Corrosion and latent heat in thermal cycles for La(Fe,Mn,Si)13 magnetocaloric compounds

• Mn doping can improve the corrosion resistance of La(Fe,Mn,Si)13 compounds.
• Mn doping speeded up the decrease of the latent heat during the thermal cycles.
• The latent heat of all compounds tends to be stable after eight thermal cycles.
• −ΔS and ΔTad decreased with the increase of Mn content.

Corrosion and latent heat in thermal cycles for LaFe11.5−xMnxSi1.5 (x=0.00, 0.10, 0.20, and 0.25) compounds were investigated for practical application. The corrosion resistance of the compounds was tested by means of potentiodynamic polarization and immersion test in the distilled water. The results show that the corrosion resistance of the compounds was improved by Mn doping. The latent heat of the compounds in the thermal cycles was tested by differential scanning calorimetry (DSC). The latent heat decreased with the increase in the number of thermal cycles. The substitution of Mn in the compounds speeded up the decrease of the latent heat in the thermal cycles. But the latent heat of all compounds tended to be stable after eight thermal cycles. The maximum ΔSM under a low magnetic field (0–1 T) was 12.7, 9.9, 8.2 and 7.6 J/kg K with increasing of Mn content from x=0.00 to 0.25, respectively. The magnetic entropy changes and adiabatic temperature changes for LaFe11.5−xMnxSi1.5 compounds decreased with the increase of Mn content.