Synthesis of carbon encapsulated magnetic nanoparticles with giant coercivity by a spray pyrolysis approach.
Carbon encapsulated magnetic (metal) nanoparticles (CEMNPs) have wide applications in biomedicine and the magnetic recording industry. However, synthesis of such particles with a high coercive force and good ferromagnetism is still a great challenge. The present study reports a new method for the continuous production of CEMNPs of high purity. This involves the spray pyrolysis of a mixture of iron pentacarbonyl and ethanol at 500-900 degrees C. Results show that the Fe (or Fe3C) particles synthesized at 700 and 900 degrees C were well encapsulated by graphitic layers with rare byproducts such as carbon nanotubes, nanofibers, or bulk amorphous carbon. Those synthesized at 700 degrees C had a particle size of 30-50 nm, a giant coercive force of 867 Oe, and a good magnetic remanence of 33% at room temperature. The present approach based on spray pyrolysis is advantageous over previous ones in suitability for large-scale production, and the synthesized material has wide applications in many fields.
Wang
Jian Nong
JN
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, People's Republic of China. jnwang@mail.sjtu.edu.cn
Zhang
Li
L
Yu
Fan
F
Sheng
Zhao Ming
ZM
D000431:Ethanol / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure
D058085:Iron Compounds; D000431:Ethanol; C515100:iron pentacarbonyl; D006108:Graphite