The high-temperature resistance range of Neodymium Iron Boron (NdFeB)s varies based on the magnet’s own magnetic properties and operating conditions. The magnet’s permeance coefficient can be used to indicate the closure degree of the magnet’s working point. A higher permeance coefficient implies a more closed magnetic circuit, resulting in a higher maximum operating temperature and more stable magnetic performance for the magnet. Therefore, there is no specific numerical value for the maximum operating temperature of neodymium iron boron magnets; it varies with the closure degree of the magnetic circuit.
Generally, the maximum operating temperature of sintered neodymium iron boron magnets under given working conditions can reach approximately 3K-3.5K Gauss (N35H grade). However, the specific maximum operating temperature also depends on factors such as the magnet’s working environment and magnetic circuit design.
The Curie temperature (Tc) of neodymium iron boron magnets refers to the fundamental working temperature limit of the material. In practice, the actual working temperature (Tw) of neodymium iron boron magnets is much lower than the Curie temperature. The Curie temperature of neodymium iron boron magnets is around 310 degrees Celsius, which means that the magnetic performance of neodymium iron boron magnets significantly decreases at temperatures above the Curie temperature.
In comparison, Samarium Cobalt (SmCo) magnets and Alnico magnets exhibit higher high-temperature resistance. The high-temperature resistance of SmCo magnets can exceed 700 degrees Celsius, while Alnico magnets have even higher high-temperature resistance, reaching over 800 degrees Celsius. They are currently the best-performing high-temperature-resistant permanent magnets. Ferrite magnets have a high-temperature resistance of around 450 degrees Celsius.
In summary, the high-temperature resistance range of neodymium iron boron magnets is between 80 degrees Celsius and 200 degrees Celsius, depending on the coercive force capability of the magnet and the level of high-temperature exposure in the working environment. If the working environment exceeds 200 degrees Celsius, it is advisable to choose SmCo magnets.
Please note that the above data is for reference only, and the specific high-temperature resistance performance needs to consider the magnet’s design and actual application conditions.