Carbon-encapsulated magnetic nanoparticles

The novel properties of magnetic nanoparticles are in focus of many fundamental research and practical applications [1,2], It is difficult to prevent metallic magnetic (Fe, Co, Ni) nanoparticles from oxidization under conventional experimental conditions. Several techniques, such as carbon encapsulation, reagent stabilizing, and passivation of nanoparticles, have been developed to protect metallic particles. 

Several fluid bed processes are under development for production and encapsulation of nanoparticles, for example, WC-Co composites, bioceramics (i.e., calcium phosphate hydroxyapapite), carbon encapsulation of iron magnetic nanoparticles, and carbon nanotubes. These nano- or ultrafine powders have broad industrial and pharmaceutical applications. Production processes usually include solution preparation (sol-gel), drying, calcination, and sintering. The last three steps may be realized in a fluidized bed, but fluidization of nano- and ultrafine powders is very difficult because of strong interparticle forces. 

Cleuziou, J. P. et al. (2011). Electrical Detection of Individual Magnetic Nanoparticles Encapsulated in Carbon Nanotubes. ACS nano, 5(3), 2348-2355. 

He C, Zhao N, Shi C, Li J, Li H. Magnetic properties and transmission election microscopy studies of Ni nanoparticles encapsulated in carbon nanocages and carbon nanotubes. Mater Res BuU 2008 43 2260-5. 

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