放电等离子烧结NdFeB磁体的磁化特征

Characteristics of Magnetization Processes for SPS NdFeB Magnet

利用放电等离子烧结技术(SPS)制备烧结钕铁硼磁体SPS NdFeB。为了更好地理解SPS Nd-FeB磁体的磁硬化机理,利用振动样品磁强计研究了SPS NdFeB磁体在室温下的磁化和反磁化过程。结果表明,在强度为800kA/m的较低外加磁场和强度为1760kA/m的较高外加磁场下的磁化特征明显不同,前者可称为形核控制模式,后者则为钉扎控制模式。比较样品的磁化过程和反磁化过程的曲线,发现样品的矫顽力大小等于样品磁化过程钉扎场的大小。

A type of sintered NdFeB permanent magnet named as SPS NdFeB magnet was prepared by spark plasma sintering（SPS） technique. To better understand the magnetic hardening mechanism of SPS NdFeB magnets, the processes of magnetization and demagnetization at the room temperature have been investigated by means of Vibrating Sample Magnetometer （VSM）. The results showed that the magnetiza- tion characters of sample under a lower extrinsic applied magnetic field of 800 kA ~ m1 were obviously different from that of processes applied a higher external field of 1760kA ~ m-~ , in which the former can be termed as nucleation-controlled mode while the latter as pinning-controlled one. Compared with the curves in the processes of magnetization and demagnetization, it could be found that the coercivity of sam- ple equals its pinning field of magnetization process.