The advantage of iron-based nanocrystalline alloy

advantage

      In order to get the best inhibition effect of common-mode interference, common-mode inductor core must have high permeability, excellent frequency characteristic and so on. Once upon a time the vast majority of the ferrite as a common-mode inductor core material, it has good frequency characteristic and the advantage of low cost. Ferrite, however, also have some can't overcome weaknesses, such as low temperature characteristics and low saturated magnetic induction, by a certain limitation in application.

      In recent years, the emergence of iron-based nanocrystalline alloy added a good common-mode inductor core material. Iron-based nanocrystalline alloy manufacturing process is: first of all made with rapid solidification technique about 20-30 microns thickness of amorphous alloy thin belt, winding into the iron core after further processing after forming nanocrystals. 

      Compared with ferrite nanocrystalline alloy has some unique advantages:

      Iron-based nanocrystalline alloy Bs 1.2 T, ferrite is more than twice. As a common-mode inductor core, an important principle is the core cannot be magnetized to saturation, otherwise the inductance sharply lower. In practical application, there are a number of occasions the interference intensity bigger (high power frequency conversion motor, for example), if using ordinary as common-mode inductor, ferrite core is saturated, can't guarantee big strength under the interference of noise suppression effect. Due to the high saturation magnetic induction intensity of nanocrystalline alloy, its resistance to saturation characteristic is obviously better than the ferrite, makes nanocrystalline alloy, very suitable for the occasion of sustain strong interference current.

      Nanocrystalline alloy, the initial permeability of up to 100000, much higher than that of ferrite, thus made the common-mode inductance of nanocrystalline alloy under the low magnetic field with large impedance and insertion loss, has good inhibition to the weak interference. For this tiny leakage current of common mode filter is especially weak interference. In certain occasions, such as medical equipment, equipment, by capacitance (such as the human body) to cause leakage current, easy to form the common mode interference, and the device itself has very strict about this. The use of high permeability nanocrystalline alloy common-mode inductor may be the best choice. In addition, the high permeability of nanocrystalline alloy coil number of turns can be reduced, to reduce the parasitic capacitance distribution parameters, such as, will thus caused by distributed parameter on the insertion loss spectrum of formant frequency increase. At the same time, high permeability of nanocrystalline core making common-mode inductor has higher inductance and resistance value, or the equivalent inductance under the premise of reduce the volume of core.

Excellent temperature stability:

      Iron-based nanocrystalline alloy above the Curie temperature is as high as 570 oc. In the case of with large temperature fluctuations, the properties of nanocrystalline alloy significantly lower rate of ferrite, with excellent stability, and the change of performance is close to linear. Generally, nanocrystalline alloy in - 50 oc - 130 oc within the temperature range of main magnetic rate within 10%. Curie temperature of ferrite, by contrast, generally under 250 oc, magnetic can sometimes change rate above 100%, and is nonlinear, is not easy to compensation. The temperature stability of the nanocrystalline alloy in combination with the characteristic of the low loss characteristics, the designers to the device provides a loose condition. And figure 3 the temperature of saturated magnetic induction intensity for different material properties.

      Through different manufacturing processes, nanocrystalline core can get different frequency characteristics, cooperate with the appropriate number of turns of the coil can be different impedance characteristics, can satisfy the demands of different wave band filter, and the impedance values compared with ferrite. It should be noted that any filter cannot be expected to use a core material can achieve the whole frequency range of noise suppression, but should be according to the requirements of the filter filter band to choose different iron core material, size and number of turns. Compared with ferrite nanocrystalline alloy can be more flexibly by adjusting the process to get the required frequency characteristic.