High energy ball milling(HEBM) is employed to produce nano-sized grains and particles. In this paper, the structure and magnetic properties are investigated in PrCo5 alloy for HEBM in an ethanol milling medium. With t...High energy ball milling(HEBM) is employed to produce nano-sized grains and particles. In this paper, the structure and magnetic properties are investigated in PrCo5 alloy for HEBM in an ethanol milling medium. With the increase of milling time, the grain size reduces and the coercivity increases. For a milling time of less than 30 min, the hysteresis loop of the aligned sample is very different from that of the un-aligned sample and it does not show a large decrease in magnetization slope, indicating a relatively good alignment of easy axes in particles due to the fact that the texture is nearly well preserved. However, when the milling time is further prolonged, the textured structure deteriorates in the powders.Even though exchange coupling exists between grains within the particle, the magnetic properties are exchange-decoupled between particles and the dipolar interaction results in a negative value of δ m in the whole range of the magnetic field.展开更多
Nd-Fe-B磁体具有较高的磁化强度和最大磁能积,PrCo_5磁体具有较高的居里温度和温度稳定性。本文将快淬Nd-Fe-B与PrCo_5磁粉混合,采用热压/热流变的方法,制备了各向异性Nd-Fe-B/PrCo_5复合磁体。X射线衍射(XRD)、扫描电镜(SEM)及热磁曲线...Nd-Fe-B磁体具有较高的磁化强度和最大磁能积,PrCo_5磁体具有较高的居里温度和温度稳定性。本文将快淬Nd-Fe-B与PrCo_5磁粉混合,采用热压/热流变的方法,制备了各向异性Nd-Fe-B/PrCo_5复合磁体。X射线衍射(XRD)、扫描电镜(SEM)及热磁曲线(M-T曲线)的测试结果均表明热流变复合磁体中Pr-Co合金仍然保持为PrCo_5相。热流变复合磁体沿不同方向的磁滞回线以及XRD图谱表明经热流变处理后,复合磁体由各向同性转变为各向异性。SEM观察表明所添加的PrCo_5在复合磁体中以较大的颗粒形式聚集存在,PrCo_5周围主相晶粒取向变差,而且在两相界面处存在由于扩散作用而产生的成分复杂的过渡层,过渡层的存在也使得磁体性能降低。热流变复合磁体的可逆回复曲线在矫顽力附近存在峰值,峰值的出现与磁体的各向异性无关,过渡层与主相间可能存在一定的交换耦合作用。热流变复合磁体的磁性能为Br=1.323 T,Hcj=682.2 k A·m^(-1),(BH)m=239.6 k J·m^(-3)。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51461033)
文摘High energy ball milling(HEBM) is employed to produce nano-sized grains and particles. In this paper, the structure and magnetic properties are investigated in PrCo5 alloy for HEBM in an ethanol milling medium. With the increase of milling time, the grain size reduces and the coercivity increases. For a milling time of less than 30 min, the hysteresis loop of the aligned sample is very different from that of the un-aligned sample and it does not show a large decrease in magnetization slope, indicating a relatively good alignment of easy axes in particles due to the fact that the texture is nearly well preserved. However, when the milling time is further prolonged, the textured structure deteriorates in the powders.Even though exchange coupling exists between grains within the particle, the magnetic properties are exchange-decoupled between particles and the dipolar interaction results in a negative value of δ m in the whole range of the magnetic field.
文摘Nd-Fe-B磁体具有较高的磁化强度和最大磁能积,PrCo_5磁体具有较高的居里温度和温度稳定性。本文将快淬Nd-Fe-B与PrCo_5磁粉混合,采用热压/热流变的方法,制备了各向异性Nd-Fe-B/PrCo_5复合磁体。X射线衍射(XRD)、扫描电镜(SEM)及热磁曲线(M-T曲线)的测试结果均表明热流变复合磁体中Pr-Co合金仍然保持为PrCo_5相。热流变复合磁体沿不同方向的磁滞回线以及XRD图谱表明经热流变处理后,复合磁体由各向同性转变为各向异性。SEM观察表明所添加的PrCo_5在复合磁体中以较大的颗粒形式聚集存在,PrCo_5周围主相晶粒取向变差,而且在两相界面处存在由于扩散作用而产生的成分复杂的过渡层,过渡层的存在也使得磁体性能降低。热流变复合磁体的可逆回复曲线在矫顽力附近存在峰值,峰值的出现与磁体的各向异性无关,过渡层与主相间可能存在一定的交换耦合作用。热流变复合磁体的磁性能为Br=1.323 T,Hcj=682.2 k A·m^(-1),(BH)m=239.6 k J·m^(-3)。
