As with sintered Samarium Cobalt magnets, raw powder of bonded Samarium Cobalt magnets is also including 1:5 type and 2:17 type. These two powders can be further divided to SmCo5, (Sm, MM)Co5 and Sm2(Co, Cu, Fe, Zr)17 bases on alloy compositions. 1:5 type and 2:17 type can either be used individually, or be mixed, but in fact, 2:17 type powder is the most utilized. Actually, the first block of rare earth permanent magnet is resin-bonded anisotropic SmCo5 magnet and its mass production also earlier than high-density anisotropic sintered SmCo5 magnet. Preparation of SmCo5 and (Sm, MM)Co5 powder is relatively simple that only need to crush alloy ingot to suitable granularity. The surface and internal defects of crushed powder can be restored by subsequent heating treatment. Sm2(Co, Cu, Fe, Zr)17 alloy ingots need solid solution treatment and magnetic hardening aging to obtain high intrinsic coercivity, thus crush ingot to 20 ~ 100μm. The manufacturing process of bonded SmCo magnets utilizes injection molding and compression molding as well.
The testing results revealed that irreversible flux loss and reversible temperature coefficient of bonded Samarium Cobalt magnets is basically maintained powder’s performance. That being said, its thermal stability is significantly better than bonded Neodymium magnets.
