| Title |
Phase Transition and Magnetic Properties of Rapidly Solidified Nd - Fe Alloys |
| Authors |
최승덕(C . J . Yang); 이우영(W . Y . Lee); 양충진(S . D . Choi) |
| Abstract |
The magnetic phase transition taking place in melt-spun NdFe₂ alloys during annealing has been discussed. The high intrinsic coercive force(iHc=2∼3.5kOe) of NdFe_7(rhombohedral system of hexagonal cell) plus a Nd-rich(85∼90 at% Nd) matrix. After annealing the NdFe_7, phase exhibiting a Curie temperature of 230∼235℃ was found to form in the melt-spun NdFe₂ alloy. The NdFe_7 phase transforms into Nd_5Fe_(17) plus Nd₂Fe_(17) together with Nd-rich phase under a vacuum atmosphere. Under an oxygen-controlled atmosphere, the NdFe_7+(Nd-rich) phases transform directly into Nd₂O₃ plus α-Fe. The Nd_5Fe_7 phase is observed to be magnetically soft(iHc=0.18 kOe) and exhibits a higher Curie temperature(Tc=240∼245℃) than that of the NdFe_7, phase. The melt-spun NdFe₂ alloy shows a magnetic anomaly indicating the spin reorientation of NdFe_7 crystals at 325∼350 K. |