Amorphous magnetic material transcended the scope of traditional crystalline magnetic material and thus regarded as an important milestone in the progress of magnetic materials. Amorphous and nanocrystalline magnetic material greatly broaden the research, production, and application of magnetic materials. Amorphous and nanocrystalline soft magnetic material is also categorized as metal soft magnetic material from viewpoints of composition and development foundation.
Solid materials can be classified into crystal, amorphous and quasicrystal according to the atomic arrangement. Among them, amorphous materials own a well-defined short-range order, but no long-range order. Amorphous alloys do not have the grain structure and thus show isotropic on magnetic properties. In the meanwhile, amorphous structure does not involve dislocations and grain boundaries, hence exhibit high permeability and low coercivity. Besides, amorphous soft magnetic material possesses low electrical resistivity so that generate low eddy current loss in high frequency applications. Non-load loss of iron base amorphous strip is only a third to a quarter of traditional silicon steel. Therefore, it can significantly reduce losses in the electric power industry.
In 1988, Hitachi Metals developed the first nanocrystalline soft magnetic material by processing crystallization treatment to amorphous alloy, then named “FINEMET”. Such alloy combined high magnetic flux density of the iron base amorphous alloy and high magnetic permeability and low loss of cobalt base amorphous alloy. Additionally, it is a low-cost iron base material. The invention of nanocrystalline soft magnetic material is a new breakthrough in the development of soft magnetic material. The commonly used nanocrystalline soft magnetic material already includes Finemet, Nanoperm, Hitperm and Nanomet nowadays. Nanocrystalline soft magnetic material is capable of replace cobalt base amorphous alloy, permalloy and soft ferrites in high frequency power electronics and electronic information field.
