Making a sintered NdFeB magnet is a bit like baking: mix the ingredients, shape them, then heat them so everything bonds together. Here is the whole process in five simple steps.
The 5 steps
- Melt the alloy — neodymium, iron and boron are melted together in a vacuum furnace and cast into thin flakes.
- Grind into powder — the flakes are crushed into a very fine powder, only a few microns across (thinner than a human hair).
- Press in a magnetic field — the powder is placed in a mold and pressed while a strong magnet aligns the grains, so the finished magnet has one clear magnetization direction.
- Sinter (heat) — the pressed part is heated until the particles fuse into a dense, solid block.
- Cut, grind and coat — the block is sliced into the final shape, ground to size, then coated with nickel, zinc or epoxy to protect it from rust.
Why each step matters
- The fine powder is what makes the magnet strong — smaller grains give better magnetic performance.
- The magnetic field during pressing is what gives the magnet its direction (which face is north).
- The sintering temperature controls strength and heat resistance.
- The coating is essential — bare NdFeB rusts easily.
Special processes for special jobs
Some magnets get extra treatments: adding dysprosium or terbium makes them work at higher temperatures, and a grain-boundary diffusion process adds these elements only to the surface layer to save cost.
Read on: what each raw element does → · coatings explained →