Introduction to the characteristics of nanocrystalline magnetic cores -

The introduction of the characteristics of the nanocrystalline magnetic core On the one hand, it can isolate the eddy current, and the data is suitable for higher frequencies; on the other hand, due to the gap effect between the particles, the data has low and constant permeability; due to the small particle size, there is basically no crust Phenomenon, the change of permeability with frequency is relatively stable; in addition, the powder core can be made into special-shaped parts of various shapes, which are used in different fields; finally, the industrial damaged strip is crushed into magnetic powder, and then made into magnetic powder core, which can reduce loss , improve the use value of data. The magnetic and electrical properties of the magnetic powder core mainly depend on the magnetic permeability of the powder material, the size and shape of the powder, the filling factor, the content of the insulating medium, the molding pressure and the heat treatment process. In the future, soft magnetic powder cores will continue to follow high Bs, high μ, high Tc, and low Pc. Magnetic powder core is a soft magnetic material mixed with ferromagnetic powder and insulating medium. Because the ferromagnetic particles are very small (0.55 μm for high frequencies), they are separated by a non-magnetic, electrically insulating film. Low Hc, high frequency, miniaturization and thinning are being developed to meet the growing trend of thin film, miniaturization and even integration of magnetic components. Characteristics and applications of nanocrystalline magnetic cores Nanocrystalline alloys have high saturation magnetic induction. Good stability, material becomes brittle after heat treatment, easy to process into alloy powder. It is possible to make a new ultrafine crystal magnetic powder core with this alloy powder. The magnetic permeability of the nanocrystalline magnetic powder core is still very low compared with the nanocrystalline magnetic core wrapped with tape, and the soft magnetic performance is unstable. Problems waiting to be solved: 1. Effective control of nanocrystal growth during heat treatment; 2. Forming of magnetic powder cores; 3. Effect of heat treatment specifications on soft magnetic properties of magnetic powder cores. Application fields of nano-magnetic cores In many power electronic devices, noise is the main interference source of the circuit. Various filters are required to reduce noise. As the main component of the differential mode inductor, the magnetic powder core plays a key role in the filter. In order to obtain a better filtering effect, the magnetic powder core material is required to have the following performance characteristics: high saturation magnetic induction, wide constant magnetic permeability, good frequency characteristics, good AC/DC superposition characteristics and low loss characteristics. In response to the above requirements, soft magnetic materials for inductors, such as iron powder cores, notched amorphous alloy cores, and iron-nickel-aluminum powder cores (MPP powder cores), have been successively developed. These materials play their respective advantages and functions under different application conditions. At present, UP powder cores occupy a major share in the high-end market. However, due to the complex manufacturing process of M powder cores, the high price of raw materials, and the high price of powder cores, its scope of application is limited to a certain extent. In recent years, iron-based nanocrystalline soft magnetic powder cores have attracted much attention because of their low price, simple preparation process, and excellent performance. Their research is quite active, and they are expected to replace the local use of UP powder cores and be used in high-frequency fields.