A Study on the Formation of Magnetic Refrigerant La(Fe,Si)13 Compounds by Spark Plasma Sintering
H. Tsuji, A. Saito, T. Kobayashi, S. Sakurada
Toshiba Corp., Kawasaki, Japan
The phase formation of magnetic-refrigerant La(Fe,Si)13 compounds with a NaZn13-type structure has been investigated using an electron probe micro analyzer (EPMA) and X-ray diffraction (XRD). The structure of a sample synthesized by solid-state reaction of fine elemental powders using a spark plasma sintering (SPS) technique was compared with that synthesized by conventional methods including a melt and solidification process. The conventional methods, namely, arc-melting and melt spinning, easily caused segregation of the Fe-rich phase. On the other hand, the remarkable NaZn 13-type structure was observed in the SPS sample. These experimental results indicate that homogenous distribution of the elements and short-range atomic diffusion are important for forming the NaZn-type structure efficiently.