Journal of Applied Physics
The effects of B and C substitution for Sn on phase components, Curie temperature T-C, and magnetocaloric effect of melt-spun Mn3Sn2-xMx (M = B, C; x = 0-0.5) ribbons have been investigated. X-ray diffraction (XRD) results show that the main phase in the as-spun Mn3Sn2-xMx (M = B, C; x = 0-0.5) ribbons is Mn3Sn2 of Ni3Sn2-type (Pnma). Minor Mn2B (when x >= 0.1) or Mn5C2 (when x > 0.1) secondary phase is formed, and their amounts increase with increasing B and C concentration, respectively. The Curie temperature T-C of these ribbons varies in the temperature range of 240-250K. The peak values of the maximal magnetic entropy change, -Delta S-M(max), are about 13.6-18.3 mJ/cm(3) K for B-substituted ribbons and 13.6-17.5 mJ/cm(3) K for C-substituted ribbons, respectively, at a maximum applied field of 50 kOe. These values are about one fifth that of Gd (81.4 mJ/cm(3) K). However, the relatively broader temperature range of the half maximum of Delta S-M peak (similar to 100K), low-cost and nontoxic elements still make Mn3Sn2-based ribbons the promising candidates for magnetic refrigeration applications close to room temperature. (C) 2012 American Institute of Physics. [doi:10.1063/1.3671789]
关键词:
room-temperature
Journal of Materials Research
The microstructure of a low-carbon steel after high current density electropulsing treatment was characterized by high-resolution transmission electron microscopy. It was found that nanostructured gamma-Fe could be formed in the coarse-grained steel after the electropulsing treatment. The mechanism of the formation of a nanostructure was discussed. It was thought that change of the thermodynamic barrier during phase transformation under electropulsing was a factor that cannot be neglected. It was reasonable to anticipate that a new method might be developed to produce nanostructured materials directly from the conventional coarse-grained crystalline materials by applying high current density electropulsing.
关键词:
room-temperature
