Simultaneous achievement of enhanced thermal conductivity and large magnetic entropy change in La-Fe-Si-H/Sn composites by optimizing interface contacts and hot pressing parameters

In this paper, we report on a systematic investigation on the microstructure, magnetocaloric effect and thermal transport properties of La-Fe-Si-H/Sn composites prepared by hot pressing. A continuously distributed Sn network is constructed to restore the mechanical integrity of La-Fe-Si-H hydrides. The hot-pressed composites show good magnetocaloric performance and improved thermal conductivity with optimized interface contacts of La-Fe-Si-H/Sn and hot-pressing parameters. A modified Hasselman-Johnson model is adopted in predicting the thermal conductivity of La-Fe-Si-H/Sn composites in terms of reasonable particle size, interfacial contact conditions and porosity. A large magnetic entropy change of 11 J/kg K in 2 T and high thermal conductivity of ∼9 W/mK could be simultaneously achieved in LaFe 11.6 Si 1.4 H x /Sn. This work contributes to the research on high performance magnetocaloric composites with combined outstanding magnetocaloric and thermal transport properties. • The mechanical integrity of La-Fe-Si-H has been restored by Sn matrix. • The large magnetocaloric effect is retained and thermal conductivity is improved. • The principles in the design of high thermal conductive functional composites are revealed.