How to ensure the performance stability of NdFeB magnets in daily use?

As the permanent magnet material with the highest commercial magnetic energy product, NdFeB magnets are widely used in new energy vehicles, wind power generation, consumer electronics and medical equipment. However, their performance is easily affected by environmental, mechanical and chemical factors. How to maintain the stability of their magnetic properties in daily use?
1. Strict temperature control: avoid irreversible demagnetization
The Curie temperature of NdFeB magnets is usually 310-400°C, but the actual operating temperature needs to be much lower than this threshold. When the temperature exceeds 80°C, some magnets may experience reversible magnetic loss; if exposed to high temperatures above 150°C for a long time, irreversible demagnetization may occur.
Recommended measures:
When used in high temperature environments (such as inside motors), magnets with high temperature resistance grades (such as N42SH, N35UH) are preferred.
Avoid direct contact with heat sources, and add heat dissipation structures or use thermal insulation coatings when necessary.
2. Anti-corrosion treatment: blocking the oxidation reaction path
NdFeB magnets contain active metals such as iron and neodymium. When exposed to a humid or corrosive environment, they are prone to oxidation, resulting in surface powdering and decreased magnetic flux. Studies have shown that unprotected magnets can lose 5%-8% of their magnetic flux within 3 months in an environment with humidity >80%.
Recommended measures:
Use electroplating (nickel, zinc, epoxy resin) or physical vapor deposition (PVD) technology to form a dense protective layer.
Use moisture-proof sealed bags and place desiccant during storage; check the integrity of the coating regularly.
3. Avoid mechanical shock: reduce the risk of structural failure
NdFeB is a brittle material with a tensile strength of only 80-120MPa. Collisions or improper installation may cause microcracks and even cause the magnet to break.
Recommended measures:
Use non-metallic tools (such as plastic tweezers) to operate, and do not knock or drop directly.
Use magnetic fixtures to assist positioning during assembly to reduce the risk of stress concentration.
4. Demagnetization protection: stay away from reverse magnetic field interference
When the external reverse magnetic field strength is close to the coercive force (Hcj) of the magnet, demagnetization may occur. For example, strong electromagnets, MRI equipment or unshielded transformers may generate interference fields.
Recommended measures:
Use a closed yoke structure when designing the magnetic circuit to reduce magnetic leakage.
Use high magnetic permeability materials (such as pure iron) for shielding during storage, and stack adjacent magnets with the same polarity.
5. Regular inspection and data traceability
Regularly monitor the flux attenuation rate through professional equipment (such as gauss meters and flux testers). If the annual attenuation rate exceeds 0.5%, it is necessary to check the environment or operation problems. It is recommended to establish a magnet usage file to record temperature, humidity and performance parameters to achieve life prediction.