Mechanical properties and magnetocaloric effects in La(Fe, Si)13 hydrides bonded with different epoxy resins

The mechanical properties and magnetocaloric effect (MCE) of bonded La(Fe, Si)(13) hydrides have been studied in detail. The mechanical strength increases with increasing the grade of epoxy resin from E-20 to E-51. This occurs because more pores and boundaries are filled with high grade resin since high epoxide content increases the degree of crosslinking and reduces the viscosity and shrinkage of resin. The compressive strength reaches 162 MPa for the bonded LaFe11.7Si1.3C0.2H1.8 with 3 wt.% E-51, which is 35% higher than that of bulk LaFe11.7Si1.3C0.2 compound (120 MPa). The mass Delta S-M values remain almost same in bonded hydrides and are in a good agreement with the theoretical value. The maximum volumetric Delta S-M values are 61.8, 58.0, and 54.7 mJ/cm(3) K for bonded hydrides with epoxy resins E-20, E-44, and E-51, respectively, much higher than those of some magnetocaloric materials in same temperature range. The improved mechanical properties and large MCE indicate that bonded LaFe11.7Si1.3C0.2H1.8 is a promising material for room temperature magnetic refrigeration. (C) 2015 AIP Publishing LLC.