Born in 1960s, amorphous soft magnetic alloy is one of greatest invention in modern history of soft magnetic technology. Amorphous alloy is composed of three elements (Fe, Si, B).It is made through the following processing flow, firstly smelt three kind of materials into alloy ingot, then melt into metal liquid, and spray to rotating copper roll with high speed, fastly cool in the speed of １０6 ℃/S, finally made into thin ribbon with 20-30um thick(see fig.1). Due to fast cooling rate, numerous atoms can not keep up queuing in order and finally form amorphous structure with long-range disorder and short –rang order like glass atomic structure. thus, also called metallic glass.
Ribbon casting process picture
Through adding Cu and Nb elements on basis of amorphous alloy, Fe-based nanocrystal material was invented by Japanese Yoshizawa in1988. From microstructure views, nanocrystalline alloy is classified as one of amorphous materials. But by annealing crystallization, nanocrystalline material forms into dual phase structure with amorphous and crystalline(see fig.4)Because the grain size is nanoscale, this alloy is called as nanocrystal or ultracrystal.
Amorphous and nanocrystalline alloys show outstanding soft magnetic characteristics including high saturation flux density ,high permeability ,low core loss , excellent high –frequency performance and temperature stability and so on .Through different annealing condition or magnetic field application including transverse and longitudinal, amorphous and nanocrystalline alloy can get different permeability characteristics and BH loop such as R-shape ,F-shape(flat loop) and Z-shape(square loop),further meet need of all kinds of inductive components including common mode choke ,normal mode choke,power transformers,current transformers, inductors in electric and electronics industry.