Nanocrystallization Of Fe-Base Amorphous Soft Magnetic Alloy By Laser Irradiation

Fe-based nanocrystallized alloy Fe_73.5Cu₁Nb₃Si_13.5B₉ (FINEMET) reveals excellent soft magnetic properties, like low coercivity, low high frequency losses, high saturation flux density, high initial permeability, good thermal stability and low cost, it has been widely applied to magnetic components in electrical and electronic fields. However, in traditional annealing, it needs long time, high energy consumption, and fraction defective is high if temperature is not accurate. Laser is with high energy, and laser processing is short-time, efficient, precise and automatic. So nanocrystallization of Fe-based amorphous alloys by laser irradiation is an important scientific problem with potential value in practical application.In this paper, nanocrystallization of Fe-based amorphous alloys is realized by continuous CO₂ laser and Yb-doped fiber laser rotational irradiation respectively. The samples are amorphous rings with internal diameter of 14 mm and external diameter of 20 mm. XRD and TEM are used for microstructure observation and analysis, the results show that by selecting proper laser irradiation power and time, nano-particles with random texture appear in the amorphous matrix, the diameter is about 10 nm, and the crystallized phase isα-Fe(Si) with bcc structure after laser irradiation. At the same time, Results of VSM and dc closed circuit test confirm that the Fe-based nanocrystallized alloys have very low coercivity and high permeability, and magnetization process is almost reversible. Therefore laser irradiation is an effective and feasible method for production of Fe-based nanocrystallized alloys.