Plasma-based synthesis of iron carbide nanoparticles

In this study, iron carbide nanoparticles (NPs) were prepared by the plasma-based method using a gas aggregation source of NPs. In-flight plasma treatment of the NPs was performed to improve their temporal stability. The auxiliary radiofrequency plasma used for the in-flight treatment resulted in trapping of the NPs in the plasma for several 10s of seconds. Scanning electron microscopy and small-angle X-ray scattering analyses showed a decrease in the size of NPs due to the plasma treatment, whereas the X-ray diffraction analysis showed that the structure of the NPs changed from amorphous iron carbide to the crystalline Fe3C (cementite). In situ and ex situ X-ray photoelectron spectroscopy measurement confirmed better temporal stability of plasma-treated NPs against oxidation.