Nanocrystalline and Amorphous
The inductive cores with nanocrystalline and amorphous basis were developed to fulfil the demands of special frequency, performance and dimensions. Tommy Invest delivers, develops and produces standard and specific inductive cores. Tommy Invest tests each of its cores and inductive products separately with a guarantee of its quality. Our products meet the requirements of DIN and ASA.
As electronics devices work at higher and higher frequencies and temperatures new materials for passive elements are necessary. Particularly, for inductive elements the only suitable materials satisfying these demands are the magnetic nanocomposites. The metal-metal type nanocomposites work up to 10 MHz and the metal-insulator type nanocomposites can be used up to the ferromagnetic resonance limit (several GHz).
At the moment our company offers nanocrysalline cores prepared from metal-metal type nanocomposites. These are actually nanocrystalline alloys obtained by suitable heat treatment from an amorphous precursor ribbon prepared by rapid quenching from the melt. We are able to prepare precursor ribbons having a width corresponding to the particular application in the range of 4-20 mm.. Wider cores can be produced by attaching the thinner cores to each other.
Heat treatments in a magnetic field can tailor the permeability to a range between 25 000 and 90 000 whereas by heat treatments under mechanical stress the permeability can be suppressed down to 200 including the permeability region between 200-1000 where powder cores are not available. These latter cores are particularly suitable for switch mode power supplies working in fly-back mode.
The frequency limit (corresponding to the maximum of the imaginary part of the permeability) ranges from 10 MHz (permeability of several 100) to 20 kHz (permeability of 100 000) and the relative permeability can be changed between 200 and 100 000 by the use of several heat treatments in magnetic fields or under mechanic pressure. It is important to emphasize that we can vary the permeability and hence the frequency limit keeping the coercivity below 5 A/m.
We are able to tailor the size of the EMC cores between 4-300 grams with an outer diameter between 10-100 mm.
We can also produce one and three phase common mode chokes with superior characteristics compared to Mn-Zn ferrite chokes. These chokes are applied in inverters, air conditioners, welding equipment, personal computers, medical and networking equipment, etc.
We also produce magnetic bead cores in small sizes and low permeability for surge voltage and current absorbers in switching circuits.