Preparation And Surface Treatment Of Iron-based Amorphous Nanocrystalline Materials

Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips can be widely used in the field of switching power supplies because of their excellent soft magnetic properties.When packing Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips with epoxy resin,expoy resin may have infiltration problem which limiting the application of nanocrystalline strips.In this paper,First,the vacuum melting process and single-roller spary process of Fe73.5Cu1Nb3Si13.5B9amorphous strips are systematically studied; Second, the relationship between the heat treatment process and the soft-magnetic properties of the amorphous strips are studied;Last, the surface treatment process such as surface oxidation surface phosphide or nickel plating method of Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips are emphasis studied.By the method of surface treatmet, a transition film betweent the matrix and epoxy resin can be formed to solve the epoxy resin serious infiltration problem.The results show that Fe73.5Cu1Nb3Si13.5B9amorphous strips with width1mm-60mm、thickness22～35μm、density7.18-7.25g/cm3、resistivity130μΩ· cm-140μ Ω· cm curie temperature530℃-570℃can be attained when the second melting temperature of master alloy is1380℃～1450℃, nozzle slit length and width separately1mm～60mm and0.7～1.lmm,copper roller speed25-30m/s,copper roller finish smooth. When the heat treatment process of Fe73.5Cu1Nb3Si13.5B9amorphous strips is550℃×120min, Fe73.5Cu1Nb3Si13.5B9amorphous strips become nanocrystalline strips,the soft-magntic properties of which are the best, such as μi=112,000、Bs=1.21T、Hc=0.76A/m.When Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips are surface treatment by the method surface phosphide and nickel plating,a silvery white Ni-P film and a brown phosphate film can separetaly form,but the binding between the matrix and the films are weak. When the nanocrystalline strips are surface treatment by the method of surface oxidation, a solid reddish brown Fe2O3slagging in back Fe3O4oxidation film can be attained.Comparison to Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips without surface treatmenr, u i and Bs of nanocrystalline strips after surface oxidation are icreased by14.6%、4.3%, He reduced by21.6%.Forming a solid oxidation film at the surface of Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips can not only improve soft-magntic properties of the strips,but also can be as a transition film between the epoxy resin and Fe73.5Cu1Nb3Si13.5B9nanocrystalline strips,which can effectively solve expoy resin serious infiltration problem.