Excellent mechanical properties and age stability of hydrogenated La0.8Ce0.2Fe12.5Mn0.2Si1.3Hδ plates with extra Fe

Abstract

Herein, hydrogenated La0.8Ce0.2Fe12.5Mn0.2Si1.3Hδ plates as thin as 0.4–0.6 mm with extra Fe were prepared, whereupon the microstructure, mechanical properties, age stability, and magnetocaloric effect (MCE) were systematically investigated. It was demonstrated that the introduction of extra α-Fe largely enhanced the mechanical properties. The bending strength was about 61 MPa for a single 0.6 mm-thick plate, while the compressive strength was as much as 352 MPa for the stacked plates. Meanwhile, the hydride plates showed considerable MCE around room temperature. The maximal entropy change was 14.2 J/kgK around its Curie temperature TC = ∼298 K and the effective refrigeration capacity was 284 J/kg under a magnetic field change of 0–5 T. Moreover, the hydride plates exhibited excellent age stability and good thermal conductivity. No age splitting occurred, even when the plates were held at room temperature for more than one year, owing to full hydrogenation. Finally, room-temperature thermal conductivity was as large as 9.5 Wm−1K−1. All of these results demonstrate that the hydride plates with extra Fe are desirable magnetic refrigerants, which is beneficial to increase the working efficiency in a device.