Hydrogen decrepitation embrittles SmCo rotor magnets and enables powder recovery but needs mechanical agitation and demagnetization to scale.
Researchers report hydrogen decrepitation can embrittle samarium–cobalt (Sm2Co17) rotor magnets and produce reusable powder, but it is not a one-step fix.
In controlled tests, sintered Sm2TM17 magnets—both loose and still constrained in rotor assemblies—were exposed to 2–10 bar hydrogen at 100 °C for 72 hours. Constrained and loose parts absorbed about 0.195–0.233 wt% H, with unit-cell expansion near 1.35–1.87%. Advanced characterization (SEM/TEM, XRD with Rietveld refinement, residual gas analysis, particle-size measurement, and vibrating-sample magnetometry) showed that hydrogen reliably embrittles the material but does not reliably liberate powder from housings without added processing.
Magnetized rotors retained significant magnetization during HD; magnetic property declines appear linked to lattice strain rather than loss of the domain-wall pinning mechanism. Practical recovery therefore requires integrating hydrogen exposure with mechanical agitation and a demagnetization step—reverse-field or thermal demagnetization—both of which add complexity and cost. High Curie temperatures of SmCo make thermal demagnetization energy-intensive, and coatings or adhesives in real-world rotors can contaminate recovered powder.
If scaled, this pathway could reduce virgin samarium and cobalt demand and ease midstream supply pressure, but industrial viability depends on engineered disassembly, contamination control, and viable demagnetization processes. Lead disclosures include Rolls‑Royce funding and a pending patent.