Hot-pressed NdFeB Magnets

Hot-pressed NdFeB magnets exhibit excellent temperature stability, corrosion resistance, and the advantage of reducing the use of heavy rare-earth elements. The hot-pressing process can achieve magnetic performance comparable to sintered NdFeB magnets. Currently, they are primarily used in the automotive electric power steering (EPS) field.

What Are Hot-pressed NdFeB Magnets?

Hot-pressed NdFeB magnets refer to magnets formed using a process that combines rapidly quenched nanocrystalline NdFeB magnetic powder and hot extrusion techniques, reducing the use of heavy rare-earth elements. They exhibit magnetic performance similar to sintered NdFeB magnets, with additional advantages such as high density, good corrosion resistance, and high coercivity. However, they have poor mechanical properties.

Advantages of Hot-pressed NdFeB Magnets

The images illustrate the structure of sintered NdFeB magnets and the nanocrystalline structure of hot-pressed NdFeB (MQ3). The nanocrystalline structure provides hot-pressed NdFeB magnets with unique advantages.

| Under conditions where heavy rare-earth elements are minimally used, they can achieve extremely high magnetic performance, with a maximum magnetic energy product of 28-43 MGOe.

| Hot-pressed NdFeB magnets feature a nanocrystalline microstructure with high density and low internal porosity, offering advantages such as corrosion resistance and high thermal stability (up to 180°C).

| Various magnetization patterns, such as multi-pole/uni-pole/skew angles, can be achieved using magnetizing fixtures.

Disadvantages of Hot-pressed NdFeB Magnets

Due to production constraints, hot-pressed magnets are currently limited to ring shapes, significantly restricting their application range. The complex hot-pressing technology also contributes to the high cost of hot-pressed NdFeB magnets.

Shapes of Hot-pressed NdFeB Magnets

Due to production constraints, hot-pressed magnets are currently limited to ring shapes.

When using hot deformation pressing methods, magnetic powder under pressure forms oriented textures at the bottom of the sidewall, uniformly converting to radial orientation. So, hot deformation pressing methods could produce thin and radially oriented magnetic rings.

Applications of Hot-pressed NdFeB Magnets

The application range of hot-pressed NdFeB magnets is somewhat limited due to their current restriction to ring shapes.

However, their radially uniform magnetic properties enable quiet motor operation and smooth torque output. Additionally, they exhibit high thermal resistance, with operating temperatures reaching 180°C to 200°C. Currently, they are primarily used in the automotive EPS motor field.