Understanding the basic knowledge and terminology of these magnets will give you a good understanding of them.

Basic knowledge of magnets

Summary of magnetic materials: magnetism is one of the basic properties of materials. Magnetic phenomena are associated with various forms of charge motion. Because the motion of electrons and spin in matter can produce a magnetic field of certain magnitude, magnetism is produced. All substances are magnetic. Nature can be divided into paramagnetic material, diamagnetic material, ferromagnetic material, antiferromagnetic material and ferromagnetic material according to the difference of magnetism. Among them, ferromagnetic material and ferromagnetic material belong to strong magnetic material, which are generally referred to as magnetic material.

Classification, properties and applications of magnetic materials:

1 Ferrite magnetic material: generally refers to the conforming oxides of iron oxide and other metal oxides. Most of them have ferromagnetism. Characteristic: The resistivity is much higher than that of metal, about 1-10 (12 th power) Euro/cm, so the eddy loss and skin effect are small and suitable for high frequency use. The saturation magnetization is low, so it is not suitable for high magnetic density applications. Curie temperature is relatively low.

Ferromagnetic material: refers to the material with ferromagnetism. For example, iron, nickel, cobalt and their alloys, and alloys of some rare earth elements. Under Curie temperature, the material has higher magnetization when applied magnetic field.

3. Ferromagnetic materials: refers to materials with ferromagnetic properties, such as various ferrites, which have high magnetization when applied below the temperature of Nail.

4. Permanent magnet material: The magnet has strong magnetism after being removed by the magnetization thickness, which is characterized by high coercivity and large magnetic energy product. It can be divided into aluminium, nickel and cobalt, rare earth cobalt, neodymium, iron and boron, etc. Ferrite permanent magnet, e.g., barium ferrite, strontium ferrite, other permanent magnets, such as plastic magnet, etc.

Soft magnetic materials: materials that are easy to magnetize and demagnetize. The working frequency of Mn-Zn ferrite soft magnetic material is between 1K and 10M. Nickel-zinc ferrite soft magnetic material, working frequency is generally 1-300 MHZ.

6. Metal soft magnetic material: Compared with ferrite, it has high saturation magnetic induction strength and low coercivity, such as engineering pure iron, iron-aluminium alloy, iron-cobalt alloy, iron-nickel alloy, etc. It is often used in transformers.

Professional terms for magnets:

Saturated magnetic induction intensity: (saturated magnetic flux density) the magnetic induction intensity of a magnet when it is magnetized to a saturated state. In practical applications, the saturated magnetic induction intensity usually refers to the magnetic induction intensity under a specified magnetic field (which basically reaches the magnetic saturation).

Remaining magnetic induction intensity: from the saturation state of the magnet, the magnetic field (including the self-demagnetizing magnetic field) is monotonously reduced to zero magnetic induction intensity.

3. Flux density coercivity, which changes the magnetic field intensity monotonously along the saturated hysteresis loop from the saturated magnetization state of the magnet, reduces the magnetic induction intensity B to zero.

4. Intrinsic coercivity: The magnetic field intensity M decreases to 0 from the saturated magnetization state of the magnet.

5 magnetic energy product: product of magnetic induction intensity and magnetic field intensity at any point on the demagnetization curve of permanent magnet.

6 Initial permeability: The limit value of permeability of a magnet in a magnetic state.

7 loss tangent: It is the ratio of imaginary part to real part of series complex permeability. Its physical meaning is the ratio of loss energy to stored energy of magnetic material in every cycle of alternating magnetic field.

8 specific loss tangent: This is the ratio of material loss tangent to initial permeability.

9 Temperature Coefficient: Between two given temperatures, the measured change is divided by the temperature change.

Specific temperature coefficient of 10 permeability: the ratio of temperature coefficient of permeability to permeability.

11 Curie temperature: At this temperature, the spontaneous magnetization is zero, that is, the critical temperature at which the ferromagnetic material (or sub-magnetic material) changes from a ferromagnetic state (or ferromagnetic state) to a paramagnetic state.