Improvement in the magnetocaloric properties of sintered La(Fe,Si)13 based composites processed by La-Co grain boundary diffusion

A novel method to combine hot pressing and grain boundary diffusion in order to fabricate La(Fe,Si)(13) based magnetocaloric composites is described. LaFe11.6Si14/La-Co magnetocaloric composites were prepared by hot-pressing, followed by diffusion annealing heat treatment. The Curie temperature (T-C) of these composites increases from 197 K to similar to 235 K due to the diffusion of Co into the NaZn13-type (1:13) majority phase. The maximum magnetic entropy change (-Delta S-M)(max) at 2 T first increases with increasing diffusion time from 5.62 to 7.60 J/(kg.K) and followed by a further increase up to 9.15 J/(kg.K) due to the recombination of the 1:13 phase. The Co content of the La-Co binder could be used to tune the formation of the desired 1:13 phase. (C) 2018 Elsevier B.V. All rights reserved.