Various Nd-Fe-B sintered magnets of different sizes were prepared by mechanical cutting and by the Bond method. Magnetic properties were measured as a function of the S/V value, which is the ratio of surface area to volume of the sample. For samples with S/V>or=1.10 mm/sup -1/, the effects of machining on magnetic properties were small, while for those with S/V>or=1.9 mm/sup -1/, local deterioration in magnetization (kink) appearing in the low negative fields on the demagnetizing curve was detected. Such kink remains when heat treatment is performed, but disappears when Nd metal is sputter-deposited on the surface of the magnet and then heat treatment is applied. The values of H/sub k/, (BH)/sub max/, and SQ decrease with the increase of the ratio of S/V. For samples with 1.0>or=S/V>or=1.9 mm/sup -1/ after machining, it was found that the magnetic properties of these samples were improved by heat treatment. In samples with a large S/V value, significant Barkhausen jumps were observed at room temperature.
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机译：通过机械切割和粘结法制备了各种尺寸的各种Nd-Fe-B烧结磁体。根据S / V值测量磁性，S / V值是样品的表面积与体积之比。对于S / V>或= 1.10 mm / sup -1 /的样品，机械加工对磁性能的影响很小，而对于S / V>或= 1.9 mm / sup -1的样品，磁化强度局部降低（检测到出现在退磁曲线的低负磁场中的扭结。当进行热处理时，这种扭结保留，但是当将Nd金属溅射沉积在磁体的表面上然后进行热处理时，这种扭结消失。 H / sub k /，（BH）/ sub max /和SQ的值随S / V比的增加而减小。对于机加工后的1.0≥S/V≥1.9mm/ sup -1的样品，发现这些样品的磁性能通过热处理而得到改善。在具有较大S / V值的样品中，在室温下观察到明显的巴克豪森跳跃。
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