Neodymium Magnets Compared to Other Types of Magnets

Neodymium Magnets Compared to Other Types of Magnets

Permanent magnet materials are a type of material with permanent magnetism and are widely used in various electronic equipment and mechanical equipment. There are currently two main types of permanent magnet materials on the market: ferrite and NdFeB. This article will compare these two permanent magnet materials.

1. Ferrite

Ferrite is an ancient permanent magnet material whose main component is iron oxide (Fe2O3). The production process of ferrite is relatively simple and the cost is low, so it is widely used in the market. However, the magnetic properties of ferrite are relatively weak, generally only reaching the level of 5-10 Gauss. In addition, the maximum magnetic energy product (BHmax) of ferrite is relatively low, usually only 4-5kJ/m3, which is much lower than the 15-20kJ/m3 of NdFeB. Therefore, the application of ferrite is limited in situations where higher magnetic field strength is required.

2. NdFeB

NdFeB is a new type of permanent magnet material whose main components are neodymium, iron, boron and other elements. NdFeB has extremely high magnetic properties and a large magnetic energy product, and can generate magnetic field strengths up to 40kJ/m3. In addition, NdFeB also has good temperature characteristics and corrosion resistance, and can work stably for a long time under harsh environmental conditions. Therefore, NdFeB has been widely used in aerospace, electronic communications, automobile industry and other fields.

3. Performance comparison

3.1 In terms of magnetic field strength: Because NdFeB has a high maximum magnetic energy product and coercive force, its magnetic field strength is usually several times or even dozens of times higher than that of ferrite. For example, the maximum operating temperature of N48 NdFeB can reach over 120°C, while the maximum operating temperature of N35 ferrite is only about 70°C; the residual magnetization density of N48 NdFeB can reach 1.2T, while the N35 ferrite has The residual magnetism density is generally below 0.1T.
3. 2 Temperature characteristics: The temperature characteristics of NdFeB are relatively stable and will not cause obvious demagnetization or saturation as the temperature changes. In contrast, ferrite has poor temperature characteristics and is susceptible to demagnetization or saturation due to the influence of ambient temperature. This is one of the reasons why some high-precision equipment and control systems need to use NdFeB as permanent magnet material.

3.3 In terms of corrosion resistance: NdFeB has good corrosion resistance and can work stably for a long time in various chemical media such as acids, alkalis, and salts. The corrosion resistance of ferrite is relatively poor, and it is easily corroded by moisture, leading to a decrease in magnetic force or failure.

4. Comparison of application areas

Due to its high performance advantages and wide range of applications, NdFeB has replaced traditional ferrite materials in many occasions. Here are some common application areas compared:
4.1 Motor field: Because NdFeB has high magnetic field strength and low price, it has been widely used in various motors, such as stepper motors, DC brushless motors, AC asynchronous motors, etc. Ferrite is mainly used in small motors and low-power motors.
4. 2 Sensor field: Because NdFeB has high sensitivity and stability, it has been widely used in various sensors, such as position sensors, speed sensors, acceleration sensors, etc. Ferrite is mainly used in special applications such as surface acoustic wave (SAW) filters.
4. 3 Medical device field: Because NdFeB has high biocompatibility and stability, it has been widely used in various medical devices.

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