Soft ferrite is a ferromagnetic oxide with Fe2O3 as the main component, which is produced by powder metallurgy method. There are several categories such as MN-ZN, CU-ZN, NI-ZN, etc., among which the output and dosage of mn-zn ferrite is the largest, the resistivity of mn-zn ferrite is low, 1 10 ohm-m, generally used in frequencies below 100kHz, the resistivity of Cu-zn, Ni-zn ferrite is 102 104 ohm-m, and the loss in the radio frequency band of 100kHz 10 MHz is small, and it is mostly used in radio antenna coils and radio intermediate frequency transformers.
Due toMagnetic ringsHigh permeability can also be obtained without using scarce materials such as nickel, and the powder metallurgy method is suitable for mass production, so the cost is low, and because it is a sinter with high hardness, it is insensitive to stress, it is very convenient in application, and the permeability changes with frequency The characteristics are stable, basically unchanged below 150kHz, with the emergence of soft ferrite, the production of magnetic powder cores has been greatly reduced, and many places where magnetic powder cores were originally used have been replaced by soft ferrite.
There are many ferrite manufacturers at home and abroad, here only to the United States Magnetics production of MN-ZN ferrite as an example to introduce its application status, divided into three categories of basic materials: basic materials for telecommunications, broadband and EMI materials, power materials, the permeability of telecommunications ferrite from 750 2300, with low loss factor, high quality factor Q, stable permeability with temperature Time relationship, is the slowest decline in permeability in the work, about 3% per decade 4%, It is widely used in high-q filters, tuned filters, load coils, impedance matching transformers, and proximity sensors.
Broadband ferrite is often referred to as high permeability ferrite, and the permeability is respectivelyMagnetic ringsIt has the characteristics of low loss factor, high permeability and high impedance frequency. It is widely used in common mode filters, saturation inductors, current transformers, leakage protectors, insulation transformers, signal and pulse transformers, and is widely used in broadband transformers and EMI.
Magnetic ringsRate ferrite has a high saturation magnetic induction intensity, which is 4000 5000 gs, and has a low-loss frequency relationship and a low-loss temperature relationship, that is, with the increase of frequency, the loss does not increase much; With the increase of temperature, the loss does not change much, and it is widely used in power chokes, parallel filters, switching power supply transformers, switching power supply inductors, and power factor correction circuits.