Strongest Commercial Permanent Magnet
Researchers and engineers have never stopped their steps to discover and develop novel permanent magnets since 1910s, and several types of permanent magnets had been commercialized and they have been widely used in motion, energy, electronics, medical and other high technologies in our daily life. However, little breakthrough has been taken in the past 18 years of the 21st century. In the current market, almost all types of commercial permanent magnets (ferrite, NdFeB, SmCo and AlNiCo, etc.) were discovered and developed in the 20th century.
In the following figure, it depicts the development of some permanent magnets’ maximum energy product (BH)max at room temperature and their different volumes with comparable energy (each permanent magnet is designed so that at a reference point 5 mm from the surface of the pole, a field of 100 mT is produced). Seen from the figure, only NdFeB magnet’s (BH)max can be higher than 35 MGOe, i.e. the N35 grade NdFeB magnet has already been stronger than the other types of permanent magnets. Besides, the volume of NdFeB magnet is the smallest to provide same power, it is averagely only around one tenth of that of ferrite magnet. It is obvious that NdFeB magnet is the most powerful material type. It should be mentioned that, although its (BH)max recorded a peaking level at round 56 MGOe in lab, the current strongest commercial permanent magnet is the N52 grade NdFeB magnet with (BH)max at a range of 50-53 MGOe at room temperature.