Recovering the Magnetocaloric Properties of La _0.8Ce _0.2Fe _11.5Mn _0.2Si _1.3H _y by Secondary Solid State Hydrogenation

Abstract

The hydrogenation of La_0.8Ce_0.2Fe_11.5Mn_0.2Si_1.3 alloy was realized by post-annealing the mixture of it and metallic hydride Sm₅Mg₄₁H_x. During the annealing, the released hydrogen from the metallic hydride was absorbed to form La_0.8Ce_0.2Fe_11.5Mn_0.2Si_1.3H_y, causing the increase of Curie temperature. Interestingly, it was found that the secondary solid hydrogenation could further release the hydrogen from the residual metallic hydride to recover the dehydrogenated La_0.8Ce_0.2Fe_11.5Mn_0.2Si_1.3H_y. This work proposes a facile way of obtaining the hydrides La(Fe, Si)₁₃H_y through a solid hydrogenation, which also exhibits a merit of potentially overcoming the problem of the dehydrogenation of magnetocaloric hydride under the service.

Keywords: Magnetocaloric Effect, Degradation Of Magnetocaloric Properties, Secondary Solid Hydrogenation, Recovering