NewswireToday - /newswire/ -
Honolulu, HI, United States, 2006/08/15 - Encapsulating metal nanoparticles inside carbon shells is of considerable significance but fraught with high manufacturing cost due to high energy consumption and intensive use of hardware..
This cost issue limits their practical applications. Researchers in China have developed a novel, simple, efficient, and economical synthesis technique for the fabrication of carbon-encapsulated nanostructures where the carbonization is conducted at a relatively low temperature of 160°C in water and no toxic reagents are added. This new technique is facile and versatile, and suitable for the coating of other transition metal with carbon.
Metallic nanoparticles such as Fe, Co, and Ni are useful in various application fields of magnetism, including magnetic data-storage, ferrofluids, and biotechnology. Compared to polymer and silica shells, carbon shells exhibited much higher stability in various chemical and physical environments such as acid or base media, as well as at high temperatures and pressures. Carbon-coated ferromagnetic particles (metal@C) have opened the way for application in ultrahigh-density magnetic recording media, since the outer carbon layers can protect metals in the core from oxidation, act as a solid lubricant, and reduce the magnetic coupling between individual particles.
A whole range of synthesis techniques have been developed for encapsulating magnetic metal nanoparticles in carbon: arc techniques, magnetron and ion-beam co-sputtering, high-temperature annealing of the mixtures of carbon-based materials and metal precursors, catalytic chemical vapor deposition, pyrolysis of organometallic compound, catalytic decomposition of methane, explosion, and spraying method.
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By Michael Berger, Copyright 2006 Nanowerk LLC