280 kJ/m³高鉄濃度サマリウムコバルト磁石の開発・実用化

抄録

We have developed Sm₂Co₁₇ sintered magnets whose Fe concentration is much higher than conventional Sm₂Co₁₇ sintered magnets. The pre-aging treatment leads to fine cell structure and improvement in squareness of demagnetization curves. As a result the (BH)_max of pre-aged magnets shows higher than that of no-pre-aged magnet. The inter-mediate heat treatment (IHT) induces the grain growth. We found that squareness of demagnetization curve has clearly improved by the IHT at adequate temperature. These results indicate that reducing the fraction of grain boundaries by increasing the grain size affects the behavior of domain-wall motion. Sm₂Co₁₇ sintered magnets fabricated adopting pre-aging treatment and IHT show (BH)_max of 282 kJ/m³.