Study On Preparation And Properties Of High Performance Fe-based Amorphous/nanocrystalline Soft Magnetic Alloys

Fe-based amorphous/nanocrystalline soft magnetic alloys have broad development prospects in high-tech fields such as power electronics and information technology due to their excellent soft magnetic properties such as high permeability,high saturation flux density,low coercivity and low high-frequency loss.However,in order to realize the development of electronic components to high frequency,miniaturization and chip,higher requirements are put forward for the performance of Fe-based amorphous/nanocrystalline materials.Therefore,since the 1980s,the development of Fe-based amorphous/nanocrystalline soft magnetic alloys with high glass-forming ability and excellent soft magnetic properties has gradually become the focus of the research of materials science at home and abroad.The effects of roller speeds on the glass-forming ability,thermal stability and soft magnetic properties of melt-spun Fe₈₄Si₂B_13–xCu₁P_x（x=0,1,2,3,4）alloy ribbons prepared by the single-roller melt spinning technology were investigated by X-ray diffraction（XRD）,differential scanning calorimeter（DSC）,transmission electron microscopy（TEM）,and vibrating sample magnetometer（VSM）measurements.Meanwhile,the effects of addition of Al and substitution of element P for element B on the structure and properties of the alloy were studied.The main results are as follows:（1）The results showed that the glass-forming ability of Fe₈₄Si₂B₁₁Cu₁P₂alloy ribbon is improved with the increase of the roller speed from 30m/s to 45m/s.When the speed reaches 40m/s,the amorphous structure is obtained,the two crystallization temperatures(T_x1and T_x2)of the alloy ribbon both increased,indicating that the thermal stability of the alloy increased with the increase of the roller speed.While maintaining high saturation flux density,the coercivity of the alloy decreased significantly with the increase of the speed.（2）The results showed that an appropriate amount of Al element replacement Fe can improve the glass-forming ability and thermal stability of Fe_84-xSi₂B₁₁Cu₁P₂Al_x（x=0,0.5,1.0,1.5,2.0）alloy ribbons,reduce the coercivity and improve the magnetic properties of the alloy without a significant decrease in the saturation flux density.The annealing temperature and holding time have a great influence on the structure and magnetic properties of Fe_84-xSi₂B₁₁Cu₁P₂Al_x（x=0,0.5,1.0,1.5,2.0）alloy ribbons.After the suitable annealing conditions,uniformα-Fe grain with a size of about 10nm can be obtained on the amorphous matrix,and the soft magnetic properties of the alloy are improved.（3）The results showed that the replacing B with P can improve the glass-forming ability of Fe₈₄Si₂B_13-xCu₁P_x（x=0,1,2,3,4）alloy.When x=2,the full amorphous structure can be obtained.All Fe₈₄Si₂B_13-xCu₁P_x（x=0,1,2,3,4）alloy show excellent soft magnetic properties,including high saturation flux density of 1.57-1.83T,and low coercivity of 5.83-13.25A/m.After annealing at 420℃and holding for 30min,tthe saturation flux density of Fe₈₄Si₂B₁₀Cu₁P₂and Fe₈₄Si₂B₉Cu₁P₃amorphous alloys increased significantly,from 1.57T and 1.60T to 1.85T and 1.84T respectively,but the coercivity did not improve significantly.