High-temperature phase transition and magnetic property of LaFe11.6Si1.4 compound

The LaFe11.6Si1.4 compounds are prepared by arc-melting and then annealed at different high temperatures from 1323 K(5 h) to 1623 K(2 h). The powder X-ray diffraction and metallographic microscopy show that 1423 K and 1523 K are two curial temperatures, at which large amount of 1:13 phase begins to form and the most amount of 1:13 phase is obtained, respectively. With annealing temperature increasing to 1573 K and 1623 K, a new phase of La5Si3 is detected in LaFe11.6Si1.4 compound. According to the DSC curve of as-cast LaFe11.6Si1.4 compound and the X-ray patterns of annealed LaFe11.6Si1.4 compounds, the high-temperature phase transition process is analyzed. For studying the influence of different high-temperature and short-time annealing on the Curie temperature, thermal and magnetic hysteresis, magnetocaloric effect of LaFe11.6Si1.4 compound annealed at different temperatures are also investigated.

► We have studies the influence of different annealing temperatures on the phase relation, microstructure, and magnetic properties of LaFe11.6Si1.4 compounds.
► The high-temperature phase transition process is also analyzed.
► More 1:13 phase can be obtained in the LaFe11.6Si1.4 compounds annealed at 1523 K under the same annealing time because 1523 K is close to the temperature of peritectic reaction: α-Fe + L → La(Fe,Si)13.
► Longer time annealing near the temperature of peritectic reaction is helpful to decrease the impurities and increase the maximal magnetic entropy change.