THE INFLUENCE OF DIFFERENT COOLING PROCESSES ON PHASE, MICROSTRUCTURE, AND MAGNETOCALORIC PROPERTIES OF LAFE_(11.6)SI_(1.4) COMPOUNDS

摘要

The LaFen_(11.6)Si_(1.4) compounds are annealed at 1503 K for 5 hours and cooled down to room temperature by furnace cooling, air cooling, and quenching in ice water, respectively. The main phase is the 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 observe in their powder X-ray diffraction patterns (XRD). The XRD and SEM show that three cooling methods have little influence on the phase relation and microstructure of LaFe_(11.6)S_(1.4) compounds prepared by different cooling processes. For studying the influence of different cooling processes on magnetic property, the Curie temperature, thermal and magnetic hysteresis, ?nagnetocaloric effect, and relative cooling power of those compounds are investigated. The result show that the maximum △S_M (T, H) and cooling power RCP of LaFe_(11.6)Si_(1.4) prepared by furnace cooling are both the largest in three compounds, and the value are 18.7 J/kg*K and 164.6 J/kg under a field change of 0-2 T, respectively.