What Safety Precautions Are Necessary When Handling NdFeB Magnets?

NdFeB magnets are the most powerful permanent magnet materials currently used in commercial applications and are widely used in motors, medical equipment, new energy, and industrial automation. However, their extremely high magnetic energy product (up to 50MGOe or more) and brittle physical properties may cause serious mechanical damage, material loss, and even fire hazards if not handled properly.
1. Mechanical risk prevention and control: avoid pinching and collision
The magnetic attraction of NdFeB magnets increases exponentially with their volume and magnetization direction. For example, the adsorption force of a 10cm diameter N52-grade magnet can exceed 600kg, far exceeding the human body's tolerance limit. The following principles should be followed during operation:

Wear protective equipment: Use wear-resistant gloves (such as Kevlar) with a thickness of ≥3mm to prevent direct skin contact with the edge of the magnet; wear goggles to avoid magnet fragmentation and splashing.
Non-contact operation: Use non-magnetic tools (such as titanium alloy tweezers and wooden partitions) to separate magnets. It is forbidden to split superimposed magnets by hand.
Safety distance management: A "metal-free isolation zone" with a radius of ≥1m shall be set up in the magnet storage area to prevent magnetic objects from being accidentally attracted and causing projection damage.
2. Material integrity protection: prevent fragmentation and demagnetization
The bending strength of NdFeB magnets is only 80-120MPa, and they are prone to cracking under high temperature or mechanical impact. The following methods need to be used to maintain their performance:

Temperature control: The operating environment temperature must be lower than the Curie temperature of the magnet (usually 80-200℃, depending on the brand) to avoid irreversible demagnetization.
Shock-absorbing packaging: EPS foam boxes are used for layered isolation during transportation, and the spacing between single-layer magnets is ≥2 times the thickness of the magnet to reduce the probability of collision between magnets.
Anti-oxidation treatment: Uncoated magnets must be operated in an environment with a relative humidity of <50%, and magnets with damaged coatings should be immediately sealed with paraffin wax.
3. Electromagnetic safety: Avoid equipment interference and fire risks
The strong magnetic field of NdFeB may cause multiple secondary hazards:

Electronic equipment protection: The magnet and precision instruments (such as CT machines, mass spectrometers) must be kept at a distance of ≥5m to avoid magnetic field interference and data distortion.
Pacemaker patients avoidance: Areas with magnetic field strength >5mT must be clearly marked, and personnel with implanted pacemakers or neurostimulators are prohibited from entering.
Combustible material management: High-speed collision of magnets may produce sparks. CO₂ fire extinguishers must be equipped at the operation site, and flammable gases within a radius of 3m must be removed.
4. Special scene enhancement measures
For industrial-grade magnet assembly (such as wind turbine yokes), additional implementation is required:

Magnetic shielding design: Use μ alloy shielding covers to reduce the magnetic field strength in the operating area to <0.5mT (ICNIRP public exposure limit).
Mechanized assembly: Use hydraulic servo clamps to achieve precise positioning of magnets, and manpower is only responsible for monitoring system parameters.
Residual magnetic field detection: After completion, use a Gauss meter to scan the equipment housing to ensure that the magnetic leakage is lower than the IEEE C95.1 standard.

According to statistics, standardized magnet operation procedures can reduce the accident rate by 87% (IMMA 2022 annual report data). Enterprises need to establish a three-level management and control system including risk identification (HIRA), operation training (≥8 hours per year) and emergency plans. Only by transforming the knowledge of material properties into systematic safety behaviors can the technical advantages of NdFeB magnets be fully utilized to achieve sustainable development of harmonious coexistence of man, machine and objects.