Crystallization Mechanism Of Fe-based Amorphous Alloy Induced By Ion Bombardment And Its Effect On Magnetic Properties

Fe-based nanocrystalline alloys have been widely used due to their excellent soft magnetic properties.The regulation of the crystallization process of the amorphous alloys is the basis for the regulation of the microstructure and properties of the nanocrystalline materials.Thermal annealing is the most commonly used method for amorphous crystallization.The grain size and volume fraction are controlled by the crystallization temperature and the crystallization time to obtain a high magnetic permeability,but the relaxation frequency is low.Increasing the relaxation frequency becomes one of the important development directions of nano soft magnetic materials.In this paper,Fe-based amorphous alloys were treated by ion bombardment-induced crystallization,and the crystallization mechanism of Fe-based amorphous alloys induced by ion bombardment was discussed.The effect of ion bombardment on the structure and magnetic properties of nanomaterials was discussed.The crystallization mechanism of amorphous alloys under the action of ion bombardment was explored by the ion beam bombardment from different angles and the substrate temperature changes of amorphous alloy phase structure.As the ion bombardment angle increases,the stress component in the vertical direction increases,and the compressive stress also increases.The presence of compressive stress allows the critical nucleation energy to be reduced to promote crystallization of the amorphous alloy,resulting in an increase in the degree of crystallization.Substrate temperature also has a great influence on the crystallization of the amorphous alloy.When?=75,the sample on the self-heating stage produces a significant crystallization,while the sample on the water-cooled stage is still amorphous;when?=90°,the degree of crystallization of the sample on the self-heating stage was significantly stronger than that on the water-cooled stage,indicating that the thermal effect caused by ion bombardment is an important factor affecting the crystallization of the amorphous alloy.The study of crystallization of amorphous alloys by ion bombardment angle and substrate temperature shows that ion bombardment-induced crystallization of amorphous alloys is the result of both the interaction of stress and temperature caused by ion bombardment.The Fe₇₈Si₁₃B₉ amorphous alloy was bombarded with Ar ion beam at different angles??=45°,60°,75°,and 90°?.When??60°,the sample did not crystallize;when??75°,Crystallization occurred,ie,low-angle bombardment promoted the migration of atoms in the short range,and high-angle bombardment resulted in the crystallization of the amorphous alloy.Ion bombardment introduces magnetic anisotropy and influences the magnetic properties of the material.The effective magnetic anisotropy constant results from the approaching saturation law increases as the bombardment angle increases,and the introduced effective magnetic anisotropy decreases the magnetic permeability and increases relaxation frequency,to some extent,increase the frequency of use of the material.However when?=90°,the crystallized product is accompanied by a small amount of Fe-B phase in addition to the?-Fe?Si?phase,which results in a sharp drop in the soft magnetic properties of the material.Therefore,the ion bombardment method is applied to treat Fe₇₈Si₁₃B₉ amorphous alloys requires the selection of suitable bombardment parameters.In order to solve the problem of Fe-B phase,obtain nano soft magnetic materials with excellent soft magnetic properties,the Fe_73.5Si_13.5B₉Cu₁Nb₃ amorphous alloy was bombarded with Ar argon ion beams with different angles.The crystallized product is only?-Fe?Si?nanocrystallites,without Fe-B phase formation.This is due to the large temperature difference between the?-Fe?Si?and Fe-B phases in Fe_73.5Si_13.5B₉Cu₁Nb₃amorphous alloys.With the increase of the bombardment angle,the magnetic anisotropy of the sample deceases,and the decrease of the effective magnetic anisotropy will increase the magnetic permeability of the material.At the same time,the saturation magnetic induction intensity also increases to some extent,and the high-frequency magnetic properties of the material are not impaired.