| 摘要 |
<p>A permanent magnet which contains R, T and B as main ingredients wherein R is Y or a rare earth element and T is Fe or Fe and Co and has a primary phase of R2T14B is produced by compacting a mixture of 60 to 95 wt% of a primary phase-forming master alloy and a grain boundary phase-forming master alloy both in powder form and sintering the compact. The primary phase-forming master alloy has columnar crystal grains of R2T14B with a mean grain size of 3-50 µm and grain boundaries of an R rich phase and contains 26-32 wt% of R. The grain boundary phase-forming master alloy is a crystalline alloy consisting essentially of 32-60 wt% of R and the balance of Co or Co and Fe. In anther form, a permanent magnet which contains R, T and B as main ingredients wherein R is yttrium or a rare earth element, T is Fe or Fe + Co/Ni and has a primary phase of R2T14B is produced by compacting a mixture of a primary phase-forming master alloy and a grain boundary-forming master alloy both in powder form and sintering the compact.
The primary phase-forming master alloy has a primary phase of R2T14B and grain boundaries of an R rich phase. The grain boundary-forming master alloy contains 40-65 wt% of R, 30-60 wt% of Fe, Co or Ni and 1-12 wt% of Sn, In or Ga.</p> |
