Magnetic microstructures of phase-separated Sm–Co 2:17-type sintered magnets

Magnetic microstructures of high-temperature Sm–Co 2:17-type sintered magnets during phase separation process have been investigated by using magnetic force microscopy. Results show that the magnetic microstructures of final Sm–Co 2:17-type magnets is an aggregation of many single domains. The evolution of domain structures was explained on the basis of variation of phase constitutions of the specimens together with crystalline microstructures due to the phase-separation process. Homogenization treatment is important to the appearance of uniform fine magnetic domains, which is prerequisite to high performance Sm–Co 2:17-type magnets. Moreover, phase shift Δϕ of magnetic image can give an indication of the vertical field strength and hence, of the saturation magnetization of magnets.