The Procedures of NdFeB Magnet

1. Raw material preparation and pre-disposal of NdFeB magnet

Process introduction: Pre-disposal of raw materials, such as weighing, breaking, and rust removal.

Process equipment: steel cutting machine, cylinder polishing machine, etc.

2. Smelting of NdFeB magnet

Process introduction: The pre-disposed raw materials such as praseodymium, pure iron, and boron iron are added correctly and joined in the vacuum melting furnace. And they will be melted at high temperature under the maintenance of argon gas and lastly dumped. This process makes rare earth NdFeB magnets with average composition, high crystalline orientation, good organizational divergence, and prevents the generation of ɑ-Fe.

Process equipment: vacuum melting furnace.

3. Hydrogen explosion of NdFeB magnet

Process introduction: The hydrogen explosion (HD) process is to use the hydrogen-absorbing property of rare earth intermetallic compound to put NdFeB alloy in a hydrogen environment, hydrogen enters the alloy along with the thin layer of neodymium-rich phase, making it shrink and break, and cracks along the thin layer of neodymium-rich phase to ensure the integrity of the main phase grains and the boundary phase between neodymium-rich grains. The HD process loosens the flaking of rare earth NdFeB magnets, which greatly improves the efficiency and reduces the cost of powder production.

Process equipment: vacuum hydrogen disposal furnace.

4. Powder making of NdFeB magnet

Process introduction: Airflow mill powder making is to use the high-speed collision of the materials to crush themselves, no wear and tear and no pollution on the wall inside the mill, at the same time prepare powder with high efficiency.

Process equipment: airflow mill.

5. Forming orientation of NdFeB magnet

Process introduction: The function of orientation is to turn the direction of magnetization of the disordered powder particles to the same direction, to obtain a large remanent magnetization. The main purpose of molding is to press the powder into a certain shape and size while maintaining the grain orientation achieved in the magnetic field orientation as much as possible.

Our design uses forming magnetic field press and isostatic press for secondary forming. For shaped magnets, special mold tooling is used for direct molding, and the sintered rare earth NdFeB magnets can be put into use with only a slight exterior treatment, which greatly saves material and subsequent processing costs.

Process equipment: magnetic field press, isostatic press.

6. Sintering of NdFeB magnet

Process introduction: Sintering is a simple and low-cost method to modify the microstructure of the material to improve the magnetic properties of the material by making a series of physicochemical changes at high temperatures. Sintering is the post-forming process of the material, which has an important impact on the density and microstructure of the magnet.

Process equipment: vacuum sintering furnace.

7. Machining of NdFeB magnet

Process introduction: After sintering, the rare earth NdFeB magnets are rough, and need to be further machined into different sizes, dimensions, and shapes of products. Rare earth NdFeB magnets are brittle and have poor mechanical properties, so they can only be processed by grinding and cutting.

Process equipment: surface grinder, double end grinder, chamfering machine.

8. Appearance treatment of NdFeB magnet

Process introduction: The appearance treatment is to reshape the rare earth NdFeB magnets with various shapes, such as electrophoresis, galvanization, nickel, nickel-copper-nickel, and phosphating, etc. This process can ensure the appearance and corrosion resistance of the products.

9. Scrap inspection and packaging of NdFeB magnet

Process introduction: Test the magnetic property, corrosion resistance, high-temperature property, etc. Then pack the products after reaching the standard, and meet the needs of customers.

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