Transient liquid phase bonding assisted spark plasma sintering of La-Fe-Si magnetocaloric bulk materials

The poor mechanical properties of La-Fe-Si based alloys restrict the potential of these magnetocaloric materials. Hence, a novel transient liquid phase bonding (TLPB) processing technique was deployed during spark plasma sintering (SPS) of La-Fe-Si based bulk materials. A series of binder-free LaFe11.8Si1.2 bulk materials were prepared by SPS and hot-pressing sintering (HPS). Transient melting, which occurred during SPS, accelerated the decomposition of the 1:13 phase, resulting in low porosity and high strength. Compared to HPS samples, SPS samples have significantly larger maximum compressive strength (sigma(bc))(max) of similar to 637.9 MPa at a strain of 4.7%, good thermal conductivity of similar to 7.6 W center dot m(-1)center dot K-1 at 300 K, and a large (-Delta S-M)(max) value of similar to 11.7 J center dot kg(-1)center dot K-1 at T-C= 193 K under a magnetic field change of 0 - 5 T. Thus, binder-free La-Fe-Si based bulk magnetocaloric materials with an excellent property set have been successfully prepared by TLPB assisted SPS technology.