Metglas® is an amorphopus metal, Amorphous metals do not have crystalline structure like other magnetic materials. All the atoms in an amorphous metal are randomly arranged, thus giving it a higher resistivity (about three times) value than that for crystalline counterparts. Amorphous alloys are prepared by cooling the melt at about million degrees per second. This fast cooling does not give the atoms enough time to rearrange into stable crystalline form. As a result one gets metastable amorphous structure. Because of the absence of crystalline structure amorphous alloys are magnetically soft (lower coercivity, lower core loss, higher permeability). High resistivity gives lower loss at higher frequencies. The losses are among the lowest of any known magnetic materials.
Nanocrystalline or Finemet® Nanocrystalline - The precursor of FINEMET® Nanocrystalline is amorphous ribbon (non-crystalline) obtained by rapid quenching at one million °C/second from the molten metal consisting of Fe, Si, B and small amounts of Cu and Nb. These crystallized alloys have grains which are extremely uniform and small, "about ten nanometers in size". Amorphous metals which contain certain alloy elements show superior soft magnetic properties through crystallization. It was commonly known that the characteristics of soft magnetic materials are "larger crystal grains yield better soft magnetic properties". Contrary to this common belief, soft magnetic material consisting of a small, "nano-order", crystal grains have excellent soft magnetic properties.
Products of soft magnetic cores made of Metglas® Amorphous Alloys:
Products of soft magnetic cores made of FINEMET® Nanocrystalline Alloys: