Soft magnetic ferrite is Fe2O3 ferrous metallic oxides of main component, using the method of powder metallurgy production. Mn - zinc, Cu - zinc, Ni - zinc and other categories, including the output of Mn - zinc ferrite and dosage the biggest, Mn - zinc ferrite of low resistivity, 1 ~ 10 ohm/meter, typically below 100 KHZ frequency of use. Cu - zinc, resistivity of Ni - zinc ferrite is 102 ~ 104 ohm/meter, the 100 KHZ ~ 10 MHZ radio spectrum loss small, multi-purpose at radio antenna, radio frequency transformer coil.
Magnetic core shape variety, E, I, U, EC, ETD, square (RM, EP, PQ), cylindrical (PC, RS, DS) and circular, etc. Is very convenient in application. Due to scarce materials such as soft magnetic ferrite without the use of nickel also can get high permeability, powder metallurgy method and suitable for mass production, so the cost is low, and because of the sinter hardness is large, is not sensitive to stress, is very convenient in application. And permeability changing with the frequency characteristics of stability, below 150 KHZ basic remain unchanged. With the emergence of soft magnetic ferrite, magnetic powder core of production greatly reduced, many original use of magnetic powder core are replaced by soft magnetic ferrite. Ferrite manufacturers at home and abroad a lot, only in the United States in this Mn - zinc ferrite Magnetics company as an example to introduce its application. Is divided into three kinds of basic materials: electric credit basic materials, broadband and EMI materials, power type materials.
The characteristics of soft magnetic ferrite is: low saturation magnetic flux density, low permeability, low Curie temperature, the low loss at high frequency, low cost. Its drawbacks, the first three is low limit the scope of its use, now are trying to improve. After the two lower is its advantages, to the high frequency market, now is trying to expand.
Electricity credit ferrite magnetic permeability from 750 to 2300, with low dissipation factor, high quality factor Q, stable magnetic conductivity with temperature/time relationship, is the permeability decline the slowest one in the work, about every ten years by 3% ~ 4%. Widely used in high Q filter, tuned filter, load coil, impedance matching transformer, close to the sensor. Broadband ferrite is often said that the high permeability ferrite, magnetic permeability, 5000, 10000, 15000, respectively. The characteristic with low loss factor, high permeability, high impedance/frequency characteristics. Widely used in the saturated inductor, current transformer, common mode filter, leakage protector, insulation transformer, signal and pulse transformer, multi-purpose in broadband transformer and EMI. Power of ferrite with high saturation magnetic induction intensity for 4000 ~ 5000 gs. In addition has the low loss/frequency and low loss/temperature relationship. That is to say, with the increase of frequency, loss increase is not big; Little change with temperature increase, loss. Widely used in power