Nanocrystalline soft magnetic materials as a new material, most people know little about it. Today, I'd like to talk about what nanocrystalline soft magnetic materials are and what are their advantages and disadvantages. Let's first explain what nanocrystals are.
Introduction to nanocrystals:
Nanocrystalline is a kind of crystal material with grain size at nanometer level, which is processed on the basis of amorphous. So what is amorphous? In the process of metal preparation, from liquid to solid is a process of natural cooling and slow solidification. In this process, the atoms will rearrange themselves regularly, and the structure formed is crystal, actually polycrystalline structure. If in its solidification process, with an ultra fast cooling rate cooling, this time the atoms in a disordered state, before rearrangement will be instantly frozen, at this time the formation of the structure is amorphous. Nanocrystalline is based on the amorphous state, through special heat treatment, let it form a crystal nucleus and grow up, but to control the grain size in the nano level, do not form a complete crystal, at this time the formation of the structure is nanocrystalline.
Introduction to nanocrystalline soft magnetic materials:
Nanocrystalline soft magnetic materials are realized by special heat treatment process. Firstly, amorphous ribbons with specific composition are put into the heat treatment furnace to generate grains within 100 nm by directional control. Nanocrystalline soft magnetic materials are actually a mixture of amorphous and nanocrystalline structures, which have more excellent soft magnetic properties.
The advantages of nanocrystalline magnetic materials are as follows
1. The frequency of current wireless charging Qi standard is between 100-200k. At this frequency, the permeability of nanocrystalline is very close to that of cobalt based amorphous, which is obviously higher than that of iron-based amorphous and ferrite, while the loss is on the contrary, significantly lower than that of iron-based amorphous and ferrite.
2. Nanocrystals also have advantages in temperature application. The stability of nanocrystals is better than that of ferrite and cobalt based amorphous at - 40 ℃ - 120 ℃.
3. In the design of magnetic materials, nanocrystals also have obvious advantages. Nanocrystals can control permeability and anti saturation magnetic field directionally. The permeability of nanocrystals can be adjusted in the range of 1000-30000.
The disadvantages of nanocrystalline soft magnetic materials are as follows
When the nanocrystalline soft magnetic materials are facing the market, there is a big disadvantage, that is, the preparation technology of nanocrystalline soft magnetic materials needs to be improved and the process needs to be optimized. The problem of the original fine crystalline nanocrystalline materials is that the suitable cooling conditions for making alloy ribbons are narrow. The rapid heating type nanocrystalline materials can not be heated rapidly when a large number of materials are heat-treated, and the rapid crystallization causes excessive heating in the material, which results in the failure of the whole material to form micro nano grain structure. The practical threshold of fast heating nanocrystalline materials is very high, so the price of Nanocrystalline soft magnetic materials is also high.
At present, nanocrystalline soft magnetic materials are mostly used in wireless charging technology. Their excellent properties such as high permeability, high saturation magnetic induction and frequency adjustable characteristics will gradually replace the traditional soft magnetic materials. The magnetic separator for wireless charging made of nanocrystalline soft magnetic materials is a customized product. The requirements of each project are different. Shenzhen Jingju microwave absorbing material factory can provide high-quality customized service for everyone.
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