁₂2 amorphous ribbon could reduce its coercivity.When 2 at%of Ni was added,the saturation magnetization of Fe₈₂Ni₂Si₄B₁₂2 amorphous ribbon was basically unchanged,and the coercivity was decreased by 41%.（3）Commercial 1K101 ribbon had the best magnetic properties after heat treatment at420℃for 10 minutes.Its coercivity was 3.7 A/m,which was reduced by 40%,the relative magnetic permeability was decreased,and the saturation magnetization was 1.60 T,which was increased by 2%.The 1K107B ribbon had the best magnetic properties after heat treatment at 480℃for 10 minutes.Its coercivity was 1.5 A/m,which was reduced by 92%,and the saturation magnetization was 1.24 T,which was increased by 1%.（4）The 1K107B ribbon without heat treat and the ribbon which was annealed at 400℃for 10 minutes was amorphous.The ribbon annealed at 500℃for 10 minutes was nanocrystalline,and the grain size is 8-15 nm.（5）The annealing time required for the ribbon to achieve the best magnetic properties after heat treatment at different temperatures was different,and was related to the precipitation ofα-Fe phase.1K101 ribbon had the best magnetic properties when it was annealed at 400℃for 40 minutes and 420℃for 10 minutes,but it was worse at 500℃due to the crystallization of 1K101 ribbon.1K107B ribbon had the best magnetic properties when it was annealed at 400℃for 80 minutes,480℃and 500℃for 10 minutes.（6）The theoretical calculations show that the magnitude of the magnetic field generated by the small magnetic source coil at the core position is in good agreement with the measurement results,but not in agreement with larger medium-sized magnetic sources.The experimental data indicated that the magnetic field decayed rapidly in the direction of the Y-axis,and it was necessary to add a tip of the convergent magnetic line to the port.