| Title |
Magnetic Properties of New Type α - Fe Based NdFeB Magnets Composed of Ultrafine Grains |
| Authors |
조용수(Y . S . Cho); 김윤배(Y . B . Kim); 김택기(T . K . Kim) |
| Abstract |
The α-Fe based Nd-Fe-B magnet with 4at% Nd content have been investigated for the development of the new type rare earth magnets. Amorphous Nd₄Fe_(85.5)B_(10.5) alloy prepared by rapid quenching technique crystallized to form only two phases, α-Fe as main phase and Nd₂Fe_(14)B as secondary phase. However, the alloy showed a poor magnetic properties (₁H₁= 12 kOe, B₁= 1.2 T). The additions of Mo and Cu to Nd₄Fe_(85.5)B_(10.5) alloy reduced the average grain size and increased the coercivity up to 2.6 kOe. Furthermore, the substitution of Co far Fe in Nd₄Fe_(82)B_(10)Mo₃Cu₁ alloy to 16 at% entirely improved the magnetic properties. The optimally annealed Nd₄Fe_(74)C_5B_(10)Mo₃Cu₁ alloy showed the best magnetic properties among the perpared alloys. The coercivity, remanence and energy products, of the alloy was 2.75 kOe. 1.42 T and 13 MGOe respectively. |