| 摘要 |
The present invention aims to provide a NdFeB system sintered magnet capable of improving the magnetization characteristic. The NdFeB system sintered magnet according to the present invention is a NdFeB system sintered magnet with the c axis oriented in one direction, characterized in that: the median of the grain size of the crystal grains at a section perpendicular to the c axis is 4.5 µm or less, and the area ratio of the crystal grains having grain sizes of 1.8 µm or smaller on the aforementioned section is 5 % or lower. The median of the grain size is decreased (to 4.5 µm or less), whereby improve the coercive force is improved. Simultaneously, the area ratio of the crystal grains having grain sizes of 1.8 µm or smaller is decreased (to 5 % or lower) to reduce the number of crystal grains having no magnetic wall formed, whereby the magnetization characteristic is improved. |
