Cold plasma reduction of surface carbon on SmCo5 nano-flakes prepared by surfactant-assisted ball-milling

Abstract Nano-flake SmCo 5 powders with typical flake thickness of 200 nm were prepared by high energy ball milling using Oleic Acid (OA) as a surfactant. In order to remove the surfactant, the as-milled powders were exposed to pulse cold plasma of argon. The effects of the plasma parameters on residual surfactant content and magnetic properties of the resulting powder were investigated. Partial (62.5 at. %) surfactant removal was observed by XPS after treatments of 4 h at 150 Watt average power under an argon pressure of 300 mTorr. In addition, the cold plasma cleaning process led to a little bit of increase of oxygen on the surface. Demagnetization measurements revealed a slight decrease of the magnetic performance after plasma treatment. These results indicate that pulse cold plasma is an effective way for surfactant removal without morphological change and magnetic property degradation of the SmCo 5 nano-flakes.