中文摘要：

使用放电等离子烧结（SPS）制备致密的纳米晶交换耦合Nd2Fe14B／a-Fe永磁合金。研究烧结温度、时间、压力对合金磁性能和显微组织的影响。结果表明，随温度、压力的升高，密度增大，磁能积增加：但温度过高或时间过长，使得晶粒长大，导致矫顽力降低。在烧结压力为500MPa，烧结温度为700℃保温3min后，得到密度为7．6g／cm^3，晶粒细小的致密块体，其磁性能为：Bt=0．81T，Hc=856kA·m^-1，（BH）m=106kJ·m^-3，其晶粒大小约20nm。

英文摘要：

The exchange coupled dense nanocomposite Nd2Fe144B/a-Fe isotropic bulk magnets were prepared by Spark Plasma Sintering （SPS） method. Influence of sintering temperature, time and pressure on the magnetic properties and microstructure was investigated. It is found that the density and magnetic energy product increased with the sintering temperature and pressure increasing; but the coercivity decreased with the temperature or time further increasing. After sintered at 700 ℃, 500 MPa, and held for 3 min, dense bulk magnets with fine grains of about 20 nm were achieved, whose magnetic properties were： Bt=0.81T, Hci =856 kA·m^-1, （BH）m =106 kJ.m^-3; the density was 7.6 g/cm^3.