Synthesis of magnetocaloric LaFe_11.6Si_1.4 alloy by spark plasma sintering

LaFe_11.6Si_1.4 alloys have been successfully fabricated by spark plasma sintering (SPS). An annealing study of the SPS LaFe_11.6Si_1.4 alloys at different temperatures ranging from 1373 to 1523 K for annealing times from 30 minutes to 72 hours was carried out. This annealing study showed that LaFe_11.6Si_1.4 samples annealed at 1473K (for annealing times between 30 minutes and 6 hours) have a significantly higher amount of the NaZn₁₃-type phase compared to samples annealed at other temperatures. Thus the critical annealing temperature which enhances the formation of the NaZn₁₃-type phase in SPS LaFe_11.6Si_1.4 compounds is 1473K. A second study investigated the effect of different particle sizes of the starting powders on the formation of the NaZn₁₃-type phase. This study found that the samples synthesized using larger sized powder particles exhibited a significantly higher amount of the NaZn₁₃-type phase compared to samples synthesized using smaller sized powder particles, for the same heat treatment. (paper)