Why are we focusing on amorphous and Nanocrystalline core for our audio output transformers and chokes? Below materials from our iron supplier will paint you a picture of why it is a better material compared to ordinary Fe alloy cores.
Fe based amorphous alloy core- Fe based amorphous alloy core is made of 80% Fe, 19% Si and some other minor compound. It has high magnetic flux saturation density value (1.54T). The permeability, excitation current, iron core loss and other magnetic properties are better than just normal SiFe core, especially the iron core loss (about 1/3 or 1/5 of grain oriented SiFe). It is used in distribution transformers, high power switching power supplies, pulse transformers, magnetic amplifiers, IF transformer and inverters largely, being suitable for 16kHz and below switching frequency.
Fe based nanocrystalline alloy core- Fe based nanocrystalline alloy core is mainly consisted of Fe, with small quantity of Nb, Cu, Si and B. It is formed by a post processed rapid solidification process, as a amorphous form. These amorphous materials, after processed, can attain a crystalline form of about 10-20nm crystals, scattered all over the amorphous base, and named as nanocrystalline materials.
- Nanocrystalline core has excellent magnetic properties: high magnetic flux saturation density value (1.2T), high initial permeability (8x10^4), low Hc(0.32A/M), low high frequency loss at high magnetic induction value (P at 0.5T, 20kHz = 30W/kg), with resistivity at 80uOhm/cm, much higher than Permalloy(50-60uOhm/cm), by longitudinal or transverse magnetization, can get high Br (0.9) or low Br (1000Gs). It is, as of now, the best compound materials, especially suitable for frequency range from 50Hz - 100kHz, the best being 20kHz - 50kHz. It is mostly used in high power switching power supply, inverters, magnetic amplifiers, high frequency transformers, high frequency converters, high frequency inductors, current transformers, leakage protection switch, common mode chokes.
J&K Audio Design