2:17-type SmCo magnets prepared by powder injection molding using a water-based binder

2:17-type SmCo permanent magnets by powder injection molding using a water-based binder have been studied. The water-based binder is methylcellulose solution, which consists of deionized water and methylcellulose. When the solution concentration is 0.5 wt%, the carbon content of the sintered magnets is below 0.1 wt% and the magnets have better magnetic properties. The magnetic properties and density of the sintered magnets can be increased through pre-sintering in vacuum (10−3 Pa) at 1200 °C. However, the Sm content of the magnets loses obviously in pre-sintering for a long period. The appropriate pre-sintering duration is 20–40 min. The magnetic properties of the magnets are: Br=0.97 T, Hcj=871 kA/m, BHmax=157 kJ/m3. The structure of the magnet consists of the matrix phases (2:17 phases) and the precipitate phases (1:5 phases).