凡是需要磁场而又不用电源来产生磁场的仪器、仪表和其他技术装备中,就需要使用永磁体。从使用和设计者的角度考虑,希望永磁体所产生的磁场不变化或者少变化。否则,仪器、仪表等设备的精度就要减低,甚至失灵。但实际上,由于种种原因,永磁体总是有所谓老化现象的。因此系统地研究永磁体的老化规律,找出产生老化的原因,寻求减低和防止老化现象的措施,乃是一件很有意义的工作。目前,在这方面所做工作还不多,资料也比较贫乏。关于产生老化现象的原因,总的说来,可以归纳为两大类,第一是由于永磁体内部因素, Permanent magnets are required in instruments, meters and other technical equipment that require a magnetic field without the need for a power source to generate a magnetic field. From the point of view of the use and the designer, it is desirable that the magnetic field generated by the permanent magnet does not change or changes little. Otherwise, the accuracy of instruments, meters and other equipment will be reduced, or even failure. In fact, however, the permanent magnet always has a so-called aging phenomenon for a variety of reasons. Therefore, it is of great significance to systematically study the law of aging of permanent magnets, find out the causes of aging and seek measures to reduce and prevent the phenomenon of aging. At present, there is not much work done in this regard, and the information is relatively poor. The reasons for aging phenomenon, in general, can be summarized into two categories, the first is due to internal factors of the permanent magnet,