Permanent Magnet
Manufacturer

Certain soft ferrites maintain relatively high magnetic permeability at high frequencies. Their high electrical resistivity helps suppress eddy-current losses, making them widely used in high-frequency and low-power electronic applications. However, ferrites generally have lower saturation magnetization and store less magnetic energy per unit volume than metallic magnetic materials. Their saturation magnetization is typically only about one-third to one-fifth that of pure iron. These characteristics limit their use in low-frequency, high-power applications that require high magnetic flux density or high magnetic energy density.

1. Ferrite Magnets

Ferrite magnets are ceramic magnets made primarily from iron oxide combined with barium or strontium compounds. They are cost-effective, corrosion-resistant, and suitable for relatively high operating temperatures. Although their magnetic strength is lower than that of rare-earth magnets, they are widely used in motors, loudspeakers, household appliances, and automotive components.

2. Neodymium Iron Boron Magnets

NdFeB magnets are among the strongest commercially available permanent magnets. Their high remanence, coercivity, and maximum energy product allow compact magnetic circuits to generate strong magnetic fields. Common applications include motors, sensors, actuators, consumer electronics, medical equipment, and renewable-energy systems.

3. Aluminum-Nickel-Cobalt Magnets

AlNiCo magnets provide high remanence, excellent temperature stability, and good corrosion resistance. However, their relatively low coercivity makes them more susceptible to demagnetization. They are commonly used in sensors, measuring instruments, holding devices, and high-temperature equipment.

4. Samarium Cobalt Magnets

SmCo magnets combine a high energy product with excellent temperature stability, high intrinsic coercivity, and good corrosion resistance. They are well suited to demanding applications such as aerospace systems, high-temperature motors, precision instruments, and specialized industrial equipment.

These magnets are widely used in premium household appliances, high-efficiency automotive motors, and pump rotors. Typical applications include dishwasher and washing-machine pump motors, inverter air conditioners, refrigerator compressors and cooling-fan motors, high-speed blenders, clothes dryers, range-hood motors, automotive angle, speed, and position sensors, and high-performance automotive auxiliary motors.

Anisotropic ferrite ring magnets are also used in miniature precision stepper motors for security cameras, smart-home devices, and other compact motion-control systems.

NdFeB is generally classified as the third generation of rare-earth permanent magnet materials. Its primary magnetic phase is the tetragonal intermetallic compound Nd₂Fe₁₄B. Among commercially produced permanent magnets, NdFeB offers the highest magnetic energy density.

The three main manufacturing routes are sintered NdFeB, bonded NdFeB, and hot-deformed NdFeB.

Key Advantages

High magnetic performance:Its high remanence and maximum energy product enable smaller and lighter magnetic assemblies than ferrite in many applications.

Cost-effective rare-earth magnet:NdFeB is generally more economical than SmCo and is widely used in industrial production.

Flexible manufacturing options:Depending on the process, NdFeB magnets can be machined or molded into different geometries. Sintered magnets are typically shaped by slicing, grinding, or other precision machining methods.

Good long-term stability:Properly selected NdFeB magnets maintain stable performance at room temperature when operated within their specified temperature and magnetic working conditions.

NdFeB magnets are widely used in electric vehicles, renewable-energy systems, industrial automation, electronics, medical equipment, and aerospace applications.

The selection process begins with the main magnetic parameters, including remanence (Br), intrinsic coercivity (Hcj), maximum energy product ((BH)max), demagnetization-curve squareness, magnetization pattern, and pole distribution.

Operating conditions must also be considered, particularly temperature, corrosive exposure, mechanical stress, and external magnetic or electromagnetic fields.

Additional requirements should be reviewed individually during technical discussions based on the specific application and assembly design.

The selection process begins with the main magnetic parameters, including remanence (Br), intrinsic coercivity (Hcj), maximum energy product ((BH)max), demagnetization-curve squareness, magnetization pattern, and pole distribution.

Operating conditions must also be considered, particularly temperature, corrosive exposure, mechanical stress, and external magnetic or electromagnetic fields.

Additional requirements should be reviewed individually during technical discussions based on the specific application and assembly design.

Reversible magnetic loss is a temporary change in magnetic performance, commonly caused by temperature variation. When the magnet returns to its original temperature, its magnetic properties recover without permanent damage.

Irreversible demagnetization does not recover after the temperature or external field returns to normal. Some losses may be restored through remagnetization, while losses caused by corrosion, cracking, or material degradation are generally permanent.

Common causes include:

- Excessively high or low temperatures

- Strong opposing magnetic fields

- Mechanical shock or physical damage

- Corrosion or chemical exposure

- Long-term magnetic aging

- Improper assembly or manufacturing processes