Abstract

The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl (Co_2(CO)_8). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar＋6vol％O_2. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.

• Keywords: Co nanoparticle;Chemical vapor condensation;Carrier gas;Powder characteristics;Magnetic property;