Introduction to soft magnetic ferrites for magnetic materials
Soft magnetic ferrite is a ferrous magnetic oxide with the main identity of Fe2O3, consumed by powder metallurgy. There are several types of mn-zn, cu-zn, ni-zn, etc., among which mn-zn ferrite has the largest production and consumption. The resistivity of mn-zn ferrite is low, ranging from 1 to 10 ohmm-m. The resistivity of cu-zn and ni-zn ferrite is 102 ~ 104 ohmm-m, and the consumption of radio frequency band from 100kHz ~ 10 MHZ is small, which is mostly used in radio antenna coils and radio intermediate frequency transformers. Magnetic core shape variety rich thick, E, I, U, EC, ETD shape, square (RM, EP, PQ), tank shape (PC, RS, DS) and round. It's easy to use. Because soft magnetic ferrite does not use rare materials such as nickel can also lose high permeability, powder metallurgy method is suitable for mass consumption, so the cost is low, and because it is sintering material hardness, stress insensitive, very convenient in use. Moreover, the permeability is stable with frequency variation, and the basic connection is stable below 150kHz. With the appearance of soft ferrite, the consumption of magnetic powder core has been greatly eliminated, and many of the centers of the original magnetic powder core have been replaced by soft ferrite. There are many domestic and external ferrite consumption manufacturers, here only in the United States Magnetics consumption of mn-zn ferrite as an example to introduce its use. It is divided into three basic materials: electrical reputation basic materials, broadband and EMI materials, power materials.
The magnetic permeability of the electroreputation ferrite ranges from 750 to 2300, with a low consumption factor, high quality factor Q, and stable permeability with temperature/time relationship, which is the slowest decline of the magnetic permeability in the work, with a decline of about 3% ~ 4% every 10 years. Perval is used in high Q filters, tuned filters, load coils, impedance chamber transformers, proximity sensors. Broadband ferrite is often referred to as high permeability ferrite, permeability discrimination of 5000, 10000, 15000. Its characteristics are low consumption factor, high permeability, high impedance/frequency characteristics. It is widely used in common - mode filters, saturation inductors, current transformers, discharge protectors, insulating transformers, signal and pulse transformers. The power ferrite has a high saturation magnetic induction intensity of 4000 ~ 5000Gs. Others have a low consumption/frequency relationship and a low consumption/temperature relationship. That is to say, with the increase of frequency, consumption does not rise much; With the increase of temperature, consumption changes little. Pervasive for power chokes, parallel filters, switching power transformers, switching power inductors, power factor correction circuits.