Influence of the type of surfactant and hot compaction on the magnetic properties of SmCo5 nanoflakes

In this study, we discuss the effects of a type of surfactant (oleylamine, oleic acid, and trioctylamine) and hot pressing on the hard magnetic properties of crystallographically anisotropic SmCo5 nanoflakes prepared by surfactant-assisted high energy ball milling. The phase, microstructure, and magnetic properties of the hot-pressed SmCo5 were investigated by using x-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The coercivities of the precursor flakes prepared using oleylamine, oleic acid, and trioctylamine were 14.9, 15.8, and 15 kOe, respectively. Hot-compacted SmCo5 magnets prepared from the nanoflakes milled with oleic acid had the lowest coercivity of 8.1 kOe. It is believed that even after repeated washing in an ultrasonic bath with different solvents, the remaining oleic acid in the SmCo5 nanoflakes led to oxidation of SmCo5 at the surface/interface of nanoflakes during the hot-pressing process. The compacted SmCo5 magnets prepared from the nanoflakes milled wi...