Cracking in La(Fe,Si)13-based magnetocaloric materials has been observed to predominantly form around La-rich (La2O3) particles and pose a threat to their long-term structural integrity. To understand the formation of these cracks, FIB cross-sectional polishing followed by SEM characterisation was employed to study local microstructural evolution after air exposure. Results suggest that volume expansion and internal degradation associated with a chemical reaction between La2O3 particles and water/moisture can lead to crack nucleation in the 1:13 phase adjacent to La-rich particles. This observation indicates that the formation of La-rich phase should be suppressed, or their size minimised during material processing to ensure the long-term structural integrity of La(Fe,Mn,Si)13 magnetocaloric materials.
@article{arxiv.2112.08719,
title = {Environment-assisted crack nucleation in La(Fe,Mn,Si)13-based magnetocaloric materials},
author = {Siyang Wang and Edmund Lovell and Liya Guo and Neil Wilson and Mary P. Ryan and Finn Giuliani},
journal= {arXiv preprint arXiv:2112.08719},
year = {2021}
}