Kyung T. Kim

Ferromagnetic cobalt nanodots, nanorices, nanowires and nanoflowers by polyol process

Various shapes and sizes of colloidal Co nanoparticles were fabricated by the polyol process using Co(acac) 3 , 1,2-hexadecanediol, oleylamine, and oleic acid within octylether. The rice-shaped Co nanoparticles with size of 30 nm and aspect ratio of 1.8 can be fabricated into a self-assembled form without assistance of surfactants. The addition of oleylamine as surfactant decreased the particle size and aspect ratio, and the addition of oleic acid made the surface of particle faceted without decreasing particle size from that of rice shape. The mixture of oleylamine and oleic acid produce differently shaped Co nanoparticles, including nanoprism, nanowire, and nanoflower according to the ratio of components, total amount of surfactant mixture, and reaction time. The fabricated nanoparticles showed ferromagnetic properties. These results showed that the various size and shape of metallic nanoparticles can be fabricated by the polyol process into controlled forms.

Characterization of Carbon Nanotubes/Cu Nanocomposites Processed by Using Nano-sized Cu Powders

Carbon nanotubes (CNTs) have attracted remarkable attention as reinforcement for composites owing to their outstanding properties. CNT/Cu nanocomposites were fabricated by mixing the nano-sized Cu powders with multi-wall carbon nanotubes and followed by the spark plasma sintering process. The CNT/Cu nanocomposite fabricated from nano-sized Cu powders shows more homogeneous distribution of CNTs in matrix compared to that fabricated from macro-sized Cu powders. The hardness of CNT/Cu nanocomposite fabricated from nano-sized Cu powders increases with increasing the volume fraction of CNTs, while the hardness of that fabricated from macro-sized Cu powders decreases with the addition of CNTs.