块状纳米晶Sm2Co17烧结磁体的研究

Study on bulk nanocrystalline Sm_2Co_(17) sintered magnet

采用高能球磨和放电等离子烧结技术制备了致密纳米晶Sm2Co17烧结磁体,研究了粉末和烧结磁体的结构和磁性能。球磨粉末在低温退火(<1023K)时,主相为TbCu7结构;高温退火(>1023K)时,主相为Th2Zn17结构。退火温度从923K增加到1223K,粉末的矫顽力从0.99T下降到0.12T。烧结磁体也具有TbCu7结构,磁体平均晶粒尺寸约为35nm。室温时磁体的剩磁为0.65T,矫顽力达0.87T。烧结磁体具有较好的高温性能,573K时的剩磁为0.6T,矫顽力为0.32T。

Bulk nanocrystalline Sm2Co17 sintered magnet was prepared by high energy ball-milling and spark plasma sintering （SPS） technique. Structure and magnetic properties of the powders and magnet were studied. XRD patterns show that annealed at low temperature （〈1023K）, the main phase of the powders is TbCu7 structure. When annealed temperature is above 1023K, the main phase is Th2 Zn17 structure. With increasing the annealed temperature from 923-1223K, the coercivity of the powders decrease from 0. 99-0.12T. The sintered magnet also exhibits TbCu7 structure after SPS process. TEM observation indicates that the average grain size of the magnet is about 35nm. Magnetic measurement of the sintered magnet shows that the remanence is 0.65T and the coercivity reaches 0.87T; The magnet exhibits a better thermal stability with a remanence of 0.6T and a coercivity of 0.32T at 573K.