The paper reports on the structural, microstructural and magnetocaloric properties of Ni47Mn40Sn13 magnetic shape memory alloy prepared by mechanical alloying (MA) technique. AC magnetic susceptibility shows a phase transition from a paramagnetic to ferromagnetic state in the austenite phase (TCA~318K) and martensitic transition around 210 K, which is also confirmed by differential scanning calorimeter (DSC) analysis. The total entropy change, associated with the transformation is estimated to be about 10.5 J/kg K by DSC measurement. Maximum magnetic entropy change of 4.3 and 2.3 J/kg K were obtained in a field change of 2 T at martensitic and magnetic transitions, respectively. The alloy shows a refrigerant capacity (57 J/kg in a field change of 2 T) at the magnetic transition temperature, comparable to the values observed in Ni-Mn alloys prepared by conventional techniques such as arc-melting and melt spinning. This study indicates that the MA technique have a potential technique for the fabrication of magnetic shape memory alloys for magnetic refrigeration.
Magnetocaloric effect in Ni47Mn40Sn13 alloy prepared by mechanical alloying
G Varvaro;
2014
Abstract
The paper reports on the structural, microstructural and magnetocaloric properties of Ni47Mn40Sn13 magnetic shape memory alloy prepared by mechanical alloying (MA) technique. AC magnetic susceptibility shows a phase transition from a paramagnetic to ferromagnetic state in the austenite phase (TCA~318K) and martensitic transition around 210 K, which is also confirmed by differential scanning calorimeter (DSC) analysis. The total entropy change, associated with the transformation is estimated to be about 10.5 J/kg K by DSC measurement. Maximum magnetic entropy change of 4.3 and 2.3 J/kg K were obtained in a field change of 2 T at martensitic and magnetic transitions, respectively. The alloy shows a refrigerant capacity (57 J/kg in a field change of 2 T) at the magnetic transition temperature, comparable to the values observed in Ni-Mn alloys prepared by conventional techniques such as arc-melting and melt spinning. This study indicates that the MA technique have a potential technique for the fabrication of magnetic shape memory alloys for magnetic refrigeration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
