The main components for hot-pressed magnets, similar to sintered magnets, include neodymium, iron powder, and boron, mixed in specific proportions. Depending on the required quality, heavy rare earths are added, albeit in significantly smaller amounts than sintered magnets.
Initially, the mixture is cold-pressed into a disc, akin to manufacturing plastic-molded parts. Subsequently, two steps in the hot-pressing process follow, during which the material is extruded, acquiring radial anisotropy directly and exhibiting outstanding corrosion resistance. Post-pressing, magnets undergo mechanical processing for length and diameter adjustments, ensuring minimal tolerances. We recommend an epoxy coating as protection.
Production process of hot-pressed magnets
The hot-pressing process facilitates the production of magnets with remarkable attributes, such as:
- Rings with radial orientation and energy products up to 390 kJ/m2
- Easy assembly, with a single ring available in various diameters and lengths
- Diverse magnetization patterns, from multipole to unipole, and various skew angles
- Precise control of magnetization waveform for high performance or low cogging
- High heat resistance (up to 180°C) with minimal heavy rare earths, notably dysprosium or terbium
- Enhanced thermal and corrosion resistance due to minimal porosity
Potential fields of application
Overall, the manufacturing of hot-pressed magnets offers numerous advantages, including impressive energy performance, magnetization flexibility, and high-temperature resistance. These qualities make this material highly appealing for a wide range of applications. Current examples include automotive motors, servo motors, power tool motors, magnetic bearings, and couplings.
