Characteristics and Classification of Magnetic Materials

1. Characteristics of magnetic materials:

Magnetic materials are mainly divided into permanent magnetic materials and soft magnetic materials. Permanent magnetic materials are also named hard magnetic materials. The magnet can retain its strong magnetism for a long time after applying an external magnetic field, and it has the characteristic of high coercivity (Hc). Soft magnetic materials are magnetic materials that are easy to be magnetized and demagnetized after applying a magnetic field. It has the characteristic of small coercivity with Hc≤1000A/m generally.

2. Four main magnetic properties of permanent magnet materials:

(1) High maximum magnetic energy product: The maximum magnetic energy product (BH) Max is a measure of the maximum magnetic energy density stored and available per unit volume of the permanent magnet material.

(2) High coercivity: Coercivity (Hc) is a measurement of the permanent magnetism of permanent magnetic materials.

(3) High residual magnetic flux density (Br): Residual magnetization (Mr) is a measurement of the strength of the magnetic field in the air gap.

(4) High stability: The high stability of the external interference magnetic field, temperature, vibration and other environmental factors.

3. Main characteristics of soft magnetic materials:

(1) Low coercivity(Hc): It shows that the magnetic material is easy to be magnetized by an external magnetic field, and easy to be demagnetized by an external magnetic field or other factors. Also, the magnetic loss is low.

(2) High saturation magnetic flux density(Bs): It is easy to get high permeability µ and low coercive force Hc, and the magnetic flux density can also be improved.

(3) Low magnetic and electrical losses: It requires low coercivity Hc and high resistivity.

(4) High stability: It has high stability to the changes in environmental factors such as temperature and vibration.