  Hydrogen decrepitation process has been applied for the first time for the
direct recycling of SmCo5 magnets. Industrially produced sintered SmCo5 magnets
were decrepitated by hydrogen gas at a pressure of 1 bar to 9.5 bar at room
temperature in a planetary rotating jar. After decrepitation, the starting
sintered magnets were reduced to a powder with a particle size of less than 200
microns. The produced powder was used for the preparation of recycled SmCo5
magnets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy,
X-ray diffraction studies and magnetic measurements were used to follow the
decrepitation and the sintering processes. The measured remanence and maximum
energy product of the recycled magnet are 0.94 T and 171.1 kJ/m3, respectively,
in comparison with 0.91 T and 156.8 kJ/m3, respectively for the original magnet
before recycling. It was also observed that, there is refinement in the
microstructure after recycling in comparison to the original magnet.
