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

In this study, electrodischarge drilling is proposed to prepare LaFe₁₁Co_0.8Si_1.2 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⁻¹ K⁻¹ 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⁻¹ is obtained. This study suggests electrodischarge drilling as a promising method for fabricating magnetocaloric regenerators with circular microchannels.