采用放电等离子烧结(SPS)技术制备了致密纳米晶SmCo5烧结磁体,研究了磁体的结构和磁性能。X衍射结果表明,烧结磁体具有CaCu5结构,说明SPS过程可以获得稳定的1:5相。TEM观察显示,磁体由平均晶粒尺寸约为30nm的1:5相构成。室温时磁体的矫顽力高达2208kA/m,而剩磁比高达0,7,说明在纳米晶之间存在强烈的晶间交换耦合作用。烧结磁体具有良好的高温性能,773K时的矫顽力为456kA/m,矫顽力温度系数β为-0.212%/K。
Bulk nanocrystalline SmCo5 sintered magnet was prepared by spark plasma sintering technique (SPS). Structure and magnetic properties of magnet was studied. XRD patterns show that the magnet exhibits CaCu5 structure, indicating a stable 1:5 phase was obtained after SPS process. TEM observation indicates that the microstructure of the magnet is composed of SmCo5 single phase grains with an average grain size of 30 nm. Magnetic measurement shows that the coercivity of the magnet reaches as high as 2208kA/m; The high ratio Mr/Ms of 0.7 demonstrates the existence of strong intergrain exchange coupling among the nanograins. The magnet exhibits a good thermal stability with the coercivity of 456kA/m at 773K, and the coercivity temperature coefficient β of -0.212%/K.