The influence of different cooling processes on phase, microstructure, and magnetocaloric properties of LaFe11.6Si1.4 compounds

The LaFe11.6Si1.4 compounds are annealed at 1503 K for 5 h and cooled down to room temperature by furnace cooling, air cooling, and quenching in ice water, respectively. The main phase is 1:13 phase in those compounds. The impurity phase is α-Fe, and the amount of LaFeSi phase is so small that it is hard to be observed in their XRD patterns. 1:13 phase has a precipitation reaction at 1308 K during cooling process and produces LaFeSi phase. But the cooling rate in the high temperature range is very high and the time kept at about 1308 K is very short, also the amount of LaFeSi phase reformed during cooling process is very small. It results in there being almost no difference in XRD patterns and SEM micrographs of LaFe11.6Si1.4 compounds annealed at 1503 K (5 h) and followed by furnace cooling, air cooling, and quenching in ice water to room temperature respectively. For studying the influence of different cooling processes on magnetic property, the TC, thermal and magnetic hysteresis, magnetocaloric effect, and relative cooling power of those compounds are investigated. The result shows that the maximum ΔSM (T, H) and RCP of LaFe11.6Si1.4 prepared by furnace cooling is not smaller than the other two alloys under the field of 0–2 T.