Selective laser melting of La(Fe,Co,Si)13 geometries for magnetic refrigeration

Magnetic cooling prototypes based on the magnetocaloric effect require the magnetic refrigerant to be shaped into geometries that enable quick and efficient heat-transfer to the transfer fluid. Simple solutions include a stack of parallel-plates or a bed of packed-spheres. Here, we demonstrate how more sophisticated geometries can be made by using selective laser melting, a rapid prototyping technique to form three-dimensional shapes. Using excellent magnetocaloric La(Fe,Co,Si)13 as starting-powder we made two geometries: a wavy-channel block with a high surface-to-volume ratio and an array of fin-shaped rods which eliminate unwanted heat conduction along the magnetic part. After annealing treatment, the geometries are intact and can survive more than 106 cycles of applying a magnetic field while still maintaining good magnetocaloric properties. This fabrication approach shows promise for making near-net shaped magnetic refrigerants with superior heat transfer properties and performance.