The performance of high performance magnet will decline with time, which is the result of many factors.
First of all, temperature is one of the key factors affecting the performance degradation of high performance magnets. In high temperature environment, the microstructure inside the magnet will change.
For example, for common NdFeB high-performance magnets, the arrangement of magnetic domains gradually becomes disordered as the temperature increases.This is because the high temperature provides enough energy for the magnetic domain to overcome the internal exchange coupling, which leads to the decrease of remanence and coercivity. According to the experimental data, when the temperature reaches a certain threshold (for example, the temperature of Nd-Fe-B magnet is about 150-200 degrees Celsius), the magnetic properties will be significantly attenuated when the temperature rises to a certain temperature. Generally speaking, the remanence may decrease at a rate of 0.1-0.2% per degree Celsius.In this high temperature environment for a long time, the performance degradation will be more significant.
Secondly, the interference of external magnetic field can also change the performance of high performance magnets. If a high-performance magnet is exposed to a strong external magnetic field for a long time, its own magnetic domain structure will be rearranged by the external magnetic field force. This rearrangement may change the magnetic field distribution inside the magnet, resulting in a decline in performance indicators such as magnetic energy product.Just as in some complex electromagnetic devices with multiple magnetic field sources, high-performance magnets may show detectable performance degradation within months or even weeks due to the continuous influence of other magnetic fields.
In addition, mechanical stress also affects high performance magnets. In some application scenarios, such as high-speed operation of motors or frequent vibration environment, high-performance magnets will be subjected to mechanical stress.This stress may lead to micro-cracks in the magnet or local destruction of the magnetic domain structure. Over time, these small damages will accumulate, making the performance of the magnet gradually decline. For example, in some large industrial motors, the coercivity of high-performance magnets may decrease by 10-20% after several years of operation due to mechanical vibration. In order to reduce the attenuation of the performance of high-performance magnets, some measures can be taken.For example, when designing application scenarios, try to avoid the magnet being exposed to high temperatures, strong external magnetic fields, and high mechanical stresses. At the same time, some protective materials or heat dissipation devices can also be used to reduce the impact of these adverse factors. Through these methods, the service life of the high-performance magnet can be prolonged to a certain extent, and the relative stability of its performance can be maintained.
