NdFeB permanent magnet

Neodymium iron boron permanent magnet materials are highly regarded for their excellent magnetic properties and are jokingly referred to as the 'magnetic king.' The market's increasing demand for them has driven continuous improvements in neodymium iron boron production processes and magnet performance. We typically use several indicators such as residual flux density (Br), coercive force (Hcb), and maximum energy product ((BH)max) to evaluate the performance of magnetic materials.

Residual flux density (Br) refers to the magnetic induction strength exhibited by magnetic steel after being magnetized to technical saturation by an external magnetic field in a closed-loop environment and then removing the external magnetic field. It can be likened to the water content of a sponge when saturated.

Coercive force (Hcb) and intrinsic coercive force (Hcj) indicate the strength of the magnetic field required to reduce the magnetic induction to zero in a reverse demagnetization field. Although the magnetization intensity of the magnet is not zero at this time, it is only the reverse magnetic field canceling out with the internal magnetic field of the magnet. If the external magnetic field is removed, the magnet will still have certain magnetic properties.

The maximum energy product ((BH)max) represents the magnetic energy density established between the two magnetic poles of the magnet, namely the static magnetic energy per unit volume of the air gap. Its magnitude directly reflects the performance of the magnet.

The performance values of neodymium iron boron magnetic steel are influenced by various factors. Firstly, the raw material composition and production process determine the inherent magnetic properties of the magnetic steel. For example, rare earth metal neodymium, pure iron, and boron are the main components, but other elements can be added to change the performance. The continuous development of production processes also affects the improvement of magnetic properties, such as adding antioxidants, lubricants, and using new preparation processes.

In addition, the working environment also affects the performance of neodymium iron boron magnetic steel, especially temperature and humidity. High temperatures can cause demagnetization of the magnet, and above the Curie temperature, this demagnetization will be irreversible. Humidity can easily cause oxidation of magnetic materials, so anti-corrosion treatments such as coating are usually adopted in production, but dry environments help maintain magnetic properties.

In summary, by optimizing raw material composition, improving production processes, and controlling the operating environment, the performance of neodymium iron boron magnetic steel can be improved and performance degradation can be avoided.