La(Fe,Si)13 – based compound has been considered as one of the excellent magnetocaloric working substance for an environmentally-friendly cooling technique of magnetic refrigeration. A new synthesis process of La(Fe,Co,Si)13 compounds was developed and compared to the conventional fabrication process. Melting the starting materials of La, Fe, Co and Si elements is the conventional method and it requires homogenized heat treatment at above 1000°Cfor over a week after melting, in order to form the La(Fe,Co,Si)13 phase by atomic inter-diffusion between La-rich and Fe-rich phases. Rotating electrode process enables to form the spherical particles of near-net-shape of magnetic refrigerant and also shorten the heat treatment time to the formation of the La(Fe,Co,Si)13-phase to 3 days, because the spherical particles have fine metallographic structure consisted of La-rich and Fe-rich phases. Moreover, applying the spark plasma sintering process to this material was investigated. The phase formation behavior depends on both the starting materials and the process conditions of SPS.As a results, a thin plate, which is another suitable shape for magnetic refrigeration, formed of almost the La(Fe,Si)13-phase was successfully obtained only by the use of the SPS process with starting material of Fe, Co, LaFeSi and LaFe2Si2 powder. This process enables to achieve a substantial reduction in time and energy to fabricate the near-net-shape magnetic refrigerant of La(Fe,Si)13–based compounds, because the post annealing is not necessary for this process.

Full text: IJEIR_1766_Final.pdf