Working Temperature of NdFeB Magnets | Reversible Loss & Irreversible Demagnetization

NdFeB rare earth permanent magnets are highly sensitive to temperature. Magnetic force decreases with rising ambient temperature. In industrial selection and practical applications, working temperature is a key indicator determining magnet stability and service life.

High-temperature induced magnetic loss in magnets mainly falls into two categories:

1. Reversible Loss (Recoverable)

When temperature rises but remains below the maximum working temperature, magnetic force drops temporarily. This loss acts like spring contraction. Once temperature returns to normal, magnetic force fully recovers without permanent damage to magnet performance.

2. Irreversible Demagnetization (Permanent Damage)

When temperature exceeds the magnet’s thermal limit, the internal magnetic domain structure collapses, resulting in permanent demagnetization. Even after cooling to room temperature, the lost magnetic force cannot be restored, and performance degrades permanently.

The maximum working temperature refers to the upper limit at which a magnet can operate long-term without significant irreversible demagnetization.

Important note:The temperature rating labeled for each grade is based on standard-sized test samples. Actual thermal resistance depends closely on magnet shape and thickness.For the same grade, thinner magnets generate higher self-demagnetizing force and lower heat resistance. A standard thick sample may withstand 150°C, while an ultra-thin sheet of the same grade may suffer irreversible demagnetization at just 130°C.

For motors, automation equipment, and high-temperature applications, proper selection based on actual size, assembly environment and working temperature is essential to maintain stable magnetic force and avoid failure.

Summary

Temperature is a core factor affecting NdFeB magnet performance. Correctly distinguishing reversible loss and irreversible demagnetization helps avoid wrong selection.We provide customized solutions including temperature grade matching, material optimization and demagnetization-resistant structure design based on working temperature, assembly structure and size requirements, ensuring stable long-term performance in high-temperature environments.