Advantages and characteristics of soft magnetic powder

Advantages and characteristics of soft magnetic powder
The metal soft magnetic powder core is made of metal soft magnetic powder by powder metallurgy process after insulation coating treatment. It has the special functions of magnetoelectric conversion and energy storage filtering. Due to the existence of insulating coating on the powder surface, the resistivity of the powder is effectively improved, so that it has low loss at medium and high frequencies; At the same time, the thickness of the insulating layer is thin, which has limited influence on the saturation magnetic induction of the material.
What is magnetic loss? Magnetic particle core loss refers to the energy loss generated by itself when working in the alternating magnetic field. It is a very important technical indicator of soft magnetic particle core, mainly including hysteresis loss, eddy current loss and residual loss.
According to the calculation formula of magnetic loss mechanism of soft magnetic particle core, the area of hysteresis loop is equal to the hysteresis loss of one cycle of magnetization in numerical value, and the hysteresis loop is narrowed by reducing the coercive force, which can effectively reduce the hysteresis loss.
Eddy current loss can be divided into eddy current loss between particles and within particles. The eddy current loss in the particle is mainly determined by the resistivity of the powder itself, and reducing the particle size can significantly reduce the eddy current loss in the particle. The eddy current loss between particles is mainly determined by the resistivity, integrity and thickness of the insulation coating.
The higher the resistivity, the more complete the coating and the greater the thickness of the coating, the smaller the eddy current loss between particles, and the regular morphology is very beneficial to the insulation coating treatment of the powder.
Therefore, in order to obtain the soft magnetic powder core with low magnetic loss, it is necessary to reduce the coercivity of the powder and control the thickness, uniformity and integrity of the insulation coating. The impurities in the powder particles have a pinning effect on the rotation of the magnetic domain, thereby improving the coercivity. The impurity content and internal structure of the powder have a great influence on the coercivity, while the particle size and morphology of the powder have a direct relationship with the thickness and uniformity of the insulation coating, and thus have a significant impact on the eddy current loss.
According to the market demand, Yue'an has launched FeSiCr, FeSi6.5, FeSi3-7 and other soft magnetic powder products, which are characterized by low oxygen, spherical and fine.
Taking the atomized FeSiCr alloy powder as an example, the original powder D50 is 25.8 μ m. Narrow particle size distribution, geometric standard deviation δ 1.75, - 500 mesh (＜ 25 μ m) The powder yield of fine powder reaches 60%. The prepared metal soft magnetic powder core has the characteristics of low loss and high DC superposition, and is suitable for new energy (photovoltaic inverter, electric vehicle charging pile), intelligent household appliances, switching power supply, power electronics and other fields.