Magnetic Field Effects on the Corrosion Behavior of Magnetocaloric Alloys Lafe13.9si1.4hy under Ferromagnetic States

La(Fe,Si)13-based alloys, with giant magnetocaloric effect, still encounter significant degradation issues prior to commercial viability. In this work, the corrosion behavior of ferro magnetic La(Fe,Si)13Hy was investigated with electrochemical linear polarization resistance measurements under conditions with zero, 1T parallel and perpendicular magnetic fields, mimicking practical application scenarios. The results demonstrated that both parallel and perpendicular magnetic fields had a suppressive effect on corrosion rates due to the combined influence of magnetohydrodynamic forces and magnetic field gradient forces. The inhibiting efficiency of the parallel field decreased with increasing exposure period, while that of the perpendicular field continued to increase over time. The magnetic field also affected the relative proportion of rust phases, and thereby the protectiveness of the rust layer. This highlights the importance of conducting experiments under service conditions to understand the degradation mechanisms of magnetic cooling devices.