Neodymium magnets are made through a multi-step manufacturing process that turns rare-earth raw materials into a precisely controlled permanent-magnet alloy.
1. Alloy Production
Neodymium magnets are not made from pure neodymium. They are typically based on an alloy of neodymium, iron and boron, with additional elements used as needed to achieve specific coercivity and temperature-performance targets.
2. Milling and Powder Preparation
The alloy is processed into a very fine powder. Particle size and chemistry must be carefully controlled because they influence the magnetic properties of the finished material.
3. Pressing and Magnetic Alignment
The powder is compacted in a die while an aligning magnetic field orients the material’s preferred magnetic direction. This alignment is a key reason sintered NdFeB magnets can achieve high magnetic performance.
4. Sintering and Heat Treatment
The pressed material is sintered in a controlled atmosphere and then heat-treated to develop the required microstructure, density and magnetic properties.
5. Machining
After sintering, the magnet material is hard and brittle. Final dimensions are produced with specialized grinding and cutting processes rather than conventional machining methods used for ductile metals.
6. Coating
Because NdFeB is susceptible to corrosion, finished magnets are commonly protected with coatings such as Ni-Cu-Ni, epoxy or other application-specific finishes.
7. Magnetization and Inspection
The finished part is magnetized in the specified direction using a strong external magnetic field. Dimensional, visual and magnetic inspections are then performed according to the customer or supplier quality plan.
