The Fabrication of Cobalt Nanopowder by Sonochemical Polyol Synthesis of Cobalt Hydroxide and Magnetic Separation Method

In this study, cobalt nanopowder is fabricated by sonochemical polyol synthesis and magnetic separationmethod. First, sonochemical polyol synthesis is carried out at 220oC for up to 120 minutes in diethylene glycol(C4H10O3). As a result, when sonochemical polyol synthesis is performed for 50 minutes, most of the cobalt precursor(Co(OH)2) is reduced to spherical cobalt nanopowder of approximately 100 nm. In particular, aggregation and growth ofcobalt particles are effectively suppressed as compared to common polyol synthesis. Furthermore, in order to obtainfiner cobalt nanopowder, magnetic separation method using magnetic property of cobalt is introduced at an early reductionstage of sonochemical polyol synthesis when cobalt and cobalt precursor coexist. Finally, spherical cobalt nanopowderhaving an average particle size of 22 nm is successfully separated