Synthesis and Characterization of Carbon-Encapsulated Magnetic Nanoparticles via Arc-Plasma Assisted CVD

Abstract

Carbon-encapsulated magnetic nanoparticles (CEMNs) were fabricated on a large scale by arc-plasma assisted CVD in acetylene. The coal-derived metal-containing (Fe, Co and Ni) carbon rods were used as anodes, while a high-purity graphite rod was used as a cathode that remained unchanged during the arcing process. The CEMNs obtained were characterized by TEM, XRD, Raman spectroscopy, N2 adsorption isotherms and VSM. The diameter distribution of the obtained CEMNs varies from 10 to 70 nm, of which the metal cores are proximately 5-50 nm. The core phases in Fe(C) nanoparticles are body-centered cubic Fe and orthorhombic Fe3C while Co(C) nanoparticles and Ni(C) nanoparticles show the characteristic of a face-centered cubic structure. The Fe(C), Co(C) and Ni(C) nanoparticles with well-ordered graphitic shells have the surface area of 89 m2/g, 72 m2/g and 75 m2/g, respectively. The CEMNs show ferromagnetic of which was characterized by a ratio of remnant magnetization (MR) to saturation magnetization (MS).