Study On Controlling The Soft Magnetic Properties Of Amorphous Alloy Based On Crystallization Kinetics

Because of its excellent soft magnetic properties,amorphous alloys have been widely used in the field of power electronics and information.However,there are still problems in the actual production process such as thermodynamic properties,unstable magnetic properties,and large error ranges.Because the magnetic properties of amorphous alloy materials are extremely sensitive to annealing temperature,people mostly study the effects of heating rate,temperature,holding time and heat treatment atmosphere on the magnetic properties from the perspective of heat treatment process.From the perspective of composition The effects of magnetic metal content and metalloid elements on the magnetic properties are studied,but there are few studies on the adjustment of the soft magnetic properties of amorphous alloys based on crystallization kinetics.In this paper,the most widely used iron-based"1K107"and cobalt-based"1K201"typical components(Fe₇₁Si₁₆B₉Cu₁Nb₃,Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃)are selected as the research objects,and the two amorphous alloy ribbons are calculated by XRD,DSC,and Kissinger and Ozawa equations.Crystallization kinetics,according to the calculation results,formulate four heat treatments with temperature gradients for 300s,perform XRD and VSM magnetic properties of the heat-treated samples,and use the Scherer formula to calculate the size of the precipitated grains of the samples,and microscopically through TEM Characterization.The effect of crystallization kinetics on the soft magnetic properties of amorphous alloys is studied,which aims to provide a theoretical basis for the production process of amorphous nanocrystalline ribbons,and has certain reference value for the actual production of amorphous nanocrystalline.The same research method was used to study the Fe₇₆Si_9.6B_8.4P₆amorphous alloy,which is made from industrial raw materials and has better soft magnetic properties and is expected to achieve large-scale applications.The result shows:(1)The crystallization method of Fe₇₁Si₁₆B₉Cu₁Nb₃and Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous alloys is a multi-stage crystallization method,and the crystallization phase is not precipitated at the same time,and with the increase of the heating rate,the T_xand T_pof the two-stage crystallization reaction move to the high temperature direction,namely The crystallization process of the two amorphous alloys has obvious kinetic effects.In the second stage of crystallization,the crystallization reaction temperature T_xand T_pof the Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous ribbon is significantly lower than that of the Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous ribbon,which indicates that the reaction heat of the Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous alloy is lower than that of the Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous alloy,and it also indicates that the amorphous alloy Fe₇₁Si₁₆B₉Cu₁Nb₃The thermal stability of crystalline alloy is higher than Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous alloy.(2)Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous alloy and Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous alloy were calculated by Kissinger and Ozawa equations,respectively.The crystallization kinetics results are close and the change trend is the same.E_x1is greater than E_p1,indicating that the crystallinity during the first-stage crystallization reaction The nucleation process is more difficult than the crystal growth process,but the initial crystallization reaction temperature in the first-stage crystallization reaction is lower than the crystallization peak temperature.Therefore,in theory,heat treatment in this temperature range will help precipitate crystal grains.Smaller grains are easy to form nanocrystals.(3)According to the calculation of crystallization kinetics,select appropriate positions to formulate the heat treatment temperature mechanism in the first stage of each crystallization reaction interval.Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous alloy is heated at786 K and 801 K at the initial stage of the first crystallization The overall magnetic performance reaches the best when processed for 300 s.?-Fe(Si)grains with an average grain size of about 10-20 nm are precipitated in the amorphous ribbon sample,and the saturation magnetic induction intensity reaches 1.22?1.27 T.The force is as low as 5.3?7.2 A/m.(4)The setting and selection of the heat treatment temperature mechanism for Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous ribbon is consistent with that of Fe₇₁Si₁₆B₉Cu₁Nb₃amorphous ribbon.When the heat treatment temperature increases from T_x1-30K(760K)to T_end+5K(816 K),With the increase of the heat treatment temperature,the saturation magnetic induction of the Co₇₀Fe₁₀Si₉B₇Cu₁Nb₃amorphous ribbon increased from 0.69 T to 0.74 T.The coercive force reaches a minimum of 1.52 A/m at T_x1-30K(760 K)isothermal heat treatment for 300 s.(5)Fe₇₆Si_9.6B_8.4P₆amorphous alloy undergoes isothermal heat treatment at 815 K for 300 s,the coercivity of the strip is as low as 1.67 A/m,the saturation magnetic induction is as high as 1.53 T,and the overall soft magnetic performance is the best.