Fine control of Curie temperature of magnetocaloric alloys La(Fe,Co,Si)13 using electrolytic hydriding

Abstract

This work demonstrates precision control of hydrogen content in La(Fe,Co,Si)13H for the development of environmentally friendly magnetocaloric-based cooling technologies, using an electrolytic hydriding technique. We show the Curie temperature, a critical parameter which directly governs the temperature window of effective cooling, can be varied easily and reproducibly in 1 K steps within the range 274 K to 402 K. Importantly, both partially (up to 10%) and fully hydrided compositions retain favorable entropy change values comparable to that of the base composition. Crucially, we show in these second-order phase transition compounds, partial hydriding is stable and not susceptible against phase separation.

The effect of hydrogen on the multiscale mechanical behaviour of a La(Fe,Mn,Si)13-based magnetocaloric material

“…La(Fe,Si)13-based intermetallics (face centred cubic crystal, NaZn13-type structure) are relatively low-cost materials which exhibit a large MCE at the magnetic phase transition between the ferromagnetic and paramagnetic states. For compositions where the MCE is most pronounced the transition is of first-order, where the phase change in response to temperature, magnetic field or other external stimuli (such as pressure) is abrupt and accompanied by an abrupt change in lattice constant and therefore volume (although for this family the crystal symmetry is unchanged) [3,[8][9][10][11]. Doping of the basic material (e.g.…”