纳米复合永磁Pr9Fe74Co12B5Snx(x=0, 0.5)的磁化行为与磁黏滞性

用熔体快淬法制备了纳米复合永磁样品Pr₉Fe₇₄Co₁₂B₅ 与Pr₉Fe₇₄Co₁₂B₅Sn_0.5，分析了样品的起始磁化、反磁化过程，测得样品的总磁化率、可逆磁化率以及样品的磁黏滞性.结果表明，两样品在室温下均表现为单一硬磁相磁化行为，在低温下表现为双相行为，且由于添加Sn后使晶粒均匀化从而导致样品低温下的双相行为更加明显.添加Sn后引起样品中软磁相含量和软磁相晶粒尺寸的增加，使磁化反转中可逆磁化部分增多，且使反磁化形核场降低.磁黏滞性研究表明，热激活体积与软磁相晶粒的大小有关. 关键词： 纳米复合永磁 磁化反转 磁粘滞

Magnetization behavior and magnetic viscosity in nanocomposite Pr9Fe74Co12B5Snx(x=0, 0.5) ribbons

Nanocomposite Pr₉Fe₇₄Co₁₂B₅ and Pr₉Fe₇₄Co₁₂B₅Sn_0.5 ribbons were directly prepared by melt-spinning. Measurements of reversible and irreversible magnetization and magnetic viscosity were performed on the ribbons. It is found that the demagnetization curves of the both samples show a single hard phase behavior at room temperature, while a two-phase behavior at low temperature. The sample with Sn addition, because of its more homogeneous microstructure, shows a more obvious two-phase behavior than the Sn free one at low temperature. Furthermore, the increase of the volume fraction and grain sizes of the soft phase, in the Sn-doped ribbons, increases the portions of reversible magnetization and decreases the nucleation field H_n. The investigation of the magnetic viscosity shows that the activation volume is related to the grain sizes of the soft phase.