Microchannel magnetic regenerators with optimized porosity by electrodischarge drilling: Microstructure and refrigeration performance

In this study, electrodischarge drilling is proposed to prepare LaFeCoSi magnetic regenerator with circular microchannels. We find that the drilling process leads to the microstructure consisting of the dominant α-Fe phase and sporadic distributed La-rich phase near the channel surface. In contrast, the microstructure away from the channels is not influenced and shows the typical dendritic morphology. Upon annealing, the microchannel blocks show a maximum entropy change of 6.0 J kg K at 0–2 T around room temperature. Further, we evaluated the regeneration performance of our magnetic refrigerators by using a one-dimension active magnetic regeneration numerical model, and a considerable specific cooling power of 11.1–18.3 W kg is obtained. This study suggests electrodischarge drilling as a promising method for fabricating magnetocaloric regenerators with circular microchannels.