Nd-Fe-B magnets are used in a number of important applications, such as generators in gearless wind turbines, and in electric motors for vehicles and computer hard drives. The work outlined in this project has focused on the use of hydrogen to remove individual or all sintered NdFeB magnets from large commercial rotor assemblies, with the aim of re-using the underlying structure once the magnets are removed. Masking agents were successfully used to protect some regions on commercial assemblies during hydrogen decrepitation which resulted in targeted removal of specific magnets. The thermal and mechanical impact of the hydrogen decrepitation process was assessed during hydrogen processing. For all forms of sintered NdFeB scrap the surface condition of the magnets is important as oxidation has been shown to inhibit the onset of the hydrogen decrepitation process. In this work a systematic study has been performed on the early stages of oxidation in atmospheric conditions using raman spectroscopy, scanning electron microscopy and 3-D laser confocal microscopy. In the final part of this project the impact of encapsulation on NdFeB magnets was investigated during the HD process by sleeving sintered NdFeB magnets in copper.
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