Carbon-Encapsulated Iron Carbide Nanoparticles in the Thermal Conversions of Ferrocene at High Pressures

Abstract

Pressure-temperature-induced transformations of ferrocene at 8 GPa and different temperatures up to 1000°C have been studied by XRD, SEM and TEM techniques. It was shown that the thermal destruction of ferrocene at 480–600°C is attended with the formation of quasi-spherical nanosized (10–30 nm) particles containing the iron carbide (Fe₇C₃) core and external carbon envelope from the fragments of graphene layers. Magnetic measurements indicate that the nanoparticles obtained at 8 GPa and 480–560°C demonstrate a superparamagnetic behaviour at room temperature. Above 600°C, the Fe₇C₃ nanoparticles decompose into Fe₃C and graphite.

Keywords:

• High pressure
• nanoparticles
• Fe₇C₃
• XRD
• microscopy
• magnetism

Acknowledgments

This work was supported by the Russian Fund of Basic Research (grant N° 09-03-00752) and by CNRS-RAS project N° 21239.